Water-tolerant solid polymer electrolyte with high ion-conductivity for simplified battery manufacturing in air surroundings

Abstract

The humidity-sensitive electrolytes necessitate the stringent conditions of lithium battery manufacturing and, thus, increase the fabrication complexity and cost. We herein report a water-tolerant solid polymer electrolyte (WT-SPE) with high Li+ conductivity (2.08 × 10−4 S cm−1 at room temperature) and electrochemically stable window (up to 4.7 V vs Li/Li+), which utilizes moisture to initiate rapid polymerization and form dense structures to achieve a facile battery manufacturing in humid air without the need of a glovebox. Molecular dynamics simulations attribute this hydrophobic behavior to the hindered transfer of a water molecule in dense WT-SPE. A stable SEI layer composed of a polymeric framework and other organic/inorganic small molecular compounds contributes to the sustainable operation of batteries. As a result, the Li|WT-SPE|LiCoO2 cells manufactured in the air exhibit a high initial capacity of 192 mA h g−1 at 0.1C and an excellent capacity retention for 300 cycles at 1C. The great advantage significantly simplifies the battery assembly process in air environment and can also maintain good interfacial contact between an electrolyte and electrodes thanks to in situ initiated polymerization, which shows great superiority and promise in the alternatives of traditional liquid and polymer electrolytes for low-cost and facile fabrication of batteries in ambient atmosphere.