Iron Single Atoms‐Assisted Cobalt Nitride Nanoparticles to Strengthen the Cycle Life of Rechargeable Zn–Air Battery

Abstract

The development of nonprecious metal catalysts with both oxygen reduction and evolution reactions (ORR/OER) is very important for Zn–air batteries (ZABs). Herein, a Co5.47N particles and Fe single atoms co‐doped hollow carbon nanofiber self‐supporting membrane (H‐CoFe@NCNF) is synthesized by a coaxial electrospinning strategy combined with pyrolysis. X‐ray absorption fine spectroscopy analyses confirm the state of the cobalt nitride and Fe single atoms. As a result, H‐CoFe@NCNF exhibits a superior bifunctional performance of Eonset = 0.96 V for ORR, and Ej = 10 = 1.68 V for OER. Density functional theory calculations show that H‐CoFe@NCNF has a moderate binding strength to oxygen due to the coexistence of nanoparticle and single atoms. Meanwhile, the Co site is more favorable to the OER, while the Fe site facilitates the ORR, and the proton and charge transfer between N and metal atoms further lower the reaction barriers. The liquid ZAB composed of H‐CoFe@NCNF has a charge–discharge performance of ≈1100 h and a peak power density of 205 mW cm−2. The quasi‐solid‐state ZAB assembled by the self‐supporting membrane of H‐CoFe@NCNF is proven to operate stably in any bending condition.

Modulation of Phase Transition in Cobalt Selenide with Simultaneous Construction of Heterojunctions for Highly‐Efficient Oxygen Electrocatalysis in Zinc–Air Battery

“…Interestingly, the WT contour plots of c‐CoSe 2 ‐CoN/NC slightly shift to the right direction compared to c‐CoSe 2 , which proves that there is charge transfer between CoN and c‐CoSe 2 to facilitate the oxygen adsorption/desorption processes. [ 43 ]…”

Recent advances in Fe‐N‐C single‐atom site coupled synergistic catalysts for boosting oxygen reduction reaction

“…These nanofibers can act as selfsupporting cathodes in ZAB, avoiding the need for conductivity-affecting binders. 99 Zhang et al 97 recently employed coaxial electrospinning and pyrolysis to create a self-supporting membrane containing Co 5.47 N particles and Fe SA sites (H-CoFe@NCNF, Figure 4C), showing excellent ORR/ oxygen evolution reaction (OER) activity. They spun a core solution (polyvinyl pyrrolidone and Fe 2þ salt in N,N-dimethylformamide) and shell solution (polyacrylonitrile and Co 2þ salt) under specific conditions, yielding the H-CoFe@NCNF membrane.…”

“…They spun a core solution (polyvinyl pyrrolidone and Fe 2þ salt in N,N-dimethylformamide) and shell solution (polyacrylonitrile and Co 2þ salt) under specific conditions, yielding the H-CoFe@NCNF membrane. 97 Sun et al 100 similarly used electrospinning to create diverse Fe-N-C catalysts. They dissolved polyacrylonitrile, cellulose acetate, polystyrene, and Fe 3þ salt in N,N-dimethylformamide, generating Fe@CNFs.…”

Single-atom sites combined with metal nano-aggregates for efficient electrocatalysis

“…8a). 84 The authors constructed the optimal catalyst structure models using DFT calculations to trace the reaction sites for the ORR and OER in H-CoFe@NCNF. The DOS illustrated that Co 5.47 N/Fe-N 4 -N featured a relatively moderate e d compared to other models, pointing to a medium oxygen adsorption strength on active sites, causing favorable ORR/OER catalytic activity (Fig.…”