Preparation of electrochromic MnO2 thin film by electrodeposition.

Abstract

Electrochromic manganese dioxide thin films have been electrodeposited on optically transparent electrodes (OTE) from an aqueous solution of manganse (II) sulfate. Brown MnO2 thin film on the OTE glass is electrochemically reduced to a lower valence state, which is almost colorless, by the reaction.MnO2+H++e_??_MnOOHThis reaction is reversible and its scheme is nearly the same as that of a dry cell.The conditions of electrolysis that yields the electrochromic brown MnO2 vary greatly depending on the temperature. The deposits was stable in alkaline solution, and at ±500mV in a NaOH solution, showing reversible coloration and bleaching for up to 104 repetition.