Towards industrial applications: Ultra-stable silicon-based pouch cell conducted via a lithiated polymer binder over a wide temperature range from −25 °C to 25 °C

Abstract

Due to the large volume expansion, the multiple issue of severe pulverized Si particles, irreversible damaged electrode structure, and incompatible solid electrolyte interphase (SEI), have greatly restricted the practical application of Si-based anodes. Herein, a neutral partially lithiated binder (PVA1-g-LiPAA3) is successfully synthesized and applied in high-loaded SiOx||Li, 200 mA h and 4 A h SiOx/graphite||LiCoO2 pouch cells. The rich netural -OH and -COOLi groups show strong interaction with the Si particles during long-term cycling processes. Neutral PVA1-g-LiPAA3 binder can induce the formation of a homogenous and stable “core-shell” SEI film on the SiOx anodes, forbidding the structural evolution and volume expansion. This -CF3-rich SEI film can also improve the ionic conductivity and accelerate the electrochemical kinetics reaction. Moreover, the integrity of fluid collection and polar ears can also be protected. Thus, the manufactured 4 A h SiOx/graphite||LiCoO2 full pouch cell maintains a high 700th discharge capacity of 3.13 A h with capacity retention of 81.3% under 25 °C and 3 C, as well as 300th discharge capacity of 2.73 A h with capacity retention of 98.6% even under 0°C and 1.5 C. This work proves the industrical applications of Si-based anodes over a wide temperature range with high energy density and long cycle life.