摘要
Composite solid electrolytes (CSEs) offer a promising approach for solid-state lithium-ion batteries (LIBs), integrating polymers, ionic liquids, and ceramics to attain high thermal stability, fast ionic conduction, and low interfacial resistance. In this study, we developed a novel CSE using a high-dielectric high-entropy oxide, Li1.3Al0.4Ti0.5Zr0.5Sn0.5Ta0.1(PO4)3 (LATZSTP), with poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (Pyr14TFSI). The CSE—incorporated with up to 20 wt% LATZSTP—achieved a high ionic conductivity of 6.79 (±0.04) × 10−4 S cm−1 and demonstrated high electrochemical stability through Li stripping and plating tests. When the CSE of 40 wt% in a solid-state LIB with a lithium metal anode and LiFePO4 cathode (denoted as Li/CSE/LiFePO4), the CSE enabled an initial discharge capacity of 158 mA h g−1, retaining 80.97% of this capacity after 400 cycles. These findings highlight this CSE for high-performance and safe solid-state LIBs.
The use of high lithium salt and ionic liquid concentrations improved ionic conductivity and interfacial wetting, while the high concentration of anion inside would inhibit the conduction of Li+ ion. In correspondence, a high-dielectric high-entropy LATZSTP content effectively mitigated the complexation between Li+ ions and anions. [Display omitted]
•High lithium salt/ionic liquid in composite solid electrolyte boosts conductivity.•High-dielectric, high-entropy oxide enhances electrochemical stability.•LFP/40wt111/Li cell retains 80.97% capacity after 400 cycles.