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