In Situ Gel Polymer Electrolyte with Rapid Li+ Transport Channels and Anchored Anion Sites for High-Current-Density Lithium-Ion Batteries

Abstract

In situ formed gel polymer electrolytes (GPEs) have advantages in safety and adaptability to current high-voltage lithium-ion batteries (LIBs). However, it is challenging for GPEs to achieve stable cycling at high current densities. A flexible framework is proposed for stable in situ GPE, by introducing ─CF₃ groups to the polymer network to establish rapid Li⁺ transport channels, and incorporating secondary amine N─H groups to anchor anion. The obtained GPE exhibits a high ionic conductivity of 2.6 mS cm⁻¹ and a high Li⁺ transference number of 0.67. The assembled Li||NCM811 cell demonstrates excellent rate performance, with a discharging capacity of 112.3 mAh g⁻¹ at 10C, and capacity retention of 87.6% after 260 cycles at 1C. Furthermore, the assembled graphite||NCM811 cell demonstrates excellent long-term cycling stability with impressive capacity retention of 73.2% after 300 cycles 3C (1.8 mA cm⁻²). This work presents a promising approach to enhancing the cycling stability of GPEs for high-voltage LIBs at high current density.