An advanced zinc air battery with nanostructured superwetting electrodes

Abstract

Rechargeable zinc air batteries (ZABs) have gained considerable attention as a promising energy technique recently owing to their high theoretical energy and power density, safety and economic viability; however, the state-of-art ZABs have been plagued by two major drawbacks, unsatisfying achievable power density and low voltage efficiency. Our superwetting electrodes are hereby designed to circumvent these issues through controlling the O2 bubbles adsorption/evolution behavior at electrode surface while maintaining the outstanding electrocatalysis performance. In this work, we demonstrate for the first time the application of superwetting catalytic electrodes in the tri-electrode rechargeable ZABs. Two different functional electrodes, namely superaerophilic cobalt-incorporated nitrogen-doped carbon nanotubes hybrid catalyst and superaerophobic NiFe-layered double hydroxide arrays, serve as exceptional catalysts for discharging and charging process respectively, thus achieving superior battery performance. The low-cost superwetting cathode pairs even exhibit a much better catalytic activity and durability than the combination of precious Pt/C and Ir/C catalysts. The as-assembled ZABs deliver a greatly improved peak power current of 245 mW cm−2 at 396 mA cm−2 over that of the ZABs composed of precious metal electrodes (186 mW cm−2), together with small polarization, high reversibility, and stability over long cycles. The design of superwetting electrode marks a general and effective strategy to achieve high-performance rechargeable ZABs.