The present invention relates to the field of electrode materials for energy
storage devices like Sodium ion (Na-ion) batteries. More particularly, the present
invention relates to a facile, cost-effective and industrially scalable method for
5 cattle manure derived hard carbon as electrode material for sodium ion batteries
and supercapacitors.
BACKGROUND OF THE INVENTION
[002] Sodium ion batteries (SIBs) present a great potential alternative for high
cost and scarce available Li-ion batteries for electric vehicles and grid energy
I 0 storage applications. However, the commercial success of SIBs needs electrode
materials having high performance, abundance and low cost.
[003] Carbon materials, being one of the most abundant elements in earth, also
showed potential as anode for sodium ion batteries. Unlike in lithium-ion
batteries, graphite showed very poor electrochemical performance for SIBs due to
15 poor intercalation of sodium ions in graphitic sheets. However, the performance
can be improved by using carbon having sufficient porosity and disordemess in
which sodium ions can intercalate-deintercalate easily. Biomass derived hard
carbon using bleached pulp, oak leaves, peat moss, banana peels, oatmeal, algal
blooms, sucrose etc. having different chemical compositions showed good
20 capacity and cyclability in sodium ion batteries. Also, cattle manure derived
carbon has shown decent performance as electrode material for Supercapacitors.
25
[004] In India, almost 70% of population lives in rural areas where cow is a major
cattle source and generates 9-15 kg of manure per day. As per 2019 Livestock
Census report, there are 145.12 million female cows in India out of which 98.17
million cows are indigenous and 46.95 million cows are crossbreed. Cattle plays a
very important role in socio-economic value of Indian villages. Cattle manure is
generally used as fertilizer in agriculture, plastering of walls and floor for
insulation purposes, as a fuel for cooking purposes, burnt cow dung as mosquito
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repellant etc. Dried cattle manure mainly consists of hydrocarbons with traces of
nitrogen, phosphorous, potassium, silicon dioxide and other elements. Cattle
manure is a biological waste which is usually discarded or used as combustion
material which contributes to carbon emissions in the atmosphere. In India, nearly
5 2 billion kg of cattle manure is produced every day. Using it as potential electrode
material for sodium ion batteries cannot only help to mitigate carbon emissions
but can also help to improve socio-economic value ofrurallndia.
[005] Publication No. CN1 04445192 relates to a novel method for prepanng
activated carbon from cattle manure. The influence of related factors on the
1 0 absorbability of the prepared activated carbon in the preparation process is
inspected to detect the optimal technological parameters and preparation
conditions for preparing activated carbon from cattle manure, so that the activated
carbon prepared from cattle manure can satisfy the relevant standard, can
implement large-scale popularization and application, and can generate economic
15 benefit, social benefit and ecological effect. The method has the following
advantages: the raw material for preparing the activated carbon has wide resources
and low price, thereby· satisfying the requirements for pollution source emission
reduction; and the prepared activated carbon has favorable adsorption effects in
the aspect of wastewater treatment.
20 [006] Publication No. CN 111087054 relates to an electro-adsorption desalination
electrode synthesized through carbonization of reed straw and a preparation
method thereof. The preparation method comprises the following steps: subjecting
reed straw to pretreating, cleaning, drying, smashing and screening to obtain reed
straw powder, then mixing the obtained reed straw powder with KOH according
25
30
n...,a .:.:.:.t. ...U...T..
to a certain mass proportion, adding a proper amount of deionized water, and
carrying out water bath heating and stirring; conducting drying to obtain a dried
mixture, putting the dried mixture into a tubular heating furnace, keeping the dried
mixture for 1 hour at a temperature of 600 DEG C, 700 DEG C and 800 DEG C
respectively, adding a proper amount of a hydrochloric acid solution into obtained
biomass charcoal powder, and carrying out neutralizing and cleaning to obtain
- 3 -
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0 .....
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0 ..........
0
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0
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-::1'
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r..'.\.!,:.:_ .I_ lrU.. .aT. .
final biomass charcoal powder; and m1xmg absolute ethyl alcohol,
polytetratluoroethylene and the final biomass charcoal powder, carrying out
heating in a water bath and conducting stirring at the same time, pressing the paste
of the obtained mixture on a stainless steel net through a hot press, and boiling
5 and drying a pressed electrode plate so as to obtain a biomass charcoal electrode
plate for capacitive deionization.
[007] Publication No. CNll 0240160 relates to a preparation method of a borondoped
biomass porous carbon nano electrode material for a sodium ion battery.
The method comprises the following steps: cleaning biomass waste successively
10 with a boric acid solution and alcohol, performing drying and grinding to obtain
powdery A; adding a boric acid solution into the powdery A, and performing
heating stirring to obtain a mixture B; moving the mixture B into a hydrothermal
induction kettle, adding copper foil as an induction source, moving the
hydrothermal induction kettle into a hydrothermal induction heating device,
15 performing a reaction, performing cooling to a room temperature, taking out the
copper foil, scraping the obtained product, performing cleaning by using
deionized water and ethanol, performing suction filtration, and performing drying
to obtain powdery C; mixing the powdery C and a boron source, and performing
ball milling to obtain powdery D; performing segmented calcination on the
20 powdery Din a protective atmosphere, performing cooling to a room temperature,
performing cleaning by using deionized water and ethanol on the obtained
product, performing suction filtration, and performing drying to obtain an E; and
performing activation on theE to obtain the boron-doped biomass porous carbon
nano material.
25
30
[008] Publication No. CNI 09950057 relates to a method for preparing a highefficacy
super capacitor material by a heavy metal related biomass, and aims at
searching for a proper resource for heavy metal related plant bodies at present.
Plant bodies rich in heavy metal in a general mine are sampled (in a five-point
sampling method), the collected plant bodies (including the roots, stems and
leaves) are preprocessed by cleaning, drying crushing and drying, and a
...,. ...'.1. '
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preparation method for obtaining the high-efficiency porous carbon material by .
dissolving, activating, and pyrolyzing the dried plant leaf powder is provided. The
heavy metal transferred by plants can be fixed, and the material can serve as an
electrode material of a super capacitor to store energy.
5 [009] Publication No. CN109755572 relates to an energy storage electrode based
on a sodium alginate (SA) modified hard carbon active material and a preparation
method thereof, belonging to the technical field of electrode materials. The
method of the invention includes the following steps of: performing multi-stage
heating on the acid-washed and dried coconut fiber, further decomposing the
I 0 coconut fiber to obtain a hard carbon material with a nano nearly parallel multichannel
structure, and then modifYing the hard carbon material by adopting
sodium alginate to prepare an electrode.
[010] Publication No. CN106517130 relates to a method for preparmg Iron
hydroxyphosphate micro-nano powder material from phosphorus-rich biomass
15 relates to the technical field of application of micro-nano materials and biomass
materials. The iron hydroxyphosphate micro-nano powder material is prepared
mainly by hydrothermal synthetic reaction of iron chloride solution and
phosphorus-rich biomass. If fish scales and animal bones are used as reaction
materials, the prepared micro-nano powder material is respectively of micro-nano
20 sphere and polyhedron in microstructure. Conventional soluble iron salts and
waste phosphorus-rich biomass are used as reaction materials herein to
successfully prepare the iron hydroxyphosphate micro-nano powder material via
one step through hydrothermal synthetic reaction. lt is proved through serial
characterizations that the prepared hydroxyphosphate micro-nano powder material
25 has the characteristics such as narrow particle size distribution and good
performance stabi I ity.
[011] Publication No. CN I 09727786 relates to an electrode material for a lithium
ion supercapacitor. The electrode material comprises a biomass-based activated
carbon as a cathode material and a porous carbon/tin dioxide composite material
- 5 -
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0 .....
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-::1'
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>'T. .M t"'' nl::l UT I ~ iJ lo.. ._ II I ....
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as an anode material, and the mass ratio of the cathode material and the anode
material in the lithium ion supercapacitor is 0.5-4:1.
[012] Publication No. CN 1 09319762 relates to a preparation method for a jack
fruit kernel derived porous carbon material. The preparation method comprises the
5 following steps: using a jack fruit kernel as a raw material, and using MgN03 as
an activating agent, through a simple dipping method, preparing a biomass porous
carbon material precursor, and calcining at a high temperature and under a
nitrogen atmosphere, to obtain a final product.
[013] IN Publication No. 1933/DELNP/20 15 relates to process for prepanng
10 magnetic activated carbons comprising the steps of a) treating an aqueous solution
comprising a biomass hydrothermally at autogenic pressure at a temperature 180
and 250°C under acidic conditions in the presence of iron ions to obtain a
precursor product b) activating the precursor product obtained in step a) by
mixing an activating agent at elevated temperatures between 550 and 850°C for a
15 period up to 9h. The invention also relates to magnetic activated carbon prepared
according to said process and use of the carbon for separation and storage of gases
and purification of liquids. Further the invention relates to a method for separation
of particles from a liquid and/or a gas and method for regenerating magnetic
activated carbon by heating using an oscillating electromagnetic field.
20 [014] Publication No. CNll 07523 79 relates to a preparation method of a one-step
formed biochar cathode, and belongs to the field of microbial fuel cells. The
method comprises the steps of firstly, preprocessing a reed raw material; secondly,
canying out oxidation forming on the biomass material, wherein the carbonization
temperature ranges from 700 DEG C to 800 DEG C; and fmal.ly, washing, drying
25 and storing to obtain the reed biochar formed electrode material, testing the
electrochemical performance, and comparing the performance of a reactor before
and after the prepared material replaces a commercial carbon felt material to
operate a sediment microbial fuel cell.
- 6 -
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.0. ..
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..0.. ....
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-::1'
..1...1....') -.... 0
[015] Publication No. CNI04787747 relates to a method for prepanng a
multiwalled carbon nanotube through mtcrowave enhanced fast pyrolysis of
biomass and/or carbonaceous organic waste. The method comprises the following
steps: biomass, carbonaceous organic waste, a mixture of the biomass and
5 carbonaceous organic waste or a mixture of the biomass and carbonaceous organic
waste uniformly mixed with a microwave absorbent is placed in a reaction vessel
in a microwave cavity; an inert gas is introduced into the reaction vessel until an
oxygen-free environment is formed; the microwave input power is adjusted to be
higher than 500w, and the reaction vessel is heated to 400-1,500 DEG C for a
10 pyrolytic reaction; the multiwalled carbon nanotube is obtained after the reaction.
[016] Publication No. US20 14349200 relates to a method for highly efficiently
decomposing and purifying biomass, organic/inorganic compounds, waste, waste
fluids, and environmental pollutants, by harnessing a catalyst action without
applying any light, and simultaneously generate electricity. First provided a
15 composite three-layered anode which has a constitution of conductive electrode
base layer, porous semiconductor layer, and catalyst layer, and then immersed the
composite anode in a liquid phase such as an aqueous solution or suspension that
contains as the fuel at least one of or a mixture of biomass, biomass waste, and
organic/inorganic compounds, and a counter cathode is disposed for oxygen
20 reduction in the liquid phase, and oxygen is supplied into the liquid phase and
thereby conducted the fuel cell reaction and the fuel is decomposed and electricity
is generated without applying external energy.
25
30
[017] Publication No. JP20 I 01944 72 relates to a method of designing a highly
efficient cell and a reaction tank and also to provide a practical application method
therefor, in an apparatus and an element for irradiating various biomass and
biomass waste with light such as sunlight to optically and completely decompose
and clean them and for simultaneously generating electric power. In the bio
photochemical cell, a unit combining an optical anode made of a porous
semiconductor, which is soaked in a liquid such as water including an electron
donor as various biomass and biomass waste, etc., as a working electrode for
- 7-
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-::1'
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~
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-::1'
1.1') .......... -..... 0
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0
performing photochemical reaction or photo electrochemical reaction, with a
cathode as a counter electrode for performing oxygen reduction reaction is
installed in a part of a large reaction tank so that the electrically conductive glass
side of the optical anode is on the outer side.
5 [018] IN Publication No. 9442/DELNP/2014 relates to biogenic activated carbon
compositions disclosed herein comprise at least 55 wt% carbon some of which
may be present as graphene and have high surface areas such as Iodine Numbers
of greater than 2000. Some embodiments provide biogenic activated carbon that is
responsive to a magnetic field. A continuous process for producing· biogenic
10 activated carbon comprises counter currently contacting by mechanical means a
feedstock with a vapor stream comprising an activation agent including water
and/or carbon dioxide; removing vapor from the reaction zone; recycling at least
some of the separated vapor stream or a thermally treated form thereof to an inlet
of the reaction zone(s) and/or to the feedstock; and recovering solids from the
15 reaction zone(s) as biogenic activated carbon.
[019] Publication No. CN110642249 relates to a preparation method of a carbonbased
electrode material and an application thereof, belonging to the field of
electrode materials. The preparation method of the carbon-based electrode
material comprises the following steps of: taking biomass waste and cutting the
20 biomass waste into required shapes or molds to obtain biomass materials with
shapes or molds; drying the biomass material with a shape or mold to obtain the
biomass material with a fixed shape or mold; the biomass material with a fixed
shape or mold is directly put into a tubular furnace, heated and carbonized under a
protective gas atmosphere, and the treated biomass material is cooled to room
25 temperature under a protective gas atmosphere to obtain a whole carbon-based
electrode material.
[020] Publication No. CN109133049 relates to a preparation method of a
biomass-based activated carbon material with a porous channel and a hierarchical
pore structure. Green bristle grass is used as a raw material, and is repeatedly
- 8 -
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I
-::1'
0
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0 .....
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-::1'
0 ..........
0
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0
~
0
-::1'
1.1') .......... -..... 0
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0
N
>1.TA. n n I ....
0 z I
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0
r..'.\, 1..:.:. :!. _U.,.T_
washed with acetone and deionized water to obtain a clean precursor material, the
above green bristle grass precursor material is pre-carbonized in a protective
atmosphere for a period of time to obtain a biomass carbonized sample, the
sample is mixed with KOH particles, thoroughly mixed with the deionized water
5 and dried, a mixture is placed in a tubular carbonization furnace, the mixture is
heated at a high temperature in an inert atmosphere, naturally cooled to room
temperature and washed successively with the deionized water and dilute
hydrochloric acid, finally filtering is conducted, washing is continuously
conducted with the deionized water until a filtrate is neutral, and drying is
10 conducted to obtain the activated carbon sample.
[021] Publication No. CN108059144 relates to hard carbon prepared from
biomass waste bagasse as well as a preparation method of the hard carbon and an
application of the hard carbon using as a negative electrode material of sodium ion
batteries and potassium ion batteries. The preparation method takes the bagasse as
15 a raw material, mechanical ball milling is performed, high-temperature treatment
is performed, and therefore the hard carbon is prepared. The hard carbon provided
by the invention exhibits excellent electrochemical performance when being used
as the negative electrode of the sodium ion batteries and the potassium ion
batteries; at the current density of 50mA/g, the sodium storage specific capacity is
20 still 267.7mAh/g after 200 cycles.
25
[022] The article entitled "Carbonized cow dung as a high performance and low
cost anode material for bioelectrochemical systems" by HuajunFeng, Zhipeng
Ge, Wei Chen, Jing Wang, Dongsheng Shen, YufengJia, Hua Qiao,
XianbinYing, Xueqin Zhang and Meizhen Wang; Front. Microbiol.; 30
November 2018 talks about the high-performance anode formed from carbonized
cow dung for bio electrochemical systems. Thermal gravimetric analysis showed
that the CD carbonization process started at 300°C and ended at approximately
550°C; the weight was reduced by 51%. After a heat-treatment at 800°C for 2 h,
the treated CD featured a good conductivity and a high specific surface area. The
- 9-
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0 .....
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0 ..........
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C>)\-r .n. ...n...
0 z I
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max 1m urn current density of 11.7 4 ± 0.41 A m-2 was achieved by CD anode
(heated at 800°C), which remained relatively stable from more than 10 days.
[023] The article entitled "Waste-to-wealth: bio-waste valorization into valuable
bio(nano)materials" by Chunping Xu, Mahmoud Nasrollahzadeh, Maurizio
5 Selva, Zahra Jssaabadi and Rafael Luque; Chemical Society Reviews, Issue 18,
2019 aims to provide an overview of present trends and future potential in the
conversiOn of residues from different food sectors into valuable
bio( nano )materials.
[024] The article entitled "Reusing cow manure for the production of activated
I 0 carbon using potassium hydroxide (KOH) activation process and its liquid-phase
adsorption performance" by Wen-Tien Tsai, Po-Cheng Huang and Yu-Quan Lin;
Processes 2019, 7(1 0), 737; 18 September 2019 talks about the cow manure (CM)
reused as a potential precursor in the production of activated carbon (AC) using a
potassium hydroxide activation process at different temperatures (i.e., 500, 600
15 and 700 oC). The optimal activated carbon from cow manure (CM-AC) with high
specific surface area (ca. 950 m2 /g) was further investigated for its adsorption
performance in the removal of a model compound (i.e., methylene blue) from
aqueous solution with various initial concentrations and adsorbent dosages at 25
oC. It was found that the resulting AC could be an effective adsorbent for removal
20 of cationic dye from aqueous solution in comparison with a commercial coalbased
AC.
25
[025] The prior arts as mentioned above, describe using manure as raw material to .
form porous carbon or activated carbon. However, it had never been explored to
synthesize hard carbon from it. Present invention presents a unique way to
synthesize hard carbon from cattle manure.
[026] Hence, present invention discloses a facile, cost-effective and industrially
scalable method for cattle manure derived hard carbon as a potential electrode
material for sodium ion batteries and supercapacitors.
- 10-
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OBJECTS OF THE INVENTION
[027] The principal object of the present invention is to provide a facile, costeffective
and industrially scalable method for cattle manure derived hard carbon
as a potential electrode material for sodium ion batteries and supercapacitors.
5 [028] Another object of the present invention is to provide an environmentally
safe method for preparation of electrode material.
[029] Yet another object of the present invention is to prepare a low cost electrode
material from biological waste.
[030] Still another object of the present invention is to provide electrode material
1 0 for sodium ion batteries and supercapacitors.
SUMMARY OF THE INVENTION
[031] Accordingly, in present invention a facile, cost-effective and industrially
scalable method for cattle manure derived hard carbon as a potential electrode
material for sodium ion batteries and supercapacitors is provided.
15 [032] For preparation of electrode material, the cattle manure is heated in a hot air
oven. Dried cattle manure is then ground into powdered form and mixed withan
acid solution. The acid mixed solution is then thoroughly washed with an aqueous
solution and vacuum dried. The dried sample is then calcined involving
single/multi-step controlled environment and heating/cooling processes.
20 BRIEF DESCRIPTION OF DRAWINGS
[033] It is to be noted, however, that the appended drawings illustrate only
typical embodiments of this invention and are therefore not to be considered
for limiting of its scope, for the invention may admit to other equally effective
embodiments.
25 [034] Figure 1 shows heating protocols for producing hard carbon .
- 11 -
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0
N ;;.Tnn
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0
[035] Figure 2 shows schematic of synthesis route.
[036] Figure 3 shows XRD pattern of prepared hard carbon.
[037] Figure 4 shows FE-SEM micrograph of cow manure derived hard carbon.
[038] Figure 5 shows specific capacity vs voltage plot of (a) HC at 0.1 C in a
5 potential range of 0.005-2.7 V (vs. Na/Na+). Cycle numbers are shown. (b)
Cyclabilitytest of HC at 0.1 C along with its Coulombic efficiency. 1 C = 250
rnA/g.
[039] Figure 6 shows electrochemical behavior of cow manure derived hard
carbon electrode in 2 M KOH aqueous electrolyte: (a) CV plots recorded at the
10 scan rate of 5, 15, 25, 50, 75, and 100 m V s-1, (b) GCD plots recorded at current
density of 1, 2, 3, and 5 A g-1. (c) Specific capacitances calculated from the GCD
curves recorded at various current density, (d) Nyquist plot.
DETAILED DESCRIPTION OF INVENTIONS:
[040] Present invention provides a facile, cost-effective and industrially scalable
15 method for cattle manure derived hard carbon showing as electrode material m
sodium ion batteries and supercapacitors in detail below.
20
25
[041] The invention is described in detail with reference to the examples
given below. The examples are provided just to illustrate the invention and
therefore, should not be construed to limit the scope of the invention.
EXAMPLES
[042] Example 1
[043] Synthesis of Cow Manure Derived Hard Carbon:
[044] Fresh cow manure was obtained from a village near Roorkee, India. The
manure was heated in a hot air oven at 80 °C. Dried cow manure was then grinded
into powdered form and 2.5 grams of it were mixed with 1.0 M hydrofluoric acid
.1.. .
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0 .....
CIO
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0 ..........
0
N
0
~
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0
~nn n~::t UT
.,.. I "'wJ ._, i.o.. t... I I ...&..
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(HF) solution via magnetic stirrer for 24 h at room temperature. The HF mixed
solution was then thoroughly washed with de-ionized (D.l.) water. The washed
material is then dried overnight at temperature of 80 °C and at pressure of 2* I o-3
torr.
5 [045] 1 gram of dried material is then calcined al atmospheric pressure via multistep
heating process in argon environment at 800 °C for 4h in a tubular furnace. It
was then naturally cooled to room temperature under argon gas.The multi-step
heating follows first heating the material to 350 °C in 2h 30 min followed by
heating at 350 °C for 3h. The third step heating process involves heating the
10 material to 600 °C from 350 °C in 1 h followed by heating at 600 °C for 2h. The
fifth step heating process involves heating the material to reaction temperature of
800 °C from 600 °C at ramping rate of 10 °C/min. The process of heating is shown
in Figure 1 and the whole synthesis procedure is shown in Figure 2 respectively.
[046] Material Characterization:
15 [047] The structural and characterization of the material was done using X-Ray
Diffraction (XRD, Rigaku SmartLab SE using CuKa 1.5406 A radiation). The
morphological ofthe material was done using Scanning Electron Microscopy (FESEM,
Carl Zeiss Gemini).
20
25
[048] Results and Discussion:
[049) Figure 3 represents X-Ray Diffraction (XRD) pattern of the synthesized
hard carbon from cow manure. XRD pattern shows presence of amorphous peaks
at 2e angles of 22° and 43°correspondingto (002) and ( 1 00) peaks of hard carbon,
respectively. The hump in those peaks represents disorderness in the carbon
structure, a proof for formation of hard carbon. Similar peaks were also observed
in the previously prepared hard carbon by bagasse (Publication CNl 08059144).
- 13-
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0 .....
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0 ..........
0
N
0
~
0
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N
0
~n n. nc:! u T
...,.. I "W' 11.oP .._ ._ I ! ...a..
0 z I
-::1'
0
[050] Figure 4 shows FE-SEM image of synthesized hardcarbon. The SEM
micrograph clearly show formation of pores in the synthesized material. This
represents formation of porous carbon after the synthesis process.
[051] Example 2
5 [052] Electrode Preparation and Cell Assembly (Sodium ion battery):
[053] For sodium storage properties assessment, the composite electrode is madeup
of synthesized hard carbon material, binder and carbon black in mass ratio of
70:15:15. A thick ink was made using the solvent i.e. 1-methyl 2-pyrro-lidone
(NMP, Sigma Aldrich, 98%) and then it was coated _onto a current collector
10 (thickness - 1 0-15 J.lm) before allowing it to get dried at 80oC in air to evaporate
the used solvent. The material coated substrate was then pressed between twin
roller and cut in to discs of the diameter of 16 mm diameter followed by demoisturizing
at 70oC before transferring to an Ar-filled glove box (M-Braun,
Germany).
15 [054] For making a Sodium ion (Na-ion) battery coin cell, standard stainless-steel
cups and lids fitted with a plastic 0-ring were used for the casing. Coin cells
(CR20 16; 20 mm diameter and 1.6 mm thick) comprised composite electrodes,
Na metal as counter electrode, glass filter fiber as the separator and 1 M NaCI04,
dissolved in ethylene carbonate (EC) and diethyl carbonate(DEC) (1 :1 by volume)
20 as the Na-ion conducting electrolyte. The electrode was placed at the center of the
cup which forms the positive terminal of the cell and wetted with a few drops of
the electrolyte. This was covered with the separator that is permeable to the Naions
but impermeable to particles of the composite electrode and electrons.
Circular Na-metal disc of the size ~ 16 mm diameter was placed centrally on the
25 separator. Then, a steel spring was placed on Na-metal disc and formed the
negative terminal of the cell. Finally, hermetic sealing was done with a
mechanical press. The weight of active material (HC)in the working electrode was
kept in the range of 1.0-2.0 mg.
- 14-
-Q)
C)
Ill
D..
Q) -1-- N
E....
0
-LL. M
0 .....
CIO
-::1'
0 ..........
0
N
0
~
0
-::1'
1.1') .......... -..... 0
N
0
.~l.'." 'lt'\ .....,
0 z I
-::1'
0
[055) Electrochemical characterization (Sodium ion battery):
(056) Galvanostatic charge-discharge cycling (GCD) study was performed at
room temperature by battery analyzer (MTI Corp. USA, BST8-WA).
(057] Sodium storage properties:
5 [058] To investigate the electrochemical behavior of the developed materials,
galvanostatic cycling tests were performed in sodium metal cells. Figure Sa shows
the electrochemical cycling performance of our novel customized hard carbon
(HC) electrode material.In terms of sodium-ion storage performance at 0.1 C,HC
delivered a reversible capacity of around 200 mAh g-1 in the potential range of
10 0.005 V - 1.0 V vs NaJNa+. Additionally, HC showed an excellent capacity
retention (-95%) at least till 50 cycles (Figure Sb).
[059] Example 3
[060] Electrode Preparation for Supercapacitor:
[061] We have also tested the supercapacitor performance of synthesized cow
15 manure derived hard carbon in three electrode system consisting of a working
electrode (active material), a counter electrode (platinum wire) and a reference
electrode (Hg/Hg2Clz) with 2 M KOH aqueous electrolyte. In order to prepare
electrode of cow manure derived hard carbon (active material), an ink-like
homogeneous slurry was prepared by mixing active material, binder and carbon
20
25
black with mass ratio of65:20:15 in an appropriate amount ofNMP with stirring
for 12 h. As prepared slurry was then uniformly coated onto 1 x 1 cm2 area of a
graphite sheet and then coated electrodes were dried at ~80 °C for ~ 12 h in a
vacuum oven. Here, the weight of active material in each electrode was ~0.9 mg
cm-2. These electrodes were utilized to test the electrochemical properties of the
synthesized materials in a three-electrode arrangement.
[062] Electrochemical characterization (Supercapacitor):
- 15-
-Q)
C)
Ill
D..
Q) -1-- N
E....
0
-LL. M
0 .....
CIO
-::1'
0 ..........
0
N
0
~
0
-::1'
1.1') .......... -..... 0
N
0
~n.n lniEI UT
+~~< 'WI' l!..:.d' n.- li- ll If..&:.
0 z I
-::1'
0
[063] The electrochemical measurements of working electrodes were examined in
terms of cyclic voltammetry (CV), galvanostatic charging-discharging (GCD) and
electrochemical impedance spectroscopy (EIS). The CV and GCD measurements
were performed with the potential window (~V) -1.0 to 0.0 Vat various low to
5 high scan rates and current density values. Some essential parameters such as
specific capacitance (Cs), imd electrochemical series resistance (ESR) were
calculated using the data of electrochemical measurements. The GCD was used to
calculate specific eapacitance (Cs) with the help of the following relation,
I~t
m~V
(1)
I 0 [064] where I = discharge current, m = mass of the active material, ~t = time for a
complete discharge, and~ V =potential window.
[065] Supercapacitor properties:
[066] The electrochemical behavior of the material in Supercapacitor is shown in
Figure 6. CV plots of the sample performed at 5, 15, 25, 50, 75, and 100 m V s·'
15 scan rates in the potential window -1.0 V to -0.2 V using Hg/Hg2Ch as reference
electrode are represented in Figure 6(a). It can be seen that shapes of all the CV
curves recorded at different scan rates are quasi- rectangular and quasi-symmetric
which directly indicates that both faradaic reactions and non-faradaic reactions are
involved during the charge-discharge process. Figure 6 (b) reveals the GCD
20
25
curves of the sample recorded at the current densities of 1, 2, 3, and 5 A g· 1• It can
be seen that all the GCD curves at various current densities are neither perfectly
symmetrical not perfectly triangular in shape, which further verifies the CV
results. Figure 6 (c) shows the variation of specific capacitances calculated from
the GCD curves using equation (1) as a function of current densities. The
calculated values of specific capacitance of the sample are 198, 153, 130, and 1 07
Fg·1 at 1, 2, 3, and 5 A g·1, respectively. From Figure 6 (c), it can be noticed that
the numerical value of specific capacitance decreases with an increase in the
current density values because at higher current densities electrolyte ions don't get
- 16-
-Q)
C)
Ill
D..
Q) -1-- N
E...
0
-LL. M
.0. ..
CIO
-::1'
..0.. ....
0
N
0
~
0
-::1'
..1...1....') -.... 0
N
0
sufficient time to interact with the active electrode material. The Nyquist plots of
the synthesized sample is shown in Figure 6 (d). The inclination of the Nyquist
curve gives the information about diffusion rate of electrolyte ions into the active
electrode material. Further, the intersection point of the Nyquist curve at the real
5 impedance axis (Z') in the higher frequency region determines the value of
equivalent series resistance (ESR).
[067] Numerous modifications and adaptations of the system of the present
invention will be apparent to those skilled in the art and thus it is intended by
the appended claims to cover all such modifications and adaptations which
1 0 fall within the scope of this invention.

WE CLAIM:
l. A process for preparation of Hard Carbon using Cattle Manure as biomass
precursor comprising the steps of-
A. Drying the biomass precursor at a temperature m the range of 50°C to
1 00°C;
B. Grinding of product received after step A;
C. Mixing the obtained material in step B with an acid solution selected from
hydrofluoric acid (HF), phosphoric acid (HJP04) or hydrochloric acid
(HCI) having molar concentration between 0.1 M to 5.0M for 1 h to 48 h, at
a temperature between 25°C to 60°C;
D. Washing the material obtained in step C thoroughly with de-ionized (D.I.)
water;
E. Dry the washed material obtained in step D at low pressure of I o-2 to l o-3
torr and at appropriate temperature between 60°C to 1 00°C;
F. High temperature calcination of dried material obtained m step E,
involving single/multi-step controlled -environment (N2or Argon gas) andheating/
cooling processes, in the range of 700°C to 1600°Cfor 0.5h to l2h;
2. The process for preparing hard carbon using cattle manure as biomass
precursor according to claim l, wherein the biomass precursor from cattle
manure is selected from cow manure, bull manure, male or female buffalo
manure, male or female goat manure, male or female sheep manure or poultry
manure.
3. A carbonaceous electrode material for supercapacitor and rechargeable metalion
battery, prepared by the method as claimed in claims l-2 wherein the
rechargeable metal-ion battery is selected from lithium ion battery, sodium ion
battery, potassium ion battery, magnesium ion battery or calcium ion battery .
4. The carbonaceous electrode material as claimed in claim 3, wherein the
composite electrode for Sodium ion battery consists of synthesized hard
carbon material, binder and carbon black in mass percentage of (80 ± x): (1 0 ±
y): (10 ± z) respectively, where the values ofx, y, and z vary between 0 to 20
in such a way that proportional percentage sum of hard carbon material, binder
and carbon black remains hundred.
5. The carbonaceous electrode material as claimed in claim 3, wherein the
composite electrode for supercapacitor consists of synthesized hard carbon
material, binder and carbon black in mass percentage of (80 ± x): (1 0 ± y): (I 0
± z) respectively, where the values ofx, y, and z vary between 0 to 20 in such
a way that proportional percentage sum of hard carbon material, binder and
carbon black remains hundred.