In Situ Synthesis of MnO2/Porous Graphitic Carbon Composites as High-Capacity Anode Materials for Lithium-Ion Batteries

Unique high-capacity MnO2/porous graphitic carbon (MnO2/PGC) composites were fabricated by a mild and efficient in situ precipitation approach using PGC derived from coal tar pitch as the carbonaceous precursor and KMnO4 as the manganese source. MnO2/PGC composites with reasonable surface areas (190–229 m2 g–1) retain the superior structure of interconnected nanopores and graphitic crystallite from PGC and contain evenly distributed MnO2 modified on the surface of the carbon skeleton in PGC, which can not only provide sufficient active sites for lithium-ion storage but also enhance electron transport capability and efficient lithium-ion diffusion capability. As a result of the synergistic effect of PGC and MnO2, MnO2/PGC composites as anode materials in lithium-ion batteries (LIBs) exhibit excellent reversible capacity, rate performance, and cycling stability. In particular, the MnO2/PGC-36 composite possesses a high initial reversible capacity of 1516 mAh g–1 at a current density of 0.05 A g–1 and an average reversible capacity of 399 mAh g–1 at a high rate of 5.00 A g–1. Moreover, such a MnO2/PGC-36 composite also exhibits a superior long-term cycling stability, with over 90.0% capacity retention after 400 cycles. These outstanding electrochemical performances demonstrate that the MnO2/PGC composite can be a promising anode material in LIBs for further practical application.