Hard carbon coated nano-Si/graphite composite as a high performance anode for Li-ion batteries

•Hard-carbon-nano-Si/Graphite composite was prepared by hydrothermal method for LIBs anodes.•Hard carbon plays important role buffering the volume expansion of silicon and as active material.•It also provided an efficient pathway for electron transfer between nano-Si to graphite.•High specific capacity and excellent cycling stability was demonstrated at high areal capacity.

With the ever-increasing demands for higher energy densities in Li-ion batteries, alternative anodes with higher reversible capacity are required to replace the conventional graphite anode. Here, we demonstrate a cost-effective hydrothermal carbonization approach to prepare a hard carbon coated nano-Si/graphite (HC-nSi/G) composite as a high performance anode for Li-ion batteries. In this hierarchical structured composite, the hard carbon coating not only provides an efficient pathway for electron transfer, but also alleviates the volume variation of Si during charge/discharge processes. The HC-nSi/G composite electrode shows excellent performance, including a high specific capacity of 878.6 mAh g−1 based on the total weight of composite, good rate performance, and a decent cycling stability, which is promising for practical applications.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide