NiFe Layered Double Hydroxide Nanoparticles on Co,N‐Codoped Carbon Nanoframes as Efficient Bifunctional Catalysts for Rechargeable Zinc–Air Batteries

• Published in: Advanced energy materials 2017-11, Vol.7 (21), p.n/a
• Main Authors: Wang, Qing, Shang, Lu, Shi, Run, Zhang, Xin, Zhao, Yufei, Waterhouse, Geoffrey I. N., Wu, Li‐Zhu, Tung, Chen‐Ho, Zhang, Tierui
• Format: Article
• Language: English
• Subjects: Anchoring; Co,N‐codoped carbon nanoframes; Cobalt; Electrical resistivity; Electrocatalysts; Hydroxides; Intermetallic compounds; Iron compounds; Metal air batteries; Nanoparticles; Nickel compounds; NiFe layered double hydroxide; oxygen evolution reaction; Oxygen evolution reactions; oxygen reduction reaction; Rechargeable batteries; rechargeable zinc–air batteries; Zinc-oxygen batteries
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.201700467

The future large‐scale deployment of rechargeable zinc–air batteries requires the development of cheap, stable, and efficient bifunctional electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). In this work, a highly efficient bifunctional electrocatalyst is prepared by depositing 3–5 nm NiFe layered double hydroxide (NiFe‐LDH) nanoparticles on Co,N‐codoped carbon nanoframes (Co,N‐CNF). The NiFe‐LDH/Co,N‐CNF electrocatalyst displayed an OER overpotential of 0.312 V at 10 mA cm−2 and an ORR half‐wave potential of 0.790 V. The outstanding performance of the electrocatalyst is attributable to the high electrical conductivity and excellent ORR activity of Co,N‐CNF, together with the strong anchoring of 3–5 nm NiFe‐LDH nanoparticles, which preserves active sites. Inspired by the excellent OER and ORR performance of NiFe‐LDH/Co,N‐CNF, a prototype rechargeable zinc–air battery is developed. The battery exhibited a low discharge–charge voltage gap (1.0 V at 25 mA cm−2) and long‐term cycling durability (over 80 h), and superior overall performance to a counterpart battery constructed using a mixture of IrO2 and Pt/C as the cathode. The strategy developed here can easily be adapted to synthesize other bifunctional CNF‐based hybrid electrodes for ORR and OER, providing a practical route to more efficient rechargeable zinc–air batteries. A bifunctional NiFe‐layered double hydroxide (LDH)/Co,N‐carbon nanoframe (CNF) electrocatalyst, comprising 3–5 nm NiFe‐LDH particles immobilized on Co,N‐doped carbon nanoframes (Co,N‐CNF), demonstrates excellent activities for both oxygen evolution reaction and oxygen reduction reaction, and outstanding performance and stability as cathode catalysts in rechargeable zinc–air batteries. Intimate contact between NiFe‐LDH and Co,N‐CNF preventing NiFe‐LDH aggregation is the key to the higher electrocatalytic activity and stability of NiFe‐LDH/Co,N‐CNF compared to precious metal‐based catalysts.