Discharge Behavior of Redox Thermogalvanic Cells

Abstract

The discharge behavior of thermogalvanic cells based on a dissolved redox couple, namely ferro‐ferricyanide, was investigated as a function of redox couple concentration, temperature difference, electrode placement and configuration, and forced convection. The principal source of cell polarization was found to be the rate of mass transfer of electroactive species to the electrode surfaces. This concentration polarization is instrumental in limiting the power output of aqueous redox thermogalvanic cells to values <0.1 mW cm−2. A practical feature of such cells, however, is that a continuous power output can be maintained indefinitely provided that the half‐cell temperature difference remains constant.

Hydrovoltaic cells. Part II: Thermogalvanic cells and numerical simulations of thermal diffusion potentials

“…One of the conditions for a scaling to meter square surfaces (i.e., 1 W/cm 2 ) is to work with a centimetre scale channel width in order to ensure the non-mixing condition along all the electrode length with a reasonable pressure drop of the flow. The present value of power density is the same as that obtained in [8] in a rotating cell with DT ¼ 50°C and the same same redox couple concentration (0.2 M). These results are also in the range given in [6], i.e., 0.3-2 W/m 2 , for the same kind of flow cell with the same redox couple concentration and a temperature difference of 40°C (the first value being experimental and the second being the prediction without mass transfer limitations).…”

“…For moderate values of the redox couple concentration, this potential difference can also represent a non-negligible component of the potential induced in a thermogalvanic cell (where the redox reaction is driven by the variation of the standard potential with temperature). Such a thermogalvanic cell can be used to extract energy from two solutions of different temperatures flowing in contact, as in previous work dedicated to convective cells [6,8,9]. In contrast, other studies have rather focused on static thermogalvanic cells [9][10][11].…”

Spin-crossover, mesomorphic and thermoelectrical properties of cobalt(ii) complexes with alkylated N3-Schiff bases

“…The presence of three rather intense reflections h0 (reflections 2, 4, 6, Fig. 7), suggests that the cobalt pyridine-imine cores are organised into long ribbons, linked through electrostatic interactions with the counter-ions and parallel to the b-lattice direction with a periodicity equal to d 20 . The strong intensity modulation of these reflections also reveals that these ribbons are not disconnected but in close contact with each other.…”

“…18 More recently another salt of the same Co couple provided record values of the potential change with temperature that is the key to thermoelectrochemical device applications. 19 For thermal energy harvesting based on the latter devices, research attention has long focused on the [Fe(CN) 6 ] 3-/4-couple in aqueous systems, 20 most recently with respect to the benefits of using high-surface-area electrodes in these devices. 21,22 The efficacy of a redox couple for thermal energy harvesting depends significantly on the dependence of the redox potential, E, on temperature, which is given by the Seebeck coefficient, S e = ∂E/∂T.…”

High Efficiency Graphene Coated Copper Based Thermocells Connected in Series

“…Pt was usually used as electrode materials in thermocells, and this restricted the commercial viability [10][11][12][13][14]. Carbon-based electrodes were gaining prominence as a promising, low-cost alternative to Pt.…”