A multifunctional polyimide enabled high performance silicon composite anode materials for Li-Ion batteries

Abstract

Herein, a conjugate carbonyl polyimide (MF-PI) and nano-silicon composite (MF-PI/Si) is designed and synthesized through a simple one-pot method to confront rapid capacity fading and complicated electrode material preparation in silicon-based electrodes for lithium ion battery. This composite can be directly used to prepare electrode without the need of further adding of binding materials. In this composite, MF-PI acts as binder for powder electrode, active reversible lithiation material, buffering media to alleviate volume change of silicon particles, and coating shell to avoid the direct contact between silicon particles and electrolyte. These functions from MF-PI collectively assigned the MF-PI/Si composite anode material a relative high specific capacity and excellent cycling stability. The electrode prepared by this as-synthesized MF-PI/Si shows preferable electrochemical interface and surface area, further enhancing the electrode kinetics and then electrochemical performance. The improved ionic and electronic conductivity compared to other binder materials also contributes the excellent performance.