Design of Poly(siloxane) Electrolytes with Small Molecule Quinone Cathodes for Long-Cycle Lithium–metal Batteries

To realize the applicability of organic small molecule quinone as an electrode material in traditional lithium batteries, two problems need to be overcome: the dissolution in electrolytes and the lack of Li. Using solid-state electrolytes instead of the existing liquid electrolytes can solve the above problems. Herein, we design and synthesize a poly(siloxane) electrolyte membrane using the Debus–Radziszewski reaction to get a gel polymer electrolyte (GPE). This GPE delivers an ionic conductivity of 1.8 × 10–4 S cm–1, a superior lithium-ion transference number of 0.75, a wide electrochemical stability window of 5.0 V, and a stable lithium deposition/dissolution ability without a significant change of overpotential at 1.0 mA cm–2 and 1.0 mAh cm–2. Depending on the design, we choose calix[4]quinone (C4Q) as the cathode in batteries,which is a typical n-type carbonyl-based small organic molecule. The lithium–metal batteries (LMBs) assembled with C4Q and the poly(siloxane) electrolytes show a sustained reversible capacity close to 100 mAh g–1 at 5 C and display stability in 1000 long charge–discharge cycles.