A strategy based on water soluble coal tar pitches to construct MnO2@C composite materials with high electrochemical performance

The water soluble coal tar pitches (WS-CTPs) were successfully prepared and used to construct the MnO2@C composite materials by a hydrothermal method. It is interestingly observed that the structures and morphologies of MnO2@C materials can be controlled by controlling the dosages of WS-CTPs and KMnO4. Meanwhile, it is aware that MnO2 exists in the MnO2@C materials in an amorphous state. Compared with MnO2, MnO2@C materials output a remarkable improvement in electrochemical performance. For instance, MnO2@C-0.3 shows the storage capacity at 965.7 mA h g−1 after 300 cycles at a current density of 0.1 A g−1. In addition, after 600 cycles at a current density of 1.0 A g−1, the storage capacity of MnO2@C-0.3 still keeps 450.3 mA h g−1, indicating that MnO2@C-0.3 owns tremendous cycle stability at a high current density. In view of the fact that the coal tar pitches possess great cost advantages, the strategy of using WS-CTPs as a carbon source to cover the metal oxides is a competitive way to expand the application of metal oxides in the fabrication of electrodes of LIBs.