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.

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