Synthesis of a nitrogen rich (2D–1D) hybrid carbon nanomaterial using a MnO2 nanorod template for high performance Li-ion battery applications†
A novel strategy is developed to synthesize a nitrogen rich few layer graphene–carbon nanotube [N-(FLG–CN)] hybrid material with the help of self-degradable MnO2 nanorod templates for the application as the anode electrode with high performance and long-term cyclic stability in Li ion batteries. During the synthesis procedure, the surfaces of MnO2 nanorods and few layer graphene (FLG) are non-covalently functionalized with anionic and cationic polyelectrolytes, respectively, for proper mixing of the constituents. Polymerization of this one- and two-dimensional hybrid composite with a nitrogen containing polymer and subsequent pyrolysis at 800 °C temperature lead to the formation of a highly porous nitrogen doped-(FLG–CN) hybrid nanocomposite with a nitrogen doping level of 9.3 wt%. The N-(FLG–CN) electrode material in Li ion batteries displays superior reversible capacities of 739 mA h g−1 after the 30th cycle at a current density of 100 mA g−1 and 445 mA h g−1 after the 500th cycle at a high current density of 500 mA g−1. As compared to the pristine graphene material, the N doped (FLG–CN) hybrid material shows a two-fold enhancement in specific capacity at high current densities (∼5000 mA g−1) and long-term cyclic stability (1000 cycles). The highly defective and porous 1D–2D morphology of the N-(FLG–CN) hybrid structure gives more adsorption sites for lithium ions, meanwhile nitrogen doping significantly reduces the charge transfer resistance of graphene based electrodes.