Germanium Nanograin Decoration on Carbon Shell: Boosting Lithium-Storage Properties of Silicon Nanoparticles
A novel heterostructured Si@C@Ge anode is developed via a two-step sol-gel method. A facile and straightforward Ge decoration signiﬁcantly boosts the Li-storage performance of core-shell Si@C nanoparticles on both mechanics and kinetics. The Si@C@Ge anode shows unprecedented electrochemical performance in terms of accessible capacity, cycling stability, and rate capability when compared to those of a core-shell Si@C anode. Based on the experimental results and analysis of the mechanism, it is evident that high-conductivity Ge nanograins on the surface facilitates the Li diffusivity and electron transport and guarantees high ion accessibility. Moreover, it is the Ge nanograins that serve as buffering cushion to tolerate the mechanic strain distribution on the electrode during lithiation/delithiation processes.