Ultrastrong nonflammable in-situ polymer electrolyte with enhanced interface stability boosting high-voltage Li metal batteries under harsh conditions

In-situ polymer electrolytes prepared by Li salt-initiated polymerization are promising electrolytes for solid-state Li metal batteries owing to their enhanced interface contact and facile and green preparation process. However, conventional in-situ polymer electrolytes suffer from poor interface stability, low mechanical strength, low oxidation stability, and certain flammability. Herein, a silsesquioxane (POSS)nanocage-crosslinked in-situ polymer electrolyte (POSS-DOL@PI-F) regulated by fluorinated plasticizer and enhanced by polyimide skeleton is fabricated by Li salt initiated in-situ polymerization. Polyimide skeleton and POSS-nanocage-crosslinked network significantly enhance the tensile strength (22.8 MPa) and thermal stability (200 degrees C) of POSS-DOL@PI-F. Fluorinated plasticizer improves ionic conductivity (6.83 x 10 4 S cm 1 ), flame retardance, and oxidation stability (5.0 V) of POSS-DOL@PI-F. The fluorinated plasticizer of POSS-DOL@PI-F constructs robust LiF-rich solid electrolyte interphases and cathode electrolyte interphases, thereby dramatically enhancing the interface stability of Li metal anodes and LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NCM811) cathodes. POSS-DOL@PI-F enables stable, long-term (1200 h), and dendrite-free cycle of Li||Li cells. POSS-DOL@PI-F significantly boosts the performance of Li||NCM811 cells, which display superior cycle stability under harsh conditions of high voltage (4.5 V), high temperature (60 degrees C), low temperature ( 20 degrees C), and high areal capacity. This work provides a rational design strategy for safe and efficient polymer electrolytes. (c) 2024 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights are reserved, including those for text and data mining, AI training, and similar technologies.