Energy Harvesting and Storage with Lithium-Ion Thermogalvanic Cells

Thermogalvanic cells (electrochemical cells under a temperature gradient) are presented as multifunctional power sources, having capabilities for both energy harvesting and energy storage. A symmetric thermogalvanic cell with lithium-ion electrodes has the ability to be charged under a temperature gradient and then discharged when the temperature gradient is removed. Presented here is the first demonstration of a cycled thermogalvanic energy storage cell. Experimental results for d E /d T (the cell voltage produced per degree temperature difference) are given for symmetric thermogalvanic cells with single-phase Li x TiS 2 or amorphous Li x V 2 O 5 electrodes and alkyl carbonate electrolyte solutions. All cells exhibit d E /d T on the order of 1 mV/K. The thermoelectric Seebeck coefficient of the electrode materials and extent of lithium intercalation ( x ) have slight or negligible effects on thermogalvanic d E /d T . There are slight dependences of d E /d T on the electrolyte anion (PF 6 − vs BF 4 − ) and electrolyte concentration, and there is no dependence on the electrolyte solvent (EC:DMC vs PC).