Polymer-based electrolytes for high-voltage solid-state lithium batteries

Increasing the charging cut-off voltage of lithium batteries is a feasible method to enhance the energy density. However, when batteries operate at high voltages (> 4.3 V), the degradation of liquid organic carbonate electrolyte is accelerated and may cause safety hazards. Polymer-based electrolytes with inherently high safety and good electrochemical stability can prevent the electrolyte degradation in high-voltage solid-state lithium batteries. This paper provides a comprehensive and in-depth review of the design strategies, recent developments, and scientific challenges associated with polymer-based electrolytes for high-voltage applications. Emphases are placed on the interfacial compatibility between electrolytes and cathodes, such as mechanical contacts and interface chemical stability, which are critical to the lifespan of high-voltage lithium batteries. Moreover, guidelines for the future development of high-voltage solid-state lithium batteries are also discussed.