Percolating coordinated ion transport cells in polymer electrolytes to realize room-temperature solid-state lithium metal batteries

Abstract

Polymer electrolytes, notable for their good mechanical properties, superior processability, and high electrochemical stability, are promising for high-energy-density lithium metal batteries. However, the ionic conduction of polymer electrolytes is seriously constrained by either the entanglement of polymer chains or binding of anions, particularly at ambient temperatures, making their practical application impossible. Herein, we employ a high-salt-concentration strategy with poly(vinylene carbonate) to construct a percolating network by linking coordinated ion transport cells. The cells, consisting of lithium-ion at the core surrounded by coordinated poly(vinylene carbonate), N,N-dimethylformamide, or incompletely bonded bis(trifluoromethanesulfonyl)imide, ensure an efficient coordination and de-coordination process for ion transport. Thus, a high rate of Li+ transport is realized, achieving an ionic conductivity of 0.82 mS cm−1 at 30 °C. Consequently, the formulated solid-state lithium metal batteries with the poly(vinylene carbonate) electrolyte enable superior stability in cycling under a wide temperature range (0–60 °C), high working voltage (4.5 V), and high mass load (>10 mg cm−2). This simple strategy for creating an ion-percolating network by linking coordinated ion transport cells not only offers new insights into understanding the mechanism for ion transport in polymer electrolytes but also paves the way for the application of solid-state lithium metal batteries.