2, Key Laboratory of Specially Functional Polymeric Materials and Related Technology, East China University of Science and Technology, Shanghai, , China
Graphene-wrapped porous spherical MnCO3 is synthesized via a facile process combining the homogeneous precipitation and the hydrothermal method. This composite material, applied as a lithium-ion battery anode, shows a superior lithium storage capacity and remarkable long cycling performance due to its special nanostructure. It delivers a reversible capacity of 1168.5 mA h g-1 at a current density of 500 mA g-1 after 200 cycles. After 1000 cycles at high rate of 3000 mA g-1, a stable capacity of 594.7 mA h g-1 can be maintained with the capacity retention of 86.3%. Full cells with the composite anode and the commercial NCM523 cathode are assembled and show good cycling stability over 100 cycles. Furthermore, a series of composite materials with different content of graphene are prepared to identify the role of graphene in electrodes during the charge/discharge process. Kinetics-analysis based on cyclic voltammograms (CVs) reveals that the presence of graphene can promote Li+ transportation at electrode/electrolyte interface, which increases its surface capacitive contribution and results in superior electrochemical performance than other MnCO3 samples.