High-Rate Lithium-Ion Cycling in Electrodeposited Binder-Free Thin-Film Vanadium Oxide Cathodes with Lithium Metal Anodes in Ionic Liquid and Polymer Gel Analogue Electrolytes

High rate and long cycle life performance for electrodeposited, binder-free V₂O₅ thin film cathodes and lithium metal anodes is described using liquid and polymer gel electrolytes of the pyrrolidinium based (C₄mpyrTFSI) ionic liquid (IL). Sharp well-defined voltammetric peaks typically seen with nanostructured V₂O₅ materials in organic electrolytes, support the fast kinetics observed. The addition of vinylene carbonate (VC) stabilises the electrolyte interface leading to higher electrode capacities than for the additive-free electrolyte, ∼120 versus ∼90 mAh g⁻¹ at 0.75 C. Polymer gel electrolytes based on the IL yield similar electrode capacities, coulombic efficiencies and high rate performances without the VC-additive. The polymer gel option delivers the better long-term stability up to 400 cycles with lithium metal anodes with minimal capacity fade at elevated charge and discharge rates up to 5 C.