Composite solid electrolyte comprising poly(propylene carbonate) and Li1.5Al0.5Ge1.5(PO4)3 for long-life all-solid-state Li-ion batteries

• Published in: Electrochimica acta Vol. 392; p. 139007
• Main Authors: Sung, Bong-Joon, Didwal, Pravin N., Verma, Rakesh, Nguyen, An-Giang, Chang, Duck Rye, Park, Chan-Jin
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2021
• Subjects: All-solid-state Li-ion battery; Composite solid polymer electrolyte; Li1.5Al0.5Ge1.5(PO4)3 inorganic filler; Long cyclability; Poly(propylene) carbonate; Li1.5Al0.5Ge1.5(PO4)3 inorganic filler; Composite solid polymer electrolyte; All-solid-state Li-ion battery; Long cyclability; Poly(propylene) carbonate
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2021.139007

•Solid polymer electrolyte (CSPE) comprised poly(propylene carbonate) and Li1.5Al0.5Ge1.5(PO4)3.•CSPE exhibited a high ionic conductivity of ∼5.63 × 10−4 S cm−1 at 60°C.•The Li/CSPE/Li cell displayed a superior stability over 1000 h with minimal over potential.•The Li/CSPE/LFP delivered a specific discharge capacity of 151 mAh g−1 at 0.1 C.•The Li/CSPE/LFP exhibited an excellent cyclability over 1000 cycles at 1 C. Solid electrolytes are a potential candidate for mitigating the safety issues associated with organic liquid-electrolyte-based conventional Lithium-Ion Batteries (LIBs). The film-forming ability, cost-effective fabrication, and superior interfacial contact of solid polymer electrolytes make them particularly appealing for application in all-solid-state LIBs (ASSLIBs). However, their practical applications are limited owing to their low lithium-ion conductivity and inadequate mechanical strength. In this study, we fabricated a highly flexible, soft, self-standing, and stable composite solid polymer electrolyte (CSPE) using poly(propylene carbonate) (PPC) as the main matrix and Na-superionic-conductor-type Li1.5Al0.5Ge1.5(PO4)3 (LAGP) as the active inorganic filler. The fabricated CSPE exhibited an attractive ionic conductivity of ∼0.56 mS∙cm−1, a wide electrochemical potential stability of ∼5 V vs. Li/Li+, a high lithium-ion transference number of ∼0.77, outstanding stability up to 1000 cycles of lithium plating/stripping, and better compatibility with lithium metal. In addition to these outstanding properties, the Li/CSPE/LiFePO4 (Li/CSPE/LFP) cell exhibited an impressive discharge capacity of 151 mAh∙g−1 at 0.1 C. Furthermore, at a rate of 1 C, the Li/CSPE/LFP cell delivered an initial discharge capacity of 96 mAh∙g−1, with a capacity retention of 63% over 1000 cycles. The interaction of lithium ions with the PPC was confirmed based on solid-state MAS NMR and XPS. The enhanced electrochemical performance of the CSPE is ascribed to the interaction of the LAGP filler with the PPC matrix, which forms a good polymer-inorganic interface, enabling the rapid lithium-ion transport. The proposed LAGP-reinforced CSPE presents new opportunities for the fabrication and engineering of ASSLIBs. A solid polymer electrolyte composed of poly(propylene carbonate) and LAGP ceramic filler opens avenue for easy Li ion transportation and exhibited outstanding stability with Li anode as well as LFP cathode. [Display omitted]