Ionic Liquid Boosting the Electrochemical Stability of a Poly(1,3‐dioxolane) Gel Electrolyte for High‐voltage Solid‐State Lithium Batteries
Tianhua Chen, Jiaxin Liu, Dušan Lošić, Jian Wang, Haitao Zhang
Abstract
Abstract Poor interfacial contact between solid‐state electrolytes and electrodes limits high‐voltage performance of solid‐state lithium batteries. A new gel electrolyte is proposed via in‐situ polymerization, incorporating fluoroethylene carbonate (FEC) solvent and ionic liquid1‐butyl‐1‐methylpiperidinium bis(trifluoromethylsulfonyl)imide (PP 14 TFSI). This combination synergistically enhances Li ion transport, achieving a transfer number of 0.58 and improved electrochemical performance. FEC protects the Al current collectors from LiPF 6 corrosion and promotes a protective interfacial layer formation. PP 14 TFSI improves interfacial contact and provides stable components. An interface layer of fluorine and nitrogen composites forms, preventing side reactions. LiCoO 2 ||PPE||Li cell exhibits robust cycling stability at 4.45 V, retaining ~80 % capacity after 200 cycles at room temperature with 0.2 C and 1 C rates, showing increased coulombic efficiency. NCM811||PPE||Li cell also displays exceptional cycling. In‐situ polymerization and FEC‐ionic liquid coordination enable high‐voltage solid‐state lithium metal batteries for practical use.