Tungsten Nitride for Capacitive Energy Storage

A material of W 2 N has been prepared via pyrolysis and subsequent nitridation of ammonium tungstate pentahydrate precursor, and has been used as electrode materials for electrochemical capacitive application. The porous W 2 N powder owns a specific surface area of 34.6 m 2 g −1 and crystallization. Electrochemical evaluation shows that the W 2 N electrode possesses a potential window of −0.3∼0.8 V in 1 mol L −1 aqueous H 2 SO 4 , and manifests a specific capacitance of 161 F g −1 at a current density of 1 A g −1 , good rate ability and a long life cycle. Moreover, reversibility and diffusion transfer controlled pseudocapacitive mechanism are discussed during charging and discharging. A capacitor of W 2 N (s)//W 2 N (s) are assembled and exhibit an underlying application.