Hengming Yan  ， Bowen Zhang  ， Xuefan Liu ， Lu Wang  ，Cunlong Hu  ，Anran Sheng  ，Congcong Zhang  ，Linglong Kong  ， Zhenzhen Wu  ， Yulin Zhong  ，Sheng Liu  ， Shanqing Zhang

Abstract

Ion transport in poly(ethylene oxide) (PEO) electrolytes is severely constrained by sluggish Li+ mobility arising from tight chelationof ether oxygens, and by insufficient lithium salt dissociation. Inspired by polycarboxylate ether (PCE) superplasticizers in cement,we demonstrate phosphonate-functionalized PCE (P-PCE) could overcome both limitations. The electron-rich -PO 3 2– groupscould liberate Li+ from the strong Li+ -PEO chelation and promote efficient salt dissociation without trapping Li+ . Instead, theyfacilitate rapid Li+ migration through a unique multi-Li+ coordination mechanism, where the electrostatic repulsion amongmultiple Li+ ions coordinated to a single -PO3 2– destabilizes solvation and promotes rapid Li+ hopping between adjacent sites.Meanwhile, P-PCE suppresses PEO crystallization and, through multi-Li+ coordination, induces a more extended conformationof PEO, which fosters high-entropy Li+ coordination environments involving TFSI – , ether oxygens, and -PO3 2– in transientcombinations, promoting long-range Li+ transport. The simultaneously enhanced Li+ concentration and mobility lead to a highionic conductivity (1.7 × 10−4 S cm−1 , 30◦C) without adding liquid plasticizers. Correspondingly, Li||LiFePO4 cells deliver highcapacities of 140.6 mAh g−1 at 0.5 C and 119.7 mAh g−1 at 1 C (30◦C). This work provides a simple yet effective strategy for developinghigh-performance solid-state batteries and molecular-level insights for rational polymer electrolyte designs.

Paper Linkage：https://advanced.onlinelibrary.wiley.com/doi/epdf/10.1002/adma.75158