Ultra-Thin Manganese Dioxide-Encrusted Vanadium Pentoxide Nanowire Mats for Electrochromic Energy Storage Applications

Abstract

V2O5 electrochromic (EC) coatings are attractive for various photonic applications owing to their multiple oxidation states discernable by distinct colors. The material also shows massive potential for electrochemical energy storage because of their layered structure and high theoretical capacitance. Here, the solution processing of the electrodes composed of an ultra‐thin layer of MnO2‐encrusted V2O5 (V2O5/MnO2) nanowire mats on fluorinated tin oxide substrates is reported that offer much enhanced electrochemical stability along with a superior energy storage performance compared to a bare V2O5 electrode. The areal capacitance of the V2O5 shows 25.7% enhancement (10.90 to 13.70 mF cm−2 at 5.0 mV cm−2) due to MnO2 encrustation. The fabricated EC devices show three distinct colors, i.e., orange (+3.0 V), green (−2.5 V), and blue (−3.0 V). Capacitance retention of bare V2O5 at 1000 cycles is 71% that increases to 93.6% after MnO2 coating due to the enhanced electrochemical stability.