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

Shiyu Cao; Fei Chen; Qiang Shen; Lianmeng Zhang

doi:10.1021/acsami.3c06179

Dual-Coordination-Induced Poly(vinylidene fluoride)/Li_6.4Ga_0.2La₃Zr₂O₁₂/Succinonitrile Composite Solid Electrolytes Toward Enhanced Rate Performance in All-Solid-State Lithium Batteries

ACS Appl Mater Interfaces. 2023 Aug 9;15(31):37422-37432. doi: 10.1021/acsami.3c06179. Epub 2023 Jul 27.

Authors

Shiyu Cao^{1

2}, Fei Chen^{1

2}, Qiang Shen¹, Lianmeng Zhang¹

Affiliations

¹ State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China.
² International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China.

PMID: 37497870
DOI: 10.1021/acsami.3c06179

Abstract

Pursuing high energy and power density in all-solid-state lithium batteries (ASSLBs) has been the focus of attention. However, due to their inferior ion transport, their rate performance is limited compared to traditional lithium-ion batteries. Herein, a dual-coordination mechanism is first proposed to construct a high-performance poly(vinylidene fluoride)/Li_6.4Ga_0.2La₃Zr₂O₁₂/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 of PVDF, realizing an increase in the free volume of the composite electrolyte. Meanwhile, SN molecules are immobilized within the electrolyte membrane by coordinating with LLZO, ensuring good interfacial stability. Profiting from the dual-coordination mechanism, the PVDF/LLZO/SN composite solid electrolyte combines enhanced electrochemical performance and interfacial compatibility. When applied to ASSLBs, the composite solid electrolyte enables the battery to operate at rates up to 6 C. The LiFePO₄/Li batteries operated at 4 C can still deliver a high capacity retention rate of 96.4% after 50 cycles. Notably, these batteries also exhibit good long-cycle stability. After 500 cycles at 0.5 C, the discharge capacity was maintained at 145.9 mAh g^-1.

Keywords: LLZO; PVDF; all-solid-state lithium batteries; composite solid electrolyte; coordination interaction; succinonitrile.