In polymer-based lithium batteries, polymer electrolytes (PEs) exhibit limited ionic conductivity at room temperature (25 °C). To address this issue, this paper describes a hexagonal-structure-based single-ion conducting gel polymer electrolyte (h-SICGPE) framework with a robust and efficient cross-linked polymer network, applicable to polymer-based batteries even at 25 °C. The proposed cross-linked polymer network backbone of the h-SICGPE, as a semisolid-state thin film type, has the homogeneous honeycomb structure incorporating anion receptor(s) inside each of its hexagonal closed cells and is obtained by cross-linking between trimethylolpropane tris(3-mercaptopropionate) and poly(ethylene glycol) diacrylate in a newly synthesized anion–receptor solution. The excellent structural capability of the h-SICGPE incorporating Li⁺/TFSI⁻ can enhance ionic conductivity and electrochemical stability by suppressing crystallinity and expanding free volume. Further, the anion receptor in its free volume helps to effectively increase the lithium-ion transference number by immobilizing counter-anions. Experimental results demonstrate dramatically superior performance at 25 °C, such as ionic conductivity (2.46 mS cm⁻¹), oxidative stability (4.9 V vs. Li/Li⁺), coulombic efficiency (97.65%), and capacity retention (88.3%). These results confirm the developed h-SICGPE as a promising polymer electrolyte for high-performance polymer-based lithium batteries operable at 25 °C.

This paper presents an effectiveness of proline in positive electrolytes for enhancing the thermal stability and performance of vanadium redox flow batteries (VRFBs) at elevated temperatures. Proline not only facilitates the redox reactions of VO2+/ VO2+ through its catalytic effect but also reduces vanadium crossover and limits V₂O₅ formation via its coordination complexing effect. The effectiveness of proline is demonstrated through various electrochemical experiments, including full-cell tests conducted over 100 cycles at 50 °C. The results indicate that proline significantly enhances the thermal and electrochemical stability of the VRFB electrolyte. This improvement is attributed to the excellent coordination and catalytic capability of carboxyl (-COOH) and protonated secondary amine (-NH2+) groups in its molecular structure. The superior electrochemical performance of proline as a thermal stability agent is evidenced by the proline-supported electrolyte, which exhibits remarkable thermal stability and improved performance over 100 cycles at 50 °C, including a high average energy efficiency of 65.57% compared to 55.97% for the pristine electrolyte, and a significantly enhanced discharge capacity retention of 51.54% at the 100th cycle, compared to just 1.51% for the pristine electrolyte.