Multifunctionalized Conductive Polymers for Self-Healing Silicon Anodes in Li-Ion Batteries

Silicon is a very promising material for lithium-ion batteries (LIBs) due to its high theoretical capacity (3579 mAh/g). However, the volumetric expansion (300%) of silicon during lithiation led to pulverization of the electrode and rapid capacity fading. Self-healing (SH) materials are thought of as a solution for the degradation of active materials, enabling higher capacity retention. Here, we synthesized and integrated an autonomous self-healing poly-(aniline-<i>co</i>-3-aminophenylboronic acid)/PVA composite (SHC) as a binder in a Si anode electrode for LIBs. The synthesized SHC was investigated by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis, and elongation and conductivity tests. Si anodes were prepared with SHC and a PVP cobinder. In addition, Si anodes were prepared separately with PVDF and the CMC-SBR binder as control electrodes. The electrodes were electrochemically characterized by electrochemical impedance spectroscopy, cyclic voltammetry, and galvanostatic charge/discharge tests. The conductive SHC binder was successfully integrated into the Si anode, and a capacity of over 1700 mAh/g was obtained after 100 cycles at C/10, and 650 mAh/g was obtained after 200 cycles at C/2.