Rechargeable MnO2-Zn batteries with a higher voltage

Researchers at the City University of New York Energy Institute (ccny.cuny.edu) have developed a low-cost battery based on manganese dioxide and zinc that reaches voltages of greater than 2 V, a first-time achievement that could allow batteries with these low-cost raw materials to compete with lithium-ion batteries. Alkaline MnO2/Zn batteries are familiar as primary (one-time discharge) batteries for small electronics, but they generate low (1.2 V) voltages because both the cathode and anode reactions occur in alkaline electrolyte. The CCNY research group has designed Zn/Mn batteries with both reversibility and higher voltage. Previous attempts to raise the voltage of the system thermodynamically has involved separating electrolytes with ceramic or ion-selective membranes so that the anode reaction occurs in alkaline conditions and the cathode half-reaction in acid environs. However, the membranes push the battery’s costs too high to compete with existing alternatives. The CCNY team, led by professor Gautam Yadav, invented a novel way to separate the battery half-cells by engineering the alkaline electrolyte into a thick gel whose interfacial properties prevent it from mixing with the liquid acidic solution and undergoing neutralization…