Bifunctional nickel ferrite-decorated carbon nanotube arrays as free-standing air electrode for rechargeable Zn-air batteries

摘要

The rational design of cost-effective bifunctional air electrodes is of great significance to advance the practical application of rechargeable metal-air batteries. Herein, we report a three-dimensional, vertically aligned carbon nanotube array-supported nickel ferrite hybrid (NiFeOx@VACNTs) as a large free-standing air electrode for rechargeable Zn-air batteries. As expected, the designed electrode exhibits exceptional catalytic activity and stability for oxygen electrochemical reactions. The rechargeable Zn-air battery using this integrated air electrode delivers a large peak power density of 194 mW cm(-2), along with ultrastable cyclability of over 1500 h at 5 mA cm(-2). Furthermore, the flexible solid-state Zn-air battery with free-standing oxygen electrode exhibits a stable discharge voltage even under bending condition, with a high discharge power density of 143 mW cm(-2). This work paves a valuable way for designing cost-effective, free-standing integrated air cathodes for Zn-air batteries and related energy conversion and storage technologies.