Tailored silicon hollow spheres with Micrococcus for Li ion battery electrodes

•Porous Si hollow spheres were synthesized using Micrococcus bacteria templates.•Excellent Li diffusion coefficient can be provided by carbon coating of Si spheres.•Carbon coated Si spheres exhibited superior cycle stability for Li ion batteries.

The porous Si hollow spheres (p-Si HSs), which feature interconnected Si nanostructures decorated with spherical-type Micrococcus bacteria, were synthesized by a combination of magnesiothermic reduction and byproduct removal and were subsequently studied as an anode material for lithium-ion batteries (LIBs). The p-Si HSs offer a high lithium-ion storage capacity because of their numerous active sites and large electrolyte contact area stemming from their large specific surface area (∼313.7 m2 g−1); in addition, their large pore volume (∼0.927 cm3 g−1) buffers large volume changes during the lithiation/delithiation processes, which is important for improving the cycle stability of anode materials. Furthermore, carbon coating resulted in the formation of a stable solid electrolyte interface through minimization of the Si/electrolyte contact area and also offered an efficient electronic conduction pathway, corresponding with improved lithium reactivity of the active Si materials. The lithium-ion diffusion coefficient of the non-clogging carbon-coated p-Si HSs was approximately five times greater than that of the p-Si HSs. As a result, the designed composite nanostructured electrodes demonstrated excellent cycle stability and superior rate capability.

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