3D-engineered WO 3 microspheres assembled by 2D nanosheets with superior sodium storage capacity.

Because of the inadequate sodium storage capacity of graphite, the exploration of high-performance SIB anodes is a crucial step forward. Herein, we report the hydrothermally synthesized self-assembled interconnected nanosheets of WO ₃ microspheres possessing admirable sodium storage in terms of cycling stability and acceptable rate capability. Benefitting from the interconnected nature of the nanosheets with a hollow interior, the WO ₃ microspheres exhibited a high sodiation capacity of 431 mA h g ^-1 at 100 mA g ^-1 and an excellent rate performance of 60 mA h g ^-1 at 500 mA g ^-1 with an impressive coulombic efficiency of around 99%. Importantly, even after continuous cycling with increasing current densities, a specific capacity as high as 220 mA h g ^-1 could be recovered at a current density of 50 mA g ^-1 , suggesting excellent sodium storage reversibility.
Competing Interests: The authors declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
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