New Self-Healing Polymer Electrolyte for Interfacial Stability in Solid-State Lithium Batteries

Solid-state lithium batteries (SSLBs) have attracted attention due to their high energy density and safety. However, the volumetric expansion/contraction of electrodes and persistent interfacial side reactions cause mechanical stress damage and failure of interfacial ion transport, affecting long-term stability.

To address this, a study published in the journal Advanced Materials reported an interfacial self-healing polymer electrolyte (SHPE) based on gradient covalent–noncovalent dynamic bonds. Through molecular engineering, this material combines high-strength boronic ester bonds with ultrafast dynamic responsive hydrogen bonds, enabling efficient room-temperature self-repair of interfacial defects in SSLBs.

This self-healing electrolyte demonstrated good ionic conductivity at room temperature. Lithium cobalt oxide (LCO)|SHPE|Li pouch cells using this electrolyte cycled stably under high voltage (4.6 V) and high cathode loading, and passed nail penetration safety tests without thermal runaway. This strategy provides a new technical pathway for developing high-energy-density and safe solid-state batteries.