Nanocrystalline WSe2 excels at high-performance anode for Na storage via a facile one-pot hydrothermal method

For the next large-scale energy storage systems, sodium-ion batteries (SIBs) with excellent electrochemical performance are promising. However, the exploration of anode materials with high specific capacity, fascinating cycling stability and rate capability is still restricted. Among transition metal dichalcogenides (TMDs), tungsten diselenide (WSe2) has been regarded as an effective anode material for SIBs and has been extensively studied, due to high theoretical capacity and unique two-dimensional layered structure. Herein, nanocrystalline WSe2 is prepared by a facile one-pot hydrothermal method. Compared with the micro-scale WSe2, benefiting from the high specific surface area of highly ordered nano-flake structures and short ion/electron transport paths, nanocrystalline WSe2 shows excellent electrochemical performance in Na storage. After 1000 cycles at a current density of 2 A center dot g(-1), a high specific capacity of 264.4 mA center dot h center dot g(-1) is still maintained. The full cell matched with the Na3V2(PO4)(3) cathode can deliver an excellent reversible specific capacity of 196.5 mA center dot h center dot g(-1) after 100 cycles at 0.5 A center dot g(-1).