Facile and cost-effective manipulation of hierarchical carbon nanosheets for pseudocapacitive lithium/potassium storage

Abstract The rising demand for high-performance energy storage devices calls for cost-effective electrode materials with large working potential windows, high specific capacities, and rapid rate capability. Herein, we propose a facile molten-salt-mediated production of ultrathin carbon nanosheets with tunable nitrogen doping using low cost precursors including asphalt and melamine. The as-obtained nitrogen doped slim carbon nanosheets (NSCN) constructed through this easy and effective in-situ method offer both high specific capacity and excellent cycling stability. Specifically, a specific capacity of 848 mAh g−1 after 800 cycles at 1 A g−1 and 214 mAh g−1 after 1500 cycles at 1 A g−1 were achieved for lithium and potassium storage, respectively. The excellent electrochemical performances benefit from the synergistic effect of structural merits including ultra-thin nanosheet, nitrogen doping, high degree of disorder and large specific surface area. Meanwhile, it also provides an avenue for realizing the value-added utilization of heavy oil in an alternative field.