Gao Zhiying, Yao Jingming, Yan Jitong, Sun Jun, Du Congcong, Dai Qiushi, Su Yong, Zhao Jun, Chen Jingzhao, Li Xiaomei, Li Hui, Zhang Pan, Ma Jun, Qiu Hailong, Zhang Liqiang, Tang Yongfu, Huang Jianyu
Clean Nano Energy Center, State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066004, P. R. China.
Hebei Key Laboratory of Applied Chemistry, College of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao, 066004, P. R. China.
Small. 2024 Jul;20(30):e2311739. doi: 10.1002/smll.202311739. Epub 2024 Feb 29.
Rechargeable aprotic lithium (Li)-oxygen battery (LOB) is a potential next-generation energy storage technology because of its high theoretical specific energy. However, the role of redox mediator on the oxide electrochemistry remains unclear. This is partly due to the intrinsic complexity of the battery chemistry and the lack of in-depth studies of oxygen electrodes at the atomic level by reliable techniques. Herein, cryo-transmission electron microscopy (cryo-TEM) is used to study how the redox mediator LiI affects the oxygen electrochemistry in LOBs. It is revealed that with or without LiI in the electrolyte, the discharge products are plate-like LiOH or toroidal LiO, respectively. The I assists the decomposition of LiOH via the formation of LiIO in the charge process. In addition, a LiI protective layer is formed on the Li anode surface by the shuttle of I , which inhibits the parasitic Li/electrolyte reaction and improves the cycle performance of the LOBs. The LOBs returned to 2e oxygen reduction reaction (ORR) to produce LiO after the LiI in the electrolyte is consumed. This work provides new insight on the role of redox mediator on the complex electrochemistry in LOBs which may aid the design LOBs for practical applications.
可充电非质子锂（Li）-氧电池（LOB）因其高理论比能量而成为一种潜在的下一代储能技术。然而，氧化还原介质在氧化物电化学中的作用仍不明确。部分原因在于电池化学的内在复杂性以及缺乏通过可靠技术在原子水平上对氧电极的深入研究。在此，低温透射电子显微镜（cryo-TEM）用于研究氧化还原介质LiI如何影响LOBs中的氧电化学。结果表明，无论电解质中有无LiI，放电产物分别为片状LiOH或环形LiO。I在充电过程中通过形成LiIO协助LiOH分解。此外，I的穿梭在Li阳极表面形成LiI保护层，抑制了寄生的Li/电解质反应并提高了LOBs的循环性能。电解质中的LiI消耗后，LOBs恢复到2e氧还原反应（ORR）以生成LiO。这项工作为氧化还原介质在LOBs复杂电化学中的作用提供了新的见解，这可能有助于设计用于实际应用的LOBs。
