1. Application in negative electrode binder
The binder has a great influence on the electrode performance of the battery, and a suitable binder can effectively improve the overall performance of the electrode and ensure the consistent contact between the active material, the conductive agent and the current collector, thereby improving the integrity of the electrode. As a binder, CMC can be widely used in different types of electrode materials such as lithium batteries, natural graphite, mesocarbon microspheres (MCMB), lithium titanate, tin-based silicon-based anode materials and lithium iron phosphate cathode materials, ensuring excellent coating processability of electrode slurry, complete and uniform coating, and improving battery capacity, cycle stability and cycle life to a certain extent. The specific effect of CMC in the application of negative binder is as follows:
The electrode active material, the conductive agent and the current collector are preferably bonded together.
The internal resistance of the cell is reduced, providing the desired electron conduction within the electrode.
Better thermal stability makes the battery cycle stable and cycle life improved.
Good electrochemical stability, stable with electrode materials and electrolyte properties.
The structure and volume of the positive and negative electrode active materials are to be changed during charge and discharge.
Improve the wettability of the electrolyte and promote the transfer of lithium ion interface.
Safe, environmentally friendly and low cost.
2. Application in graphite modification
CMC has a good coating effect on natural graphite, which can effectively improve the interface properties of natural graphite, inhibit the strong reduction reaction of electrolyte at the interface and prevent the structural delamination caused by the insertion of solvated ions into the graphite layer, improve the electrochemical properties of natural graphite, and effectively prevent the graphite from peeling off during charge and discharge, thus effectively improving the cycle stability of composite carbon materials and improving the stability and performance of batteries. The specific effects of CMC in the application of graphite modification are as follows:
When CMC is dissolved in water, the hydrophilic groups such as carboxymethyl group and hydroxyl group swell with water molecules first, and the molecular chain reunites. CMC can reduce the surface tension of water and adsorb on the surface of non-polar graphite by van der Waals force to improve the wettability of graphite particles.
It can prevent the co-insertion of solvated lithium ions and weaken the reduction reaction of solvent molecules on the carbon electrode.
After coating treatment, the cycling performance of graphite is obviously improved, and the capacity decay of graphite is effectively inhibited.
Can effectively improve the discharge platform and discharge capacity retention rate.
3. Application in negative electrode gel
CMC as a gelling agent can make the active substance and electrolyte form a stable and uniformly dispersed paste, so that the electrolyte can be uniformly maintained around the active substance particles, and the surface of the active substance particles can be uniformly and sufficiently covered with the electrolyte when the battery is discharged. At the same time, the uneven settlement of the active substance particles and the electrolyte during the storage of the paste can be prevented. In addition, the contact between the active substance particles and the current collector can be promoted, the generation of abnormal voltage drop when the battery is subjected to vibration and in use is improved. The specific effects of CMC in the application of gel agent for negative electrode protection are as follows:
Good stability, not easy to delamination, good battery storage performance.
The absorption rate of the electrolyte can be improved, and the internal resistance of the battery can be reduced.
Use at room temperature to prevent terminal voltage fluctuations at the end of intermittent discharge.
Better liquid retention, battery long-term room temperature or high temperature retention performance deterioration rate is low.
The negative electrode has almost no swaying in the gel state, and the performance is stable after the battery is dropped and vibrated.
With sodium acrylate, can effectively improve the battery high current discharge performance.