by josh perry, editor
[email protected]

researchers from the university of tsukuba (japan) have developed a thermoelectric, thin-film system from two redox materials that harnesses small energy differences at low temperatures, according to a report from the university.

the research showed the viability of thermoelectric solid-state batteries. (university of tsukuba)

“in the device, changing the temperature alters the ability of different layers in the device to hold onto electrons,” the report explained. “if one layer has a greater affinity for electrons that another, this creates a potential difference. the flow of electrons from one layer to the other can then be harnessed to do work as the cell is discharged, in the same way that a normal battery works.”

during tests at room temperature, the device produced 2.3 mev per heat cycle around 25-50°c. the result was an efficiency of around 1.0 percent, with a theoretical maximum of 8.7 percent.

efficiency is still an issue that the researchers will be working on to improve the results, but they are confident that this demonstrates the viability of solid-state thermoelectric batteries.

the research was recently published in applied physics express. the abstract stated:

“we demonstrate that a sodium-ion secondary battery (sib)-type thermocell consisting of two types of prussian blue analogue (pba) with different electrochemical thermoelectric coefficients (s _ec ≡ ∂v/∂t; v and t are the redox potential and temperature, respectively) produces electrical energy during heat cycles.

“the device produces an electrical energy of 2.3 mev/pba per heat cycle between 295 k (= t _l) and 323 k (= t _h). the ideal thermal efficiency (η = 1.0%), which is evaluated using the heat capacity (c = 4.16 mev/k) of ideal na₂co[fe(cn)₆], reaches 11% of the carnot efficiency (η_th = 8.7%).

“our sib-type thermocell is a promising thermoelectric device that harvests waste heat near room temperature.”