Molten Salt Derived Graphene-Like Carbon Nanosheets Wrapped SiOx/Carbon Submicrospheres with Enhanced Lithium Storage†

Abstract

There is no doubt that SiOx and carbon composite is one of the promising anode materials for lithium-ion batteries owing to its high capacity and rational cycling stability. Herein, we report a sol-gel synthesis followed by molten salt carbonization route to fabricate graphene-like carbon nanosheet wrapped SiOx/C submicrospheres (SiOx/C@2D-C). The in-situ generated carbon nanosheets under molten salt condition can further improve the electroconductivity, restrain the volumetric expansion and guarantee the structural integrity of the electrode. As a result, the as-obtained SiOx/C@2D-C delivers a discharge capacity of 559 mAh·g−1 at 0.5 A·g−1 after 200 cycles and 548 mAh·g–1 at 1.0 A·g−1 even after 1000 cycles. The full cell assembled with SiOx/C@2D-C as anode and commercial LiFePO4 as cathode can achieve an energy density of 200 Wh·kg−1 and maintain a capacity of 66.7% after 100 cycles with a working potential of 2.8 V. The approach is simple and cost effective, which is promising for mass production of SiOx-based materials for high energy LIBs.