Dual-Coordination-Induced Poly(vinylidene fluoride)/Li6.4Ga0.2La3Zr2O12/Succinonitrile Composite Solid Electrolytes Toward Enhanced Rate Performance in All-Solid-State Lithium Batteries

Pursuing high energy and power density in all-solid-statelithiumbatteries (ASSLBs) has been the focus of attention. However, due totheir inferior ion transport, their rate performance is limited comparedto traditional lithium-ion batteries. Herein, a dual-coordinationmechanism is first proposed to construct a high-performance poly(vinylidenefluoride)/Li6.4Ga0.2La3Zr2O12/succinonitrile (PVDF/LLZO/SN) composite solid electrolyte.The dual-coordination interactions of SN with both LLZO and Li+ in lithium salts allow SN to act like a branched chain ofPVDF, realizing an increase in the free volume of the composite electrolyte.Meanwhile, SN molecules are immobilized within the electrolyte membraneby coordinating with LLZO, ensuring good interfacial stability. Profitingfrom the dual-coordination mechanism, the PVDF/LLZO/SN composite solidelectrolyte combines enhanced electrochemical performance and interfacialcompatibility. When applied to ASSLBs, the composite solid electrolyteenables the battery to operate at rates up to 6 C. The LiFePO4/Li batteries operated at 4 C can still deliver a high capacityretention rate of 96.4% after 50 cycles. Notably, these batteriesalso exhibit good long-cycle stability. After 500 cycles at 0.5 C,the discharge capacity was maintained at 145.9 mAh g(-1).

Automated summary

A dual-coordination mechanism is proposed to construct a high-performance PVDF/LLZO/SN composite solid electrolyte, which combines enhanced electrochemical performance and interfacial compatibility. The composite solid electrolyte enables ASSLBs to operate at high discharge rates and exhibit good long-cycle stability.