Identifying the Lewis Base Chemistry in Preventing the Deposition of Metal Oxides on Ketone-Enriched Carbon Cathodes for Highly Durable Metal-Air Batteries.

Metal-air batteries have exhibited unlimited potential and economic value because of their considerably high energy density. However, under repeated cycling, air cathodes undergo a well-known problem, the deposition of metal oxide, clogging the active surface and ultimately leading to the severe degradation of the cyclic performance. Herein, we address this challenge in a zinc-air battery by introducing ketone as the Lewis base into the air catalyst. As illustrated by in situ X-ray diffraction observations, the ketone-enriched material could generate an ultrahigh negative potential to prevent the access of negatively charged zincate ions and thus enable the nondeposition of zinc oxide on the air cathode because of the strong electrostatic repulsion. Using this strategy, we demonstrate 650 highly stable cycles of a zinc-air battery under a high rate (25 mA cm-2). Such a Lewis-base-assisted method opens up new avenues to prevent air cathodes from being poisoned for highly durable metal-air batteries.