Harvesting Waste Thermal Energy Using a Surface-Modified Carbon Fiber-Based Thermo-Electrochemical Cell

Abstract

An important direction in the development of energy saving policy is harvesting and conversion into electricity of low-grade waste heat. The present paper is devoted to the improvement of the efficiency of thermo-electrochemical cells based on carbon fiber electrodes and potassium ferri-/ferrocyanide redox electrolyte. The influence of the carbon fiber electrode surface modification (magnetron deposition of silver and titanium or infiltration implantation of nanoscale titanium oxide) on the output power and parameters of the impedance equivalent scheme of a thermo-electrochemical cell has been studied. Two kinds of cell designs (a conventional electrochemical cell with a salt bridge and a coin cell-type body) were investigated. It was found that the nature of the surface modification of electrodes can change the internal resistance of the cell by three orders of magnitude. The dependence of the equivalent scheme parameters and output power density of the thermoelectric cell on the type of electrode materials was presented. It was observed that the maximum power for carbon fiber modified with titanium metal and titanium oxide was 25.2 mW/m2 and the efficiency was 1.37%.

Double-network thermocells with extraordinary toughness and boosted power density for continuous heat harvesting

“…These include activated carbon textiles, 39,40 free-standing carbon-based materials, 41,42 multiwall carbon nanotube foams, 43 nickel hollow microspheres, 44 and surface-modified carbon fibers. 45 The large electroactive surface area of porous electrodes enables rapid diffusion of the electrolyte and results in an increase in exchange current density between the electrode and the electrolyte. Therefore, to further improve the thermoelectric performance of thermocells, optimization of electrode materials would be helpful.…”

Flexible N-Type Thermoelectric Composites Based on Non-Conductive Polymer with Innovative Bi2Se3-CNT Hybrid Nanostructured Filler

“…Besides already known chalcogenides properties of the p- and n-type conducting thermoelectric materials may be improved with various metallic [ 6 ], metal oxide [ 7 ] as well as carbon based materials like graphene [ 8 ], carbon fibers [ 9 ] and carbon nanotubes (CNTs) [ 10 , 11 ]. In CNT based polymer-CNT composite materials the CNTs within the polymer matrix form electrically but not thermally conductive networks, thus improving thermoelectrical ZT of the composite, as well as their thermal stability and mechanical properties [ 12 , 13 ].…”

Low-Grade Thermal Energy Harvesting and Self-Powered Sensing Based on Thermogalvanic Hydrogels

“…They may become the primary materials for liquid and gas adsorption and environmental protection. Therefore, Denis et al investigated the modification of carbon fiber electrode surfaces using magnetron sputtering by depositing silver and titanium or infiltration injection of titanium oxide nanoparticles to improve the electrodes and its effect on the output power and impedance equivalent scheme parameters of thermoelectric cells [ 113 ], as shown in Figure 7 a–f. It was found that the nature of the electrode surface modification can increase the internal resistance of the cell by three orders of magnitude.…”

“…Plots of maximum power density versus temperature difference between the hot and cold sides of the cell ( e ) for cells with a salt bridge and ( f ) for cells in the coin cell CR2025. (Reproduced with permission from [ 113 ]. Copyright 2021 MDPI).…”