Hollow CoS2@C nanocubes for high-performance sodium storage

Abstract Exploration for high energy density, power density, and cyclability is challengeable to the application of sodium ion batteries (SIBs). Cobalt sulfide (CoS2) nanomaterials have been applied in the various energy storage and conversion fields. In this work, Co(OH)2 hollow nanocubes derived CoS2@C composite was successfully synthesized through the carbon coating and sulfidation processes. The three-dimensional hollow architecture can not only effectively restrict the volume expansion, but also shorten the ion/electron transport pathway and provide more active sites for reaction. The CoS2@C electrode exhibited outstanding cycling performance (529.3 mA h g−1 at 0.1 A g−1 after 100 cycles and 367.6 mA h g−1 at 5 A g−1 after 200 cycles) and superior rate capacity (302.8 mA h g−1 at 10 A g−1) for sodium storage. The kinetic analysis indicates that the pseudocapacitive behavior dominated the sodium storage of the CoS2@C hollow cubes.