As a core component, the catalyst layer (CL) is widely used in fuel cell, metal-air battery, and other energy conversion devices. Herein, a highly efficient method for CL preparation via fast current-driven synthesis followed by pyrolysis is proposed. Compared with previously reported fabrication procedures of zeolite imidazolate frameworks (ZIF)-based CLs, this method directly deposits the ZIF precursor onto the conductive substrate in a very short time (≤15 min). The self-supporting CL, converted from ZIF membrane by simple single-step pyrolysis, is assembled with the gas diffusion layer to obtain cathode. Electrochemical tests exhibit a small potential gap (0.83 V) between the oxygen reduction and evolution reactions, as well as high performance and excellent stability for Zn-air battery (241 mW cm-2 at 390 mA cm-2 ), due to the unique design of a bi-continuous framework (interconnected pores and long carbon nanotubes) and Co-based active sites. This work may provide new directions for the fast fabrication of non-platinum group metal CLs for metal-air batteries or fuel cell applications.
Keywords: Zn-air batteries; catalyst layers; fast current-driven synthesis; oxygen reduction reaction; zeolite imidazolate framework membranes.
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