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DOI number:10.1002/aenm.202003789

Journal:Advanced Energy Materials

Abstract:Na-O2 batteries are attractive for energy storage due to their high theoretical energy density. In order to alleviate Na dendrite formation, artificial protective coatings have been widely investigated in Na-metal batteries (NMBs). Although it can be intuitive to expect transferable Na protection methodologies from NMBs to Na-O2 batteries, the performance of anode protection coatings in Na-O2 batteries remains obscure, because Na-O2 batteries undergo a unique reaction mechanism involving superoxide. Here, the effect of superoxide crossover on the polymeric Na protection layer in Na-O2 batteries is revealed, and an effective strategy to eliminate the implications of a superoxide-sensitive protecting layer is proposed. Using polymeric alucone protected Na anode as an example, the alucone layer actually decomposes under superoxide attack and is incapable of facilitating long-term cycling of Na-O2 batteries in sharp contrast to its stable performance in NMBs. By blocking superoxide crossover with solid-state electrolytes (SSEs), significantly improved Na-O2 cell performance is demonstrated, recovering the Na dendrite suppressing effect of the alucone film. Benefiting from the synergistic effect of SSE and alucone layer, Na-O2 batteries can achieve a long life of 325 cycles at 0.2 mA cm−2. This work indicates that the stability of the Na protection layer against superoxide should be taken into serious consideration.

Indexed by:Journal paper

Translation or Not:no

Date of Publication:2021-01-05

Links to published journals:https://advanced.onlinelibrary.wiley.com/doi/abs/10.1002/aenm.202003789