Stretchable ionic hydrogel with high thermopower for low-grade heat harvesting

A method of making an ionic thermoelectric hydrogel, comprising:

• combining an acrylamide and an alginate;
• adding an initiator and a cross-linker;
• curing under UV light;
• soaking in an ionic fluid;
• and
• soaking in a glycol aqueous fluid to provide the ionic thermoelectric hydrogel.

An ionic thermoelectric hydrogel cell, comprising:

• an ionic thermoelectric hydrogel comprising a poly(acrylamide) crosslinked with an alginate, 1-ethyl-3-methylimidazolium tetrafluoroborate, and a poly glycol;
• at least two electrodes each at least partially surrounding the ionic thermoelectric hydrogel;
• and
• a metal lead coupled to each electrode.

A method of making an ionic thermoelectric hydrogel cell, comprising the steps of;

• dissolving acrylamide and alginate in deionized water at about 25° C. to make a homogeneous aqueous solution;
• adding an APS initiator and BIS cross-linker to the aqueous solution:
• degassing the aqueous solution for about 5 minutes in a vacuum chamber;
• pouring the degassed aqueous solution into a mold;
• covering the mold with a substrate to keep air out and to form a Pam-alginate hybrid hydrogel;
• curing the hydrogel under ultraviolet illumination for about 1.5 hours;
• and
• soaking the cured hydrogel in EmimBF4 ionic liquid for 16 hours;
• and
• subjecting the cured hydrogel to a second soaking step in PEG aqueous solution for about 1 hour.