One-pot prepared silicon-silver-polydopamine ternary composite anode materials with high specific capacity and cycling stability

Abstract

The silicon-based materials show high capacities. However, the poor intrinsic conductivity and severe volume change during the process of lithiation and delithiation restrict the application. In this work, the nanoscale silicon (Si) with silver-polydopamine (Ag/PDA) hybrid coating was designed and successfully prepared by a simple one-pot liquid-phase redox reaction method. The electrochemical properties of the anode materials for lithium ion batteries were characterized, and the mechanism for the excellent cycling performance were investigated by cyclic voltammetry (CV), Electrochemical impedance spectra (EIS), scanning electron microscopy (SEM) and the operando visual observation during lithiation/delithiation process. According to the results, the presence of PDA and Ag is advantageous to enhance the electronic conductivity in the charge-discharge process. The Si/Ag/PDA ternary composite electrode exhibits high capacity and more stable cycling characteristics than Si and Si/PDA electrodes especially at large current densities, which remains 1168.8 mAh g−1 and after 100 cycles at 2 A g−1.