Poly (siloxane imide) Binder for Silicon Based Lithium-Ion Battery Anode via Rigidness/Softness Coupling.

Binder plays a crucial role in maintaining mechanical integrity of electrodes in lithium-ion batteries. However, the conventional binders lack proper elasticity, which are not suitable for high-performance silicon anodes featured with huge volume change during cycling. Herein, a poly (siloxane imide) copolymer (PSI) is designed, synthesized, and utilized as a binder for the silicon based anode. A rigidness/softness coupling mechanism is demonstrated by the PSI binder, which can accommodate volume expansion of the silicon anode upon lithiation. The electrocechemical performance in terms of cyclic stability and rate capability can be effectively improved with the PSI binder as demonstrated by a silicon nanoparticle anode.