Ji Dongxiao, Fan Li, Li Linlin, Peng Shengjie, Yu Deshuang, Song Junnan, Ramakrishna Seeram, Guo Shaojun
Jiangsu Key Laboratory of Electrochemical Energy Storage Technologies, College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China.
Department of Mechanical Engineering, National University of Singapore, 117574, Singapore, Singapore.
Adv Mater. 2019 Apr;31(16):e1808267. doi: 10.1002/adma.201808267. Epub 2019 Feb 25.
Metal single-atom materials with their high atom utilization efficiency and unique electronic structures usually show remarkable catalytic performances in many crucial chemical reactions. Herein, a facile and easily scalable "impregnation-carbonization-acidification" strategy for fabricating a class of single-atom-anchored (including cobalt and nickel single atoms) monolith as superior binder-free electrocatalysts for developing high-performance wearable Zn-air batteries is reported. The as-prepared single atoms, supported by N-doped carbon flake arrays grown on carbon nanofibers assembly (M SA@NCF/CNF), demonstrate the dual characteristics of excellent catalytic activity (reversible oxygen overpotential of 0.75 V) and high stability, owing to the greatly improved active sites' accessibility and optimized single-sites/pore-structures correlations. Furthermore, wearable Zn-air battery based on Co SA@NCF/CNF air electrode displays superior stability under deformation, satisfactory energy storage capacity, and good practicality to be utilized as an integrated battery system. Theoretical calculations reveal a mechanism for the promotion of the catalytic performances on single atomic sites by lowering the overall oxygen reduction/evolution reaction barriers comparing to metal cluster co-existing configuration. These findings provide a facile strategy for constructing free-standing single-atom materials as well as the engineering of high-performance binder-free catalytic electrodes.
金属单原子材料因其高原子利用效率和独特的电子结构，通常在许多关键化学反应中表现出卓越的催化性能。在此，报道了一种简便且易于扩展的“浸渍-碳化-酸化”策略，用于制备一类单原子锚定（包括钴和镍单原子）的整体材料，作为开发高性能可穿戴锌空气电池的优异无粘结剂电催化剂。所制备的单原子负载在碳纳米纤维组件上生长的氮掺杂碳片阵列（M SA@NCF/CNF）上，由于活性位点的可及性大大提高以及单原子位点/孔结构相关性得到优化，展现出优异的催化活性（可逆氧过电位为0.75 V）和高稳定性的双重特性。此外，基于Co SA@NCF/CNF空气电极的可穿戴锌空气电池在变形下显示出优异的稳定性、令人满意的储能容量以及作为集成电池系统的良好实用性。理论计算揭示了与金属簇共存构型相比，通过降低整体氧还原/析氧反应势垒来促进单原子位点催化性能的机制。这些发现为构建独立的单原子材料以及高性能无粘结剂催化电极的工程设计提供了一种简便策略。
