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

Abstract

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.