431413 Charge-Storage Mechanisms for High Surface Area Carbides and Nitrides

摘要

Early transition-metal carbides and nitrides are being considered for use as electrode materials in supercapacitors due to their high accessible surface areas, high electronic conductivities and low cost. They possess high pseudocapacitances, good capacitance retention during cycling and wide voltage windows. The nitrides of vanadium (VN) and molybdenum (γ-Mo_2N) have received the most attention due to their high pseudocapacitances [1]. Previously, we demonstrated, using ion isolation experiments, that H~+ and OH~- were the active ions that gave rise to the pseudocapacitance [2]. Using X-ray absorption spectroscopy to track changes in the oxidation state of V and Mo in the VN and y-Mo_2N materials, respectively, a pseudocapacitive charge storage mechanism was proposed for both materials in aqueous electrolytes [3].