Flexible energy storage device with carbon electrodes

A flexible energy storage device, comprising:

• a pair of electrodes separated by a redox-active biopolymer organogel electrolyte, wherein each electrode of the pair of electrodes comprises a metal support coated with a film comprising activated carbon, conductive carbon, and a binder,
• wherein the redox-active biopolymer organogel electrolyte comprises:
• a biopolymer organogel comprising a biopolymer gelator and a gel solvent;
• redox-active molybdenum-containing ions;
• and
• a secondary ionic substance which is at least one selected from the group consisting of a lithium salt and a sodium salt,
• wherein the flexible energy storage device retains greater than 75% of an unbent energy storage capacity when bent at an angle of 10 to 170°,
• wherein the biopolymer gelator is agarose,
• wherein the biopolymer gelator is present in the biopolymer organogel in an amount of 7.5 to 40 wt. %, based on a total weight of biopolymer organogel,
• wherein the gel solvent is glycerol,
• wherein the redox-active molybdenum-containing ions are molybdate anions,
• wherein the redox-active molybdenum-containing ions are present in an amount of 0.1 to 15.0 wt. %, based on a total weight of the redox-active biopolymer organogel electrolyte, and
• wherein the secondary ionic substance is present in an amount of 1.0 to 20.0 wt. %, based on a total weight of redox-active biopolymer organogel electrolyte.