In situ TEM visualization of single atom catalysis in solid-state Na–O2 nanobatteries. Issue 11 (18th November 2021)

• Record Type: Journal Article
• Authors: Sun, Haiming; Liu, Qiunan; Gao, Zhiying; Geng, Lin; Li, Yanshuai; Zhang, Fengyu; Yan, Jitong; Gao, Yufei; Suenaga, Kazu; Zhang, Liqiang; Tang, Yongfu; Huang, Jianyu
• Is Part Of: Journal of materials chemistry. Volume 10:Issue 11(2022)
• Page Start: 6096
• Page End: 6106
• Publication Date: 2021-11-18
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d1ta08080f
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : In situ TEM observation and DFT calculation provide an atomic-scale understanding of the electrocatalysis mechanism of single-atom catalysts in an Na–O2 nanobattery, where single-atomic Co sites facilitate the formation/decomposition of Na2 O2 . Abstract : Single-atom catalysts (SACs) exhibit high catalytic activities in many systems including metal–air batteries. However, the fundamental catalytic mechanism of SACs during the charge/discharge process is still unclear. Herein, we report a real-time imaging of the microscopic evolution of single-atom Co/reduced graphene oxide (SA-Co/rGO) in Na–O2 nanobatteries via an in situ environmental transmission electron microscope. Clearly, Na2 O2 spheres were formed on the surface of the SA-Co/rGO scaffold during discharging, which can be easily decomposed during charging. In contrast, the formation and decomposition of Na2 O2 on bare rGO without SACs were very sluggish. Moreover, a coin cell Na–O2 battery with an SA-Co/rGO air cathode also displays superior performance to a bare rGO cathode. DFT calculations reveal that the local coordination environment (Co + 4N) played a key role in tuning the charge density and oxidation states of the isolated Co active sites, thus activating O2 molecules and facilitating the oxygen reduction reaction/oxygen evolution reaction processes. This study suggests that SA-Co/rGO may be a promising catalyst for enhancing the performance of Na–O2 batteries.