Si@Nitrogen-Doped Carbon Nanoparticles for Lithium-Ion\nBattery Anodes

Abstract

The\nformation of a core–shell structure by coating silicon\n(Si) nanoparticles with a carbon layer is considered a promising method\nto address the poor conductivity of a Si-based anode and volume expansion\nof silicon particles during the charging/discharging process. However,\nSi/C composite anodes usually perform below expectations with a single\nlayer of carbon utilized as the coating layer, while introducing multilayer\ncarbon coating results in the additional complexity and cost. To overcome\nthis challenge, in this work, waterborne polyurethane (WPU) had been\nsimply mixed with the Si nanoparticles to form the Si/WPU composite\nvia the hydrogen bonds, and the core–shell structure with the\nsingle carbon layer containing N atoms (Si@NC) was obtained after\nthe pyrolysis of the composite. The carbon layer not only significantly\nalleviated the breakage of the anode caused by the volume expansion\nof Si nanoparticles but also optimized the rate performance of the\nanode. At a current density of 0.5 A g^–1, the discharge\nspecific capacity of the Si@NC anode is still as high as 945.63 mAh\ng^–1 after 300 cycles, surpassing various single-layer\ncarbon and multilayer carbon-coated Si-based anodes. This work provides\na convenient and feasible method for preparing economical Si/C composite\nanode materials.