Enhanced electrochemical properties of a Si-based anode using an electrochemically active polyamide imide binder

Polyamide imide (PAI), one of the classes of copolyimides containing both high mechanical properties and processibility, is used as a polymeric binder of a Si particulate electrode. The initial coulombic efficiency is improved from 28.9% (Si-PVdF) to 74.9% (Si-PAI) by introducing a PAI binder into a Si-based electrode. Variations in thickness measured at various states of charge (SOCs) and depths of discharge (DODs) indicate that the PAI binder is a much more effective restraint on volume expansion in active Si materials during the charging process than poly(vinylidene fluoride) (PVdF) binder. The discharge capacity of Si-PAI electrodes is approximately 1700 mAh g−1 after 20 cycles, which is attributed to the excellent maintenance of an electrical-conducting network during cycling.