A flexible energy storage device with a redox-active polymer hydrogel electrolyte is provided. The flexible energy storage device can include a pair of electrodes separated by the redox-active polymer hydrogel electrolyte. The redox-active polymer hydrogel electrolyte can include a polymer hydrogel, charge balancing anions and redox-active transition metal cations at least one selected from the group consisting of vanadium, chromium, manganese, cobalt, and copper. The flexible energy storage device may retain greater than 75% of an unbent specific capacitance when bent at an angle of 10° to 170°.

A flexible energy storage device with a redox-active polymer hydrogel electrolyte is provided. The flexible energy storage device can include a pair of electrodes separated by the redox-active polymer hydrogel electrolyte. The redox-active polymer hydrogel electrolyte can include a polymer hydrogel, charge balancing anions and redox-active transition metal cations at least one selected from the group consisting of vanadium, chromium, manganese, cobalt, and copper. The flexible energy storage device may retain greater than 75% of an unbent specific capacitance when bent at an angle of 10° to 170°.

A flexible energy storage device with a glycerol-based gel electrolyte is provided. The flexible energy storage device can include a pair of electrodes separated by the gel electrolyte. The electrolytes can be in gel form, bendable and stretchable in a device. The gel electrolyte can include glycerol, redox-active molybdenum-containing ions, and a secondary ionic substance. The secondary ionic substance can include a salt. The gel electrolyte can have a density of 1.4 to 1.9 g/cm.sup.3 and an ionic conductivity of 2.3×10.sup.−4 to 3.2×10.sup.−4 Scm.sup.−1. The flexible energy storage device may retain greater than 95% of an unbent energy storage capacity when bent at an angle of 10 to 170°.

A flexible energy storage device with a glycerol-based gel electrolyte is provided. The flexible energy storage device can include a pair of electrodes separated by the gel electrolyte. The electrolytes can be in gel form, bendable and stretchable in a device. The gel electrolyte can include glycerol, redox-active molybdenum-containing ions, and a secondary ionic substance. The secondary ionic substance can include a salt. The gel electrolyte can have a density of 1.4 to 1.9 g/cm.sup.3 and an ionic conductivity of 2.3×10.sup.−4 to 3.2×10.sup.−4 Scm.sup.−1. The flexible energy storage device may retain greater than 95% of an unbent energy storage capacity when bent at an angle of 10 to 170°.

Provided are plastic crystal-type solid electrolyte having high ion conductivity and a power storage device using the solid electrolyte. The solid electrolyte contains a plastic crystal doped with an electrolyte. The plastic crystal contains two or more types of cations in total, at least one of which is selected from the group of imidazoliums and quaternary ammoniums.

An interfacial protective coating layer of LTO is effective in preventing unwanted interfacial reactions between the solid-state electrolyte and cathode electrodes from occurring. Incorporation of the inventive coating into sodium-based all-solid-state batteries allows for room temperature operation, high voltage, and long cycle life.

Provided herein are a variety of electrolytes, electrolyte systems, and separator systems, as well as batteries comprising the same and precursors thereof. In specific embodiments are semi-solid or gel electrolytes, particularly those prepared using (i) a cross-linkable polysilsesquioxane with high ionic conductivity and (ii) a liquid electrolyte (e.g., ionic liquid).

An electrolytic solution for an electrochemical device, including: a cation (C) that is a monovalent to trivalent metal ion; an anion (A); a solvent (SO) that is a compound having a molecular weight of 1,000 or less; and a polymer (P) that has a weight-average molecular weight of more than 10,000, wherein a content ratio of the solvent (SO) relative to 1 mol of the cation (C) is 0.5 to 4 mol, and a content ratio of the polymer (P) is 0.5% by weight or more. Also provided are a plastic composition, an electrode sheet, an insulating layer, and an electrochemical device including the electrolytic solution, as well as producing methods of these.

A technique that can improve ionic conductivity is provided.

An electrolyte includes an inorganic composite particle that is a composite of an inorganic particle with a compound having a betaine structure and one or more functional groups selected from a (meth)acryloxy group, a Si(OR).sub.3 group (R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms), and an Al(OR).sub.2 group (R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms).

An electrochemical device capable of more sufficiently preventing swelling due to generation of a gas such as carbon dioxide and decomposition of a lithium salt while having a simple structure. The electrochemical device includes a non-aqueous electrolytic solution, wherein the non-aqueous electrolytic solution contains a metal-organic framework containing: an azole-based organic molecule optionally having a hydrophobic group, and a metal atom.