Super‐Toughness Self‐Healing Composite Solid Electrolyte With Structured Interfacial Reconstruction Enabling Fast Ion Transport and Stable Interface for High‐Performance Solid‐State Lithium Metal Batteries
Feng Zou, Zhihong Yao, Bo Peng, Shixin Liu, Runwei MoABSTRACT
Lithium–metal batteries are widely regarded as a key direction for next‐generation energy storage systems due to high energy density. However, LiNi 0 . 8 Co 0 . 1 Mn 0 . 1 O 2 ||Li battery systems face severe challenges in practical application, including lithium dendrite growth, interfacial side reactions and structural degradation of high‐nickel cathodes. Here, we proposed a versatile modification strategy combining in‐situ interfacial transformation with polymer phase regulation to fabricate self‐healing solid polymer electrolyte with fast ion transport and stable interface. This strategy not only constructs fast ion channels and suppresses hydrofluoric acid production by in‐situ converting Li 2 CO 3 on the Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 surface into Li 2 PO 3 F interfacial layer, but also induces the transition of PVDF from α‐phase to high polarity β‐phase using ethylenediaminetetraacetic acid to promote lithium salt dissolution and reduce Li + migration resistance. The as‐prepared electrolyte exhibits extended electrochemical voltage windows (5.13 V), high room‐temperature ionic conductivity (1.694 mS cm − 1 ), excellent thermal stability (200°C), high elongation at break (422.6%), and superior cycling stability (89.4% retention after 500 cycles at 1 C). A non‐destructive monitoring method based on d p /|d Q | and d T /|d Q | differential signals has been developed to track electrochemical‐mechanical‐thermal responses during battery operation. This work provides an effective strategy for designing solid polymer electrolytes with high ionic conductivity and interfacial stability.