Details

Autor(en) / Beteiligte

• Yin, Jie
• Jin, Jing
• Liu, Hongbo
• Huang, Bolong
• Lu, Min
• Li, Jianyi
• Liu, Hanwen
• Zhang, Hong
• Peng, Yong
• Xi, Pinxian
• Yan, Chun‐Hua

Titel

NiCo2O4‐Based Nanosheets with Uniform 4 nm Mesopores for Excellent Zn–Air Battery Performance

Ist Teil von

• Advanced materials (Weinheim), 2020-10, Vol.32 (39), p.n/a

Ort / Verlag

Weinheim: Wiley Subscription Services, Inc

Erscheinungsjahr

2020

Quelle

Wiley Online Library All Journals

Beschreibungen/Notizen

• Herein, a strategy is reported for the fabrication of NiCo2O4‐based mesoporous nanosheets (PNSs) with tunable cobalt valence states and oxygen vacancies. The optimized NiCo2.148O4 PNSs with an average Co valence state of 2.3 and uniform 4 nm nanopores present excellent catalytic performance with an ultralow overpotential of 190 mV at a current density of 10 mA cm−2 and long‐term stability (700 h) for the oxygen evolution reaction (OER) in alkaline media. Furthermore, Zn–air batteries built using the NiCo2.148O4 PNSs present a high power and energy density of 83 mW cm−2 and 910 Wh kg−1, respectively. Moreover, a portable battery box with NiCo2.148O4 PNSs as the air cathode presents long‐term stability for 120 h under low temperatures in the range of 0 to −35 °C. Density functional theory calculations reveal that the prominent electron exchange and transfer activity of the electrocatalyst is attributed to the surface lower‐coordinated Co‐sites in the porous region presenting a merging 3d–eg–t2g band, which overlaps with the Fermi level of the Zn–air battery system. This favors the adsorption of the *OH, and stabilized *O radicals are reached, toward competitively lower overpotential, demonstrating a generalized key for optimally boosting overall OER performance. Optimized NiCo2.148O4 mesoporous nanosheets with an average Co valence state of 2.3 and uniform 4 nm mesopores demonstrate exceptional performance for Zn–air batteries under a wide temperature range from 80 to −35 °C, which arises from the high activities of electron exchange and transfer by the surface lower‐coordinated Co‐sites within the porous region.