DESC:FIELD OF THE INVENTION:
This invention relates in general to the field of gel polymer electrolytes (GPEs). The present invention particularly relates to a nanoparticle decorated cellulose based gel polymer electrolyte. More particularly, the invention relates to a method of preparation of nanoparticle decorated cellulose based gel polymer electrolyte and a metal-ion battery comprising a nanoparticle decorated cellulose based gel polymer electrolyte.
BACKGROUND OF THE INVENTION:
A metal-ion battery (MIB) consists of cathode and anode materials with metal foil current collectors, a separator, and an electrolyte. Typical battery uses liquid electrolytes (LEs) which hold high ionic conductivity (10-3–10-2 S cm-1) and can form a good interfacial contact with the electrode active materials to function as a good pathway for metal-ion during the charge/discharge cycling process. The LEs can easily be injected during the manufacturing process of LIBs and permeate into the electrodes and separators. However, leakage and flammability of liquid electrolytes may cause a safety issue of MIBs at abnormal conditions. LEs have a risk that the battery can easily explode or catch fire when the battery cell temperature unexpectedly rises due to the internal short or by external impact or formation of dendrites inside. Especially, lithium/sodium dendrite is electrically segregated and tends to grow at the anode surface as the battery cycling proceeds. This causes lithium/sodium loss with the repeating cycles followed by consumption of excess metal ions to replenish it, thus resulting in overall capacity loss. To overcome these issues, research on solid-state electrolytes has been actively conducted to ensure the safety and good electrochemical stability of MIBs. Solid electrolytes can be largely categorized into inorganic ceramics (oxide, sulfide, halides ) based materials and polymer-based electrolytes.
Polymer-based electrolytes (PEs) are also relatively free from safety issues such as explosions and fire incidents compared with LEs. Most importantly, PEs based on polymers have good processability and flexibility that can easily be applied to battery manufacturing process. Polymeric host materials commonly used in solid-phase electrolytes are poly (ethylene oxide) (PEO), poly (vinylidene fluoride) (PVDF), poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), poly(acrylonitrile) (PAN), poly (methyl methacrylate) (PMMA), poly (vinyl chloride) (PVC), poly (propylene carbonate) (PPC), Poly(diallydimethylammonium) chloride (PDADMACl), and Poly(vinylbenzyltrimethylammonium) bis(trifluoromethanesulfonyl) imide (PVBTMATFSI).
Gel polymer electrolytes (GPEs) typically composed of lithium/sodium salts, polymers, and organic solvent. GPEs entraps electrolytes in the polymer matrix which have diffusivity of liquid and cohesiveness of solid.
WO2001089021A1 provides a novel composite polymer electrolyte, lithium secondary battery comprising the composite polymer electrolyte and their fabrication methods. More particularly, the present invention provides the composite polymer electrolyte comprising super fine fibrous porous polymer electrolyte matrix with particles having diameter of 1 - 3000 nm, polymers and lithium salt-dissolved organic electrolyte solutions incorporated into the porous polymer electrolyte matrix. This specific patent depicts synthesis of polymer electrolyte matrix in the form of super fine fibers generated via high voltage electrospinning technique.
There exists a need for a gel polymer electrolyte that has a superior electrochemical performance and stability for long cycles and where the polymer electrolyte matrix is prepared via a simple chemical mixing method.
OBJECTIVES OF THE PRESENT INVENTION:
The main objective of this invention is to provide a gel polymer electrolyte.
The second objective of the present invention is to provide a nanoparticle decorated cellulose based gel polymer electrolyte.
The third objective of this invention is to provide a method of preparation of a gel polymer electrolyte.
The fourth objective of the present invention is to provide a method of preparation of a nanoparticle decorated cellulose based gel polymer electrolyte.
The fifth objective of the present invention is to provide a metal-ion battery comprising a nanoparticle decorated cellulose based gel polymer electrolyte.
The sixth objective of the present invention is to provide a nanoparticle decorated cellulose based gel polymer electrolyte, when used in metal-ion battery has a superior electrochemical performance and stability for long cycles.
SUMMARY OF THE PRESENT INVENTION:
This summary is provided to introduce a selection of concepts, in a simplified format, that are further described in the detailed description of the invention. This summary is neither intended to identify key or essential inventive concepts of the invention nor is it intended to determine the scope of the invention.
In yet another embodiments, the present invention provides a gel polymer electrolyte comprising; a nanoparticle decorated cellulose, a plasticized polymer and an electrolyte salt.
In another embodiments, the present invention provides a gel polymer electrolyte, wherein the cellulose is decorated with nanoparticle selected from one or more of metal oxide, alkaline metal oxide, alkali metal oxide, non-metal oxide, alkali metal fluorides or alkali metal nitrites.
In another embodiments, the present invention provides a gel polymer electrolyte, wherein the cellulose is decorated with nanoparticle selected from one or more of metal oxide, alkaline metal oxide, alkali metal oxide, non-metal oxide, alkali metal fluorides or alkali metal nitrites, wherein the one or more of metal oxide, alkaline metal oxide, alkali metal oxide, non-metal oxide, alkali metal fluorides or alkali metal nitrites comprises CaO, TiO2, BaTiO3, Li2O, BaO, Na2O, MgO, SiO2, Al2O3, CuO, ZnO, Mn2O3, NiO, Fe2O3, LiF, NaF or Li3N.
In a preferred embodiments, the present invention provides a gel polymer electrolyte, wherein the nanoparticle is CaO.
In another embodiments, the present invention provides a gel polymer electrolyte, wherein the electrolyte salt comprises of a lithium salt, or a sodium salt.
In another embodiments, the present invention provides a gel polymer electrolyte, wherein the plasticizer is selected from the group consisting of glycol diethers/glymes and carbonate based solvents,.
In another embodiments, the present invention provides a gel polymer electrolyte, wherein the plasticizer is selected from the group consisting of glycol diethers/glyme and carbonate based solvents, wherein the glycol diethers is selected from the group consisting of tetraglyme, diglyme, triglyme, and monoglyme, wherein the carbonate based solvents is selected from the group consisting of propylene carbonate (PC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC) and Tetrahydrofuran (THF).
In another embodiments, the present invention provides a gel polymer electrolyte, wherein the polymer is selected from the group consisting of polyethylene, polypropylene, polyvinylpyrrolidone- vinyl acetate, poly[bis(2-(2-methoxyethoxyethoxy))phosphagene], poly- ethyleneimide, poly(ethyleneoxide) (PEO), polyethylenesuccinate, polyethylenesulfide, poly(oxymethylene-oligo-oxyethylene), polypropyleneoxide, polyvinyl acetate, polyacrylonitrile (PAN), poly(acrylonitrile-co-methylacrylate), polymethylmethacrylate (PMMA), poly(methylmethacr late-co-ethylacrylate), polyvinylchloride, poly(vinylidene- chloride-co-acrylonitrile), poly(vinylidene fluoride) (PVDF), poly(vinyl chloride) (PVC), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), poly(propylene carbonate) (PPC), Poly(diallydimethylammonium) chloride (PDADMACl), and Poly(vinylbenzyltrimethylammonium) bis(trifluoromethanesulfonyl) imide (PVBTMATFSI) or mixtures thereof.
In another embodiments, the present invention provides a gel polymer electrolyte, wherein the sodium salt is selected from the group consisting of sodium hydroxides, sodium phosphates, sodium-containing chloric acids, sodium fluoride, sodium sulfate (Na2SO4), sodium nitrate (NaNO3), sodium lignosulfonate (C20H24Na2O10S2), sodium hexafluoroarsenate (NaAsF6), sodium tetrafluoroborate (NaBF4), sodium hexafluorophosphate (NaPF6), sodium hexafluoroantimonate (NaSbF6), sodium trifluoromethanesulfonate (NaCF3SO3), and sodium trifluoromethanesulfonimide (NaN(SO2CF3)2).
In another embodiments, the present invention provides a gel polymer electrolyte, wherein the sodium salt is selected from the group consisting of sodium hydroxides, sodium phosphates, sodium-containing chloric acids, sodium fluoride, sodium sulfate (Na2SO4), sodium nitrate (NaNO3), sodium lignosulfonate (C20H24Na2O10S2), sodium hexafluoroarsenate (NaAsF6), sodium tetrafluoroborate (NaBF4), sodium hexafluorophosphate (NaPF6), Sodium hexafluoroantimonate (NaSbF6), sodium trifluoromethanesulfonate (NaCF3SO3), and Sodium trifluoromethanesulfonimide (NaN(SO2CF3)2), wherein sodium borates is selected from the group consisting of sodium tetraborate (Na2B4O7) and sodium fluoroborate (NaBF4),wherein sodium phosphates is selected from the group consisting of sodium phosphate tribasic (Na3PO4), sodium pyrophosphate (Na2HPO4), Sodium Hexametaphosphate (NaPO3)6, Monosodium Phosphate (NaH2PO4), and Disodium Phosphate (Na2HPO4) and sodium-containing chloric acids is selected from the group consisting of Sodium perchlorate (NaClO4), Sodium tetrachloroaluminate (NaAlCl4) and Sodium Hypochlorite (NaClO).
In another embodiments, the present invention provides a gel polymer electrolyte, wherein the lithium salt is selected from the group consisting of Lithium hexafluorophosphate (LiPF6), Lithium perchloratec (LiClO4), Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and Lithium triflate (LiCF3SO3).
In yet another embodiments, the present invention provides a gel polymer electrolyte comprising; a CaO decorated cellulose, a plasticized poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) polymer and a sodium salt.
In one of the embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, the method comprising;
a) dispersing a cellulose powder with a nanoparticle to obtain a dispersion;
b) hydrolyzing the dispersion obtained in step a) to obtain a nanoparticle decorated cellulose;
c) dispersing the nanoparticle decorated cellulose in a mixture of a plasticizer and an electrolyte salt to obtain a solution (a);
d) mixing a polymer in a solvent to obtain a solution (b);
e) mixing and stirring the solution (a) and (b) to obtain a solution (c);
f) sonicating the solution (c) to obtain a nanoparticle decorated cellulose powder dispersed polymer salt suspension;
g) forming a polymer film from the nanoparticle decorated cellulose powder dispersed polymer salt suspension;
h) drying the polymer film;
i) soaking the polymer film in a liquid electrolyte obtain the gel polymer electrolyte.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the solution (c)is sonicated for 1 hour.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the polymer film is formed by doctor blade coating, electrospinning, dip coating, phase inversion or spraying on a substrate.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the substrate comprises a glass plate, a PTFE membrane, or a ceramic plate etc.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the polymer film is dried in vacuum.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the polymer film is peeled from the substrate.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the polymer film are cut in circles.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the polymer film is soaked in the liquid electrolyte for 5 minutes to 4 hours.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the weight percentage of the nanoparticle on cellulose is in a range of 1% to 50%.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the polymer film is coated on the glass plate by a doctor blade method.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the nanoparticle is selected from one or more of metal oxide, alkaline metal oxide, alkali metal oxide, non-metal oxide, alkali metal fluorides or alkali metal nitrites.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the nanoparticle is selected from one or more of metal oxide, alkaline metal oxide, alkali metal oxide, non-metal oxide, alkali metal fluorides or alkali metal nitrites, wherein the one or more of metal oxide, alkaline metal oxide, alkali metal oxide, non-metal oxide, alkali metal fluorides or alkali metal nitrites comprises CaO, TiO2, BaTiO3, Li2O, BaO, Na2O, MgO, SiO2, Al2O3, CuO, ZnO, Mn2O3, NiO, Fe2O3, LiF, NaF or Li3N.
In a preferred embodiment, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the nanoparticle is CaO.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the plasticizer is selected from the group consisting of glycol diethers/glyme and carbonate based solvents.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the plasticizer is selected from the group consisting of glycol diethers/glymes and carbonate based solvents, wherein the glycol diethers is selected from the group consisting of tetraglyme, diglyme, triglyme, and monoglyme, wherein the carbonate based solvents is selected from the group consisting of propylene carbonate (PC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC) and Tetrahydrofuran (THF).
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the polymer is selected from the group consisting of polyethylene, polypropylene, polyvinylpyrrolidone- vinyl acetate, poly[bis(2-(2-methoxyethoxyethoxy))phosphagene], poly- ethyleneimide, poly(ethyleneoxide) (PEO), polyethylenesuccinate, polyethylenesulfide, poly(oxymethylene-oligo-oxyethylene), polypropyleneoxide, polyvinyl acetate, polyacrylonitrile (PAN), poly(acrylonitrile-co-methylacrylate), polymethylmethacrylate (PMMA), poly(methylmethacr late-co-ethylacrylate), polyvinylchloride, poly(vinylidene- chloride-co-acrylonitrile), poly(vinylidene fluoride) (PVDF), poly(vinyl chloride) (PVC), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), poly(propylene carbonate) (PPC), Poly(diallydimethylammonium) chloride (PDADMACl), and Poly(vinylbenzyltrimethylammonium) bis(trifluoromethanesulfonyl) imide (PVBTMATFSI) or mixtures thereof.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the solvent to dissolve the polymer is selected from the group of dimethyl formamide (DMF), dimethyl sulfoxide (DMSO), dimethylacetamide (DMAc), water, and mixtures thereof.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the electrolyte salt comprises of a lithium salt, or a sodium salt.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the liquid electrolyte comprises a lithium salt, or a sodium salt dispersed in an organic solvent with or without additives selected from the group consisting of vinylene carbonate, fluoro ethylene carbonate, sodium difluoro oxalato borate, or ethylene sulphate etc.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the sodium salt is selected from the group consisting of sodium hydroxides, sodium phosphates, sodium-containing chloric acids, sodium fluoride, sodium sulfate (Na2SO4), sodium nitrate (NaNO3), sodium lignosulfonate (C20H24Na2O10S2), sodium hexafluoroarsenate (NaAsF6), sodium tetrafluoroborate (NaBF4), sodium hexafluorophosphate (NaPF6), sodium hexafluoroantimonate (NaSbF6), sodium trifluoromethanesulfonate (NaCF3SO3), and sodium trifluoromethanesulfonimide (NaN(SO2CF3)2).
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the sodium salt is selected from the group consisting of sodium hydroxides, sodium phosphates, sodium-containing chloric acids, sodium fluoride, sodium sulfate (Na2SO4), sodium nitrate (NaNO3), sodium lignosulfonate (C20H24Na2O10S2), sodium hexafluoroarsenate (NaAsF6), sodium tetrafluoroborate (NaBF4), sodium hexafluorophosphate (NaPF6), Sodium hexafluoroantimonate (NaSbF6), sodium trifluoromethanesulfonate (NaCF3SO3), and Sodium trifluoromethanesulfonimide (NaN(SO2CF3)2), wherein sodium borates is selected from the group consisting of sodium tetraborate (Na2B4O7), and sodium fluoroborate (NaBF4),wherein sodium phosphates is selected from the group consisting of sodium phosphate tribasic (Na3PO4), sodium pyrophosphate (Na2HPO4), Sodium Hexametaphosphate (NaPO3)6, onosodium Phosphate (NaH2PO4),and Disodium Phosphate (Na2HPO4), and sodium-containing chloric acids is selected from the group consisting of Sodium perchlorate (NaClO4), Sodium tetrachloroaluminate (NaAlCl4), and Sodium Hypochlorite (NaClO).
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the lithium salt is selected from the group consisting of Lithium hexafluorophosphate (LiPF6), Lithium perchloratec (LiClO4), Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and Lithium triflate (LiCF3SO3).
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the organic solvent for the liquid electrolyte is selected from the group consisting of trimethyl phosphate (TMP), triethyl phosphate (TEP), methyl ethyl carbonate, methylpropionate carbonate, ethyl propionate, ethyl acetate, ethyl methyl carbonate, methyl formate, propylene carbonate, ethylene carbonate, vinylene carbonate, fluoroethylene carbonate, methyl acetate, triethylene glycoldimethyl ether, dimethyl sulfone, dimethyl ether, ethylene sulfite, diethyl carbonate, dimethyl carbonate, propylene oxide, propylene sulfite, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propyl acetate, methyl butanone, methyl isobutylketone, toluene cyclohexanone, ethylene glycol dimethylether and Tetraethylene glycol dimethyl ether.
In yet another embodiments, the present invention provides a metal-ion battery comprising; a positive electrode, a negative electrode and a nanoparticle decorated cellulose gel polymer electrolyte.
In yet another embodiments, the present invention provides a metal-ion battery comprising; a positive electrode, a negative electrode and a nanoparticle decorated cellulose gel polymer electrolyte, wherein the nanoparticle decorated cellulose gel polymer electrolyte is configured as an electrolyte and a separator.
In another embodiments, the present invention provides a metal-ion battery, wherein the cellulose is decorated with nanoparticle selected from one or more of metal oxide, alkaline metal oxide, alkali metal oxide, non-metal oxide, alkali metal fluorides or alkali metal nitrites.
In another embodiments, the present invention provides a metal-ion battery, wherein the cellulose is decorated with nanoparticle selected from one or more of metal oxide, alkaline metal oxide, alkali metal oxide, non-metal oxide, alkali metal fluorides or alkali metal nitrites, wherein the one or more of metal oxide, alkaline metal oxide, alkali metal oxide, non-metal oxide, alkali metal fluorides or alkali metal nitrites comprises CaO, TiO2, BaTiO3, Li2O, BaO, Na2O, MgO, SiO2, Al2O3, CuO, ZnO, Mn2O3, NiO, Fe2O3, LiF, NaF or Li3N.
In a preferred embodiments, the present invention provides a metal-ion battery, wherein the cellulose is decorated with nanoparticle CaO.
In yet another embodiments, the present invention provides a metal-ion battery comprising; a positive electrode, a negative electrode and a Cao decorated cellulose gel polymer electrolyte.
In yet another embodiments, the present invention provides a metal-ion battery, wherein the positive electrode (cathode) and the negative electrode (anode) comprises any active metal ions selected from the group consisting of Li+, Na+, K+, Ca2+, Mg2+, Zn2+ and Al3+ .
In yet another embodiments, the present invention provides a metal-ion battery, wherein the positive electrode is selected from Na3V2(PO4)3 (NVP), Na3V2(PO4)2F3(NVPF), polyanionic compounds, layered oxides, Prussian blue, Prussian white, Na(NieFeyMnz)O2 etc.
In yet another embodiments, the present invention provides a metal-ion battery, wherein the negative electrode is sodium metal.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
These and other features, aspect, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings are explained in more detail with reference to the following drawings:
Figure 1 illustrates FESEM image of bare and CaO decorated Cellulose (also referred as CaO@Cellulose)
Figure 2 illustrates Galvanostatic charge-discharge curves at different C-rates of NVP with CaO@Cellulose gel polymer electrolyte soaked in 1M NaClO4 PC with 5%VC.
Figure 3 illustrates Rate capability of NVP with CaO@Cellulose gel polymer electrolyte soaked in 1M NaClO4 PC with 5% VC
Figure 4 illustrates Cyclability of NVP with CaO@Cellulose gel polymer electrolyte soaked in 1M NaClO4 PC with 5%VC cycled at 1C rate.
Figure 5 illustrates Galvanostatic charge-discharge curves at different C-rates of NVPF with CaO@Cellulose gel polymer electrolyte soaked in 1M NaClO4 PC with 5%VC.
Figure 6 illustrates Rate capability of NVPF with CaO@Cellulose gel polymer electrolyte soaked in 1M NaClO4 PC with 5%VC.
Figure 7 illustrates Cyclability of NVPF with CaO@Cellulose gel polymer electrolyte soaked in 1M NaClO4 PC with 5%VC cycled at 1C rate.
Figure 8 illustrates Galvanostatic charge-discharge curves at different C-rates of NVP with CaO@Cellulose gel polymer electrolyte soaked in PC.
Figure 9 illustrates Rate capability of NVP with CaO@Cellulose gel polymer electrolyte soaked in PC.
Figure 10 illustrates Cyclability of NVP with CaO@Cellulose gel polymer electrolyte soaked in PC cycled at 1C rate.
Figure 11 illustrates Galvanostatic charge-discharge curves at different C-rates of NVP with gel polymer electrolyte without CaO@Cellulose soaked in 1M NaClO4 PC with 5%VC.
Figure 12 illustrates Rate capability of NVP with gel polymer electrolyte without CaO@Cellulose soaked in 1M NaClO4 PC with 5%VC.
Figure 13 illustrates Cyclability of NVP with gel polymer electrolyte without CaO@Cellulose soaked in 1M NaClO4 PC with 5%VC cycled at 1C rate.
DETAILED DESCRIPTION OF THE INVENTION:
For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skilled in the art to which this invention belongs. The system, methods, and examples provided herein are illustrative only and not intended to be limiting.
Before the present process and methods are described, it is to be understood that this invention is not limited to compounds, formulas, or steps described, as such may, of course, vary. It is also to be understood that the terminology used herein is to describe particular embodiments only and is not intended to be limiting.
Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, the preferred methods and materials are now described. All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited.
It must be noted that as used herein and in the appended claims, the singular forms "a", "and", and "the" include plural referents unless the context dictates otherwise. Thus, for example, reference to "a compound" includes a plurality of such compounds, and reference to "the step" includes reference to one or more steps and equivalents thereof known to those skilled in the art, and so forth.
The term “some” as used herein is defined as “none, or one, or more than one, or all.” Accordingly, the terms “none,” “one,” “more than one,” “more than one, but not all” or “all” would all fall under the definition of “some.” The term “some embodiments” may refer to no embodiments or to one embodiment or to several embodiments or to all embodiments. Accordingly, the term “some embodiments” is defined as meaning “no embodiment, or one embodiment, or more than one embodiment, or all embodiments.”
The terminology and structure employed herein is for describing, teaching and illuminating some embodiments and their specific features and elements and does not limit, restrict or reduce the spirit and scope of the claims or their equivalents.
More specifically, any terms used herein such as but not limited to “includes,” “comprises,” “has,” “consists,” and grammatical variants thereof do NOT specify an exact limitation or restriction and certainly do NOT exclude the possible addition of one or more features or elements, unless otherwise stated, and furthermore must NOT be taken to exclude the possible removal of one or more of the listed features and elements, unless otherwise stated with the limiting language “MUST comprise” or “NEEDS TO include.”
Whether or not a certain feature or element was limited to being used only once, either way it may still be referred to as “one or more features” or “one or more elements” or “at least one feature” or “at least one element.” Furthermore, the use of the terms “one or more” or “at least one” feature or element do NOT preclude there being none of that feature or element, unless otherwise specified by limiting language such as “there NEEDS to be one or more . . . ” or “one or more element is REQUIRED.”
Unless otherwise defined, all terms, and especially any technical and/or scientific terms, used herein may be taken to have the same meaning as commonly understood by one having an ordinary skill in the art.
Reference is made herein to some “embodiments.” It should be understood that an embodiment is an example of a possible implementation of any features and/or elements presented in the attached claims. Some embodiments have been described for the purpose of illuminating one or more of the potential ways in which the specific features and/or elements of the attached claims fulfil the requirements of uniqueness, utility and non-obviousness.
Use of the phrases and/or terms such as but not limited to “a first embodiment,” “a further embodiment,” “an alternate embodiment,” “one embodiment,” “an embodiment,” “multiple embodiments,” “some embodiments,” “other embodiments,” “further embodiment”, “furthermore embodiment”, “additional embodiment” or variants thereof do NOT necessarily refer to the same embodiments. Unless otherwise specified, one or more particular features and/or elements described in connection with one or more embodiments may be found in one embodiment, or may be found in more than one embodiment, or may be found in all embodiments, or may be found in no embodiments. Although one or more features and/or elements may be described herein in the context of only a single embodiment, or alternatively in the context of more than one embodiment, or further alternatively in the context of all embodiments, the features and/or elements may instead be provided separately or in any appropriate combination or not at all. Conversely, any features and/or elements described in the context of separate embodiments may alternatively be realized as existing together in the context of a single embodiment.
Any particular and all details set forth herein are used in the context of some embodiments and therefore should NOT be necessarily taken as limiting factors to the attached claims. The attached claims and their legal equivalents can be realized in the context of embodiments other than the ones used as illustrative examples in the description below.
Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
The present invention is drawn to a gel polymer electrolyte comprising; a nanoparticle decorated cellulose, a plasticized polymer and an electrolyte salt. The present invention is also drawn to a method of preparation of a nanoparticle decorated cellulose gel polymer electrolyte. The present invention also relates to a metal-ion battery comprising; a positive electrode, a negative electrode and a nanoparticle decorated cellulose gel polymer electrolyte wherein the nanoparticle decorated cellulose gel polymer electrolyte is configured as an electrolyte and a separator. This nanoparticle decorated cellulose gel polymer electrolyte when used in metal-ion battery has superior electrochemical performance and stability for long cycles.
In yet another embodiments, the present invention provides a gel polymer electrolyte comprising; a nanoparticle decorated cellulose, a plasticized polymer and an electrolyte salt.
In another embodiments, the present invention provides a gel polymer electrolyte, wherein the cellulose is decorated with nanoparticle selected from one or more of metal oxide, alkaline metal oxide, alkali metal oxide, non-metal oxide, alkali metal fluorides or alkali metal nitrites.
In another embodiments, the present invention provides a gel polymer electrolyte, wherein the cellulose is decorated with nanoparticle selected from one or more of metal oxide, alkaline metal oxide, alkali metal oxide, non-metal oxide, alkali metal fluorides or alkali metal nitrites, wherein the one or more of metal oxide, alkaline metal oxide, alkali metal oxide, non-metal oxide, alkali metal fluorides or alkali metal nitrites comprises CaO, TiO2, BaTiO3, Li2O, BaO, Na2O, MgO, SiO2, Al2O3, CuO, ZnO, Mn2O3, NiO, Fe2O3, LiF, NaF or Li3N.
In a preferred embodiments, the present invention provides a gel polymer electrolyte, wherein the nanoparticle is CaO.
In another embodiments, the present invention provides a gel polymer electrolyte, wherein the electrolyte salt comprises of a lithium salt, or a sodium salt.
In another embodiments, the present invention provides a gel polymer electrolyte, wherein the plasticizer is selected from the group consisting of glycol diethers/glymes and carbonate based solvents,.
In another embodiments, the present invention provides a gel polymer electrolyte, wherein the plasticizer is selected from the group consisting of glycol diethers/glymes and carbonate based solvents, wherein the glycol diethers is selected from the group consisting of tetraglyme, diglyme, triglyme, and monoglyme, wherein the carbonate based solvents is selected from the group consisting of propylene carbonate (PC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC) and Tetrahydrofuran (THF).
In another embodiments, the present invention provides a gel polymer electrolyte, wherein the polymer is selected from the group consisting of polyethylene, polypropylene, polyvinylpyrrolidone- vinyl acetate, poly[bis(2-(2-methoxyethoxyethoxy))phosphagene], poly- ethyleneimide, poly(ethyleneoxide) (PEO), polyethylenesuccinate, polyethylenesulfide, poly(oxymethylene-oligo-oxyethylene), polypropyleneoxide, polyvinyl acetate, polyacrylonitrile (PAN), poly(acrylonitrile-co-methylacrylate), polymethylmethacrylate (PMMA), poly(methylmethacr late-co-ethylacrylate), polyvinylchloride, poly(vinylidene- chloride-co-acrylonitrile), poly(vinylidene fluoride) (PVDF), poly(vinyl chloride) (PVC), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), poly(propylene carbonate) (PPC), Poly(diallydimethylammonium) chloride (PDADMACl), and Poly(vinylbenzyltrimethylammonium) bis(trifluoromethanesulfonyl) imide (PVBTMATFSI) or mixtures thereof.
In another embodiments, the present invention provides a gel polymer electrolyte, wherein the sodium salt is selected from the group consisting of sodium hydroxides, sodium phosphates, sodium-containing chloric acids, sodium fluoride, sodium sulfate (Na2SO4), sodium nitrate (NaNO3), sodium lignosulfonate (C20H24Na2O10S2), sodium hexafluoroarsenate (NaAsF6), sodium tetrafluoroborate (NaBF4), sodium hexafluorophosphate (NaPF6), sodium hexafluoroantimonate (NaSbF6), sodium trifluoromethanesulfonate (NaCF3SO3), and sodium trifluoromethanesulfonimide (NaN(SO2CF3)2).
In another embodiments, the present invention provides a gel polymer electrolyte, wherein the sodium salt is selected from the group consisting of sodium hydroxides, sodium phosphates, sodium-containing chloric acids, sodium fluoride, sodium sulfate (Na2SO4), sodium nitrate (NaNO3), sodium lignosulfonate (C20H24Na2O10S2), sodium hexafluoroarsenate (NaAsF6), sodium tetrafluoroborate (NaBF4), sodium hexafluorophosphate (NaPF6), Sodium hexafluoroantimonate (NaSbF6), sodium trifluoromethanesulfonate (NaCF3SO3), and Sodium trifluoromethanesulfonimide (NaN(SO2CF3)2), wherein sodium borates is selected from the group consisting of sodium tetraborate (Na2B4O7), and sodium fluoroborate (NaBF4),wherein sodium phosphates is selected from the group consisting of sodium phosphate tribasic (Na3PO4), sodium pyrophosphate (Na2HPO4), Sodium Hexametaphosphate (NaPO3)6, onosodium Phosphate (NaH2PO4), Disodium Phosphate (Na2HPO4) and sodium-containing chloric acids is selected from the group consisting of Sodium perchlorate (NaClO4), Sodium tetrachloroaluminate (NaAlCl4),and Sodium Hypochlorite (NaClO).
In another embodiments, the present invention provides a gel polymer electrolyte, wherein the lithium salt is selected from the group consisting of Lithium hexafluorophosphate (LiPF6), Lithium perchloratec (LiClO4), Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and Lithium triflate (LiCF3SO3).
In yet another embodiments, the present invention provides a gel polymer electrolyte comprising; a CaO decorated cellulose, a plasticized poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) polymer and a sodium salt.
In one of the embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, the method comprising;
a) dispersing a cellulose powder with a nanoparticle to obtain a dispersion;
b) hydrolyzing the dispersion obtained in step a) to obtain a nanoparticle decorated cellulose;
c) dispersing the nanoparticle decorated cellulose in a mixture of a plasticizer and an electrolyte salt to obtain a solution (a);
d) mixing a polymer in a solvent to obtain a solution (b);
e) mixing and stirring the solution (a) and (b) to obtain a solution (c);
f) sonicating the solution (c) to obtain a nanoparticle decorated cellulose powder dispersed polymer salt suspension;
g) forming a polymer film from the nanoparticle decorated cellulose powder dispersed polymer salt suspension;
h) drying the polymer film;
i) soaking the polymer film in a liquid electrolyte obtain the gel polymer electrolyte.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the solution (c)is sonicated for 1 hour.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the polymer film is formed by doctor blade coating, electrospinning, dip coating, phase inversion or spraying on a substrate.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the substrate comprises a glass plate, a PTFE membrane, or a ceramic plate etc.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the polymer film is dried in vacuum.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the polymer film is peeled from the substrate.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the polymer film are cut in circles.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the polymer film is soaked in the liquid electrolyte for 5 minutes to 4 hours.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the weight percentage of the nanoparticle on cellulose is in a range of 1% to 50%.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the polymer film is coated on the glass plate by a doctor blade method.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the nanoparticle is selected from one or more of metal oxide, alkaline metal oxide, alkali metal oxide, non-metal oxide, alkali metal fluorides or alkali metal nitrites.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the nanoparticle is selected from one or more of metal oxide, alkaline metal oxide, alkali metal oxide, non-metal oxide, alkali metal fluorides or alkali metal nitrites, wherein the one or more of metal oxide, alkaline metal oxide, alkali metal oxide, non-metal oxide, alkali metal fluorides or alkali metal nitrites comprises CaO, TiO2, BaTiO3, Li2O, BaO, Na2O, MgO, SiO2, Al2O3, CuO, ZnO, Mn2O3, NiO, Fe2O3, LiF, NaF or Li3N.
In a preferred embodiment, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the nanoparticle is CaO.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the plasticizer is selected from the group consisting of glycol diethers/glymes and carbonate based solvents.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the plasticizer is selected from the group consisting of glycol diethers/glymes and carbonate based solvents, wherein the glycol diethers is selected from the group consisting of tetraglyme, diglyme, triglyme, and monoglyme, wherein the carbonate based solvents is selected from the group consisting of propylene carbonate (PC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC) and Tetrahydrofuran (THF).
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the polymer is selected from the group consisting of polyethylene, polypropylene, polyvinylpyrrolidone- vinyl acetate, poly[bis(2-(2-methoxyethoxyethoxy))phosphagene], poly- ethyleneimide, poly(ethyleneoxide) (PEO), polyethylenesuccinate, polyethylenesulfide, poly(oxymethylene-oligo-oxyethylene), polypropyleneoxide, polyvinyl acetate, polyacrylonitrile (PAN), poly(acrylonitrile-co-methylacrylate), polymethylmethacrylate (PMMA), poly(methylmethacr late-co-ethylacrylate), polyvinylchloride, poly(vinylidene- chloride-co-acrylonitrile), poly(vinylidene fluoride) (PVDF), poly(vinyl chloride) (PVC), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), poly(propylene carbonate) (PPC), Poly(diallydimethylammonium) chloride (PDADMACl), and Poly(vinylbenzyltrimethylammonium) bis(trifluoromethanesulfonyl) imide (PVBTMATFSI) or mixtures thereof.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the solvent to dissolve the polymer is selected from the group of dimethyl formamide (DMF), dimethyl sulfoxide (DMSO), dimethylacetamide (DMAc), water, and mixtures thereof.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the electrolyte salt comprises of a lithium salt, or a sodium salt.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the liquid electrolyte comprises a lithium salt, or a sodium salt dispersed in an organic solvent with or without additives selected from the group consisting of vinylene carbonate, fluoro ethylene carbonate, sodium difluoro oxalato borate, or ethylene sulphate etc.
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the sodium salt is selected from the group consisting of sodium hydroxides, sodium phosphates, sodium-containing chloric acids, sodium fluoride, sodium sulfate (Na2SO4), sodium nitrate (NaNO3), sodium lignosulfonate (C20H24Na2O10S2), sodium hexafluoroarsenate (NaAsF6), sodium tetrafluoroborate (NaBF4), sodium hexafluorophosphate (NaPF6), sodium hexafluoroantimonate (NaSbF6), sodium trifluoromethanesulfonate (NaCF3SO3), and sodium trifluoromethanesulfonimide (NaN(SO2CF3)2).
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the sodium salt is selected from the group consisting of sodium hydroxides, sodium phosphates, sodium-containing chloric acids, sodium fluoride, sodium sulfate (Na2SO4), sodium nitrate (NaNO3), sodium lignosulfonate (C20H24Na2O10S2), sodium hexafluoroarsenate (NaAsF6), sodium tetrafluoroborate (NaBF4), sodium hexafluorophosphate (NaPF6), Sodium hexafluoroantimonate (NaSbF6), sodium trifluoromethanesulfonate (NaCF3SO3), and Sodium trifluoromethanesulfonimide (NaN(SO2CF3)2), wherein sodium borates is selected from the group consisting of sodium tetraborate (Na2B4O7), and sodium fluoroborate (NaBF4),wherein sodium phosphates is selected from the group consisting of sodium phosphate tribasic (Na3PO4), sodium pyrophosphate (Na2HPO4), Sodium Hexametaphosphate (NaPO3)6, onosodium Phosphate (NaH2PO4), and Disodium Phosphate (Na2HPO4) and sodium-containing chloric acids is selected from the group consisting of Sodium perchlorate (NaClO4), Sodium tetrachloroaluminate (NaAlCl4), and Sodium Hypochlorite (NaClO).
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the lithium salt is selected from the group consisting of Lithium hexafluorophosphate (LiPF6), Lithium perchloratec (LiClO4), Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and Lithium triflate (LiCF3SO3).
In another embodiments, the present invention provides a method of preparation of a gel polymer electrolyte, wherein the organic solvent for the liquid electrolyte is selected from the group consisting of trimethyl phosphate (TMP), triethyl phosphate (TEP), methyl ethyl carbonate, methylpropionate carbonate, ethyl propionate, ethyl acetate, ethyl methyl carbonate, methyl formate, propylene carbonate, ethylene carbonate, vinylene carbonate, fluoroethylene carbonate, methyl acetate, triethylene glycoldimethyl ether, dimethyl sulfone, dimethyl ether, ethylene sulfite, diethyl carbonate, dimethyl carbonate, propylene oxide, propylene sulfite, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propyl acetate, methyl butanone, methyl isobutylketone, toluene cyclohexanone, ethylene glycol dimethylether and Tetraethylene glycol dimethyl ether.
In yet another embodiments, the present invention provides a metal-ion battery comprising; a positive electrode, a negative electrode and a nanoparticle decorated cellulose gel polymer electrolyte.
In yet another embodiments, the present invention provides a metal-ion battery comprising; a positive electrode, a negative electrode and a nanoparticle decorated cellulose gel polymer electrolyte, wherein the nanoparticle decorated cellulose gel polymer electrolyte is configured as an electrolyte and a separator.
In another embodiments, the present invention provides a metal-ion battery, wherein the cellulose is decorated with nanoparticle selected from one or more of metal oxide, alkaline metal oxide, alkali metal oxide, non-metal oxide, alkali metal fluorides or alkali metal nitrites.
In another embodiments, the present invention provides a metal-ion battery, wherein the cellulose is decorated with nanoparticle selected from one or more of metal oxide, alkaline metal oxide, alkali metal oxide, non-metal oxide, alkali metal fluorides or alkali metal nitrites, wherein the one or more of metal oxide, alkaline metal oxide, alkali metal oxide, non-metal oxide, alkali metal fluorides or alkali metal nitrites comprises CaO, TiO2, BaTiO3, Li2O, BaO, Na2O, MgO, SiO2, Al2O3, CuO, ZnO, Mn2O3, NiO, Fe2O3, LiF, NaF or Li3N.
In a preferred embodiments, the present invention provides a metal-ion battery, wherein the the cellulose is decorated with nanoparticle CaO.
In yet another embodiments, the present invention provides a metal-ion battery comprising; a positive electrode, a negative electrode and a Cao decorated cellulose gel polymer electrolyte.
In yet another embodiments, the present invention provides a metal-ion battery, wherein the positive electrode (cathode) and the negative electrode (anode) comprises any active metal ions selected from the group consisting of Li+, Na+, K+, Ca2+, Mg2+, Zn2+ and Al3+ .
In yet another embodiments, the present invention provides a metal-ion battery, wherein the positive electrode is selected from Na3V2(PO4)3(NVP), Na3V2(PO4)2F3(NVPF), polyanionic compounds, layered oxides, Prussian blue, Prussian white, Na(NieFeyMnz)O2 etc.
In yet another embodiments, the present invention provides a metal-ion battery, wherein the negative electrode is sodium metal.
SYNTHESIS METHOD (CaO decorated Cellulose):
1 gm cellulose powder was dispersed in 0.2M Calcium nitrate tetrahydrate (Ca(NO3). 4H2O) in 20ml water (H2O) by sonication for 15 mins. The solution is kept stirring for 15 mins, 0.4M potassium hydroxide (KOH) in 10ml water was added drop by drop and mixture was Stirred for 1hour. The precipitate along with cellulose was filtered, washed with water and dried in vacuum oven at 100 ? to obtain CaO decorated cellulose also referred as CaO modified Cellulose or CaO@cellulose Figure 1. illustrates FESEM image of bare and CaO modified Cellulose. The weight percentage of CaO on cellulose can be from 1% to 50%.
1 gm poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF HFP) is dissolved in 1.5 ml of dimethyl formamide (DMF). 200 mg Sodium tetrafluoroborate (NaBF4 ) is dissolved in 2 ml of tetraglyme to it 200 mg CaO@cellulose powder is dispersed. The dispersed cellulose solution is mixed with PVDF-HFP solution and stirred well until a uniform viscous dispersion/suspension is obtained. This viscous cellulose PVDF-HFP NaBF4 polymer is coated on to a glass plate using doctor blade, dried in vacuum. The dried polymer film is peeled from the glass plate and cut to 19mm diameter circles, soaked in liquid electrolyte (1M Sodium tetrafluoroborate (NaBF4) in Tetraglyme or 1M Sodium perchlorate (NaClO4) propylene carbonate (PC) with 5% vinylene carbonate (VC) for 5 mins to 2 hrs.

CELL FABRICATION
Na3V2(PO4)3 (NVP) and Na3V2(PO4)2F3(NVPF) were used as cathode to test the gel polymer battery. The dried Gel polymer is cut in to 19 mm diameter and soaked in the liquid electrolyte for some time (2 to 2hrs). It is dried with lint free cloth and assembled in to a coin cell. Cell is fabricated with Na3V2(PO4)3 / Na3V2(PO4)2F3 as cathode, soaked gel-polymer electrolyte as separator/electrolyte and sodium metal as anode.

Galvanostatic charge discharge studies were conducted with Na3V2(PO4)3 and with gel polymer electrolyte soaked in 1 M NaClO4 PC with 5%VC. Figure 2 depicts the galvanostatic charge-discharge curves at different C-rates of NVP with CaO@Cellulose gel-polymer electrolyte. The discharge capacity obtained were 109, 108, 106, 104, 102, 100, 97, 91 and 75 mAh/g at the C-rates of 0.1, 0.2, 0.5, 1, 2, 3, 5, 10 and 20C. The rate capability graph is depicted in Figure 3. The cyclic stability of 90% retention after 550 cycles at 1C rate is obtained and is shown in Figure 4. This novel gel-polymer electrolyte can be potential candidate for safe metal ion battery.
Galvanostatic charge discharge studies were conducted with Na3V2(PO4)2F3 and with gel polymer electrolyte soaked in 1M NaClO4 PC with 5% VC. Figure 5 depicts the galvanostatic charge-discharge curves at different C-rates of NVPF with CaO@Cellulose gel-polymer electrolyte. The discharge capacity obtained were 92, 90, 82, 75, 47, 40, 33 and 15 mAh/g at the C-rates of 0.1, 0.2, 0.5, 1, 2, 3, 5, and 10C. The rate capability graph is depicted in Figure 6. The cyclic stability of 90% retention after 600 cycles, 76% retention after 1800 cycles at 1C rate are obtained and is shown in Figure 7. This novel gel-polymer electrolyte can be potential candidate for safe metal ion battery.
Galvanostatic charge discharge studies were conducted with Na3V2(PO4)3 and with gel polymer electrolyte soaked only in PC solvent. Figure 8 depicts the galvanostatic charge-discharge curves at different C-rates of NVP with CaO@Cellulose gel-polymer electrolyte. The discharge capacities at low C-rate matches with the cell fabricated with the gel polymer soaked in 1M NaClO4 PC with 5%VC (Refer Figure 2), but the capacity at high C-rate is poor, that can be inferred from the rate capability graph is depicted in Figure 9. Nevertheless, the cyclic stability is 91% retention after 500 cycles at 1C rate which is comparably good and it is shown in Figure 10. The inference is that the gel polymer can be soaked only in solvent to get good performance.
To check the credibility of CaO@Cellulose in the gel-polymer, control experiment without CaO@Cellulose is done. Galvanostatic charge discharge studies were conducted with Na3V2(PO4)3 and with gel polymer electrolyte without CaO@Cellulose soaked in 1M NaClO4 PC with 5% VC. Figure 11 depicts the galvanostatic charge-discharge curves at different C-rates of NVP gel-polymer electrolyte without CaO@Cellulose. The discharge capacity obtained were 106, 105, 102, 100, 97, 93, 88, 82, 75 and 64 mAh/g at the C-rates of 0.1, 0.2, 0.5, 1, 2, 3, 5, 10, 20 and 30C. Here compared to the one with CaO@Cellulose gel-polymer electrolyte, capacity is little less, but the rate capability is found to be good. The rate capability graph is depicted in figure 12. The cyclic stability of only 60% retention after 530 cycles at 1C rate and is shown in figure 13. The stability is found to be very poor compared to the gel-polymer with CaO@Cellulose.
Advantages of the invention:
The present invention methodology of gel polymer film fabrication is via a simple doctor blade technique and the film is prepared via a simple chemical mixing methodology and by using cheap fillers like CaO decorated Cellulose. The fabricated film when used for sodium ion battery displayed excellent specific capacity and rate capability.
,CLAIMS:1. A method of preparation of a gel polymer electrolyte, the method comprising;
a) dispersing a cellulose powder with a nanoparticle to obtain a dispersion;
b) hydrolyzing the dispersion obtained in step a) to obtain a nanoparticle decorated cellulose;
c) dispersing the nanoparticle decorated cellulose in a mixture of a plasticizer and an electrolyte salt to obtain a solution (a);
d) mixing a polymer in a solvent to obtain a solution (b);
e) mixing and stirring the solution (a) and (b) to obtain a solution (c);
f) sonicating the solution (c) to obtain a nanoparticle decorated cellulose powder dispersed polymer salt suspension;
g) forming a polymer film from the nanoparticle decorated cellulose powder dispersed polymer salt suspension;
h) drying the polymer film;
i) soaking the polymer film in a liquid electrolyte obtain the gel polymer electrolyte.
2. The method of preparation of a gel polymer electrolyte as claimed in claim 1, wherein the weight percentage of the nanoparticle on cellulose is in a range of 1% to 50%.
3. The method of preparation of a gel polymer electrolyte as claimed in claim 1 wherein the nanoparticle is selected from one or more of metal oxide, alkaline metal oxide, alkali metal oxide, non-metal oxide, alkali metal fluorides or alkali metal nitrites.
4. The method of preparation of a gel polymer electrolyte as claimed in claim 1, wherein the plasticizer is selected from the group consisting of glycol diethers and carbonate based solvents.
5. The method of preparation of a gel polymer electrolyte as claimed in claim 1, wherein the polymer is selected from the group consisting of polyethylene, polypropylene, polyvinylpyrrolidone- vinyl acetate, poly[bis(2-(2-methoxyethoxyethoxy))phosphagene], poly- ethyleneimide, poly(ethyleneoxide) (PEO), polyethylenesuccinate, polyethylenesulfide, poly(oxymethylene-oligo-oxyethylene), polypropyleneoxide, polyvinyl acetate, polyacrylonitrile (PAN), poly(acrylonitrile-co-methylacrylate), polymethylmethacrylate (PMMA), poly(methylmethacr late-co-ethylacrylate), polyvinylchloride, poly(vinylidene- chloride-co-acrylonitrile), poly(vinylidene fluoride) (PVDF), poly(vinyl chloride) (PVC), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), poly(propylene carbonate) (PPC), Poly(diallydimethylammonium) chloride (PDADMACl), and Poly(vinylbenzyltrimethylammonium) bis(trifluoromethanesulfonyl) imide (PVBTMATFSI) or mixtures thereof.
6. A method of preparation of a gel polymer electrolyte as claimed in claim 1, wherein the solvent to dissolve the polymer is selected from the group of dimethyl formamide (DMF), dimethyl sulfoxide (DMSO), dimethylacetamide (DMAc), water, and mixtures thereof.
7. The method of preparation of a gel polymer electrolyte as claimed in claim 1, wherein the electrolyte salt comprises of a lithium salt, or a sodium salt.
8. The method of preparation of a gel polymer electrolyte as claimed in claim 1, wherein the liquid electrolyte comprises a lithium salt, or a sodium salt dispersed in an organic solvent with or without additives selected from the group consisting of vinylene carbonate, fluoro ethylene carbonate, sodium difluoro oxalato borate, or ethylene sulphate.
9. The method of preparation of a gel polymer electrolyte as claimed in any of the preceding claims, wherein the sodium salt is selected from the group consisting of sodium hydroxides, sodium phosphates, sodium-containing chloric acids, sodium fluoride, sodium sulfate (Na2SO4), sodium nitrate (NaNO3), sodium lignosulfonate (C20H24Na2O10S2), Sodium hexafluoroarsenate (NaAsF6), Sodium tetrafluoroborate (NaBF4), Sodium hexafluorophosphate (NaPF6), Sodium hexafluoroantimonate (NaSbF6), Sodium trifluoromethanesulfonate (NaCF3SO3), and Sodium trifluoromethanesulfonimide (NaN(SO2CF3)2).
10. The method of preparation of a gel polymer electrolyte as claimed in any of the preceding claims, wherein the lithium salt is selected from the group consisting of Lithium hexafluorophosphate (LiPF6), Lithium perchlorate (LiClO4), Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and Lithium triflate (LiCF3SO3).
11. The method of preparation of a gel polymer electrolyte as claimed in claim 10, wherein the organic solvent for the liquid electrolyte is selected from the group consisting of trimethyl phosphate (TMP), triethyl phosphate (TEP), methyl ethyl carbonate, methylpropionate carbonate, ethyl propionate, ethyl acetate, ethyl methyl carbonate, methyl formate, propylene carbonate, ethylene carbonate, vinylene carbonate, fluoroethylene carbonate, methyl acetate, triethylene glycoldimethyl ether, dimethyl sulfone, dimethyl ether, ethylene sulfite, diethyl carbonate, dimethyl carbonate, propylene oxide, propylene sulfite, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propyl acetate, methyl butanone, methyl isobutylketone, toluene cyclohexanone, ethylene glycol dimethylether and Tetraethylene glycol dimethyl ether.
12. A gel polymer electrolyte comprising; a nanoparticle decorated cellulose, a plasticized polymer and an electrolyte salt.
13. A metal-ion battery comprising; a positive electrode, a negative electrode and a nanoparticle decorated cellulose gel polymer electrolyte.
14. The metal-ion battery as claimed in claim 13, wherein the positive electrode and the negative electrode comprises any active metal ions selected from the group consisting of Li+, Na+, K+, Ca2+, Mg2+, Zn2+ and Al3+.