A H 2 O-initiated Crosslinking Strategy for Ultrafine Nanoclusters Reinforced High Toughness Polymer-In-Plasticizer Solid Electrolyte.

Incorporating plasticizers is an effective way to facilitate ions conduction in solid polymer electrolytes (SPEs). However, this conductivity enhancement often comes at the cost of reduced mechanical properties, which can make the electrolyte membrane more difficult to process and increase safety hazards. Here, we proposed a novel crosslinking strategy where metal alkoxy terminated polymers can be crosslinked by precisely controlling the content of H 2 O as an initiator. As a proof-of-concept, we use trimethylaluminum (TMA) functionalized poly(ethylene oxide) (PEO) to demonstrate that ultrafine Al-O nanoclusters can serve as nodes to crosslink PEO chains with a wide range of molecular weights from 10,000 to 8,000,000 g mol -1 . The crosslinked polymer network can incorporate a high concentration of plasticizers, with a total weight percentage over 75%, while still maintaining excellent stretchability (4640%) and toughness (3.87 × 10 4  kJ m -3 ). The resulting electrolyte demonstrates high ionic conductivity (1.41 mS cm -1 ), low interfacial resistance towards Li metal (48.1 Ω cm 2 ) and a wide electrochemical window (> 4.8 V versus Li + /Li) at 30 °C. Furthermore, the LiFePO 4 /Li battery shows stable cycle performance with a capacity retention of 98.6% (146.3 mAh g -1 ) over 1000 cycles at 1C (1C = 170 mAh g -1 ) at 30 °C. This article is protected by copyright. All rights reserved.