TEC-G-Zelle

Abstract

TEC-G cell comprehensive - two electrodes arranged in a continuous, membrane-free cell space, wherein - the cell space is filled with an electrolyte mixture, - and the electrolyte mixture includes natural and / or synthetic fulvic and / or humic acids.

Description

[0001] TEC-G cells have been known for some time and are explained in more detail, for example, by Burmistrow et al. in "Advances in Thermo-Electrochemical (TEC) Cell Performances for Harvesting Low-Grade Heat Energy: A Review" (Sustainability 2022, 14, 9483; https: / / doi.org / 10.3390 / su14159483). A disadvantage is that the concepts discussed there require a thermal gradient to generate electricity. In 2021, Heubner et al. reveal a concept in "Intercalation electrochemistry for thermoelectric energy harvesting from temperature fluctuations" (Chem. Commun., 2022, 58, 1203; DOI: 10.1039 / d1cc06121f) that harvests electrical energy from temperature fluctuations using a suitable energy harvesting circuit. This is disadvantageous because it can only provide a peak power output in the microwatt range.

[0002] Regenerative concepts that could independently harvest energy from waste heat in cycles are discussed by Maldifassi et al. in 20241014 in "Evaluation of redox pairs for low-grade heat energy harvesting with a thermally regenerative cycle" (Energy Adv., 2024,3, 2877; DOI: 10.1039 / d4ya00368c). In 20251021, Li et al. describe endothermic and exothermic ion exchange reactions in "Thermodynamic insights into the interplay between calcium and iron(II) hydroxycarboxylates: impacts on solubility, speciation, and bioavailability," in which Fe2+ and Ca2+ mutually replace each other in complexes. When a more stable, exothermic complex is converted into a less stable complex, this reaction absorbs heat according to Hess's law, thus lowering the temperature of the mixture. The detection is carried out by isothermal titration calorimetry, abbreviated ITC.The question was whether a hydrophilic decomposition product produced with sulfuric acid from natural raw materials could be consistently attributed with thermally regenerating TEC-G properties. This document answers this question based on relevant research and compiled literature, and aims to derive specific product concepts. GENERAL BACKGROUND

[0003] The present invention relates to an electrolyte for a current-supplying TEC-G cell as specifically described in WO 2025 / 040254 A and WO 2025 / 040759 A. The information disclosed and the documents cited in those documents define the starting point of the present document and are hereby fully incorporated by reference into the present disclosure. DESCRIPTION OF THE STATE OF THE TECHNOLOGY

[0004] TEC-G cells of the genus contain a hydrophilic electrolyte, which was obtained from a natural substance by decomposition with sulfuric acid.

[0005] The task was to create a sound, scientific reference point that could explain the type and properties of the electrolyte without contradiction to previous measurements.

[0006] This problem is solved by referring to humic substances and their properties according to the features of the independent claims. Advantageous embodiments are described in the dependent claims and the following description. SUMMARY OF THE INVENTION

[0007] According to the invention, a TEC-G cell comprises two electrodes which are arranged in a continuous, membrane-free cell space, wherein the cell space is filled with an electrolyte mixture and the electrolyte mixture comprises natural and / or synthetic fulvic and / or humic acids. DESCRIPTION OF THE INVENTION AND ADVANTAGEOUS FEATURES

[0008] According to the invention, a TEC-G cell comprises two electrodes which are arranged in a continuous, membrane-free cell space, wherein the cell space is filled with an electrolyte mixture and the electrolyte mixture comprises natural and / or synthetic fulvic and / or humic acids.

[0009] Natural decomposition products of cellulose, wood, or even plants take on an earthy appearance after some time and comprise cross-linked macromolecules with the main component CHO, also known as humic substances. Dispersible and soluble, carbon-based macromolecules of this mixture are called humic and fulvic acids, respectively, and can also be produced from sugars or cellulose by decomposition with H₂SO₄ using established methods. Comparison of the available data on these humic and fulvic acids with the properties of the present electrolyte revealed consistent agreement: The observed properties can be reconciled with the known properties. The use of these substances in a TEC-G cell is novel and is therefore claimed for the first time in this document.

[0010] Preferably, the electrolyte mixture was obtained by - partial carbonization of at least one polyol, fat, oil or carbohydrate with H2SO4, preferably rapeseed oil and / or at least one sugar selected from the group consisting of fructose, psicose, tagatose, Partial carbonization of rancid rapeseed oil is particularly preferred.

[0011] Carbonization is the preferred method. - with successive addition of concentrated H2SO4 - in the presence of a metal sulfate, preferably iron sulfate, FeSO4*7H2O is particularly preferred; - with final dilution with H2O and / or a polyol, preferably H2O and polyethylene glycol, particularly preferably dilution with H2O and PEG400, - to a pH value < 7, preferably 0 <pH<3, besonders bevorzugt <0,1.

[0012] Preferably, all starting materials have a technical purity of 95% to 99%, the remainder being impurities and contaminants.

[0013] Preferably, the first electrode is a C-based electrode, preferably a graphitized foil or fiber of technical purity; - the second electrode is an iron-based electrode, preferably made of low-carbon steel with a carbon content of <1%, particularly preferably in the form of an unalloyed steel sheet and / or steel fabric of technical purity with a carbon content of <0.2%.

[0014] Preferably, the TEC-G cell exhibits an open cell voltage in the range of 0.5V to 1V at a constant room temperature in the range of 15°C to 30°C.

[0015] Preferably, the electrolyte comprises at least one adjusting agent and auxiliary substance, comprising up to 25% by weight of the total composition. The adjusting agent and auxiliary substance is selected from the group consisting of buffers, hydrochloric acid, phosphoric acid, organic acids, acetic acid, acid buffers, acetic acid acetate buffers, humectants, xanthan gum, sorbitol, xylitol, fructose, sugars, conductivity additives, NaCl, LiCl, KCl, halogen salt mixtures of alkali metals, alkali metal sulfates, anthrones, flavones, metal soaps, fatty acid salts, sugar anthraquinone-based food colorings, carminic acid, siderophores, amino acids, ethanol, glycerol, thickeners, defoamers, complexing agents, starch extract, sodium salt mixtures, sodium salts, sodium sulfate, sodium chloride, sodium acetate, molasses, beet juice, cane sugar syrup, syrup, alkaline earth salts, aluminum salts, potato starch, sugar beet pulp, flour, silicates, and glass powder. Molar sieves, framework silicates, powdered separators, paper separators, paper scraps, electrode powders,Electrode packings.

[0016] Preferably, the TEC-G cell is designed as a button cell comprising a two-part steel housing with an airtight seal with tightly inserted graphite foil, electrolyte sponge with electrolyte, metal disc and internally contacting pressure spring.

[0017] Preferably, the TECG cell is designed as a flexible, flat, planar cell with a total thickness in the range of 0.3 mm to 4 mm, comprising a light- and air-tight enclosing outer film and at least two electrodes in film and / or fabric form with an electrolyte sponge with electrolyte arranged between them.

[0018] Preferably, the TEC-G cell is integrated as a generator, preferably a self-discharge compensator, into an energy management system, preferably a clocked energy management system.

[0019] Further advantages become apparent from the exemplary embodiments. The features and advantages described above and the following exemplary embodiments are not to be considered limiting. The independent claims define the scope of protection of the invention. Additional advantageous features and combinations of features, as explained in the description and disclosed in the documents cited in the application and referenced therein, can be implemented within the scope of the independent claims in the subject matter of the invention, both individually and in different combinations, without departing from the scope of the invention. DETAILED EXPLANATION OF THE INVENTION BASED ON LITERATURE AND EXAMPLES OF EXECUTION: HUMIC ACIDS

[0020] 19590501 - Lecture notes “SOIL ORGANIC MATTER”, Visiting Prof. Dr. W. Flaig of the Department of Agronomy, Iowa State College, Ames, Iowa, USA, at the Institute for Plant Nutrition and Soil Science, Braunschweig; reveals that organic decomposition products have been studied since the 18th century; the carbon content of humic acids and fulvic acids is outlined here as 58% and >55%; it was assumed early on that these decomposition products are essentially formed by the dehydration of CHO compounds and can be produced similarly by reaction with strong acids (such as H2SO4) (pp. 18, 20 and 22).

[0021] In 1975, the article "Kinetics and Equilibrium of binding Fe3+ by a fulvic acid" revealed that, for a dissolved humic acid of natural origin—referred to here as fulvic acid—the complex formation constants for the fulvic acid-Fe3+ complex increased with decreasing pH, while the amount of bound Fe3+ changed little. The reverse reaction, which would release Fe3+, is slow and, in light of the heterogeneous composition of humic acids, could explain the inhibited migration of Fe3+ ions within the macromolecule. The authors assume that with increasing pH, more Fe3+ ions are present, but also more protonable groups within the fulvic acid accept charge, making rapid complexation via many suitable, uncharged structures increasingly difficult. A slow, continuous uptake / migration of Fe3+ during natural complexation and migration in soil layers over days / months would also be consistent with these results.

[0022] In 1992, "Proton and metal ion binding to humic substances," page 22 reveals typical functional groups found in humic fractions and develops various models for the complexation of cations in correspondingly diverse macromolecules, comparing them with available data. Secondary reactions within the macromolecules are also analyzed. The study concludes that considering competing binding sites within the macromolecule and the migration / slow distribution of cations to the optimal binding sites is a necessary component for future models.

[0023] 20050630 reveals “Characterization of humic substances by fractionation and determination of metal content...” in the introduction that Fe3+ complexes have a higher stability than Fe2+ complexes; a possible classification and characterization is presented in light of known concepts; humic substance structure models and possible binding sites are illustrated in schematic diagrams.

[0024] 20070315 reveals in the abstract “Thermal Stability of solid and aqueous solutions of humic acid” that for biogenic humic acids irreversible structural changes occur from 70°C and decomposition processes occur from 110°C.

[0025] In the abstract of 20071015, “Buffer capacity of humic acid: Thermodynamic approach”, it is revealed that commercial humic acid can act as an effective buffer in the range 5.5 < pH < 8, absorbing and releasing protons, which is attributed to chemisorptive hydroxyl groups.

[0026] 20100702, “Reduction and Reoxidation of Humic Acid: Influence on spectroscopic properties and proton binding”, further reveals that 0.54 mol / kg of electrons could be introduced or removed via electrochemical redox processes without showing significant changes in the spectroscopic properties. Thus, humic acid was used here as an electrochemically redox-reactive element without significantly altering the essential bonding states and the associated spectroscopic properties.

[0027] In their publication "Interactions of humic acids with metals" (20130101), Boguta et al. provide a comprehensive overview of biogenic humic substances, their classification, and properties with regard to metal complexes. Iron complexes based on chlorides, nitrates, or sulfates are mobile and readily formed (Table 4); at low pH, an Fe3+ complex is more stable than an Fe2+ complex (p. 24), and complexation occurs gradually, with changes in binding sites and mechanisms (p. 39), and can include radical redox processes and chelate complexations ( Fig. 11) Protons and / or hydrogen may be involved. Complexes can be further stabilized by additional complexing agents and / or redox-active additives and auxiliary substances (p. 40). According to page 42, more energy is released by the complexation of Fe3+ than by the complexation of Fe2+; conversely, the release of Fe3+ will require more energy than the release of Fe2+. This is consistent with the complex formation constants of the parallel data sources. Fe3+ forms more stable complexes with hydroxyl and carbonyl groups than Fe2+. According to page 50, Fe ions promote the coagulation of humic acids; with decreasing pH, coagulation via hydrogen bonds is increasingly inhibited, since Fe3+ ions will no longer form sparingly soluble hydroxides that could serve as a coagulation nucleus (p. 51).At low pH, humic acids arrange themselves in more compact aggregates and fibrous structures, and the sites available for complexation and coagulation are sterically blocked. Elevated salt concentrations also alter the three-dimensional conformation of humic acids (p. 66). Methods for the classification and characterization of biogenic humic acids are presented and analyzed.

[0028] In their publication "Entropy-enthalpy compensation: Role and ramifications in biomolecular ligand recognition and design" (20140806), Chodera et al. further explain isothermal titration calorimetry for processes in which macromolecules form complexes and / or compounds with much smaller partners. Examples are given for conformational reactions with a strong entropic contribution (p. 21). Fig. 1b).

[0029] In their publication "Influence of humic acid complexation with metal ions on extracellular electron transfer activity" (20151123), Zhou et al. describe the investigation of the function of humic acid complexes as electron shuttles; increased activity was observed for Fe complexes, while Cu- or Al-based complexes reduced the activity. This indicates that Fe-humic acid complexes should be considered highly redox-reactive and can participate more effectively in redox equilibria.

[0030] In the introduction published on August 19, 2017, Mol et al. reveal various ways in which humic substances can be synthetically obtained through simple, water-based decomposition of sugars; for methanol-based syntheses, models and optimal reaction conditions for the synthesis of HMF are described; a reaction at 100°C can be completed within 40 minutes.

[0031] In 20180801, Björnerbäck et al. reveal in “Microporous Humins Synthesized in Concentrated Sulfuric Acid Using 5-Hydroxymethyl Furfural” how microporous, structurally amorphous humins with a high surface area can be synthesized from sugars via HMF as an intermediate.

[0032] In 20180901, Yang reveals in “Synthesis and Use of Synthetic Humic-like Acid (SHLA) for The Remediation of Metal-Contaminated Water and Soil” how humic substances can be specifically produced from precursors through abiotic decomposition processes.

[0033] In 20190101, Rosenberg et al. reveal in “Organic redox-flow-batteries using compounds out of bark and peat as well as humic acids” in the graphical abstract battery systems in which humic acids serve as a redox component and exhibit constant, battery-typical power characteristics in the 10mW range.

[0034] In 20200101, Yang et al. describe known synthesis and production routes for humic substances in "The sleeping Giant: A Polymer View on Humic Matter in Synthesis and Applications"; in section 4.4, they mention possible charge densities of 80 Ah / kg for redox-active humic acids; furthermore, they describe humic acids as a component for anti-corrosive coatings and as electron shuttles in electrolytes.

[0035] As a result, the yellow to black, dark, aqueous mixtures produced from a natural substance – here rapeseed oil – by decomposition with H2SO4 can be consistently assigned the properties known for humic substances: An iron electrode is passivated and enables a redox buffer for H+ / H2 to undergo an electrochemical reaction; the release of Fe3+ from the humic complex by reduction to Fe2+ at a graphite electrode and recomplexation is, according to the literature, a heat-absorbing, slow, electrode-selective process, the reverse reaction of which can gradually restore an original starting state by absorbing ambient temperature. THE TRIGLYCERIDE-H2SO4 SYSTEM

[0036] The question was whether the decomposition of oil produces components that contradict the previous process.

[0037] 19340918 - US1,973,790 A discloses a process for purifying vegetable oils, in which the cleavage of vegetable oils with H2SO4 in the presence of metal salts for the production of pigment dye bases is described as established; after separation from a sediment and aqueous washing, an oil mixture with an increased proportion of free fatty acids and an indeterminate proportion of H2SO4 and sulfonic acids is obtained; these partially colored mixtures show increasing discoloration from 120°C until they become opaque, black liquids with increasing viscosity; with 75% phosphoric acid in a proportion of a few percent by weight, cleavage of the triglycerides can be achieved even from 30°C.

[0038] 19501114 - US 2,529,539 A discloses a process for the sulfonation of unsaturated esters, in which sulfonation is most successful at 40°C with equal mass parts of acid and allyl ester at SO3 contents of 30% to 60%, while anhydrous reactions with lower SO3 contents form increased amounts of byproducts such as acid esters. 19660201 Chemistry and Technology of Fuels and Oils, Volume 2, pages 92-95, Antonishin et al.The abstract of "Sulfonation of residual oils and utilisation of the oil sulfonation product" reveals that the reaction of H2SO4 and SO3-containing H2SO4 with oil also involves oxidation and condensation of the oil components; in oils with aromatic components, side chains and cycloalkyls are cleaved to form carboxyl groups and phenolic hydroxyl groups, releasing CO2 and H2O; aromatization of ring systems and oxidative condensation occur concurrently with water removal; the condensed products with sulfone groups exhibit ion-exchange properties.20050101 discloses “Interactions between rapeseed oil fuel and engine oil” as typical aging reactions of rapeseed oil: fat splitting, saponification, auto-oxidation, and polymerization with an increase in viscosity up to the point of resinification; heating to 280°C with exposure to air causes polymerization, while at up to 110°C in a closed container, mainly short-chain fatty acids are enriched; oxygen or an oxygen-rich compound such as water or acetic acid is essential for the increase in viscosity; the neutralization number increases, and the iodine number rapidly drops to zero; the addition of sulfuric acid accelerates the cross-linking / increase in viscosity in oil-fuel mixtures, indicating slightly accelerated aging; however, the addition of soot, iron powder, and / or sulfuric acid did not cause solidification; only the presence of copper significantly catalyzed polymerization / thickening.

[0039] 20070630 reveals “Influence of Iron Oleate Complex Structure on Iron Oxide Nanoparticle Formation” similarly shows that iron oleates release water at 70°C but only decompose at T>380°C to form iron oxide nanoparticles.

[0040] The release of passivating fatty acids, the generation of OH functionalities, and the cross-linking of the fragments into macromolecules are consistent with information from the field of humic substances. Similarly, the production of humins from oil extraction residues is also known. Therefore, humins can also be produced from natural oil through polymerization. IRON ELECTRODES, ESPECIALLY IN H2SO4

[0041] 19300726 reveals a letter in the journal 'Nature' that uniformly anodically pretreated iron anodes can be stable in acidic solution.

[0042] 19620516 “passivity of iron and nickel”, JHBartlett et al.; reveals for the anodic conditioning of Fe electrodes that after the formation of a 10 -6 A layer several centimeters thick shows no further corrosion in the acid; furthermore, an acetate buffer can contribute to stabilization as a complexing agent; iron can be kept stable in H₂SO₄ acidic solutions from an anodic potential of 0.175 V; higher acid concentrations reduce the thickness of the passivating layer. 19670301, “Electrode Passivation Studies,” reveals an overvoltage for the dissolution of Fe electrodes in H₂SO₄ battery systems and the possibility of preventing this reaction, for example in 6N HClO₄, by forming a passivating oxide layer. With a uniform oxide layer, the corrosion of an iron electrode can be limited to less than 0.05 millimeters per year in strongly acidic solution. Without passivation, typical corrosion currents are around 10 -3Amperes per square centimeter are equated to a dissolution rate of 1.25 mm per quarter (5 mm per year). For the Fe-H₂SO₄ system, an initial dissolution process involving the formation of sulfates and the formation of a frequently inhomogeneous, locally further acid-reactive, oxygen-rich, passivating layer is considered established.

[0043] 19810101 reveals “The influence of the polarisation time on the passivation of iron in sulfuric acid” as a passivating layer for iron electrodes at varied H2SO4 concentrations the salts FeSO4*7H2O and FeSO4*H2O.

[0044] In the abstract of 19930301, “Anodic passivity of iron in sulfuric acid”, the formation of a passivating layer with the release of SO2 and the presence of different oxidation states of iron and sulfur are revealed for concentrations >40 wt% (from 5M), which is interpreted as an indication of defective chemical and / or combined, partially reduced compounds with stabilizing transition regions.

[0045] In their publication "Modeling of H2SO4-FeSO4-H2O...." on March 21, Kobylin et al. unanimously revealed that from 40 wt% H2SO4 content in aqueous, dilute solution, FeSO4*H2O is a stable crystal modification, whereby FeSO4*7H2O can also be formed at increased salt content; from approximately 70 wt% H2SO4, the sulfate exists as FeSO4.

[0046] In their 20120202 study, "Corrosion of carbon steel pipes and tanks by concentrated sulfuric acid: A review," Panossian et al. revealed significant corrosion rates for carbon-containing steels due to H₂SO₄: At least 10 g of H₂SO₄ dissolve per day and square decimeter in 6.5 M H₂SO₄; the corrosion rate increases dramatically with increasing carbon content. Only at H₂SO₄ concentrations of 8 mol / L or 75 wt% is the solubility of the resulting FeSO₄ sufficiently restricted and the crystal structure of the resulting salt sufficiently homogeneous for passivating layers to form. Polarization tests can be helpful in examining / identifying passivating coatings. Anodic conditioning to form a passivating layer of various compounds of the Fe-SOH system is recommended.

[0047] In their publication "Optimization of the iron-ion / hydrogen redox flow cell with iron chloride catholyte salt" on January 1, 2014, Tucker et al. revealed a redox flow battery for the cell combination Fe2+ / Fe3+ with H2 / H+; a porous carbon electrode with hydrochloric acid Fe-Cl solution is combined with a hydrogen electrode via a membrane and, with optimized concentrations, allows peak powers of up to 257 mW / cm². 2 with optimized self-discharge.

[0048] In their publication “Phase transition of FeSO4*7H2O to FeSO4*H2O in the H2SO4-HCl-H2O-System by modeling solubility” on December 28, 2017, Zhou et al. revealed a transition of iron(II) sulfate from heptahydrate to monohydrate depending on temperature and H2SO4 concentration: At around 70°C, recrystallization occurs in 20% sulfuric acid with the release of water; the solubility of the sulfate can be increased by adding HCl.

[0049] In 20180414, D. Mitra et al. in 2018 J. Electrochem. Soc. 165 F392 revealed how a porous iron electrode can be manufactured and equipped with Ni nanoparticles for alkaline cells.

[0050] In 20180602, BS Jayathilake et al. reveal in “Improvements to the Coulombic Efficiency of the Iron Electrode for an All-Iron Redox-Flow Battery” how the efficiency of an iron-based redox flow battery can be improved and adjusted to an optimum via adjusting and auxiliary substances and optimized operating parameters.

[0051] In their study "Investigation of Mentha spicata extract as Green Corrosion Inhibitor for Mild Steel in 2M Sulphuric Acid Medium" published on 20181001, Bhawsar et al. revealed how corrosion can be limited by adding an aqueous extract of vegetable oil to a 2M H2SO4 solution; this indicates that with better film-forming, passivating substances, preparatory passivation of an Fe-based electrode could even be dispensed with: Sufficiently reactive substances should be directly applicable with an electrolyte during cell construction.

[0052] In 20181001, Khanra et al. revealed in “Application of Unsaturated Fatty Acid Molecules Derived from Microalgae toward Mild Steel Corrosion Inhibition in HCl Solution: A Novel Approach for Metal-Inhibitor Association” that biogenic, free fatty acids can directly adhere to unalloyed steel in a thin, passivating layer and protect it from corrosion; this indicates that free fatty acids can effectively contribute to the passivation of iron electrodes.

[0053] In their graphical abstract of 20210722, Dutton et al. reveal that under reducing conditions / in the presence of H2 Fe2+ can be the thermodynamically most stable compound; Fe3+ would then only be stable within complexes and / or as a mixed oxide, which again agrees with the data from the field of humic substances and the properties of the cell studied here. GRAPHITE ELECTRODE

[0054] Graphite electrodes are combined with iron-based electrodes in electrochemical cells for wastewater treatment and the removal of organic contaminants via the Fenton reaction. For example, Zhai et al., in their abstract published on April 9, 2019, in ACS Sustainable Chemistry and Engineering, Vol. 7, Issue 9, “Surface Modification of graphite support as an effective strategy to enhance the electro-fenton activity of Fe3O4-graphite composites in situ fabricated from acid mine drainage using an air cathode fuel cell,” reveal how a combined electrode can be produced directly in an iron(II)-containing wastewater stream and used for the removal of organic contaminants. Similarly, Gao et al., in their article “Electrocatalytic Activity of Modified Graphite Felt in Five Anthraquinone Derivative Solutions for Redox Flow Batteries,” published on August 19, 2019, describe how a graphite-based felt electrode can be optimized and modified.

[0055] In their abstract of 20201201, Song et al. “Performance of graphite felt as anodes in the electro-fenton oxidation systems: changes in catalysis, conductivity and adsorption properties” reveal how the surface structure and wettability of C-based fibers can be optimized. TECHNOLOGY IN COMPARISON

[0056] The recovery of low-temperature waste heat is a crucial objective for meeting the demands of modern energy production. It reduces dependence on fossil fuels and critical raw materials, utilizes existing energy potential, and opens up new technological possibilities. For years, researchers worldwide have been trying to efficiently generate electricity from available low-temperature heat, but so far with limited success, as conventional materials achieve only very low efficiencies. Currently, room temperature and waste heat sources below 90 °C cannot be used for profitable energy production, even though there is enormous potential: In Germany alone, the potential of industrial and commercial waste heat amounts to approximately 243 TWh per year, with around 77% occurring at temperatures below 90 °C (Source: Federal Office for Energy Efficiency (BfEE; as of July 29, 2025)).

[0057] "Waste heat potential" encompasses thermal energy generated as a byproduct of industrial, commercial, or technical processes—such as manufacturing, data centers, or energy conversion—and which is typically released directly into the environment. This heat is not part of any further process and, provided suitable, cost-effective technologies are available, can be captured and converted into usable energy such as electricity. Low-temperature waste heat below 90 °C is particularly widespread and remains largely unused due to technological and economic limitations.

[0058] The electrolyte used offers an innovative technology platform to meet this challenge and efficiently convert waste heat and ambient heat into electrical energy at temperatures as low as 10°C, without requiring an external power source or cable connection. The concept relies solely on ambient temperature to repeatedly recharge itself and continuously generate electricity. This provides, for the first time, a sustainable, economical, and self-contained energy source. Its production primarily utilizes industrially available, non-fossil raw materials and hydrophilic decomposition products that can be derived from organic waste and / or oil. This makes the concept scalable and leverages established production processes, thereby unlocking enormous market potential in the field of green energy technologies. It opens up new possibilities in the energy sector and in the utilization of previously unused waste heat.The TEC-G cell converts ambient heat into electricity at temperatures as low as 10°C, without requiring a temperature gradient. The key component is the electrolyte, composed of metal salts and commercially available organic materials such as rapeseed oil. Production is based on locally available, commercially accessible raw materials and requires no rare earth elements or exclusive additives, representing a significant geopolitical advantage: the concept enhances supply chain resilience by avoiding critical raw materials and utilizing local resources. This enables the provision of a sustainable, economical, and renewable energy supply. Scalable, mechanically flexible, and chemically robust energy harvesting units, which can be directly integrated into industrial systems such as pipes, containers, tanks, heat exchangers, or process surfaces, represent the further development of this fundamental principle.

[0059] As a product proof, reproducible validation, and characterization platform, a standardized CR2032 coin cell based on the proprietary electrolyte was developed. While this coin cell format enables controlled performance tests, long-term stability studies, and feasibility studies in the field of electronics, it primarily serves as a technology demonstrator. The core objective of this project is the transfer of the validated electrochemical system to large-area, industrially manufacturable HARVEST modules, intended for use in industry, construction, and building design to recover significant amounts of waste heat; these modules will be simultaneously protected under further patenting requirements.

[0060] The TEC-G cell, similar to a Fenton cell, consists of two electrodes (Fe and graphite) with an electrolyte mixture between them. Ambient heat acts as the driving force, inducing chemical reactions within this material. When a load is applied, the external circuit closes, and a current begins to flow due to the Fe³⁺ complexes within the liquid electrolyte and their selective reactivity with the carbon-based graphite electrode. As electrical energy is released and Fe³⁺ recomplexes to Fe²⁺, the cell cools down, causing the current to gradually decrease until the circuit is opened. After discharge, ambient heat is absorbed, and the initial state is restored. The process can be restarted by closing the circuit with the load, resulting in an iterative charge and discharge cycle that includes at least two complex equilibria (Fe³⁺ / Fe²⁺ and H₂ / H⁺).

[0061] Since the complex compounds are electrode-selective, no membrane is required. Therefore, the processing possibilities for the electrolyte mixture are diverse, ranging from printed circuit board solutions to printing on textiles and liquid tanks. This offers a wide spectrum of applications. Whether for discharge compensation, waste heat recovery, self-sufficient power supply, or innovative cooling – the technology opens up a multitude of applications in industry, construction, and everyday life. Laboratory cells based on the TEC-G electrolyte exhibit peak power outputs in the milliwatt range and continuous power outputs in the microwatt range and can already power electronic devices such as watches or sensors.Even though further optimizations are needed, the current TEC-G cells already deliver 1000 times higher peak power combined with a cost-effective and simple cell design (no membrane required; significant voltage of 0.3 V to 0.8 V directly available; for the likely chemical reactions, see Xu and Tsang, Carbon Research (2022) 1:9; https: / / doi.org / 10.1007 / s44246-022-00010-8). This can be considered a groundbreaking innovation that unlocks the previously commercially inaccessible area of ​​low-temperature waste heat. This area has been neglected until now because the industry simply lacked established, profitable solutions for it.

[0062] This unusual concept is unique worldwide and sets a new standard for energy generation. Feasibility tests in external laboratories using low-energy devices such as charge compensators, wall clocks, kitchen thermometers, and LED lights have already been successfully completed. In the field of low-power electronics and IoT devices, the need for batteries can be effectively eliminated.

[0063] By utilizing unused heat on an industrial scale, for example in data centers, buildings, and production facilities, significant amounts of thermal energy could be unlocked that are currently released unused into the environment. The solution would convert this waste heat into a reliable, locally available energy source for electricity generation, thus transforming an unavoidable byproduct—waste heat—into a productive asset.

[0064] The electrolyte currently functions even at ambient temperatures as low as 10 °C and requires no temperature difference (temperature difference between two points), thus overcoming a fundamental limitation of conventional thermoelectric technologies. The technology can therefore be used in locations where conventional heat recovery or thermoelectric solutions are not feasible.

[0065] This approach reduces overall energy losses, improves the energy efficiency of energy management in factories and buildings such as data centers, and reduces dependence on grid power, fail-safe generators and auxiliary batteries, thereby also reducing maintenance costs.

[0066] In parallel, further applications will become accessible on an industrial scale, including self-powered building sensors, infrastructure monitoring, control systems and auxiliary power supply for digital and automated energy management devices. Unique selling points

[0067] Unique features of the TEC-G cell: - It even works at ambient temperatures of only 10 °C. - No temperature gradient is required. - Self-regenerating cycle through thermochemical, electrode-selective reactions of metal complexes. - Cost-effective raw materials of technical purity can be used for the synthesis. - Abundantly available core materials (vegetable oil, H2SO4, iron salts) enable local synthesis, effectively reducing the CO2 footprint and logistical effort. - Simple cell design leads to a scalable, highly adaptable technology. - Ready-to-use voltage in the range of 0.5 V to 1 V per cell. - Peak performance of button cell-sized samples already in the mW range without optimization. - Supports Europe's strategic autonomy and ESG goals. Economic benefits.

[0068] The production process is energy-efficient, requiring only a few hours at 140°C and using water as the primary solvent for the electrolyte, making the chemistry easy to handle and climate-friendly. Cost-effective products that can be manufactured industrially and locally eliminate the need for expensive, specialized, or imported raw materials and the associated risks within supply chains. Furthermore, this significantly reduces production costs and logistics (including the carbon footprint of raw materials) and minimizes the risks associated with geopolitical influences and tariffs.

[0069] Industrial waste heat and waste heat from buildings represent an untapped energy sector; despite the identification and assessment of this energy (e.g., the EU's EnABLES project), no concept has yet led to significant recovery. The TEC-G electrolyte has the potential to profitably meet this need. Planar electrodes are known from lithium-ion pouch cells. The integration of flexible / permeable large-area elements into waste heat mass flows is known from filter applications in exhaust air systems.

[0070] Complementary devices based on this technology do not require a conventional energy source, thus incurring no operating costs. Once installed, these systems continuously produce free electricity / data at room temperature. sustainability

[0071] Production: The electrolyte mixture is manufactured using an energy-efficient production process that does not require high temperatures or pressures, thus shortening supply chains and avoiding imports. Iron salts, H₂SO₄, and oils such as rapeseed oil are available from local manufacturers in industrialized countries. This enables local production with optimized logistics and a low carbon footprint.

[0072] Concept: This concept utilizes existing waste heat from the surrounding environment for energy generation, thereby reducing energy demand and the consumption of fossil fuels in industrial production and operation. Short transport routes and local procurement make this concept a sustainable and future-oriented solution that significantly enhances energy management on an industrial scale. Self-sufficiency

[0073] TEC-G cells require only ambient heat as the driving force for power generation. Combined with a simple cell design, this makes them well-suited for customized, large-scale deployment in factories, buildings, data centers, and general industrial environments where heat is continuously generated and currently goes unused. By utilizing proven panels and plates in combination with established bag electrodes, the systems can be adapted to surfaces and installations, enabling flexible waste heat recovery ranging from local auxiliary power supply to decentralized energy generation in larger infrastructures.

[0074] The electrolyte mixture has reached the feasibility of being used as an electronic component in an operational environment (TRL 5). This level of maturity is demonstrated by the validated development of the proprietary electrolyte and its successful transfer to other production sites (USA), as well as the confirmation of the data in independent measurement setups (Germany; USA). The use of the electrolyte in a standardized button cell format offers a directly integrable component for the definition and validation of indoor electronics. The use of the electrolyte in large-area cells enables scaling up to industrial harvest applications.

[0075] Using the button cell as a standardized test platform, we have already achieved power outputs in mW / cm². 2The target range has been reached. Industrial device under test (DUT) and climate chamber tests have confirmed a constant, self-contained, and repeatable power output and the corresponding product feasibility. Furthermore, there is potential for further efficiency improvements through continuous enhancement of the electrolyte, electrode conditioning, electrode arrangement, operating mode, and cell architecture. The button cell format provides a starting point and exhibits reproducible electrochemical behavior. The transition from this scalable reference architecture to large-area heat recovery modules is planned for the medium term. The button cell confirms that the core functional components (electrolyte + electrodes) can serve as building blocks for the next product stage.

[0076] With the Mark One electrolyte chemistry and a basic cell architecture based on TRL 5, further and continuous industrial improvements will focus on optimizing the synthesis, additives and auxiliary materials for higher efficiency, adapting the respective cell architectures and scaling up to large-area cells, as well as certifying these functional demonstrators for defined HARVEST use cases, such as power sources in buildings and industrial waste heat recovery systems. INDUSTRIAL APPLICABILITY

[0077] A TEC-G cell is used. Established TEC-G cells disadvantageously require an external temperature gradient or external temperature fluctuations.

[0078] The task was to overcome this disadvantage. The solution is achieved using an electrolyte comprising synthetic and / or natural humic substances, H2SO4, and iron salts.

[0079] Independent, regenerative energy sources for microwatt power in button cell format are already manufacturable; flat cells for waste heat recuperation are also feasible and complement modern heat management systems in a meaningful way.

[0080] Chronologically sorted bibliography YYYYMMDD - Title; Date; DOI 19300726 - Nature, 126, 130-131, (1930), "Isolation of the Film responsible for the Passivity of an Iron Anode in Acid Solution"; 19340918 - US1,973,790 A discloses a process for reacting vegetable oils with H2SO4 and / or H3PO4; 19501114 - US 2,529,539 A discloses a process for the sulfonation of unsaturated esters; 19590501 - Lecture script excerpt “SOIL ORGANIC MATTER”, Visiting Prof. Dr. W. Flaig of the Department of Agronomy, Iowa State College, Ames, Iowa, USA, at the Institute for Plant Nutrition and Soil Science, Braunschweig;

[0081] 19620516 „passivity of iron and nickel“, J.H.Bartlett et al.; technical report no. 8; department of physics; University of Illinois; unclassified by ASTI;

[0082] 19660201 Chemistry and Technology of Fuels and Oils, Volume 2, pages 92-95, Antonishin et al.; „Sulfonation of residual oils and utilisation of the oil sulfonation product“

[0083] 19670301, „Electrode Passivation Studies“, S.B.Brummer et al.; technical report afapl-TR-67-35; unclassified by airforce aero propulsion lab;

[0084] 19751015, „Kinetics and Equilibrium of binding Fe3+ by a fulvic acid“, C.H. Langford et al.; Canadian Journal of Chemistry; Vol. 53; No.20; 2979-2984.

[0085] 19810101 „The influence of the polarisation time on the passivation of iron in sulfuric acid“; Krstulovic et al.; Corrosion Science; Vol. 21; Issue 2; p95-100.

[0086] 19921223 “Proton and metal ion binding to humic substances”; Han de Wit; thesis; Wageningen; ISBN 90-5485-057-4;

[0087] 19930301 “Anodic passivity of iron in sulfuric acid”; Electrochemica Acta; 38; Issue 4; March 1993; p495-502; abstract;Mazurkiewicz et al.;

[0088] 20050101 “Interactions between rapeseed oil fuel and engine oil”; Reports from the TFZ; Thuneke et al.; Straubing; 2005; ISSN 1614-1008;

[0089] 20050630 “Characterization of humic substances by fractionation and determination of metal content using a coupled system: capillary electrophoresis – inductively coupled plasma mass spectrometer”; Thesis; Dirk Eifler; University of Hamburg; Department of Chemistry; 2005. 20070315 C. Kolokassidou et al.; “Thermal Stability of solid and aqueous solutions of humic acid”; Thermochimica Acta; Vol. 454; Issue 2; 15 March 2007; p 78-83; abstract;

[0090] 20070321 Kobylin et al.; „Modeling of H2SO4-FeSO4-H2O and H2SO4-Fe2(SO4)3-H2O Systems for metallurgical applications“; Industrial and Engineering Chemistry Research; Vol46; Issue 8;ACS; abstract

[0091] 20070630 Bronsten et al.; „Influence of Iron Oleate Complex Structure on Iron Oxide Nanoparticle Formation“; Chemistry of materials; Vol 19, Issue 15, abstract;

[0092] 20071015 Pertusatti et al.; „Buffer capacity of humic acid: Themodynamic approach“; Journal of Colloid and Interface Science; Vol. 314; Issue 2; 15 Oct 2007; p 484-489; abstract; 20100702 Maurer et al.; „Reduction and Reoxidation of Humic Acid: Influence on spectroscopic properties and proton binding“; Environmental Science and Technology; Vol44; Issue 15; ACS; abstract

[0093] 20120202 Panossian et al.; „Corrosion of carbon steel pipes and tanks by concentrated sulfuric acid: A review“; Corrosion Science 58 (2012) 1-11; doi:10.1016 / j.corsci.2012.01.025

[0094] 20130101 Boguta et al.; „Interactions of humic acids with metals“; Acta Agrophysica Monographiae; ISBN 978 83 89969 12 5; 2013(2); Instytut Agrofizyki; w Lublinie;

[0095] 20140101 Tucker et al.; „Optimization of the iron-ion / hydrogen redox flow cell with iron chloride catholyte salt“; Journal of Power Sources; Volume 245 1 January 2014; p 691-697; abstract 20140806 Chodera et al.; „Entropy-enthalpy compensation: Role and ramifications in biomolecular ligand recognition and design“ Annu. Rev. Biophys. 2013; 42: 121-141; doi:10.1146 / annurev-biophys-083012-130318; free access author manuscript;

[0096] 20151123 Zhou et al.; „Influence of humic acid complexation with metal ions on extracellular electron transfer activity“;nature; scientific reports; 5:17067; DOI: 10.1038 / srep17067

[0097] 20170819 Mol et al.; „Fructose Dehydration in Methanol“; 2017-09-18; Rijksuniversiteit Groningen; online publication; 20171228 Zhou et al.; „Phase transition of FeSO4*7H2O to FeSO4*H2O in the H2SO4-HCl-H2O-System by modeling solubility“; ACS sustainable chemistry and engineering; Vol6; Issue2; 20171228; abstract

[0098] 20180414 D. Mitra et al 2018 J. Electrochem. Soc. 165 F392 „An Efficient and Robust Surface-Modified Iron Electrode for Oxygen Evolution in Alkaline Water Electrolysis“

[0099] 20180602 B. S. Jayathilake et al 2018 J. Electrochem. Soc. 165 A1630; „Improvements to the Coulombic Efficiency of the Iron Electrode for an All-Iron Redox-Flow Battery“;

[0100] 20180801 ACS Omega 2018, 3, 8537-8545; Björnerbäck et al.; „Microporous Humins Synthesized in Concentrated Sulfuric Acid Using 5-Hydroxymethyl Furfural“

[0101] 20180901 Yang „Synthesis and Use of Synthetic Humic-like Acid (SHLA) for The Remediation of Metal-Contaminated Water and Soil“; thesis; University of York; Environment and Geography; 20181001 Bhawsar et al.; Research J. Pharm. and Tech. 11(10): October 2018; „Investigation of Mentha spicata extract as Green Corrosion Inhibitor for Mild Steel in 2M Sulphuric Acid Medium“

[0102] 20181001 Khanra et al.; ACS Omega 2018, 3, 12369-12382; „Application of Unsaturated Fatty Acid Molecules Derived from Microalgae toward Mild Steel Corrosion Inhibition in HCl Solution: A Novel Approach for Metal-Inhibitor Association“, 20181219 Kanari et al.; Metals 2018, 8, 1084; doi:10.3390 / met8121084; „Thermal Behavior of Hydrated Iron Sulfate in Various Atmospheres“;

[0103] 20190101 Rosenberg et al.; „Organic redox-flow-batteries using compounds out of bark and peat as well as humic acids“; World Journal of Chemical Education; 2019 7(2); 145-152; graphical abstract;

[0104] 20190409 Zhai et al.; ACS sustainable Chemistry and engineering; Vol7; Issue 9; „Surface Modification of graphite support as an effective strategy to enhance the electro-fenton-activity of Fe3O4-Graphite-composites in situ fabricated from acid mine drainage using an air cathode fuel cell“

[0105] 20190819 Gao et al.; „Electrocatalytic Activity of Modified Graphite Felt in Five Anthraquinone Derivative Solutions for Redox Flow Batteries“; ACS Omega 2019, 4, 13721-13732 20200101 Yang et al.; „The sleeping Giant: A Polymer View on Humic

[0106] Matter in Synthesis and Applications"; public access author manuscript of: Progress in Polymer Science, 100: 101182. doi:10.1016 / j.progpolymsci.2019.101182.

[0107] 20200114 Go LC, Depan D, Holmes WE, Gallo A, Knierim K, Bertrand T, Hernandez R. 2020. „Kinetic and thermodynamic analyses of the corrosion inhibition of synthetic extracellular polymeric substances.“ PeerJ Materials Science 2:e4 DOI 10.7717 / peerj-matsci.4

[0108] 20200521 Schotten et al. „Making electrochemistry easily accessible to the synthetic chemist"; Green Chem., 2020, 22,3358;

[0109] 20201201 Song et al.; „Performance of graphite felt as anodes in the electro-fenton oxidation systems:changes in catalysis, conductivity and adsorption properties“; Applied Surface Science; 532;1 December 2020; 147450; abstract

[0110] 20210615 Sailer-Kronlachner et al.; „Sulfuric Acid-Catalyzed Dehydratization of Carbohydrates for the Production of Adhesive Precursors“; ACS Omega 2021, 6, 16641-16648; 20210722 Dutton et al.; „Correcting Frost diagram misconceptions using interactive frost diagrams“; Journal of Chemical Education; Vol 98; Issue 8; ACS

[0111] 20211221 Heubner et al.; „Intercalation electrochemistry for thermoelectric energy harvesting from temperature fluctuations“; Chem. Commun., 2022, 58, 1203; DOI: 10.1039 / d1cc06121f

[0112] 20220412 Ahmed et al.; „Recent developments in hazardous pollutants removal from wastewater and water reuse within a circular economy“; npj Clean Water (2022) 5:12 ; https: / / doi.org / 10.1038 / s41545-022-00154-5;

[0113] 20220629 Xu et al.; „Redox-induced transformation of potentially

[0114] toxic elements with organic carbon in soil"; Xu and Tsang Carbon Research (2022) 1:9; https: / / doi.org / 10.1007 / s44246-022-00010-8

[0115] 20220802 Burmistrow et al.; „Advances in Thermo-Electrochemical (TEC) Cell Performances for Harvesting Low-Grade Heat Energy: A Review“; Sustainability 2022, 14, 9483; https: / / doi.org / 10.3390 / su14159483;

[0116] 20220926 Cobos et al.; „Chelating agents for diluted geothermal brine reinjection“; Geothermal Energy (2022) 10:17 https: / / doi.org / 10.1186 / s40517-022-00227-1;

[0117] 20220927 Xie et al.; „Electrode Kinetic Data: Geometric vs. Real Surface Area“; Batteries 2022, 8, 146. https: / / doi.org / 10.3390 / batteries8100146;

[0118] 20230314 Deng et al.; „Critical Review on theMEchanisms of Fe2+ Regeneration in the Electro-Fenton Process: Fundamentals ans Boosting strategies“; Chemical Reviews Vol123 / Issue 8; March 14; 2023; abstract;

[0119] 20230510 Wu et al.; „Research and Application Progress of Modified Graphite Felt Gas Diffusion Cathode in Organic Wastewater Degradation“; Pol. J. Environ. Stud. Vol. 32, No. 4(2023), 2993-3006; DOI: 10.15244 / pjoes / 163504; 20231208 Tamilselvi et al.; „Investigation of Corrosion Inhibition of Mild Steel in 0.5 M H2SO4 with Lachancea fermentati Inhibitor Extracted from Rotten Grapefruits (Vitis vinifera): Adsorption, Thermodynamic, Electrochemical, and Quantum Chemical Studies“; ACS Phys. Chem Au 2024, 4, 67-84; 20240513 Klucakova et al.; „Physico-Chemical Aspects of Metal-Fulvic Complexation“; Processes 2024, 12, 989. https: / / doi.org / 10.3390 / pr12050989;

[0120] 20241014 Maldifassi et al.; „Evaluation of redox pairs for low-grade heat energy harvesting with a thermally regenerative cycle“;Energy Adv., 2024,3, 2877; DOI: 10.1039 / d4ya00368c 20250531 He et al.; „Aqueous iron-based redox flow batteries for large-scale energy storage“; National Science Review 12: nwaf218, 2025; https: / / doi.org / 10.1093 / nsr / nwaf218

[0121] 20251021 Li et al.;"Thermodynamic insights into the interplay between calcium and iron(II) hydroxycarboxylates: impacts on solubility, speciation, and bioavailability"; RSC Adv., 2025, 15, 39847; DOI: 10.1039 / d5ra04858c;

[0122] 20251118 Pan et al.; “Electrolyte design strategies for next-generation supercapacitors and metal-ion batteries”; Emergent Materials; https: / / doi.org / 10.1007 / s42247-025-01284-5 20260120 Wang et al.; “Optimizing electrode structure parameters for enhanced performance in alkaline-zinc iron flow batteries”; Materials Letters; Volume 407; March 2026; prepublished abstract: carbon felt electrodes at 20% compression with 3mm thickness operate best. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] WO 20220802 [0001, 0115] WO 20211221 [0001, 0111] WO 20241014

[0002] WO 2025 / 040254 A

[0003] WO 2025 / 040759 A

[0003] WO 19590501 [0020, 0080] WO 19751015 [0021, 0084] WO 19921223 [0022, 0086] WO 20050630 [0023, 0089] WO 20070315

[0024] WO 20071015 [0025, 0092] WO 20100702 [0026, 0092] WO 20130101 [0027, 0094] WO 20140806 [0028, 0095] WO 20151123 [0029, 0096] WO 20170819 [0030, 0097] WO 20180801 [0031, 0100] WO 20180901 [0032, 0101] WO 20190101 [0033, 0103] WO 20200101

[0034] WO 19340918

[0037] US 1,973,790 A [0037, 0080] WO 19501114 [0038, 0080] US 2,529,539 A [0038, 0080] WO 19660201 [0038, 0082] WO 20070630 [0039, 0091] WO 19300726

[0041] WO 19620516 [0042, 0081] WO 19670301 [0042, 0083] WO 19810101 [0043, 0085] WO 19930301

[0044] WO 20070321 [0045, 0090] WO 20120202 [0046, 0093] WO 20140101

[0047] WO 20171228 [0048, 0097] WO 20180414 [0049, 0098] WO 20180602 [0050, 0099] WO 20181001 [0051, 0052, 0102] WO 20210722

[0053] WO 20190409 [0054, 0104] WO 20190819 [0054, 0105] WO 20201201 [0055, 0109] US 19340918

[0080] WO 20050101

[0088] WO 20200114

[0107] WO 20200521

[0108] WO 20210615

[0110] WO 20220412

[0112] WO 20220629

[0113] WO 20220926

[0116] WO 20230510

[0119] Cited non-patent literature

[0000] Burmistrow et al. in “Advances in Thermo-Electrochemical (TEC) Cell Performances for Harvesting Low-Grade Heat Energy: A Review” (Sustainability 2022, 14, 9483; https: / / doi.org / 10.3390 / su14159483

[0001] Heubner et al. in „Intercalation electrochemistry for thermoelectric energy harvesting from temperature fluctuations“ (Chem. Commun., 2022, 58, 1203; DOI: 10.1039 / d1cc06121f)

[0001] Maldifassi et al. in „Evaluation of redox pairs for low-grade heat energy harvesting with a thermally regenerative cycle“ (Energy Adv., 2024,3, 2877; DOI: 10.1039 / d4ya00368c

[0002] Li et al. in „Thermodynamic insights into the interplay between calcium and iron(II) hydroxycarboxylates: impacts on solubility, speciation, and bioavailability

[0002] SOIL ORGANIC MATTER“, Gast-Prof. Dr. W. Flaig des Department of Agronomy, Iowa State College, Ames, Iowa, USA [0020, 0080] Kinetics and Equilibrium of binding Fe3+ by a fulvic acid

[0021] Chodera et al. ergänzend in „Entropy-enthalpy compensation: Role and ramifications in biomolecular ligand recognition and design

[0028] Zhou et al. in "Influence of humic acid complexation with metal ions on extracellular electron transfer activity"

[0029] Mol et al. in „Fructose Dehydration in Methanol

[0030] Björnerbäck et al. in „Microporous Humins Synthesized in Concentrated Sulfuric Acid Using 5-Hydroxymethyl Furfural

[0031] Yang in „Synthesis and Use of Synthetic Humic-like Acid (SHLA) for The Remediation of Metal-Contaminated Water and Soil

[0032] Rosenberg et al. in „Organic redox-flow-batteries using compounds out of bark and peat as well as humic acids

[0033] Yang et al. in „The sleeping Giant: A Polymer View on Humic Matter in Synthesis and Applications

[0034] Chemistry and Technology of Fuels and Oils, Volume 2, pages 92-95, Antonishin et al.; „Sulfonation of residual oils and utilisation of the oil sulfonation product [0038, 0082] Influence of Iron Oleate Complex Structure on Iron Oxide Nanoparticle Formation

[0039] passivity of iron and nickel“, J.H.Bartlett et al

[0042] The influence of the polarisation time on the passivation of iron in sulfuric acid

[0043] Kobylin et al. in „Modeling of H2SO4-FeSO4-H2O...

[0045] Panossian et al. in „Corrosion of carbon steel pipes and tanks by concentrated sulfuric acid: A review

[0046] Tucker et al. in „Optimization of the iron-ion / hydrogen redox flow cell with iron chloride catholyte salt“ eine redox-flow-Batterie für die Zellkombination Fe2+ / Fe3+ mit H2 / H+;

[0047] Zhou et al. in „Phase transition of FeSO4*7H2O to FeSO4*H2O in the H2SO4-HCl-H2O-System by modeling solubility

[0048] D. Mitra et al 2018 J. Electrochem. Soc. 165 F392 in „An Efficient and Robust Surface-Modified Iron Electrode for Oxygen Evolution in Alkaline Water Electrolysis

[0049] B. S. Jayathilake et al in „Improvements to the Coulombic Efficiency of the Iron Electrode for an All-Iron Redox-Flow Battery

[0050] Bhawsar et al. In „Investigation of Mentha spicata extract as Green Corrosion Inhibitor for Mild Steel in 2M Sulphuric Acid Medium

[0051] Khanra et al. in „Application of Unsaturated Fatty Acid Molecules Derived from Microalgae toward Mild Steel Corrosion Inhibition in HCl Solution: A Novel Approach for Metal-Inhibitor Association

[0052] Dutton et al. in „Correcting Frost diagram misconceptions using interactive frost diagrams

[0053] Zhai et al. in ACS sustainable Chemistry and engineering; Vol7; Issue 9; „Surface Modification of graphite support as an effective strategy to enhance the electro-fenton-activity of Fe3O4-Graphite-composites in situ fabricated from acid mine drainage using an air cathode fuel cell

[0054] Gao et al in „Electrocatalytic Activity of Modified Graphite Felt in Five Anthraquinone Derivative Solutions for Redox Flow Batteries

[0054] Song et al. „Performance of graphite felt as anodes in the electro-fenton oxidation systems:changes in catalysis, conductivity and adsorption properties

[0055] Xu und Tsang, Carbon Research (2022) 1:9; https: / / doi.org / 10.1007 / s44246-022-00010-8

[0061] Daten; DOI

[0080] 19300726 - Nature, 126, 130-131, (1930), „Isolation of the Film responsible for the Passivity of an Iron Anode in Acid Solution"

[0080] J.H.Bartlett et al.; technical report no. 8; department of physics; University of Illinois; unclassified by ASTI

[0081] Electrode Passivation Studies“, S.B.Brummer et al.; technical report afapl-TR-67-35; unclassified by airforce aero propulsion lab

[0083] Kinetics and Equilibrium of binding Fe3+ by a fulvic acid“, C.H. Langford et al.; Canadian Journal of Chemistry; Vol. 53; No.20; 2979-2984

[0084] The influence of the polarisation time on the passivation of iron in sulfuric acid“; Krstulovic et al.; Corrosion Science; Vol. 21; Issue 2; p95-100

[0085] Proton and metal ion binding to humic substances“; Han de Wit; Thesis; Wageningen; ISBN 90-5485-057-4;

[0086] 19930301

[0087] Anodic passivity of iron in sulfuroc acid“; Electrochimica Acta; Vol. 38; Issue 4; March 1993; p495-502; abstract;Mazurkiewicz et al

[0087] Wechselwirkungen zwischen Rapsölkraftstoff und Motorenöl“; Berichte aus dem TFZ; Thuneke et al.; Straubing; 2005; ISSN 1614-1008

[0088] Characterization of humic substances by fractionation and determination of metal content using a coupled system capillary electrophoresis - inductively coupled plasma mass spectrometer; Thesis; Dirk Eifler; University of Hamburg; Department of Chemistry; 2005. 20070315 C. Kolokassidou et al.; “Thermal Stability of solid and aqueous solutions of humic acid”; Thermochimica Acta; Vol. 454; Issue 2; 15 March 2007; p 78-83

[0089] Kobylin et al.; “Modeling of H2SO4-FeSO4-H2O and H2SO4-Fe2(SO4)3-H2O Systems for metallurgical applications”; Industrial and Engineering Chemistry Research; Vol46; Issue 8;ACS

[0090] Bronsten et al.; “Influence of Iron Oleate Complex Structure on Iron Oxide Nanoparticle Formation”; Chemistry of materials; Vol 19, Issue 15, abstract

[0091] Pertusatti et al.; “Buffer capacity of humic acid: Themodynamic approach”; Journal of Colloid and Interface Science; 314; Issue 2; 15 Oct 2007; p 484-489

[0092] Maurer et al.; „Reduction and Reoxidation of Humic Acid: Influence on spectroscopic properties and proton binding“; Environmental Science and Technology; Vol44; Issue 15

[0092] Panossian et al.; „Corrosion of carbon steel pipes and tanks by concentrated sulfuric acid: A review“; Corrosion Science 58 (2012) 1-11; doi:10.1016 / j.corsci.2012.01.025

[0093] Boguta et al.; „Interactions of humic acids with metals“; Acta Agrophysica Monographiae; ISBN 978 83 89969 12 5; 2013(2); Instytut Agrofizyki; w Lublinie

[0094] Chodera et al.; „Entropy-enthalpy compensation: Role and ramifications in biomolecular ligand recognition and design“ Annu. Rev. Biophys. 2013; 42: 121-141; doi:10.1146 / annurev-biophys-083012-130318

[0095] Zhou et al.; „Influence of humic acid complexation with metal ions on extracellular electron transfer activity“;nature; scientific reports; 5:17067; DOI: 10.1038 / srep17067

[0096] Mol et al.; „Fructose Dehydration in Methanol“; 2017-09-18; Rijksuniversiteit Groningen; online publication; 20171228 Zhou et al.; „Phase transition of FeSO4*7H2O to FeSO4*H2O in the H2SO4-HCl-H2O-System by modeling solubility“; ACS sustainable chemistry and engineering; Vol6; Issue2

[0097] D. Mitra et al 2018 J. Electrochem. Soc. 165 F392 „An Efficient and Robust Surface-Modified Iron Electrode for Oxygen Evolution in Alkaline Water Electrolysis

[0098] B. S. Jayathilake et al 2018 J. Electrochem. Soc. 165 A1630; „Improvements to the Coulombic Efficiency of the Iron Electrode for an All-Iron Redox-Flow Battery

[0099] ACS Omega 2018, 3, 8537-8545; Björnerbäck et al.; „Microporous Humins Synthesized in Concentrated Sulfuric Acid Using 5-Hydroxymethyl Furfural

[0100] Yang „Synthesis and Use of Synthetic Humic-like Acid (SHLA) for The Remediation of Metal-Contaminated Water and Soil“; thesis; University of York; Environment and Geography; 20181001 Bhawsar et al.; Research J. Pharm. and Tech. 11(10): October 2018; „Investigation of Mentha spicata extract as Green Corrosion Inhibitor for Mild Steel in 2M Sulphuric Acid Medium

[0101] Khanra et al.; ACS Omega 2018, 3, 12369-12382; „Application of Unsaturated Fatty Acid Molecules Derived from Microalgae toward Mild Steel Corrosion Inhibition in HCl Solution: A Novel Approach for Metal-Inhibitor Association“, 20181219 Kanari et al.; Metals 2018, 8, 1084; doi:10.3390 / met8121084; „Thermal Behavior of Hydrated Iron Sulfate in Various Atmospheres

[0102] Rosenberg et al.; „Organic redox-flow-batteries using compounds out of bark and peat as well as humic acids“; World Journal of Chemical Education; 2019 7(2); 145-152

[0103] Zhai et al.; ACS sustainable Chemistry and engineering; Vol7; Issue 9; „Surface Modification of graphite support as an effective strategy to enhance the electro-fenton-activity of Fe3O4-Graphite-composites in situ fabricated from acid mine drainage using an air cathode fuel cell

[0104] Gao et al.; „Electrocatalytic Activity of Modified Graphite Felt in Five Anthraquinone Derivative Solutions for Redox Flow Batteries“; ACS Omega 2019, 4, 13721-13732 20200101 Yang et al.; „The sleeping Giant: A Polymer View on Humic

[0105] Synthesis and Applications"; public access author manuscript of: Progress in Polymer Science, 100: 101182. doi:10.1016 / j.progpolymsci.2019.101182

[0106] Go LC, Depan D, Holmes WE, Gallo A, Knierim K, Bertrand T, Hernandez R. 2020. „Kinetic and thermodynamic analyses of the corrosion inhibition of synthetic extracellular polymeric substances.“ PeerJ Materials Science 2:e4 DOI 10.7717 / peerj-matsci.4

[0107] Schotten et al. „Making electrochemistry easily accessible to the synthetic chemist"; Green Chem., 2020, 22,3358

[0108] Song et al.; „Performance of graphite felt as anodes in the electro-fenton oxidation systems:changes in catalysis, conductivity and adsorption properties“; Applied Surface Science; 532;1 December 2020; 147450

[0109] Sailer-Kronlachner et al.; „Sulfuric Acid-Catalyzed Dehydratization of Carbohydrates for the Production of Adhesive Precursors“; ACS Omega 2021, 6, 16641-16648; 20210722 Dutton et al.; „Correcting Frost diagram misconceptions using interactive frost diagrams“; Journal of Chemical Education; Vol 98; Issue 8; ACS

[0110] Heubner et al.; „Intercalation electrochemistry for thermoelectric energy harvesting from temperature fluctuations“; Chem. Commun., 2022, 58, 1203; DOI: 10.1039 / d1cc06121f

[0111] Ahmed et al.; „Recent developments in hazardous pollutants removal from wastewater and water reuse within a circular economy“; npj Clean Water (2022) 5:12 ; https: / / doi.org / 10.1038 / s41545-022-00154-5

[0112] Xu et al.; „Redox-induced transformation of potentially

[0113] toxic elements with organic carbon in soil"; Xu and Tsang Carbon Research (2022) 1:9; https: / / doi.org / 10.1007 / s44246-022-00010-8

[0114] Burmistrow et al.; „Advances in Thermo-Electrochemical (TEC) Cell Performances for Harvesting Low-Grade Heat Energy: A Review“; Sustainability 2022, 14, 9483; https: / / doi.org / 10.3390 / su14159483

[0115] Cobos et al.; „Chelating agents for diluted geothermal brine reinjection“; Geothermal Energy (2022) 10:17 https: / / doi.org / 10.1186 / s40517-022-00227-1

[0116] 20220927 Xie et al.; „Electrode Kinetic Data: Geometric vs. Real Surface Area“; Batteries 2022, 8, 146. https: / / doi.org / 10.3390 / batteries8100146

[0117] 20230314 Deng et al.; „Critical Review on theMEchanisms of Fe2+ Regeneration in the Electro-Fenton Process: Fundamentals ans Boosting strategies“; Chemical Reviews Vol123 / Issue 8; March 14; 2023

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[0122]

Claims

[01] TEC-G cell comprising - two electrodes arranged in a continuous, membrane-free cell space, wherein - the cell space is filled with an electrolyte mixture, - and the electrolyte mixture includes natural and / or synthetic fulvic and / or humic acids. [02] TEC-G cell according to the preceding claim, characterized by that the electrolyte mixture was obtained by - partial carbonization of at least one polyol, fat, oil or carbohydrate with H2SO4, preferably rapeseed oil and / or at least one sugar selected from the group consisting of fructose, psicose, tagatose, Partial carbonization of rancid rapeseed oil is particularly preferred. [03] TEC-G cell according to the preceding claim, characterized by that the charring - with successive addition of concentrated H2SO4 - in the presence of a metal sulfate, preferably iron sulfate, FeSO4*7H2O is particularly preferred; - with final dilution with H2O and / or a polyol, preferably H2O and polyethylene glycol, particularly preferably dilution with H2O and PEG400, - to a pH value < 7, preferably 0 <pH<3, besonders bevorzugt <0,1; erfolgte. [04] TEC-G cell according to one of the preceding claims, characterized by that all raw materials have a technical purity of 95% to 99%. [05] TEC-G cell according to one of the preceding claims, characterized by , that - the first electrode is a C-based electrode, preferably a graphitized foil or fiber of technical purity; - the second electrode is an Fe-based electrode, preferably made of low-carbon steel with a carbon content of <1%, particularly preferably in the form of an unalloyed steel sheet and / or steel fabric of technical purity with a carbon content of <0.2%. [06] TEC-G cell according to one of the preceding claims, characterized by , that - the TEC-G cell exhibits an open cell voltage in the range of 0.5V to 1V at a constant room temperature in the range of 15°C to 30°C. [07] TEC-G cell according to one of the preceding claims, characterized bythat the electrolyte comprises at least one adjusting and auxiliary substance with a total weight of up to 25%, the adjusting and auxiliary substance being selected from the group consisting of buffer, hydrochloric acid, phosphoric acid, organic acid, acetic acid, acid buffer, acetic acid acetate buffer, humectant, xanthan gum, sorbitol, xylitol, fructose, sugar, conductivity additive, NaCl, LiCl, KCl, halogen salt mixture of alkali metals, sulfates of alkali metals, anthrones, flavones, metal soaps, fatty acid salts, sugar anthraquinone-based food colorings, carminic acid, siderophores, amino acid, ethanol, glycerol, thickener, defoamer, complexing agent, starch extract, sodium salt mixture, sodium salt, sodium sulfate, sodium chloride, sodium acetate, molasses, beet juice, cane sugar syrup, syrup, alkaline earth salts, aluminum salts, potato starch, sugar beet pulp, flour, silicates, Glass powder, molecular sieves, framework silicates, powdered separators, paper separators, paper scraps, electrode powders,Electrode packings. [08] TEC-G cell according to one of the preceding claims, characterized by , that the TEC-G cell is designed as a button cell comprising a two-part steel housing with an airtight seal with tightly inserted graphite foil, electrolyte sponge with electrolyte, metal disc and internally contacting pressure spring. [09] TEC-G cell according to any one of claims 1 to 7, characterized by , that the TECG cell is designed as a flexible, flat, planar cell with a total thickness in the range of 0.3 mm to 4 mm, comprising a light- and air-tight enclosing outer film and at least two electrodes in film and / or fabric form with an electrolyte sponge with electrolyte arranged between them. [10] TEC-G cell according to any of the preceding claims, characterized bythat the TEC-G cell is integrated as a generator, preferably a self-discharge compensator, into an energy management system, preferably a clocked energy management system.