Thiol-Ene crosslinked cellulose-based gel polymer electrolyte with good structural integrity for high cycling performance lithium-metal battery

Abstract Gel polymer electrolytes (GPEs) are considered the most promising replacements for liquid electrolytes that can be easily applied with long-life, safe, and solid-state lithium-metal batteries. However, the mechanical properties of GPE usually deteriorate dramatically when plasticized by the liquid electrolyte, which results in a significant decrease in the performance of the battery. Therefore, the long-term structural integrity and desirable mechanical strength are critical parameters for GPE to be ustilized in the high-performance battery. Here, an environment-friendly cellulose-based GPE is crosslinked by simple and effective thiol-ene click chemistry. The thiol-ene crosslinked GPE not only possesses higher mechanical strength (10.95 MPa) and rigid structure, but also enables the LiFePO4|Li batteries with ultra-long cycling stability. The capacity retention of crosslinked cellulose GPE can reach to 84% at 0.5C even after 350 cycles, which is much better than the non-crosslinked GPE suffering a rapid capacity decline after 200 cycles. This work provides a promising GPE to replace the commercial liquid electrolyte for lithium metal battery.