Tailoring charge and mass transport in cation/anion-codoped Ni₃N / N-doped CNT integrated electrode toward rapid oxygen evolution for fast-charging zinc-air batteries

Searching for the highly active and low cost electrocatalysts with fast-charging capability for rechargeable zinc-air batteries are paramount in terms of their commercial-scale application. Here, we propose an innovative cation/anion-codoped nickel nitrides (FC-Ni₃N) along with creating 3D architecture by integrating N-doped carbon nanotubes (NCNT), which is found to be an outstanding bifunctional oxygen electrocatalyst for Zn-air batteries with ultrafast charging rate (Potential =2.02V at 50 mA cm⁻² with area capacity of 4 mAh cm⁻²) and long cycling life (700 cycles at 20 mA cm⁻²). Through varying the cation/anion moiety, the optimal FC-Ni₃N/NCNT shows low overpotential of 260 mV at 10 mA cm⁻² and Tafel slope of 46 mV dec⁻¹, much outperforming the RuO₂ benchmark with overpotential of 337 mV and Tafel slope of 91 mV dec⁻¹. The extraordinary oxygen evolution reaction performance (corresponding to the charge process) stems from the simultaneous regulation of charge- and mass-transport kinetics in air electrodes. The proposed strategy and results may pave the way for promoting commercial application of rechargeable zinc-air batteries or other metal-air batteries.