Porous Ultra-Capacitor Electrodes Fabricated by Solution Precursor Plasma Spray: Molybdenum Oxide vs. Molybdenum Nitride

Abstract

Abstract Solution precursor plasma spray has been shown capable of depositing high surface area transition metal oxide coatings of interest as ultra-capacitor electrodes. These materials exhibit mixed double layer and pseudo-capacitive properties, enabling larger charge storage capacity than electrical double layer capacitor electrodes such as carbon. This investigation explored potential of SPPS to deposit molybdenum oxide with microstructures suitable for use as pseudo-capacitive electrodes. It further identified a two-step temperature-programmed heat treatment that resulted in the topotactic phase transformation of the α-MoO3 deposits into high specific surface area molybdenum nitrides exhibiting a higher electrochemical stability window (i.e. a higher specific area capacitance). The electrochemical behavior of molybdenum oxide and molybdenum nitride deposits formed under different deposition conditions was studied using cyclic voltammetry in order to assess the influence of the resulting microstructure on the charge storage behavior and potential for use in ultra-capacitors.