Aqueous based dual-electrolyte rechargeable Pb?Zn battery with a 2.8 V operating voltage

A novel rechargeable PbO2-Zn battery system using Zn as negative and PbO2 as positive electrodes in a KOHH2SO4 dual-electrolyte is developed. Using a bi-polar ion exchange membrane that effectively prevents the H+ and OH- from neutralization, the positive and negative electrodes operate in the respective electrolytes with different pH. The Zn electrode provides a low potential of -1.3 V in KOH solution and the PbO2 has a high potential of +1.5 V in H2SO4 solution. This resulted in a cell operating voltage of 2.8 V in an aqueous electrolyte. The system also demonstrated a high rate performance and good rechargeability. This simple, low-cost system not only overcomes the thermodynamic limit of water decomposition and achieves a high voltage aqueous based battery, but also provides a new approach in design of future electrochemical devices.