Simultaneous High Ionic Conductivity and Lithium‐Ion Transference Number in Single‐Ion Conductor Network Polymer Enabling Fast‐Charging Solid‐State Lithium Battery

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2023-10, Vol.19 (43), p.e2303344-n/a
• Main Authors: Wang, Yongyin, Sun, Qiyue, Zou, Junlong, Zheng, Yansen, Li, Jiashen, Zheng, Mingtao, Liu, Yingliang, Liang, Yeru
• Format: Article
• Language: English
• Subjects: Charge transfer; Charging; Conductors; Electric cells; Electrolytes; fast charging; high‐rate performance; Ion currents; Ion dynamics; Lithium; Lithium batteries; Lithium compounds; Lithium ions; lithium‐ion kinetic; Locomotion; Nanotechnology; polymer electrolyte design; Polymers; Room temperature; solid‐state lithium batteries
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202303344

Developing solid‐state electrolyte with sufficient ionic conduction and flexible‐intimate interface is vital to advance fast‐charging solid‐state lithium batteries. Solid polymer electrolyte yields the promise of interfacial compatibility, yet its critical bottleneck is how to simultaneously achieve high ionic conductivity and lithium‐ion transference number. Herein, single‐ion conducting network polymer electrolyte (SICNP) enabling fast charging is proposed to positively realize fast lithium‐ion locomotion with both high ionic conductivity of 1.1 × 10−3 S cm−1 and lithium‐ion transference number of 0.92 at room temperature. Experimental characterization and theoretical simulations demonstrate that the construction of polymer network structure for single‐ion conductor not only facilitates fast hopping of lithium ions for boosting ionic kinetics, but also enables a high dissociation level of the negative charge for lithium‐ion transference number close to unity. As a result, the solid‐state lithium batteries constructed by coupling SICNP with lithium anodes and various cathodes (e.g., LiFePO4, sulfur, and LiCoO2) display impressive high‐rate cycling performance (e.g., 95% capacity retention at 5 C for 1000 cycles in LiFePO4|SICNP|lithium cell) and fast‐charging capability (e.g., being charged within 6 min and discharged over than 180 min in LiCoO2|SICNP|lithium cell). Our study provides a prospective direction for solid‐state electrolyte that meets the lithium‐ion dynamics for practical fast‐charging solid‐state lithium batteries. A network‐structured polymer electrolyte with simultaneous enhancement of ionic conductivity and lithium‐ion transference number is proposed as a positive strategy to boost fast ion transport and limit anion migration for kinetically propelling its lithium‐ion transport. These structural advantages with a synergistic effect obviously ameliorate the high‐rate cycling performance and fast‐charging capability of solid‐state lithium batteries.