Cubic-shaped WS2 nanopetals on a Prussian blue derived nitrogen-doped carbon nanoporous framework for high performance sodium-ion batteries

Despite the cost-effectiveness of sodium sources, sodium-ion based electrochemical energy storage devices still have a few challenges in competing with lithium-ion based batteries (LIBs) for commercialization and practical applications. In particular, the high rate performance and long cycling lifetimes are very difficult to be achieved in sodium-ion batteries (SIBs). Herein, we report a simple solvothermal method to prepare cubic-shaped nanostructures with vertical rose petal-like layers, which are used as anode materials in SIBs. The well-designed WS2@NC structures consist of WS2 nanosheets and Prussian blue-derived nitrogen doped carbon nanocubic framework, which possess unique 2D WS2 nanosheets and are vertically grown on the well-defined 3D porous carbon hierarchical structures. As anode materials for SIBs, this structure displayed high rate capacity at 384 and 151 mA h g(-1) at 100 and 5000 mA g(-1), respectively. More importantly, the performance of the electrode materials can be maintained at more than 200 cycles with coulombic efficiency not less than 99%. The excellent electrochemical performance is attributed to the synergistic effect of the composites that enhances the electrochemical transport properties of the WS2 due to the well-defined, nano-structured hierarchical scaffolding and the highly conductive nature of the framework. From the results shown, this unique design method provides unexplored insights into new and simple methods in improving the electrochemical performance of the 2D-TMDs based SIBs electrode materials.