Ion-Selective Graphene Oxide/Polyvinyl Alcohol Composite Membranes for Rechargeable Alkaline Zinc Manganese Dioxide Batteries

Blocking the zincate ion ([Zn(OH)(4)](2-)) and limiting its reaction with the cathode material are key requirements for improving the energy density and rechargeability of alkaline zinc manganese dioxide (Zn|MnO2) batteries. Zincate is the soluble anode discharge product, which undergoes a side reaction with the reduced cathode material to form a resistive and irreversible spinel material. Such a side reaction prevents deeper discharge of MnO2, reduces the battery's achievable energy, and prevents it from further cycling. In this article, we report the design and fabrication of an ion-selective graphene oxide/poly(vinyl alcohol) composite membrane and demonstrate its superiority in suppressing zincate ion crossover while minimally impairing the conduction of hydroxyl ions (OH-). With this advanced separator, near full utilization of the MnO2 electrode's two-electron capacity (& SIM;617 mA h/g-MnO2) with a high areal capacity of 20 mA h/cm(2) is reported for both primary and secondary cells. In the primary cell, the energy density is almost doubled, and in the rechargeable cell, a cycle life of 300 cycles is achieved, which is more than 3 times better than the case with no zincate blocking separator.