Tailoring the Polymer-Derived\nCarbon Encapsulated\nSilicon Nanoparticles for High-Performance Lithium-Ion Battery Anodes

Abstract

The structure, dopants, and surface area of carbon determine\nthe\nperformance of the core–shell structured silicon and carbon\ncomposite (Si@C) anode for Li-ion batteries (LIBs). Herein, we report\nthe synthesis of Si@C composite from poly­(vinyl alcohol) (PVA)/melamine\nresin (MR) dual layer polymer derived carbon encapsulated Si nanoparticles\nusing a polymerization–carbonization approach. The dual polymer\nlayer derived carbon coating has adequate void spaces and dopants,\npossesses a disordered structure, and seals the Si core sufficiently.\nHence, the obtained Si@C_MR anode delivers a superior specific\ncapacity of 1279.3 mA h/g at a current density of 2 A/g and with a\nretention rate of 88.9% after 500 cycles. A full cell with a Li­(Ni_0.6Co_0.2Mn_0.2)­O₂ cathode and\na prelithiated Si@C_MR anode exhibits a high energy density\nabove 518 Wh/kg and capacity retention of 90.1% after 100 cycles.\nIn parallel, the other three polymer-derived Si@C composites were\nprepared to study the effect of carbon on the performance of the composite\nanodes. Overall, constructing a dual-polymer layer holds the promise\nfor rationally designing Si@C anodes for high-performance LIBs through\nthe polymerization–carbonization approach.