Cobalt selenide with ordered cation vacancies for efficient oxygen reduction and frigostable Al-air batteries.

Aluminum-air batteries are still inhibited by the sluggish cathodic oxygen reduction reactions, especially in low temperature conditions. Thus, it is urgent to develop efficient electrocatalysts for Al-air batteries to allow their use in extreme weather conditions. In this work, hexagonal Co 0.85 Se-decorated N,Se co-doped carbon nanofibers (Co 0.85 Se@N,Se-CNFs) were synthesized via facile carbonization/selenization of electrospun ZIF-67 nanocubes. The as-prepared metallic Co 0.85 Se with ordered structural cation vacancies endows Co 0.85 Se@N,Se-CNFs with remarkable oxygen reduction reaction activity, including high onset and half-wave potentials (0.93 V and 0.87 V vs. RHE, respectively). Consequently, the corresponding Al-air battery exhibits superior performance in a wide range of operating temperatures (-40-50 °C). For instance, this Al-air battery exhibits a voltage from 0.15-1.2 V with a peak power density of about 0.7 mW cm -2 at -40 °C. It is expected that TMSe-decorated N,Se co-doped carbon nanofibers could be applied in extensive energy fields.