article epub_ahead yes Shengnan Zhang author Guifang Zeng author Jing Yu author Sharona Horta author 03a7e858-01b1-11ec-8b71-99ae6c4a05bc Xuan Lu author Qing Sun author Yuchuan Ren author Maria Ibáñez author 43C61214-F248-11E8-B48F-1D18A9856A870000-0001-5013-2843 Jordi Llorca author Jordi Jacas Biendicho author Jordi Arbiol author Lijie Ci author Andreu Cabot author MaIb department HighTE: The Werner Siemens Laboratory for the High Throughput Discovery of Semiconductors for Waste Heat Recovery project Solid-state polymer electrolytes (SPEs) are promising for high-safety, high-energy-density lithium metal batteries, but their adoption is limited by low room-temperature ionic conductivity and insufficient mechanical robustness. This study reports an improved SPE architecture consisting of a three-dimensional (3D) polyacrylonitrile (PAN)–Li6.4La3Zr1.4Ta0.6O12 (LLZTO) fibrous skeleton infused with a polymer electrolyte ionic liquid (PIL), which promotes lithium-salt dissociation, accelerates Li+ transport, and enhances mechanical strength. The resulting SPE achieves an ionic conductivity of up to 0.51 mS cm−1. Li|Li symmetric cells using a 40-µm-thick SPE cycle stably for 2500 h at 0.2 mA cm−2 with a low overpotential of 30 mV. In Li|LiFePO4 (LFP) full cells, the electrolyte enables 86.8% capacity retention after 1000 cycles at 0.5 C and maintains stable operation at 130 °C. Flexible pouch-cell tests further confirm improved safety and durability under harsh conditions, highlighting the potential of this SPE design for high-voltage lithium metal batteries. Springer2026 eng 2524-7921 2524-793X10.1007/s42765-026-00775-2 S. Zhang <i>et al.</i>, “Reinforced poly(ionic liquid)-in-salt electrolytes for highly stable solid-state Lithium metal batteries,” <i>Advanced Fiber Materials</i>. Springer, 2026. Zhang S, Zeng G, Yu J, et al. Reinforced poly(ionic liquid)-in-salt electrolytes for highly stable solid-state Lithium metal batteries. <i>Advanced Fiber Materials</i>. 2026. doi:<a href="https://doi.org/10.1007/s42765-026-00775-2">10.1007/s42765-026-00775-2</a> Zhang, S., Zeng, G., Yu, J., Horta, S., Lu, X., Sun, Q., … Cabot, A. (2026). Reinforced poly(ionic liquid)-in-salt electrolytes for highly stable solid-state Lithium metal batteries. <i>Advanced Fiber Materials</i>. Springer. <a href="https://doi.org/10.1007/s42765-026-00775-2">https://doi.org/10.1007/s42765-026-00775-2</a> Zhang S, Zeng G, Yu J, Horta S, Lu X, Sun Q, Ren Y, Ibáñez M, Llorca J, Biendicho JJ, Arbiol J, Ci L, Cabot A. 2026. Reinforced poly(ionic liquid)-in-salt electrolytes for highly stable solid-state Lithium metal batteries. Advanced Fiber Materials. S. Zhang, G. Zeng, J. Yu, S. Horta, X. Lu, Q. Sun, Y. Ren, M. Ibáñez, J. Llorca, J.J. Biendicho, J. Arbiol, L. Ci, A. Cabot, Advanced Fiber Materials (2026). Zhang, Shengnan, et al. “Reinforced Poly(Ionic Liquid)-in-Salt Electrolytes for Highly Stable Solid-State Lithium Metal Batteries.” <i>Advanced Fiber Materials</i>, Springer, 2026, doi:<a href="https://doi.org/10.1007/s42765-026-00775-2">10.1007/s42765-026-00775-2</a>. Zhang, Shengnan, Guifang Zeng, Jing Yu, Sharona Horta, Xuan Lu, Qing Sun, Yuchuan Ren, et al. “Reinforced Poly(Ionic Liquid)-in-Salt Electrolytes for Highly Stable Solid-State Lithium Metal Batteries.” <i>Advanced Fiber Materials</i>. Springer, 2026. <a href="https://doi.org/10.1007/s42765-026-00775-2">https://doi.org/10.1007/s42765-026-00775-2</a>. 229662026-09-20T22:01:49Z2026-10-06T11:57:17Z