Claims:CLAIMS:
I / We Claim:
1. A method for synthesis of graphitic carbon derived from waste tissue papers for hybrid sodium-ion capacitors, comprising:
washing a waste tissue paper with deionised water, and leaching in dilute hydrochloric acid for 24 hours to obtain an acid leached tissue paper;
washing said acid-leached tissue paper repeatedly with deionised water and ethanol to remove said hydrochloric acid from said acid-leached tissue paper, and drying for 24 hours to obtain dried tissue paper;
burning said dried tissue paper to obtain black carbon ash followed by refining and grinding said black carbon ash;
exfoliating said ground black carbon ash with different amounts of sodium dodecyl sulphate (SDS) to obtain a black carbon ash-SDS mixture;
treating said black carbon ash-SDS mixture with the deionised water and ethanol for 5 hours of sonication to obtain a black sonicated black carbon ash-SDS mixture, followed by centrifugation of said black sonicated black carbon ash-SDS mixture;
filtering said black sonicated black carbon ash-SDS mixture with a filter paper and drying black said sonicated black carbon ash-SDS mixture at 60 °C for 24 hours to obtain graphitic carbon sheets;
mixing said graphitic carbon sheets with polyvinylidene fluoride binder, and conductive additive in a solvent to obtain a homogenous anode material;
coating said homogenous anode material on a carbon cloth, and drying said carbon cloth at 60 °C to obtain a graphitic carbon anode of said hybrid sodium-ion capacitor.
whereby said waste tissue paper based sustainable graphitic carbon for said hybrid sodium-ion capacitors provides enhanced conductivity and energy storage capacity.
2. The method for synthesis of graphitic carbon derived from waste tissue papers for hybrid sodium-ion capacitors as claimed in claim 1, wherein said conductive additive is acetylene black, increases conductivity of said homogenous anode material.
3. The method for synthesis of graphitic carbon derived from waste tissue papers for hybrid sodium-ion capacitors as claimed in claim 1, wherein 70 weight percentages of said graphitic carbon sheets is mixed with 20 weight percentages said acetylene black and 10 weight percentages of said polyvinylidene fluoride for fabrication of said graphitic carbon anode.
4. The method for synthesis of graphitic carbon derived from waste tissue papers for hybrid sodium-ion capacitors as claimed in claim 1, wherein said solvent is N-methyl-2-pyrrolidone.
5. The method for synthesis of graphitic carbon derived from waste tissue papers for hybrid sodium-ion capacitors as claimed in claim 1, wherein 70 weight percentages of said NaCo2O4 is mixed with 20 weight percentages said acetylene black and 10 weight percentages of said polyvinylidene fluoride for fabrication of a NaCo2O4 cathode.
6. The method for synthesis of graphitic carbon derived from waste tissue papers for hybrid sodium-ion capacitors as claimed in claim 1, wherein said graphitic carbon anode and said NaCo2O4 cathode is assembled in a hybrid sodium-ion capacitor coin-cell with 1M NaOH electrolyte.
7. The method for synthesis of graphitic carbon derived from waste tissue papers for hybrid sodium-ion capacitors as claimed in claim 1, wherein said black carbon ash-SDS mixture is treated with the deionised water and ethanol of 1:1 ratio.
8. The method for synthesis of graphitic carbon derived from waste tissue papers for hybrid sodium-ion capacitors as claimed in claim 1, wherein said black sonicated black carbon ash-SDS mixture centrifuged is at 6000 rpm. , Description:DESCRIPTION:
Field of the invention:
The present disclosure generally relates to the technical field of electrode materials, and in specific relates to recycle paper based sustainable graphitic carbon nanosheets (GCNSs) as competent anode material that enhances conductivity and energy storage capacity of sodium-ion capacitors.
Background of the invention:
Electrochemical energy storage devices such as batteries and super-capacitors are gaining importance, since they aid in reduction of fossil fuel energy consumption in transportation. The application of different energy storage devices primarily depends on electrode materials, especially carbon materials. Biomass-derived carbon materials have received extensive attention as electrode materials for energy storage devices because of their adjustable physical/chemical properties, environmental concerns, and economic value. However, demerits of existing energy storage devices such as low energy density, high cost, and safety, demand a need for alternative energy devices.

In general, the graphene family of layered materials is a common electrode material for new generation advanced energy storage devices. One of the two-dimensional layered materials is graphitic carbon nanosheets, which are highly explored as electrode materials in batteries and super-capacitors. Graphite is primarily used as a generic anode material in batteries and super-capacitors, due to its low price and ideal cycle properties. As the material with which an anode is made dominates the electrochemical output of hybrid-capacitors. Attempts have been made to create potential anode material that has the potential to replace the graphite. Further, due to the high costs of electrode materials, high-performing metal oxides are commercialized.

The progress of energy storage devices has extended impact to meet the energy demands of modern life. In particular, hybrid-ion capacitors and their production from recyclable sources have gained particular attention. The energy storage device manufacturers are constantly focusing on developing batteries with high energy density, power density, and long cycle-life. Thus, it is crucial to develop hybrid ion-capacitors that bring out the advantages of batteries on a single platform. Hence the Lithium-ion capacitors are used in everyday applications as it provides high energy density, power density, and long cycle-life.

However, lithium is a relatively less abundant element, which can limit the demand of energy in the world. Sodium-ion capacitors are a strong alternative, due to abundant availability of sodium and good storage capacity. The sodium-ion capacitors are also used in certain consumer electronics. However, the usage of sodium-ion batteries and capacitors has some demerits such as limited retention rate, poor cycling stability, and short life cycle.

Therefore, there is a need for a hybrid sodium-ion capacitor with high energy density, power density, and long cycle-life. There is a need for an eco-friendly method to provide an alternative and sustainable electrode material for sodium-ion capacitors. There is a need for a cost-effective method for the production of electrode materials. There is a need for an eco-friendly method for preparation of anode that yields enhanced conductivity.
Objectives of the invention:
The primary objective of the invention is to provide recycle paper based sustainable graphitic carbon nanosheets as competent anode material that enhances conductivity and energy storage capacity of sodium-ion capacitors.

Another objective of the invention is to provide sustainable approach for development of graphitic carbon nanosheets as competent anode material by recycling waste paper.

Other objective of the invention is to provide a hybrid sodium-ion capacitor that exhibits high energy density, power density, and long cycle-life.

Another objective of the invention is to develop a hybrid sodium-ion capacitor with high coulombic efficiency, and high stability.

Another objective of the invention is to develop anode and cathode that are synthesised by facile, low cost, low hazardous chemicals.

Another objective of the invention is to develop a hybrid sodium-ion capacitor that consists of NaCo2O4 cathode and graphitic carbon anode and provide an alternative for lithium batteries.

Yet another objective of the invention is to provide an eco-friendly method for preparation of anode that yields enhanced conductivity.

Further objective of the invention is to provide sodium-ion hybrid capacitors that use battery-type and capacitive-type electrode materials for overall enhancement of electrochemical energy storage.

Another objective of the invention is to design a sodium-ion hybrid capacitor with an advantage of electrochemical performance of battery and super-capacitor on single platform.

Another objective of the invention is to provide a sodium-ion rich electrolyte that helps in ion conductivity, prevents capacity fading and results in longer cycle-life.
Summary of the invention:
The present disclosure proposes a graphitic carbon derived from waste tissue papers for sodium-ion capacitors and their preparation method thereof. The following presents a simplified summary in order to provide a basic understanding of some aspects of the claimed subject matter. This summary is not an extensive overview. It is not intended to identify key/critical elements or to delineate the scope of the claimed subject matter. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.

In order to overcome the above deficiencies of the prior art, the present disclosure is to solve the technical problem to provide recycle paper based sustainable graphitic carbon nanosheets as competent anode material that enhances conductivity and energy storage capacity of sodium-ion capacitors.

According to an aspect, the invention provides a method for synthesis of graphitic carbon derived from waste tissue papers for hybrid sodium-ion capacitors. The recycle waste tissue paper based sustainable graphitic carbon provides enhanced conductivity and energy storage capacity for hybrid sodium-ion capacitors.

First, a waste tissue paper is washed with deionised water, and leached in dilute hydrochloric acid for 24 hours to obtain an acid leached tissue paper. Next, the acid-leached tissue paper is repeatedly washed with deionised water and ethanol to remove the hydrochloric acid from the acid-leached tissue paper, and then it is dried for 24 hours to obtain a dried tissue paper. Next, the dried tissue paper is burned to obtain black carbon ash and then, it is refined and ground. Next, the ground black carbon ash is exfoliated with different amounts of sodium dodecyl sulphate (SDS) to obtain a black carbon ash-SDS mixture.

Next, the black carbon ash-SDS mixture is treated with deionised water and ethanol for 5 hours of sonication to obtain a black sonicated carbon ash-SDS mixture. In specific, the black carbon ash-SDS mixture is treated with a solution comprising deionised water and ethanol in the ratio 1:1. Then, the black sonicated carbon ash-SDS mixture is centrifugated at 6000 rpm. Later, the black sonicated carbon ash-SDS mixture is filtered with a filter paper and dried at 60 °C for 24 hours to obtain graphitic carbon sheets.

Next, the graphitic carbon sheets are mixed with polyvinylidene fluoride binder, and conductive additive in a solvent to obtain a homogenous anode material. In specific, the conductive additive is acetylene black, increases conductivity of the homogenous anode material and the solvent is N-methyl-2-pyrrolidone. Finally, the homogenous anode material is coated and dried on a carbon cloth at 60 °C to obtain a graphitic carbon anode of the hybrid sodium-ion capacitor.

Further, 70 weight percentages of the graphitic carbon sheets are mixed with 20 weight percentages the acetylene black and 10 weight percentages of the polyvinylidene fluoride for fabrication of the graphitic carbon anode.

Further, 70 weight percentages of NaCo2O4 is mixed with 20 weight percentages of acetylene black and 10 weight percentages of polyvinylidene fluoride for fabrication of a NaCo2O4 cathode. The graphitic carbon anode and the NaCo2O4 cathode are assembled in a hybrid sodium-ion capacitor coin-cell with 1M NaOH electrolyte.

Further, objects and advantages of the present invention will be apparent from a study of the following portion of the specification, the claims, and the attached drawings.
Detailed description of drawings:
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention, and, together with the description, explain the principles of the invention.

FIG. 1 illustrates a process for synthesis of graphitic carbon derived from waste tissue papers for hybrid sodium-ion capacitors in accordance to an exemplary embodiment of the invention.

FIG. 2 illustrates SEM images of the surface of fabricated graphitic carbon exfoliated by different amounts of SDS and energy dispersive x-ray analysis (EDAX) of CWP-SDS-2 in accordance to an exemplary embodiment of the invention.

FIG. 3A illustrates CV curves of fabricated graphitic carbon electrodes exfoliated by different amounts of SDS in accordance to an exemplary embodiment of the invention.

FIG. 3B illustrates CV curves of carbon ash-SDS mixture with 2g of SDS at different scan rate in accordance to an exemplary embodiment of the invention.

FIG. 3C illustrates CV curves of NaCo2O4 in 1M NaOH electrolyte in accordance to an exemplary embodiment of the invention.

FIG. 4A illustrates electrochemical performance for CV curves of hybrid sodium-ion capacitor at different potential window in accordance to an exemplary embodiment of the invention.

FIG. 4B illustrates electrochemical performance for CV curves hybrid sodium-ion capacitor at different scan rate in accordance to an exemplary embodiment of the invention.

FIG. 4C illustrates electrochemical performance for charge-discharge profiles of hybrid sodium-ion capacitor at different current density in accordance to an exemplary embodiment of the invention.

FIG. 5A illustrates Ragone plot for hybrid sodium-ion capacitor at different potential window in accordance to an exemplary embodiment of the invention.

FIG. 5B illustrates cycle life of hybrid sodium-ion capacitor depicting coulombic efficiency, and capacity retention in accordance to an exemplary embodiment of the invention.

FIG. 5C illustrates Nyquist plot for sodium-ion capacitor before and after 10,000th cycle in accordance to an exemplary embodiment of the invention.
Detailed invention disclosure:
Various embodiments of the present invention will be described in reference to the accompanying drawings. Wherever possible, same or similar reference numerals are used in the drawings and the description to refer to the same or like parts or steps.

The present disclosure has been made with a view towards solving the problem with the prior art described above, and it is an object of the present invention to provide recycle paper based sustainable graphitic carbon nanosheets as a competent anode material that enhances conductivity and energy storage capacity of sodium-ion capacitors.

According to an exemplary embodiment of the invention, FIG. 1 refers to a method 100 for synthesis of graphitic carbon derived from waste tissue papers for hybrid sodium-ion capacitors. The recycled waste tissue paper based sustainable graphitic carbon for hybrid sodium-ion capacitors provides enhanced conductivity and energy storage capacity.

At step 101, a waste tissue paper is washed with deionised water, and leached in dilute hydrochloric acid for 24 hours to obtain an acid leached tissue paper. Then at step 102, the acid-leached tissue paper is repeatedly washed with deionised water and ethanol to remove the hydrochloric acid from the acid-leached tissue paper, and then it is dried for 24 hours to obtain a dried tissue paper. Later at 103, the dried tissue paper is burned to obtain black carbon ash and then it is refines and ground. From here on black carbon ash is referred as CWP through the description. At 104, the ground CWP is exfoliated with different amounts of sodium dodecyl sulphate (SDS) to obtain a CWP-SDS mixture. The amount of SDS is added to the CWP at different amount of 0.5 g, 1 g, 2 g, and 3.

The mixture of CWP added with no SDS is referred as CWP-SDS-0, 0.5 g of SDS is added to CWP is referred as CWP-SDS-05, 1 g of SDS is added to CWP is referred as CWP-SDS-1, 2 g of SDS is added to CWP is referred as CWP-SDS-2, and 3 g of SDS is added to CWP is referred as CWP-SDS-3.

At step 105, the CWP-SDS mixture is treated with deionised water and ethanol at for 5 hours of sonication to obtain a black sonicated CWP-SDS mixture. In specific, the black carbon ash-SDS mixture is treated with a solution comprising deionised water and ethanol in the ratio 1:1. Then, the black sonicated CWP-SDS mixture is centrifugated at 6000 rpm. At step 106, the black sonicated CWP-SDS mixture is filtered with a filter paper and dried at 60 °C for 24 hours to obtain graphitic carbon sheets.

At step 107, the graphitic carbon sheets are mixed with polyvinylidene fluoride binder, and conductive additive in a solvent to obtain a homogenous anode material. In specific, the conductive additive is acetylene black, increases conductivity of the homogenous anode material and the solvent is N-methyl-2-pyrrolidone. Finally at step 108, the homogenous anode material is coated and dried on a carbon cloth at 60 °C to obtain a graphitic carbon anode of the hybrid sodium-ion capacitor.

According to another exemplary embodiment of the invention, a mixture of sodium nitrate and cobalt nitrate is mixed in 1:2 ratios at 80°C and fuelled with urea to obtain a sol-gel. The sol-gel is subjected to heat at 800°C for 4 hours to obtain powder NaCo2O4, and it is ground to obtained uniform powder NaCo2O4. The 70 weight percentages of uniform powder NaCo2O4 is mixed with 10 weight percentages of polyvinylidene fluoride, and 20 weight percentages of acetylene black in N-methyl-2-pyrrolidone solvent to obtain a homogenous cathode material. Finally, the homogenous cathode material is coated and dried on a carbon cloth at 60 °C to obtain a NaCo2O4 cathode of the hybrid sodium-ion capacitor. The graphitic carbon anode and the NaCo2O4 cathode are assembled in a hybrid sodium-ion capacitor coin-cell with 1M NaOH electrolyte.

According to another exemplary embodiment of the invention, the graphitic carbon samples exfoliated by different amounts of SDS are examined by powder X-ray diffraction using a diffractometer equipped with CuKa radiation of wavelength 1.5184 * 10-10 meters. The diffraction data are collected in the 2? range of 10° - 80°, and at a scan rate of 4° per minute. The XRD pattern confirms the extracted samples of the graphitic carbon are graphene. All the samples obtained by different amounts of SDS have carbon peaks in the X-ray diffraction.

According to another exemplary embodiment of the invention, Raman spectra of extracted samples of graphitic carbon exfoliated by different amounts of SDS are recorded using a Raman spectroscopy. It is observed that the Raman spectrum of the graphitic carbon has two intense peaks of ID and IG. The high intense peaks near 1305 cm-1 and 1594 cm-1 are ascribed to D and G bands of the graphene. The peaks are noticeable, as the SDS amounts increase from SDS-0 to SDS-3, which confirms a dominant graphitic nature in the samples. The surfactant SDS is intercalated into the layers of carbon during exfoliation and formed graphitic carbon sheets.

According to another exemplary embodiment of the invention, FIG. 2 refers to SEM images of the surface of fabricated graphitic carbon exfoliated by different amounts of SDS and energy dispersive x-ray analysis (EDAX) of CWP-SDS-2. A scanning electron microscope (SEM) is used to examine the morphology and composition of the prepared samples of graphitic carbon.

From the SEM images, it is observed that the CWP in spherical morphology, where the SDS treatment in liquid exfoliation has tuned the CWP spheres into layered sheets. The CWP-SDS-2 (SDS added amount 2 g) is well exfoliated to free sheet type nature. The CWP-SDS-3 looks layered, but highly agglomerated. In conclusion, it is estimated that 1 gram of carbon ash with 2 grams of SDS (carbon ash to SDS in 1:2 ratio) is an optimized amount for exfoliation of carbon ash into layers. The EDAX profile is recorded to determine the elements present in the graphitic carbon sample. The EDAX profile shows that the peaks corresponding to sodium, sulfur, oxygen, and carbon are visible.

According to another exemplary embodiment of the invention, every electrochemical study is conducted in aqueous 1M NaOH. To determine the electrochemical characterization of graphitic carbon samples, a working cathode is prepared from a slurry of 70 weight percentages of extracted NaCo2O4, 20 weight percentages of carbon black, and 10 weight percentages polyvinylidene fluoride (PVDF) binder using N-methyl-2-pyrrolidone as a solvent. Similarly, a working anode is prepared from a slurry of 70 weight percentages of graphitic carbon sheets, 20 weight percentages of carbon black, and 10 weight percentages polyvinylidene fluoride (PVDF) binder using N-methyl-2-pyrrolidone as the solvent.

The obtained homogenous slurry is coated on a carbon cloth substrate as a current collector, with an exposed area of one square centimeter and dried overnight at 60 °C. Using an electronic balance, the mass of the coated carbon cloth and the mass of the uncoated carbon cloth are measured and their difference is calculated to find the mass of active material. The active mass of the working electrodes is kept at 2 mg cm-2. A three-electrode cell is constructed with the coated carbon cloth as working electrode, platinum as a counter electrode with the exposed area of one square unit, and Ag/AgCl as a reference electrode.

According to another exemplary embodiment of the invention, a proto type coin cell of hybrid sodium-ion capacitor is fabricated by using the NaCo2O4 as positive electrode and the graphitic as a negative electrode, where Whatman filter paper soaked in NaOH, is used as separator with few drops of 1M NaOH electrolyte.

Cyclic voltammetry (CV) studies are carried out at different scan rates and the galvanostatic charge-discharge cycles are carried out at different current densities. The cycle-life data of the electrode are recorded for 10,000 charge-discharge cycles. The electrochemical impedance is recorded in the frequency range of 0.01 Hz - 100 kHz with an excitation potential of 10 mV. All the electrochemical characterizations are carried out using an electrochemical workstation at room temperature.

According to another exemplary embodiment of the invention, FIG. 3A refers to CV curves for of fabricated graphitic carbon electrodes exfoliated by different amount of SDS. The electrochemical performance is examined by the CV study in 1M NaOH in the three-electrode cell configuration. Quasi-rectangular CV curves are plotted in a potential range of 0 V to -1 V at 50 mV s-1, which indicates that the graphitic carbon electrode generated from the waste papers is electrochemically active and experienced definite capacitive nature change storage.

The CWP-SDS-2 exhibited higher current and charge storage than other graphitic carbon samples, which proves the morphology distribution of the graphitic carbon samples. The addition of SDS and ultra-sonication resulted in the exfoliation of the graphitic carbon, which leads to the activation of the electrode material. The CWP-SDS-05 has higher electrochemical activity than CWP-SDS-0. With the increase in the amount of SDS, the current is reduced in the electrode. This concludes that a higher amount of SDS is not good for electrochemical performance.

According to another exemplary embodiment of the invention, FIG. 3B refers to CV curves of CWP-SDS-2 at different scan rate. The CV study is conducted at various scan rates such as 10, 20, 40, 60, 80, and 100 mV s-1 for the CWP-SDS-2 electrode and CV curves are obtained as shown in FIG. 3B. The current of the graphitic carbon layers in the aqueous electrolyte of 1M NaOH is increased with the scan rate from 10 to 100 mV s-1.

According to another exemplary embodiment of the invention, FIG. 3C refers to CV curves of NaCo2O4 in 1M NaOH electrolyte. The electrochemical nature of fabricated cathode NaCo2O4 is examined in 1M NaOH and CV curves are obtained. Quasi-rectangular shape CV curves are observed in all the scan rates in potential window 0 to 0.5 V. The specific capacitance of the graphene electrode is calculated from the charge-discharge profiles using the following formula:
Cs= (I×t)/(m×V)
Where Cs is specific capacitance (F g-1), I is the current (A), t is discharge time (s), m is the active mass (g) and V is a potential window (V). The capacitance of both the cathode and anode is calculated and then charges are balanced for the fabrication of a two-electrode configuration.

According to another exemplary embodiment of the invention, FIG. 4A refers to CV curves for electrochemical analysis of hybrid sodium-ion capacitor at a different potential window. The electrochemical analysis of the cathode NaCo2O4 and graphitic carbon anode i.e., CWP-SDS-2 in the three-electrode cell configuration shows that the asymmetric hybrid sodium-ion capacitor works at a wide potential window in 1M NaOH. Therefore, the CV curves for the hybrid sodium-ion capacitor fabricated in the form of coin cells are performed at different potential windows at a scan rate of 50 mV s-1. The CV curves for electrochemical analysis implies that the hybrid sodium-ion capacitor is capable of operating up to a potential of 1.6 V, which states that 1.5 V is the optimum temperature for the aqueous sodium-ion capacitor.

According to another exemplary embodiment of the invention, FIG. 4B refers to electrochemical performance for the CV curves of the hybrid sodium-ion capacitor are recorded at different scan rates in the optimized potential window of 0- 1.5 V.

According to another exemplary embodiment of the invention, FIG. 4C refers to electrochemical performance for the CV curves charge discharge profiles of the hybrid sodium-ion capacitor at different current density. The charge-discharge profiles are recorded for the fabricated coin cell hybrid sodium-ion capacitor at different current densities in a potential window of 0-1.5 V. The obtained asymmetric charge and discharge profiles substantiate the CV data. Clear plateau is observed during the charging and discharging process, confirming the hybrid nature of charge storage in the hybrid sodium-ion capacitor. From the charge-discharge profiles, the energy density and power density of the hybrid sodium-ion capacitor are calculated by using the formulae:
E = 0.5×C ?(?V)?^2
P = E×3600/ ?t
Where E is energy density (W h kg-1), C is the specific capacitance of the hybrid device, ?V is potential window and P is power density (W kg-1).

According to another exemplary embodiment of the invention, FIG. 5A depicts Ragone plot for the fabricated coin cell hybrid sodium-ion capacitor. The fabricated coin cell hybrid sodium-ion capacitor delivers the energy density of 35.8 W-h kg-1 at a power density of 1500 W kg-1. Further, the fabricated coin cell hybrid sodium-ion capacitor exhibited energy density of 6.25 W h kg-1 at power density of 7500 W kg-1.

According to another exemplary embodiment of the invention, FIG. 5B depicts cycle life of hybrid sodium-ion capacitor depicting coulombic efficiency. The life-cycle data of the fabricated coin cell hybrid sodium-ion capacitor with coulombic efficiency and capacity retention for 10,000 cycles. The capacity retention is at 99 % till 10,000 cycles, where fabricated coin cell hybrid sodium-ion capacitor exhibits coulombic efficiency of 94.4% at 10,000th cycle. Therefore, the fabricated coin cell hybrid sodium-ion capacitor exhibits excellent stability.

FIG. 5C depicts Nyquist plot for the fabricated coin cell hybrid sodium-ion capacitor before and after the 10,000th cycle.

Numerous advantages of the present disclosure may be apparent from the discussion above. In accordance with the present disclosure, recycle paper based sustainable graphitic carbon nanosheets as competent anode material that enhances conductivity and energy storage capacity of sodium-ion capacitors is disclosed.

The aqueous sodium-ion conducting electrolyte provides a wide potential window, better stability, and safety for the hybrid sodium-ion capacitor operation. The recycling graphitic carbon electrode is a competent electrode material for the hybrid sodium-ion capacitor. The hybrid sodium-ion capacitor provides the best alternative to lithium batteries, as the graphitic carbon electrode used in hybrid sodium-ion capacitors are cost-effective and provide high power density. The mass production of hybrid sodium-ion capacitors assures industrialists its achievable usage for advanced electronics.

The proposed sustainable method reduces tissue paper waste and recycles it to make battery-type and capacitive-type electrode materials for the overall enhancement of electrochemical energy storage. Since, the electrode is made of sodium which is an abundant material, results in the reduction of the overall cost. The sodium-ion rich electrolyte helps in ion conductivity, prevents capacity fading, and results in a longer cycle-life. The proposed eco-friendly method is less hazardous and time-saving.

It will readily be apparent that numerous modifications and alterations can be made to the processes described in the foregoing examples without departing from the principles underlying the invention, and all such modifications and alterations are intended to be embraced by this application.