Facile synthesis of ceramic SiC-based nanocomposites and the superior electrochemical lithiation/delithiation performances

Abstract

Ceramic SiC-based nanocomposites as the novel electrochemical materials are synthesized by the direct current (DC) arc-discharge plasma method via controlling the carbonaceous source of methane (CH4) in the preparation atmosphere. The electrochemical performances such as the lithiation/delithiation capacity, cycling stability and rate capability are experimentally measured and theoretically analyzed by density-functional theory (DFT) calculations. It is indicated that the carbon-coated SiC (SiC@C) nanorods electrode delivers a superior capacity of 1065 mAh.g(-1) with a coulombic efficiency of 98.49% at a current density of 100 mA g(-1) after 200 cycles, even reserves the capacity of 776 mAh.g(-1) at a higher current density of 2 A g(-1). The enhanced cycling stability and rate capability are attributed to the excellent conductivity of graphite-like layers, strong bonds of ceramic SiC crystals, appropriate compositions as well as interconnected network microstructures of the SiC-based nanocomposites. The experimental/theoretic evidences confirm the possible insertion of 1-2 Li+ ions into one SiC single crystal at the potential of similar to 0.76 V. The facile synthesis of SiC nanocrystals by a physical vapor technique and its excellent electrochemical performances take great potential for such ceramic nanomaterials as anodes for lithium ion batteries.