[17a-D411-1~7] 9.4 Thermoelectric conversion

[17a-D411-4] The entropy effect of guanidinium addition on thermo-electrochemical cells

〇Kazuhiko Seki¹, Vikas Nandal¹, Qingshuo Wei¹, Masakazu Mukaida¹, Shohei Horike², Kazuhiro Kiriharta¹ (1.AIST, 2.Kobe Univ.)

Keywords:Thermo-electro-chemical cells, Seebeck coefficient, guanidinium

Thermo-electro-chemical cells have attracted attention because of directly and continuous convert of waste heat into electricity by using redox reactions with a simple design. In particular, Ferricyanide/ferrocyanide/guanidinium-based thermoelectrochemical cells have been recently investigated. By addition of guanidinium in ferricyanide/ferrocyanide electrolytes, the higher power and energy densities are obtained. We show both theoretically and experimentally that the enhanced performance is due to the configuration entropy change resulting from the selective binding of guanidinium ion to Ferrocyanide rather than the ionic Seebeck effect of guanidinium. Although the performance is enhanced by addition of guanidinium, the device shows degradation. We report the possible reasons behind the degradation and challenges to overcome for the steady state operation.