We report considerable chemical and morphological changes of reaction products in binder-free, vertically-aligned carbon nanotube (VACNT) electrodes during Li-O 2 battery cycling with a 1,2-dimethoxyethane (DME)-based electrolyte. X-ray absorption near edge structure (XANES) of discharged oxygen electrodes shows direct evidence for the formation of Li 2 CO 3 -like species at the interface between VACNTs and Li 2 O 2 , but not significantly on the Li 2 O 2 surfaces exposed to the electrolyte. Although Li 2 O 2 and Li 2 CO 3 -like species were largely removed upon first charge, the oxidation kinetics became increasingly difficult during Li-O 2 cycling, which is accompanied by the accumulation of Li 2 CO 3 in the discharged and charged electrodes as evidenced by selected area electron diffraction (SAED) and transmission electron microscopy (TEM). Together, these results indicate that the irreversibility during Li-O 2 cycling in DME can be attributed largely to the growth of Li 2 CO 3 -like species associated with the reactivity between carbon and Li 2 O 2 or other reaction intermediates.

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Rechargeable aqueous zinc‐ion batteries (ZIBs) have been emerging as potential large‐scale energy storage devices due to their high energy density, low cost, high safety, and environmental friendliness. However, the commonly used cathode materials in ZIBs exhibit poor electrochemical performance, such as significant capacity fading during long‐term cycling and poor performance at high current rates, which significantly hinder the further development of ZIBs. Herein, a new and highly reversible Mn‐based cathode material with porous framework and N‐doping (MnOx@N‐C) is prepared through a metal–organic framework template strategy. Benefiting from the unique porous structure, conductive carbon network, and the synergetic effect of Zn2+ and Mn2+ in electrolyte, the MnOx@N‐C shows excellent cycling stability, good rate performance, and high reversibility for aqueous ZIBs. Specifically, it exhibits high capacity of 305 mAh g−1 after 600 cycles at 500 mA g−1 and maintains achievable capacity of 100 mAh g−1 at a quite high rate of 2000 mA g−1 with long‐term cycling of up to 1600 cycles, which are superior to most reported ZIB cathode materials. Furthermore, insight into the Zn‐storage mechanism in MnOx@N‐C is systematically studied and discussed via multiple analytical methods. This study opens new opportunities for designing low‐cost and high‐performance rechargeable aqueous ZIBs.