Conclusions
Possibility of the Si/C composites forming with fullerene-like structure via quantum-chemical calculations has been shown. It has been established that nanoclusters (SiC)12 form stable associative agglomerates n(SiC)12 that has a higher electron affinity than monomer analogs. The charge/discharge processes do not affect the volume values of the silicon-carbon matrix. Therefore, electrodes based on composites (SiС)12 and n(SiС)12 will not have periodic oscillation of mechanical strain and the lithiation/dilithiation process will not affect their current tap settings. As a result, highly stable qualitative electrochemical characteristics of such electrode materials remain and a significant increase in the number charge/discharge cycles will be observed. In (SiC)12 system the carbon concentration (~ 30%) is close to the optimal for the best Si/C based electrodes that lead to the 3051 mA*H*g-1 specific capacity value. Based on the obtained theoretical result it could be concluded that Si/C composites are a very attractive electrode material for use in lithium-ion batteries.
Keywords: Si/C fullerene-like nanocomposites, lithiation/delithiation process, specific volume, quantum-chemical study