Reducing the cost of zinc-oxygen batteries by oxygen recycling

With the increasing demand of energy storage towards renewable energy technologies, electrochemical systems with low-cost, high safety levels, and low environmental impact are critically needed. Zinc-air/oxygen batteries, which were always considered to be cheap, are losing their competitive advantages due to the poor cyclic performance and energy efficiency. Herein, we report an effective strategy of oxygen recycling which reduces the cost of oxygen to as low as 0.2 ¢ kWh-1 per cycle. With the use of oxygen, the performance of zinc-oxygen batteries is largely increased with the maximum power density of 290 mW cm-2, stable cycling for nearly 1500 cycles with an average energy density of 60% and elimination of carbonates. A 1kW/1kWh zinc-oxygen battery system is also integrated and exhibits a satisfactory energy efficiency of 58% and a high working power density of 75 mW cm-2.