Bamboo-like SiOx/C nanotubes with carbon coating as a durable and high-performance anode for lithium-ion battery

SiOx, as a high-performance anode for lithium-ion batteries, has gained extensive attention because of its high capacity and low cost, but its further commercial value is hindered by volume expansion and bad conductivity. Herein, we develop and fabricate a novel bamboo-like SiOx/C@C structure, which is similar to hollow nanotubes (NTs) separated by many continuous partitions, through the sol-gel method and polymer coating technology based on the polydivinylbenzene NTs. During the periodic lithiation-delithiation, this ingenious structure enables a self-buffering space for the expansion and prevents the electrolyte from directly contacting the interior of NT, thereby avoiding the accumulation of solid-electrolyte interphase (SEI) layer. Furthermore, the outer carbon coating transformed from the exterior polymer layer provides a directional mechanical constraint for the inward volume expansion while achieving at a high electron transfer rate. The as-designed bamboo-like architecture exhibits a large reversible capacity (702 mA h g-1 after 200 cycles at 100 mA g-1) and a durable cycle life (capacity of 511 mA h g-1 after 450 cycles at 500 mA g-1). There will probably be potential value in diverse energy storage materials by this unique and scalable bamboo-like structure.

Automated summary

The bamboo-like SiOx/C@C structure developed in this study provides a self-buffering space and prevents direct contact of the electrolyte with the interior of NT during lithiation-delithiation cycles, avoiding the accumulation of solid-electrolyte interphase (SEI) layer. The outer carbon coating also provides directional mechanical constraint for inward volume expansion and helps achieve a high electron transfer rate, leading to a large reversible capacity and durable cycle life. This unique and scalable structure shows potential value for diverse energy storage materials.