Development of monodispersed MnCO3/graphene nanosheet composite as anode for lithium-ion battery by hydrothermal synthesis

A unique monodispersed MnCO3/graphene nanosheet composite is synthesized by a simple one-step hydrothermal method and used as anode of lithium-ion battery. X-ray diffraction patterns show the typical rhombohedral structure of MnCO3. A transmission electron micrograph reveals that MnCO3 is evenly distributed on the graphene nanosheet surface with a uniform diameter of 100 nm. Electrochemical performance results show that the specific discharge capacities of MnCO3/graphene nanosheet composite remain above 1015.9 mAh g(-1) at a rate of 0.2 C after 85 cycles in the potential window of 0.01-2.0 V and even at a high rate of 1.0 C this parameter remains at 683.5 mAh g(-1) after 100 cycles. Thus, the composite also exhibits favorable rate performance. The excellent reversible capacities are attributed to the highly dispersed and large nanosheet structure of the composite, which may not only facilitate the fast transport of Li+ ions between the electrode and electrolyte but also provide enough surfaces to accommodate extra Li+ ions that contribute to partial interfacial storage capacities. Additionally, graphene nanosheet can effectively improve electrical conductivity of the composite. Therefore, MnCO3/graphene nanosheet composite can be a great potential anode material for lithium-ion batteries.