Facile coating strategy of Si/C composite anode for high-performance lithium-ion battery

Abstract

Abstract Attributed to its high capacity by alloying with lithium, silicon is considered to be new generation of anodes that can replace graphite and receives much attention. Alleviating the electrode failure caused by volume expansion during lithiation and shrink during delihiation in silicon anodes plays a pivotal role in promoting the industrial application of silicon anodes. In this article, we proposed a facile carbon coating strategy on the surface of silicon nanospheres to buffer the stress during charge and discharge. By controlling the low molecular weight, an ethanol-soluble phenolic resin was synthesized and further self-assembled on the surface of silicon nanoparticles to form the precursor. Uniform Si/C composites were fabricated via pyrolysis. Diffraction of x-rays confirmed that the silicon retained the pristine crystalline structure. Scanning electron microscopy revealed a homogeneous wrap of the amorphous carbon layer on the superficies of the silicon. The galvanostatic charge-discharge test proved the excellent durability of Si/C anodes. Undergoing 50 cycles of galvanostatic lithiation/delithiation at 0.2C, the retention capacity was 96%, as high as 800 mAh/g. This facile but efficient strategy is compatible with large-scale production and improves the feasibility of the practical application of silicon-based anodes.