Chromium ions-doped titanium nitride/nitrogen-doped carbon composites as oxygen electrocatalyst for high-performance Zn-Air battery

Recently, transition metal nitrides (TMNs) are a suitable candidate for electrode materials due to their high conductivity, large surface area, electronic structure, and interesting mechanical properties. However, the activity of oxygen reduction reaction (ORR) is too poor to meet the performance and cost requirements in zinc-air batteries. Doping with the other foreign atoms can optimize the structure and performance of TMNs. In this paper, the d-band center of titanium nitride (TiN) was regulated by introducing Cr ions into the lattice, which can lower the energy barrier of the rate determination step (RDS). Moreover, the degree of graphitization of carbon materials and the surface area can be optimized directly by doping amount of chromium into the lattice of TiN. Benefiting from that, the Ti0.95Cr0.05N/NC/C exhibited an onset potential as high as 0.854 V, an ultimate current density of 4.1 mA center dot cm(-2), remarkable stability and durability. The zinc-air battery based with Ti0.95Cr0.05N/NC/C has 1.25 V open-circuit voltage, a 760.26 mAh center dot g(-1) specific capacity, and excellent long-time discharge performance. This work provides a reliable way to develop stable and efficient binary transition metal nitride electrocatalysts.

Automated summary

Recently, transition metal nitrides (TMNs) have received attention as electrode materials due to their high conductivity, large surface area, electronic structure, and mechanical properties. However, their poor activity in the oxygen reduction reaction (ORR) limits their use in zinc-air batteries. This study introduces Cr ions into the lattice of titanium nitride (TiN) to regulate its d-band center and optimize its structure and performance. The resulting Ti0.95Cr0.05N/NC/C shows improved catalytic activity, stability, and durability, making it a promising candidate for zinc-air batteries.