Synthesis of Molybdenum Nitride as a High Power Electrode Material for Electrochemical Capacitors

Electrochemical capacitors (ECs) have drawn much attention owing to their fast charging/discharging rate, and long lifetime up to millions of cycles. Applications of EC range from large scale transportation to miniaturized electronics. The research reported herein explores the development of an economical process for the synthesis of high performance electrode material for high power ECs. A two stage synthesis process which consists of electroplating of molybdenum oxide followed by thermal nitridation was developed. X-ray diffraction and X-ray photoelectron spectroscopy revealed the material to be Mo oxide with nitrogen substitution, Moz(O,N). In a three electrode system, the Moz(O,N) electrodes showed capacitance as high as 16 mF/cm2. Symmetric EC cells achieved state of the art time constant of 100 ms. Ultrahigh power ECs were demonstrated for the first time using Moδ(O,N) electrodes and SiWA-H3PO4-PVA electrolyte, achieving with 10 ms time constant one of the lowest time constants reported for EC.MAS