Work

Composite Separator with Superior Thermal Shrinkage Resistance for the Safety of Lithium Metal Batteries

Year: 2026

Type: article

Abstract: ABSTRACT High‐energy‐density batteries have raised numerous safety concerns, particularly thermal runaway. Separators play an indispensable role in battery safety. Herein, an Al 2 O 3 ‐coated composite separator (LSO‐Al 2 O 3 @PE) with superior thermal shrinkage resistance is prepared with lithium polysilicate (LSO) as a binder. Different from the common organic binder, the binding force of inorganic LSO binder to Al 2 O 3 particles can be further strengthened through the in situ dehydration and condensation at elevated temperatures, significantly enhancing the thermal shrinkage resistance of the composite separator (∼ zero thermal shrinkage at 200°C). The LSO‐Al 2 O 3 @PE separator also demonstrates thermal shutdown and acid impurity scavenging properties, effectively improving the safety and cycling performance of lithium metal batteries. The Li|LSO‐Al 2 O 3 @PE|LiFePO 4 cells retains 70% capacity after 1000 cycles, and the Li|LSO‐Al 2 O 3 @PE|LiNi 0.8 Co 0.1 Mn 0.1 O 2 cells retains 81% capacity after 200 cycles. This work provides a new solution to improve the thermal shrinkage resistance of commercial polyolefin separators.

Source: Small

DOI: 10.1002/smll.73915