Graphene-wrapped mesoporous MnCO3 single crystals synthesized by a dynamic floating electrodeposition method for high performance lithium-ion storage

Abstract

A unique structure of graphene-wrapped mesoporous single crystals (MSCs) of MnCO₃ has been successfully synthesized and used as the anode for lithium-ion batteries (LIBs). In a departure from previous high-temperature (>500 °C) synthesis approaches to MSCs, we have developed a simple, low-temperature (70 °C) and template-free method, referred to as dynamic floating electrodeposition (DFE), to fabricate graphene-wrapped MnCO₃ MSCs. In the DFE method, we achieved the reduction of GOs to RGOs, the deposition of MnCO₃ MSCs on graphene, and a graphene-wrapped morphology, all three goals in one electrochemical process. The resulting submicron, graphene-wrapped MnCO₃ MSCs reached a high reversible capacity of 900 mA h g⁻¹ after the initial cycle and delivered over 1000 mA h g⁻¹ after 130 cycles. The reversible capacity also remained at this high level for more than 400 cycles, and maintained 422 mA h g⁻¹ at a high rate of 5000 mA g⁻¹. It is the first time that this high performance has been achieved using MnCO₃ for lithium-ion storage. Furthermore, this superior electrochemical performance was found to be highly related to the designed structure, graphene-wrapped MSCs, of MnCO₃.