High-performance composite electrolytes for solid-state lithium metal batteries: Enhancing ionic conductivity and interfacial compatibility through polyvinylpyrrolidone blending and inorganic filler incorporation

Abstract

One of the significant challenges in advancing safe and high-energy-density solid-state lithium metal batteries is achieving high ionic conductivities and ensuring good interfacial compatibility between the solid electrolyte and the electrodes. To address these challenges, the study proposes a composite electrolyte that is made through a solution casting method, utilizing polyvinylidene fluoride hexafluorophosphate (PVDF-HFP) and polyvinylpyrrolidone (PVP) in conjunction with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt and mid-entropy inorganic filler Li1.5Sn1.0Al0.5Zr0.5(PO4)3. The polymer blend with an optimized ceramic filler exhibits an exceptional room-temperature ionic conductivity 1.48 × 10−4 S cm−1, a significantly high Li-ion transference number of 0.74, and shows electrochemical stability up to 4.58 V. The symmetric Li

Li cell fabricated with the composite electrolyte exhibits uniform Li+ deposition/stripping for over >500 h at 2 mA cm−2. Further, a full cell with LiFePO4 cathode and lithium anode is fabricated and shows excellent electrochemical performance with 78% capacity retention after 1000 cycles at 2C. The findings from this study advance the development of practical inorganic polymer electrolytes for fast-charging lithium batteries. © 2026 Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.