Guangdong Xiaowei New Energy Technology Co.,Ltd.

Study on preparation and performance of aqueous binder for lithium iron phosphate electrodes in lithium-ion battery CAO Jianing 1 GAO Xiang 1, 2 LUO Yingwu 1 SU Rongxin 3 Abstract: LiFePO 4 is a widely used cathode material for lithium-ion batteries. Polyvinylidenefluoride (PVDF), as a traditional organic solvent soluble binder, is still used in the preparation of LiFePO 4 cathode. The water-based binder which can be used in the preparation of LiFePO 4 cathode still needs to be further studied. A novel water-based binder PSEHA with different structures for LiFePO 4 cathodes was prepared via copolymerizing polystyrene (St) and 2-ethylhexyl acrylate (2-EHA) with a reactive emulsifier to improve the performance of lithium-ion battery. The influence of binder structure on battery performance was studied. Without unsaturated double bonds, PSEHA binder has good oxidation resistance. Its low swelling ratio can effectively prevent structural damage caused by excessive swelling, and the use of reactive emulsifiers can solve the residue of emulsifier. The LiFePO 4 cathode prepared with the optimal binder showed excellent electrochemical stability. After 100 cycles, the LiFePO 4 cathode in coin cells maintained stable cycling performance with retention of 96% at the rate of 1 C, while the SBR was only 93.9%. The capacity retention rate of the soft-packed full battery after 170 cycles at 1 C rate is still 98.9%. This new type of water-based binder is of great significance to promote the preparation of LiFePO 4 cathode in water-based systems. Keywords: electrochemistry；electrode binder；emulsions；polymers；acrylate binder；reactive emulsifier；LiFePO 4 cathode； lithium-ion battery

Study on preparation and performance of aqueous binder for lithium iron phosphate electrodes in lithium-ion battery CAO Jianing 1 GAO Xiang 1, 2 LUO Yingwu 1 SU Rongxin 3 Abstract: LiFePO 4 is a widely used cathode material for lithium-ion batteries. Polyvinylidenefluoride (PVDF), as a traditional organic solvent soluble binder, is still used in the preparation of LiFePO 4 cathode. The water-based binder which can be used in the preparation of LiFePO 4 cathode still needs to be further studied. A novel water-based binder PSEHA with different structures for LiFePO 4 cathodes was prepared via copolymerizing polystyrene (St) and 2-ethylhexyl acrylate (2-EHA) with a reactive emulsifier to improve the performance of lithium-ion battery. The influence of binder structure on battery performance was studied. Without unsaturated double bonds, PSEHA binder has good oxidation resistance. Its low swelling ratio can effectively prevent structural damage caused by excessive swelling, and the use of reactive emulsifiers can solve the residue of emulsifier. The LiFePO 4 cathode prepared with the optimal binder showed excellent electrochemical stability. After 100 cycles, the LiFePO 4 cathode in coin cells maintained stable cycling performance with retention of 96% at the rate of 1 C, while the SBR was only 93.9%. The capacity retention rate of the soft-packed full battery after 170 cycles at 1 C rate is still 98.9%. This new type of water-based binder is of great significance to promote the preparation of LiFePO 4 cathode in water-based systems. Keywords: electrochemistry；electrode binder；emulsions；polymers；acrylate binder；reactive emulsifier；LiFePO 4 cathode； lithium-ion battery