Wiping off oxygen bonding to maximize heteroatom-induced improvement in oxygen reaction activity of metal site for high-performance zinc-air battery

摘要

Heteroatom doping has recently been utilized to improve the catalytic performance of transition metal-based electrocatalysts. However, the doping process is inevitably accompanied by the introduction of oxygen, influencing the heteroatom-induced asymmetric spin density over the active sites and leading to inconspicuous promotion in the property. Herein, by wiping off the undesired heteroatom-oxygen bonding, we maximize the heteroatom-induced improvement in oxygen reaction activity of metal site, providing descendant energy barrier and favorable reaction efficiency for zinc-air batteries. The proof-of-concept material delivers a superior halfwave potential of 0.88 V versus reversible hydrogen electrode for oxygen reduction reaction, a small overpotential of 410 mV at the current density of 10 mA cm(-2) for oxygen evolution reaction, and a reversible oxygen electrode index of 0.76 V in electrochemical measurements. Aqueous zinc-air battery with such catalysts delivers an excellent power density of 162.3mWcm(-2) and superior durability over 635 cycles. Moreover, in consideration of high safety and flexibility of solid-state batteries, all-solid-state zinc-air battery adopting gel electrolyte is assembled and used to illumine an LED wristband, showing great promises for the next-generation energy system.