FIELD OF INVENTION
[001] The present disclosure generally relates to the field of electrochemical cells,
more specifically to dry electrode composites comprising a surface modified binder
for use in anodes of such cells.
5
BACKGROUND OF THE INVENTION
[002] In the field of electrochemical cells, particularly in the manufacturing of
batteries, the use of dry electrode composites is common. These composites
typically comprise an active material, a conductive carbon, and binders. The active
10 material, often graphite or silicon, is the primary component that interacts with the
electrolyte during the charge and discharge cycles of the battery. The conductive
carbon, such as Super P, carbon black, or carbon nanotubes (CNT), enhances the
electrical conductivity of the electrode, facilitating the movement of electrons
during the electrochemical reactions.
15 [003] Binders play a pivotal role in maintaining the structural integrity of the
electrode. They hold the active material and conductive carbon together, ensuring
that they remain in close contact for efficient electron transfer. Commonly used
binders include polyvinylidene difluoride (PVDF), polyacrylic acid (PAA),
carboxy methyl cellulose (CMC), poly(methyl methacrylate) (PMMA), polyvinyl
20 pyrrolidone (PVP), chitosan, and cross-linked silicone polymers.
[004] Among these binders, polytetrafluoroethylene (PTFE) is often used due to
its excellent chemical resistance and mechanical properties. Also, PTFE is known
to fibrillate, forming thin fibrous structures, when subjected to mechanical stress
during the electrode manufacturing process. This fibrillation can affect the overall
25 performance of the electrode. However, the employment of fluorinated polymers,
such as PTFE for binder purposes, can detrimentally affect the performance of the
batteries. This reduction in electrochemical performance can be attributed towards
the high reactivity of PTFE with Li ions to form LiF salts and thereby increase in
resistance and low cycle performance. There are many strategies adopted to mitigate this reactivity issue, some of them being replacement of PTFE with other
polymers; and modifications of the Li based material to reduce the reactivity.
However, the replacement of PTFE with any other low reactive binder exhibited
tediousness in fibrillation and inconvenience in selection and optimization of
5 weight ranges.
[005] Therefore, there is a need in the art to develop an electrode material with
better electrochemical performance by reducing the reactivity of PTFE with
Lithium ions in the anode.
SUMMARY OF INVENTION
10 [006] In a first aspect of the present disclosure, there is provided a dry electrode
composite comprising a thiamine modified fluorinated fibrillating binder; an
adhesive binder; an active material; and a conductive carbon; wherein the thiamine
modified fluorinated fibrillating binder comprises a fluorinated fibrillating binder
and a thiamine compound (TA); and the thiamine compound is selected from
15 thiamine hydrochloride, thiamine monophosphate (ThMP), thiamine
pyrophosphate (TPP), thiamine triphosphate (ThTP), adenosine thiamine
diphosphate (AThDP), adenosine thiamine triphosphate (AThTP), or mixtures
thereof.
[007] In a second aspect of the present disclosure, there is provided a process of
20 preparing the dry electrode composite as disclosed herein, the process comprising:
(a) mixing an active material, a conductive carbon, and an adhesive binder to obtain
a mixture; and (b) adding a fluorinated fibrillating binder, followed by the addition
of a thiamine compound to the mixture to obtain the dry electrode composite.
[008] In a third aspect of the present disclosure, there is provided an anode
25 comprising the dry electrode composite as disclosed herein.
[009] In a fourth aspect of the present disclosure, there is provided an
electrochemical cell comprising: a) an anode comprising the dry electrode
composite as disclosed herein; b) a cathode; and c) an electrolyte.
[0010] These and other features, aspects, and advantages of the present subject
matter will be better understood with reference to the following description. This
summary is provided to introduce a selection of concepts in a simplified form. This
summary is not intended to identify key features or essential features of the claimed
5 subject matter, nor is it intended to be used to limit the scope of the claimed subject
matter.

/We Claim:
1. A dry electrode composite, comprising:
a) a thiamine modified fluorinated fibrillating binder;
b) an adhesive binder;
5 c) an active material; and
d) a conductive carbon;
wherein the thiamine modified fluorinated fibrillating binder comprises a
fluorinated fibrillating binder and a thiamine compound; and the thiamine
compound is selected from thiamine hydrochloride, thiamine monophosphate
10 (ThMP), thiamine pyrophosphate (TPP), thiamine triphosphate (ThTP),
adenosine thiamine diphosphate (AThDP), adenosine thiamine triphosphate
(AThTP), or mixtures thereof.
2. The dry electrode composite as claimed in claim 1, wherein the fluorinated
fibrillating binder is polytetrafluoroethylene.
15 3. The dry electrode composite as claimed in claim 1, wherein the thiamine
modified fluorinated fibrillating binder comprises the fluorinated fibrillating
binder and the thiamine compound in a weight ratio range of 1:1 to 20:1.
4. The dry electrode composite as claimed in claim 1, wherein the thiamine
modified fluorinated fibrillating binder is in a weight range of 0.1 to 1.5% with
20 respect to the total weight of the dry electrode composite.
5. The dry electrode composite as claimed in claim 1, wherein the thiamine
modified fluorinated fibrillating binder comprises the thiamine compound in a
weight range of 0.05 to 0.5%; and the fluorinated fibrillating binder in a weight
range of 0.5 to 0.95% with respect to the total weight of the dry electrode
25 composite.
6. The dry electrode composite as claimed in claim 1, wherein the adhesive binder
is selected from polyvinylidene difluoride (PVDF), polyacrylic acid (PAA),
carboxy methyl cellulose (CMC), poly(methyl methacrylate) (PMMA),
polyvinyl pyrrolidone (PVP), chitosan, cross-linked silicone polymers, or
mixtures thereof.
7. The dry electrode composite as claimed in claim 1, wherein the adhesive binder
is in a weight range of 0.75 to 1.25% with respect to the total weight of the dry
5 electrode composite.
8. The dry electrode composite as claimed in claim 1, wherein the active material
is selected from graphite, silicon, or mixtures thereof.
9. The dry electrode composite as claimed in claim 1, wherein the active material
is in a weight range of 96.5 to 98% with respect to the total weight of the dry
10 electrode composite.
10. The dry electrode composite as claimed in claim 1, wherein the conductive
carbon is selected from Super P, carbon black, carbon nanotubes (CNT), or
mixtures thereof.
11. The dry electrode composite as claimed in claim 1, wherein the conductive
15 carbon is in a weight range of 0.75 to 1.25% with respect to the total weight of
the dry electrode composite.
12. A process of preparing the dry electrode composite as claimed in claim 1, the
process comprising:
a) mixing an active material, a conductive carbon, and an adhesive binder to
20 obtain a mixture; and
b) adding a fluorinated fibrillating binder, followed by the addition of a
thiamine compound to the mixture to obtain the dry electrode composite.
13. The process as claimed in claim 12, wherein the process further comprises
processing the dry electrode composite in the form of a film; and laminating
25 on a current collector.
14. The process as claimed in claim 13, wherein the laminating is carried out at a
temperature in a range of 120 to 160 ℃.
15. An anode comprising the dry electrode composite as claimed in claim 1.
16. The anode as claimed in claim 15, wherein the anode has a peel strength in a
range of 0.03 to 0.06 kgF.
17. The anode as claimed in claim 15, wherein the anode has a conductivity in a
range of 1.1 to 2.5 mS/cm.
5 18. The anode as claimed in claim 15, wherein the anode exhibits up to 97% of
initial capacity for 50 cycles.
19. An electrochemical cell comprising:
a) the anode as claimed in claim 15;
b) a cathode; and
10 c) an electrolyte.