NiCo2O4-Based Nanosheets with Uniform 4 nm Mesopores for Excellent Zn-Air Battery Performance
NiCo2O4-Based Nanosheets with Uniform 4 nm Mesopores for Excellent Zn-Air Battery Performance
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具有均匀 4 nm 介孔的 NiCo2O4 基纳米片可实现出色的锌空气电池性能
DOI：
10.1002/adma.202001651
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发表时间：
2020
影响因子：
29.4
通讯作者：
Yan Chun-Hua
中科院分区：
文献类型：
--
作者：
Yin Jie;Jin Jing;Liu Hongbo;Huang Bolong;Lu Min;Li Jianyi;Liu Hanwen;Zhang Hong;Peng Yong;Xi Pinxian;Yan Chun-Hua
本文报道了一种制备具有可调钴价态和氧空位的NiCo 2 O 4基介孔纳米片（PNS）的策略。优化的NiCo2.148O4PNS具有平均Co价态为2.3和均匀的4 nm纳米孔，表现出优异的催化性能，在10 mA cm− 2的电流密度下具有190 mV的超低过电位和碱性介质中析氧反应（OER）的长期稳定性（700 h）。此外，使用NiCo2.148O4PNS构建的锌空气电池分别具有83 mW cm-2和910 Wh kg-1的高功率和能量密度。此外，使用NiCo2.148O4PNSs作为空气阴极的便携式电池盒在0至−35 °C的低温下具有120 h的长期稳定性。密度泛函理论计算表明，电催化剂的显著的电子交换和转移活性归因于多孔区域中的表面低配位的Co位，其呈现合并的3d-eg-t2 g带，其与Zn-空气电池系统的费米能级重叠。这有利于 *OH的吸附，并且达到稳定的 *O自由基，朝向竞争性地较低的过电位，证明了用于最佳地提高总体OER性能的通用关键。
Herein, a strategy is reported for the fabrication of NiCo2O4‐based mesoporous nanosheets (PNSs) with tunable cobalt valence states and oxygen vacancies. The optimized NiCo2.148O4PNSs 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−2and long‐term stability (700 h) for the oxygen evolution reaction (OER) in alkaline media. Furthermore, Zn–air batteries built using the NiCo2.148O4PNSs present a high power and energy density of 83 mW cm−2and 910 Wh kg−1, respectively. Moreover, a portable battery box with NiCo2.148O4PNSs 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–t2gband, 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.