Flame-retardant polycarbonate-based single-ion conducting polymer electrolyte for high-safety lithium batteries

Abstract

The low lithium transference number of conventional dual-ion polymer electrolytes will lead to concentration polarization and lithium dendrite growth, thereby affecting the safety and cycling performance of lithium batteries. Herein, we report a flame-retardant polycarbonate-based single-ion conducting polymer electrolyte (PAGEC-B/PFN). Due to the immobilization of anions within the polycarbonate cross-linking network, PAGEC-B/PFN exhibits a high lithium transference number (0.86), which is beneficial for alleviating concentration polarization and suppressing the growth of lithium dendrite. With the assistance of the TEP flame retardant and FEC, as well as LiNO₃ additives, PAGEC-B/PFN exhibits excellent flame retardancy, high ionic conductivity, and outstanding interfacial compatibility with the lithium metal anode. As expected, PAGEC-B/PFN achieves a high critical current density of up to 2.0 mA cm⁻² and stable cycling of Li||Li cell for over 2200 h. Meanwhile, LFP||PAGEC-B/PFN||Li cell delivers a specific capacity of 147.8 mA h g⁻¹ at 0.5 C and exhibits excellent cycling performance over 600 cycles. This work provides a strategy for designing solid-state lithium batteries with high safety and high performance.