Balanced Anion‐Cation‐EO Interaction Enables Ultrahigh Lithium‐Ion Transport in 4.5 V‐Class PEO‐Based All‐Solid‐State Lithium Batteries

作者：Zi-Xiang Kong, Yingying Wu, Jian‐Fang Wu, Xinmiao Liang, Yunsong Li, Yuxiao Lin, Jilei Liu · 发表于：Advanced Materials · 年份：2025 · DOI：10.1002/adma.202514236 · 被引用次数：13 · 研究领域：Advanced Battery Materials and Technologies、Advancements in Battery Materials、Advanced Battery Technologies Research

Abstract The sluggish lithium‐ion transport in high‐concentration polyethylene oxide (hc‐PEO) solid electrolytes (SEs) and across the electrode/hc‐PEO SE interface causes failure of high‐voltage PEO‐based all‐solid‐state lithium batteries (ASSLBs). Here, bi‐salt hc‐PEO SEs with TFSI − and PO 2 F 2 − are creatively fabricated, where PO 2 F 2 − possesses higher Li + ─PO 2 F 2 − bonding energy, balancing anion‐Li + ‐EO interactions by weakening Li + ‐EO interaction while strengthening Li + ‐anion interaction, and decomposes at electrode/SE interfaces, enabling facilitated lithium‐ion transport in the SE and across interfaces. Li + interactions in anion‐Li + ‐EO aggregations are counterintuitively optimized when two anions reach an approximate molar ratio. Consequently, the ionic conductivity at 60 °C is enhanced by ≈20 times to 1.2 × 10 −4 S cm −1 , compared to hc‐PEO SE with LiTFSI (5.8 × 10 −6 S cm −1 ) or dominated LiPO 2 F 2 (5.2 × 10 −6 S cm −1 ). Using the bi‐salt hc‐PEO SE, Li//Li cells deliver an ultrahigh critical current density of 2 mA cm −2 with 20 times enhanced exchange current, and 4.5 V Li//LiCoO 2 ASSLBs exhibit a capacity retention of 80% after 200 cycles, superior to reported results. The synergistic anion decomposition, yielding pure lithium‐ion conductive electrode/SE interfaces containing Li 3 PO 4 and Li x POF y , depresses adverse side reactions and breaks sluggish ionic transport. This work explicitly demonstrates the utility of coordination regulations ...