Achieving long cycle life for all-solid-state rechargeable Li-I<sub>2</sub> battery by a confined dissolution strategy.

Cheng, Zhu; Pan, Hui; Li, Fan; Duan, Chun; Liu, Hang; Zhong, Hanyun; Sheng, Chuanchao; Hou, Guangjin et al. · Nat Commun · 2022

basic_science · Level V

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Abstract

Rechargeable Li-I<sub>2</sub> battery has attracted considerable attentions due to its high theoretical capacity, low cost and environment-friendliness. Dissolution of polyiodides are required to facilitate the electrochemical redox reaction of the I<sub>2</sub> cathode, which would lead to a harmful shuttle effect. All-solid-state Li-I<sub>2</sub> battery totally avoids the polyiodides shuttle in a liquid system. However, the insoluble discharge product at the conventional solid interface results in a sluggish electrochemical reaction and poor rechargeability. In this work, by adopting a well-designed hybrid electrolyte composed of a dispersion layer and a blocking layer, we successfully promote a new polyiodides chemistry and localize the polyiodides dissolution within a limited space near the cathode. Owing to this confined dissolution strategy, a rechargeable and highly reversible all-solid-state Li-I<sub>2</sub> battery is demonstrated and shows a long-term life of over 9000 cycles at 1C with a capacity retention of 84.1%.