1. Unlocking the Poly(vinylidene fluoride-co-hexafluoropropylene)/Li10GeP2S12 composite solid-state Electrolytes for Dendrite-Free Li metal batteries assisting with perfluoropolyethers as bifunctional adjuvant.
- Author
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Cong, Lina, Li, Yanan, Lu, Wei, Jie, Jing, Liu, Yulong, Sun, Liqun, and Xie, Haiming
- Subjects
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SOLID state batteries , *ELECTROLYTES , *ELECTRIC batteries , *SOLID electrolytes , *POLAR solvents , *IONIC conductivity - Abstract
Sulfide-based composite solid-state electrolyte has been deemed as "Holy Grail" for unlocking solid-state lithium metal batteries (SSLMBs) with high-energy density, combining the extremely high ionic conductivity of sulfide and machinability of organic polymer. However, this appealing system is hitherto stymied by two hindrances, difficult to synthesize due to the chemical incompatibility of sulfide with moisture and polar solvents, moreover, interfacial instability with lithium (Li) anode inducing severe Li dendrite grown. Herein, by utilizing perfluoropolyethers as bifunctional adjuvant, we initiatively fabricate sulfide-based composite electrolyte, Poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)/Li 10 GeP 2 S 12 and assemble SSLMBs. Perfluoropolyethers with low molecular weight facilitate the stable dispersion of Li 10 GeP 2 S 12 in casting solution, ascribed to their strong electronegativity of C–F bonds. In addition, high molecular weight perfluoropolyethers function as interfacial stabilizer, dramatically improving the interfacial compatibility with Li anode by in-situ forming a LiF-rich solid electrolyte interphase layer. This composite electrolyte exhibits high room temperature ionic conductivity (0.18 mS cm−1), outstanding lithium ion transfer number (0.68), good mechanical strength and nonflammability. The solid-state LiFePO 4 ǁLi battery presents superior long-term cycling stability and rate capability. Our study paves a new way for fabricating the sulfide-based composite electrolyte, provides an effective strategy for constructing compatible solid-state electrolyteǁLi interface. Image 1 • PVDF-HFP/Li 10 GeP 2 S 12 electrolyte is prepared by binary solution casting method. • PFPE 500 as dispersing solvents exhibit good chemical compatibility with Li 10 GeP 2 S 12. • A high ion conductivity (σ RT = 10−4 S cm−1) and Li+ transfer number (0.68) are obtained. • PFPEs as interfacial stabilizers enhance the compatibility of Li 10 GeP 2 S 12 with Li. • LiFePO 4 ‖Li battery shows good cycling stability and rate capability. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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