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Abstract A green physical route for producing novel multifunctional polyvinyl alcohol/kappa-carrageenan alkaline gel polymer electrolyte is developed, which is based on double-network physical cross-linked hydrogel. The alkaline gel polymer electrolyte has excellent tensile stress (2.22 MPa), stretchability (12.43 mm/mm) and ionic conductivity (0.21 S/cm). In this study, KOH is served as not only ionic donator but also cross-linking agent. A supercapacitor is assembled from polyvinyl alcohol/kappa-carrageenan alkaline gel polymer electrolyte and activated carbon electrodes, which exhibits ideal electrochemistry behavior. The electrode specific capacitance is 470 F/g at 0.5 A/g, and retains above 95% after 2000 charge/discharge cycles. Additionally, the electrochemical performance of supercapacitor under different tensile deformations (≤200%), bending angles (0–230°) and temperatures (≥-40 °C) displays a slightly reduction, indicating that the supercapacitor possesses good flexibility and low temperature resistance. These findings are desirable for applications in supercapacitor devices of flexibility or low working temperature. Graphical abstract Image 1 Highlights • KOH playing two roles of ionic donator and cross-linking agent in the AGPE. • Outstanding tensile property and ionic conductivity of PVA/carrageenan AGPE. • Superior properties of supercapacitor under deformation and low temperature. [ABSTRACT FROM AUTHOR]

[Display omitted] • A gel electrolyte with asymmetric structure was prepared. • The gel electrolyte possesses thermal stability and flame retardant. • The gel electrolyte utilizes an electro-spun network as structural scaffolds. • The SiO 2 -polyvinyl alcohol was loaded at one surface of an electro-spun network. • The gel electrolyte simultaneously solves problems of the S cathode and Li anode. A main huddle against the practical application of lithium-sulfur battery lies in serious safety concerns due to liquid organic electrolyte, shuttling of polysulfides and formation of lithium dendrites. Herein, we have devised an asymmetric and structurally stable gel electrolyte system to enable high ionic conductivity, flame-retardancy, and effective blockage of shuttling. Such a multi-functional gel electrolyte utilizes an electro-spun network of interwoven nano-fibers of poly vinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) as structural scaffolds, with SiO 2 -polyvinyl alcohol (SiO 2 @PVA) suspension being loaded at one surface by blade coating. Such asymmetrically coated PVDF-HFP membranes are highly wettable that is essential to thorough gelling, with its well-connected porous channels to enable outstanding ionic conductivity above the limit by conventional Celgard separator, to accommodate huge volumetric changes over redox reactions, to shield polysulfides and fend off lithium dendrites. Ultimately, application of the gel electrolyte to a model Li-S cell with cathode containing 90% S delivered high initial capacity of 1439 mA h g−1 at 0.1C and a remarkable cycling stability over 300 cycles at 1C. The current gel electrolyte is expected to provide a valuable means for developing safe low-cost and durable Li–S batteries of practical importance. [ABSTRACT FROM AUTHOR]