LAUSR

Aqueous sodium polysulfide–air batteries are a promising system for enabling low-cost, high energy density, environmentally benign batteries for grid-scale deployment. However, the sluggish redox kinetics of aqueous polysulfide requires the use of a catalyst. Cobalt sulfide is a traditional catalyst with good activity and stability, but it uses expensive and toxic cobalt. This study demonstrates for the first time the long-term cycling performance of a sodium polysulfide–air battery with a low-cost copper sulfide catalyst for polysulfide redox. Alkaline sodium polysulfide anolyte is paired with an acidic sodium phosphate buffered air catholyte by means of a Na+-ion solid-state electrolyte, which eliminates chemical crossover between the two electrodes while serving as a mediator-ion solid electrolyte. Long-term cycling is achieved by means of a decoupled charge and discharge air electrode. Furthermore, the effect of CuS redox activity in the polysulfide–air voltage window is tested by pre-discharging CuS ...