A highly ionic transference number eutectogel hybrid electrolytes based on spontaneous coupling inhibitor for solid-state lithium metal batteries

• Published in: Nano research 2023, Vol.16 (1), p.1717-1725
• Main Authors: Bi, Linnan, Wei, Xiongbang, Qiu, Yuhong, Song, Yaochen, Long, Xin, Chen, Zhi, Wang, Sizhe, Liao, Jiaxuan
• Format: Article
• Language: English
• Subjects: Atomic/Molecular Structure and Spectra; Biomedicine; Biotechnology; Chemistry and Materials Science; Condensed Matter Physics; Materials Science; Nanotechnology; Research Article
• ISSN: 1998-0124; 1998-0000
• DOI: 10.1007/s12274-022-4759-7

Polymer-based solid electrolytes have been extensively studied for solid-state lithium metal batteries to achieve high energy density and reliable security. But, its practical application is severely limited by low ionic conductivity and slow Li + transference. Herein, based on the “binary electrolytes” of poly(vinylidene fluoride-chlorotrifluoroethylene) (P(VDF-CTFE)) and lithium salt (LiTFSI), a kind of eutectogel hybrid electrolytes (EHEs) with high Li + transference number was developed via tuning the spontaneous coupling of charge and vacated space generated by Li-cation diffusion utilizing the Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO) dopant. LLZTO doping promotes the dissociation of lithium salt, increases Li + carrier density, and boosts ion jumping and the coordination/decoupling reactions of Li + . As a result, the optimized EHEs-10% possess a high Li-transference number of 0.86 and a high Li + conductivity of 3.2×10 −4 S·cm −1 at room temperature. Moreover, the prepared EHEs-10% composite solid electrolyte presents excellent lithiumphilic and compatibility, and can be tested stably for 1,200 h at 0.3 mA·cm −2 with assembled lithium symmetric batteries. Likewise, the EHEs-10% films match well with high-loading LiFePO 4 and LiCoO 2 cathodes (> 10 mg·cm −2 ) and exhibit remarkable interface stability. Particularly, the LiFePO 4 //EHEs-10%//Li and LiCoO 2 //EHEs-10%//Li cells deliver high rate performance of 118 mA·hg −1 at 1 C and 93.7 mAh·g −1 at 2 C with coulombic efficiency of 99.3% and 98.1%, respectively. This work provides an in-depth understanding and new insights into our design for polymer electrolytes with fast Li + diffusion.