Accelerating lithium ion conduction via activated interfacial dipole layer for long-life and high-voltage solid-state lithium-metal battery
Xu Lv, Yao Meng, Liyu Du, Yong Chen, Yanqiang Wei, Du Yuan, Hao Bin Wu, Haitao Zhang, Yun Zhang, Guoxiu Wang
Abstract
By introducing an interfacial dipole layer to suppress the space charge layer between the polymer/filler interfaces, we developed a composite solid electrolyte (D-CSE) with activated and interpenetrating lithium-ion conduction channels, which facilitates rapid lithium-ion transport and enables uniform deposition on the lithium anode. The absence of efficient ion transport pathways in composite solid-state electrolytes (CSEs) usually results in low ionic conductivity, which remains a great challenge for developing solid-state lithium-metal batteries (SLMBs). Herein, we report achieving accelerated Li + conduction in CSEs by a novel activation of the interfacial dipole layer. Polycationic ionic liquids and polyacrylonitrile with highly polar functional groups (–C≡N) are utilized to modulate the interfacial dipole layer in MOF-based CSEs, facilitating long-range pathways for the connectivity of Li + conduction and enhancing rapid transport kinetics. The as-synthesized CSEs exhibit a high ionic conductivity of 0.59 mS cm −1 and a lithium transfer number of 0.85. The assembled SLMBs (Li/CSE/LiNi 0.9 Co 0.05 Mn 0.05 O 2 ) delivered a high-capacity retention of 88.7% with a minimal discharge voltage attenuation of 17.1 mV after 500 cycles (0.03 mV per cycle) at 0.5 C. This work offers an effective approach to creating interpenetrating lithium-ion transport pathways with rapid ion transport kinetics for solid-state electrolytes, thereby advancing the development of solid-state lithium metal batteries.