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Enhanced Stability of Coated Carbon Electrode for Li‐O 2 Batteries and Its Limitations
Author(s) -
Bae Youngjoon,
Ko DongHyun,
Lee Sunyoung,
Lim HeeDae,
Kim YunJung,
Shim HyunSoo,
Park Hyeokjun,
Ko Youngmin,
Park Sung Kwan,
Kwon Hyuk Jae,
Kim Hyunjin,
Kim HeeTak,
Min YoSep,
Im Dongmin,
Kang Kisuk
Publication year - 2018
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201702661
Subject(s) - materials science , electrode , electrolyte , carbon fibers , coating , degradation (telecommunications) , chemical engineering , electrochemistry , battery (electricity) , energy storage , nanotechnology , composite material , chemistry , electrical engineering , power (physics) , physics , engineering , quantum mechanics , composite number
Abstract Li‐O 2 batteries are promising next‐generation energy storage systems because of their exceptionally high energy density (≈3500 W h kg −1 ). However, to achieve stable operation, grand challenges remain to be resolved, such as preventing electrolyte decomposition and degradation of carbon, a commonly used air electrode in Li‐O 2 batteries. In this work, using in situ differential electrochemical mass spectrometry, it is demonstrated that the application of a ZnO coating on the carbon electrode can effectively suppress side reactions occurring in the Li‐O 2 battery. By probing the CO 2 evolution during charging of 13 C‐labeled air electrodes, the major sources of parasitic reactions are precisely identified, which further reveals that the ZnO coating retards the degradation of both the carbon electrode and electrolyte. The successful suppression of the degradation results in a higher oxygen efficiency, leading to enhanced stability for more than 100 cycles. Nevertheless, the degradation of the carbon electrode is not completely prevented by the coating, because the Li 2 O 2 discharge product gradually grows at the interface between the ZnO and carbon, which eventually results in detachment of the ZnO particles from the electrode and subsequent deterioration of the performance. This finding implies that surface protection of the carbon electrode is a viable option to enhance the stability of Li‐O 2 batteries; however, fundamental studies on the growth mechanism of the discharge product on the carbon surface are required along with more effective coating strategies.