Direct thermal charging cell for converting low-grade heat to electricity.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31515483.
- Also identified by DOI 10.1038/s41467-019-12144-2 and PMC identifier 6742635.
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Abstract
Efficient low-grade heat recovery can help to reduce greenhouse gas emission as over 70% of primary energy input is wasted as heat, but current technologies to fulfill the heat-to-electricity conversion are still far from optimum. Here we report a direct thermal charging cell, using asymmetric electrodes of a graphene oxide/platinum nanoparticles cathode and a polyaniline anode in Fe<sup>2+</sup>/Fe<sup>3+</sup> redox electrolyte via isothermal heating operation. When heated, the cell generates voltage via a temperature-induced pseudocapacitive effect of graphene oxide and a thermogalvanic effect of Fe<sup>2+</sup>/Fe<sup>3+</sup>, and then discharges continuously by oxidizing polyaniline and reducing Fe<sup>3+</sup> under isothermal heating till Fe<sup>3+</sup> depletion. The cell can be self-regenerated when cooled down. Direct thermal charging cells attain a temperature coefficient of 5.0 mV K<sup>-1</sup> and heat-to-electricity conversion efficiency of 2.8% at 70 °C (21.4% of Carnot efficiency) and 3.52% at 90 °C (19.7% of Carnot efficiency), outperforming other thermoelectrochemical and thermoelectric systems.