Despite the advantage of high capacity, the practical use of the silicon anode is still hindered by large volume expansion during the severe pulverization lithiation process, which results in electrical contact loss and rapid capacity fading. Here, a combined electrochemical and computational study on the factor for accommodating volume expansion of silicon-based anodes is shown. 1D silicon-based nanostructures with different internal spaces to explore the effect of spatial ratio of voids and their distribution degree inside the fibers on structural stability are designed. Notably, lotus-root-type silicon nanowires with locally distributed void spaces can improve capacity retention and structural integrity with minimum silicon pulverization during lithium insertion and extraction. The findings of this study indicate that the distribution of buffer spaces, electrochemical surface area, as well as Li diffusion property significantly influence cycle performance and rate capability of the battery, which can be extended to other silicon-based anodes to overcome large volume expansion.
Keywords: anodes; lithium-ion batteries; nanowires; silicon; strain.
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