Green Energy – Frontis Energy

Posted on March 25, 2026 by admin

Life cycle analysis of natural graphite

Natürliches Graphitgranulat aus einer österreichischen Mine

In the production of lithium-ion batteries, not only lithium is a crucial raw material, but also graphite. The widespread use of graphite is attributed to its low price, natural availability, high energy and power density, and long lifespan. This makes graphite a very advantageous choice for anodes in lithium-ion batteries.

As alternatives to lithium-graphite anodes, silicon anodes have been explored in recent years due to their high theoretical capacity, availability, and low cost. However, issues such as volumetric expansion and reliability reduce the chances of successful commercialization, especially in electric vehicles.

Battery-grade anode active material is derived from naturally mined or synthetic graphite. Graphite from natural ores generally has lower production costs but also lower purity and quality. Its anisotropic crystal structure can impair performance in lithium-ion batteries, even though it often allows for higher capacities. However, this advantage typically comes with a reduced lifespan.

In contrast, synthetic graphite is more expensive to produce but offers significantly higher purity and consistency. Synthetic graphite is obtained from carbon precursors such as petroleum coke or coal tar. Due to its higher purity, it accounted for a higher market share of 60% of global revenue in 2025. The higher revenue share is also attributed to higher prices.

Due to its isotropic crystal orientation, synthetic graphite possesses better thermal stability, lower thermal expansion, and faster lithiation kinetics. As a result, it provides overall stronger battery performance and a longer lifespan, although it typically has lower capacities.

As the global battery market grows, its supply chain must also be robust and sustainable. Canada has rich resources of natural graphite, which is mined and processed in the province of Quebec. To better understand the environmental impacts of this new supply chain, a sustainability analysis was conducted for one graphite mine and one graphite processing facility in Quebec by researchers at Concordia University in Montreal. The results were recently published in the journal MDPI Batteries.

The study integrated site-specific data on mining and processing (2022–2025) with Ecoinvent in OpenLCA and mainly focuses on the potential for greenhouse gas (CO₂ equivalents) reduction and water usage.

The researchers showed that the production of one ton of anode-capable graphite in Quebec generates approximately 1.44 tons of CO₂ equivalents. This is significantly less than the 9.6 tons of CO₂ generated per ton of Chinese graphite. Therefore, the sustainability analysis in Quebec indicates a significant reduction in carbon intensity.

The modeled chain included open-pit mining through drilling, blasting, and hauling, as well as processing through crushing, grinding, flotation, and dewatering. Finally, the final processing of anode-capable graphite through micronization and spheronization, acid leaching purification, and carbon coating, followed by finishing and packaging, was also investigated. Spheronization converts the concentrate into spherical graphite granules to enhance bulk density and packing efficiency in the anode. Significant by-products are generated, e.g., as fine particles.

Within the processing facility in Quebec, micronization and spheronization, as well as purification and coating, are the most energy-intensive steps. Acid leaching purification also represents the largest single contributor to CO₂ and water scarcity impacts. However, the very low carbon intensity of the grid (hydropower) significantly mitigates the footprint of these electrical loads. In contrast, natural gas used for high-temperature purification and coating remains the largest direct source of CO₂.

The CO₂ emissions from mining are mainly caused by diesel in trucks and heavy equipment. Detailed equipment data showed that hauling dominates fuel consumption. Water impacts at the concentrator are elevated due to flotation and waste treatment. However, a closed water system and dedicated wastewater treatment reduced fresh water intake and stress from waste effluent.

The researchers also interpreted the results of their sustainability analysis to assess impacts, identify sustainability focal points, and determine the phases with the highest resource intensity and the highest emissions profiles. This analysis facilitated the representation of environmentally burdensome intermediate steps. Natural gas used for purification and coating in the processing facility was the largest source of CO₂, followed by diesel and electricity consumption.

In addition to graphite, the extraction of lithium and trace elements also plays a significant role in the sustainability of batteries. However, these were not the focus of the study. Nevertheless, graphite dominates the market for anode materials, accounting for up to 98% of the market share, while Li₄Ti₅O₁₂ makes up only about 2%.

The study concluded with an integrated synthesis of the results and provided targeted recommendations for process optimization, emission reduction, and improving sustainability throughout the entire supply chain. This systematic and transparent methodology ensured a robust assessment of the environmental impact of the production of anode-grade graphite.

Despite the significant reduction in CO₂ emissions compared to graphite extraction and processing in China, the research highlights further opportunities for improvement. In particular, electrification of mining equipment to reduce diesel consumption and minimizing or substituting natural gas consumption during cleaning and coating at the facility could further decrease CO₂ emissions.

At Frontis Energy, we are closely monitoring the decarbonization and diversification of supply chains and provide products from various sources

Vegh, et al., 2026, Toward sustainable anode materials: LCA of natural graphite processing in Québec, MDPI Batteries, 12, 68. DOI: 10.3390/batteries1202006

Image: Natural graphite from an Austrian mine

Posted on March 10, 2026 by admin

Electrochemical formate as precursor for microbial ectoine

Ectoine is a valuable raw material for the cosmetics industry and is used in day creams and for UV protection. Its synthesis involves several chemical transformations based on complex raw materials, which makes its production expensive. In the search for simpler raw materials, CO₂ is particularly interesting.

Among the emerging strategies for utilizing CO₂ as a raw material, its electrochemical reduction into fuels and other raw materials has gained significant attention. In an earlier article, we had already reported on our own experiments. One of the easily producible products is formic acid, which can serve as an intermediate for microbial synthesis. This is partly due to the high solubility of formic acid in water, its relatively high purity without many by-products, and the low overpotential during CO₂ reduction.

The microbial synthesis of higher-value products from formic acid has generated increasing interest. This can be achieved, for example, through genetic modifications of Escherichia coli. To combine electrochemical CO₂ reduction with microbial synthesis, other microorganisms such as Cupriavidus necator, Methylobacterium extorquens, and acetic acid bacteria have also been investigated. Usable products have included bioplastics, long-chain carboxylic acids, amino acids, and alcohols.

However, these efforts have largely focused on bulk products or precursors such as acetic acid, ethanol, butanol, polyhydroxyalkanoates, etc. The potential for the synthesis of high-quality products is still vastly underexplored.

Researchers at the Helmholtz Centre for Environmental Research – UFZ in Leipzig (Germany) have now demonstrated the feasibility of producing ectoine from formic acid and published their findings in the journal Engineering in Life Sciences.

They utilized Methyloligella halotolerans, which has the ability to grow using formic acid as its sole energy source. The researchers compared ectoine production using four different substrates: methanol, formic acid, and electrochemically produced formic acid from CO₂.

Thus, the electrochemical reduction of CO₂ on tin-based gas diffusion electrodes was performed prior to biological processing. This resulted in a methanol-formic acid mixture. CO₂ was reduced in a flow cell with a tin-based gas diffusion cathode and a platinum anode. A Nafion 117 proton exchange membrane separated the chambers. Both sides were filled with salt medium to minimize the ionic transition before the direct feeding of the catholyte into the culture.

Moreover, the researchers showed that saline microbiological media could be used as an electrolyte solution for the combined electrochemical-microbial synthesis. This is important because salt solutions have better conductivity.

This study establishes formate as a suitable carbon source for ectoine synthesis in the halophilic methylotrophic bacterium Methyloligella halotolerans. By using electrochemical formic acid for ectoine synthesis, the researchers demonstrated that saline electrolytes can be utilized for the combined electrochemical-microbial synthesis of valuable compounds in electro-biorefining.

Substrate-specific ectoine yields were consistently higher with methanol. A substrate mixture of formic acid and methanol improved the uptake of formic acid but fell short of pure methanol. This underscores the importance of future optimizations for formic acid uptake by microorganisms.

Optimizing electrochemical parameters, including improved buffering, electrolyte composition, and electrode selectivity in saline solutions, could further enhance yields. Additional advancements through strain breeding or genetic modification, better substrate mixtures, and the recovery of ectoine through gentler methods instead of cell lysis could significantly increase productivity.

At Frontis Energy, we are always eager to see how the proposed solution can be scaled industrially and how products like microbial ectoine can be established in markets such as pharmaceuticals and cosmetics.

Kas et al., 2026, Exploring ectoine production from methanol, formate, and electrochemically produced formate by Methyloligella halotolerans, Engineering in Life Sciences, 26:e70063, DOI: 10.1002/elsc.70063

Image: Pixabay

Posted on February 9, 2026 by admin

Ammonia electrosynthesis in a palladium membrane flow cell

Ammonia (NH₃) is a crucial raw material for fertilizer production and a potential renewable, carbon-free energy storage solution. It is produced in the Haber-Bosch process using natural gas (CH₄). During this process, natural gas is converted into hydrogen (H₂) and CO₂ by steam reforming. The Haber-Bosch process accounts for approximately 1-3% of global CO₂ emissions. This method requires stable energy supply and CAPEX intensive facilities, leading to highly centralized ammonia production. In contrast, alternative electrochemical pathways for ammonia production represent sustainable and decentralized solutions.

Electrochemical ammonia production is not a new process and is based on hydrogen electrolysis. In a subsequent step, hydrogen is used for catalytic nitrogen reduction. Experimentally, lithium and calcium have been used as electrocatalysts. Ammonia has been produced in continuous flow cells with efficiencies of up to 76%, as well as in other electrochemical cells. However, stable ammonia production in flow cells requires dry and purified hydrogen.

The primary issue with moist hydrogen is the excessive formation of lithium hydroxide (LiOH):

2 Li + 2 H₂O → 2 LiOH + H₂

However, water electrolysis could be completely eliminated if the protons (H⁺) generated from water oxidation were directly supplied to the lithium-coated cathode. This would further simplify systems and lower investment costs.

Researchers at Imperial College London followed exactly that approach. They coupled continuous water oxidation directly to lithium-mediated nitrogen reduction under non-aqueous conditions in a two-chamber flow cell. They recently published their results in the journal ACS Energy Letters.

The coupling was achieved through an electrically isolated, hydrogen-permeable palladium membrane between the chambers. On the anodic side (aqueous), water was oxidized at an iridium oxide-coated titanium anode to produce protons, meaning adsorbed H. This form of hydrogen permeated the palladium membrane. It then entered the dry, non-aqueous cathodic chamber, where N₂ was reduced on lithium.

The palladium membrane was not integrated into the external circuit during nitrogen reduction. It simultaneously served as both a proton source and sink, made possible by its electrical conductivity and hydrogen permeability.

The scientists first validated proton transport through the palladium membrane while preventing water crossover through symmetric cell tests and ¹H-NMR isotopic exchange using water (H₂O) and deuterium oxide (D₂O, heavy water).

Real-time mass spectrometry of D₂O at the anode confirmed that deuterons supplied through the palladium membrane were incorporated into ammonia (ND₂H). This demonstrates that the protons in NH₃ originated from water oxidation and not solely from the ethanol used as well. It was evidence for linear charge transfer while maintaining negligible water transport.

As a control, an experiment was conducted using a Nafion™ membrane to demonstrate that membranes allowing water crossover prevented lithium-mediated ammonia synthesis. Nafion™ permits proton transfer while being permeable to water.

The researchers showed that the electrical conductivity of the palladium membrane enabled it to operate simultaneously as both an anode and a cathode. This allowed for continuous conversion of nitrogen and water into ammonia without producing molecular hydrogen as an intermediate. The Nafion™ control proved that the transport of protons while preventing water crossover allowed for lithium-mediated ammonia synthesis.

The necessity for pre-hydration of the membrane and the gradual increase in membrane potential during pulsed operation indicated that the kinetics of hydrogen transfer and membrane stability were key factors for performance. This was because the system was optimized for the neutral aqueous electrolyte with isotopic labeling. The researchers proposed ways to improve efficiency in their article, including the exploration of alternative hydrogen-permeable metals and alloys.

The presented membrane could find applications beyond ammonia synthesis, in other electrochemical transformations where anhydrous conditions and controlled proton release are required. These include CO₂ reduction and non-aqueous redox flow batteries.

For further research, the authors suggested:

Increase proton flow and reduce membrane transition resistance,
Test alternative hydrogen-permeable metals or alloys to reduce costs, and
Conduct pulse and idle protocols to monitor lithium loss.

At Frontis Energy, we are eager to see how individual monolithic palladium membranes will enter in the market. Continuous ammonia electrosynthesis represents a conceptual advancement towards simpler, more robust green fertilizer production and energy storage.

Ye et al. 2026, Continuous ammonia electrosynthesis from nitrogen and water in a monolithic Pd membrane-based flow cell, ACS Energy Letters, DOI: 10.1021/acsenergylett.5c03617

Image: Pixabay

Posted on December 26, 2025 by admin

Sulfonated clay and carbon nanotubes Nafion™-based proton exchange membranes

The demand for sustainable energy has accelerated the development of electrochemical systems for energy conversion. This includes, in particular, proton exchange membrane fuel cells (PEMFCs). PEMFCs offer numerous advantages, including high energy density, low operating temperatures, fast start-up times, and compact design. These characteristics make them especially suitable for mobile and decentralized energy applications. The development of high-performance proton exchange membranes is crucial for the advancement of fuel cell technology, particularly under demanding operating conditions.

The central component, the proton exchange membrane, is characterized by high proton conductivity, excellent chemical and physical stability, low gas permeability, and adequate water uptake under a variety of conditions. Nafion™, a perfluorosulfonic acid (PFSA) ionomer, is considered the gold standard for proton exchange membranes due to its outstanding proton conductivity and chemical resistance.

However, its performance degrades significantly at elevated temperatures (>80 °C) and low relative humidity due to excessive water loss. These limitations restrict its applicability in next-generation high-temperature fuel cells. To overcome these limitations, extensive efforts have been made to develop PFSA-based composite membranes. For this purpose, inorganic or organic fillers such as silica, metal oxides, and carbon-based nanomaterials have been used. These additives aim to improve water retention, mechanical strength, and thermal stability.

Italian researchers from the University of Calabria have developed Nafion™ membranes reinforced with sulfonated clay and carbon nanotubes to address issues with water retention and proton transport. They recently published their results in the journal Materials for Renewable and Sustainable Energy. The hybrid fillers created a synergistic effect. The clay improved the hydrophilic properties, while carbon nanotubes enhanced the structural integrity and conductivity.

In tests with hydrogen fuel cells at 120 °C and 20% relative humidity—conditions that typically severely impair normal PFSA membranes—the new composition achieved a peak power of 443 mW/cm². This was four times that of Nafion™ membranes. This breakthrough suggested that integrating nanofillers could yield further improvements in durability and efficiency of proton exchange membranes. At the same time, the experiments paved the way for robust fuel cells in the automotive and stationary energy sectors, where such performance improvements are particularly needed.

The incorporation of sulfonated clay and carbon nanotubes not only improved the ion exchange capacity and hydrolytic stability but also critically modulated the water dynamics. The result was superior water retention and sustained proton diffusion, particularly at elevated temperatures. The significantly higher proton conductivity under low humidity conditions was a crucial factor for the operation of high-temperature fuel cells in the study presented.

This study successfully demonstrated the significant potential of sulfonated clay and carbon nanotubes to enhance the performance and durability of Nafion-based proton exchange membranes for fuel cell applications. The incorporation of the additives also increased the structural integrity of the membrane. Dynamic mechanical analysis showed a significant reinforcement effect from the inclusion of the additives, with a consistent increase in storage modulus and a shift of the glass transition temperature to higher temperatures. For the improved membrane, the glass transition temperature increased from 120 °C for conventional Nafion to approximately 150 °C.

Moreover, the nanocomposite membrane exhibited a remarkable conductivity of 42.3 mS/cm at low humidity. This represented a significant improvement compared to pure Nafion™.

In summary, the nanohybrid membrane consistently overcame significant limitations of conventional PFSA membranes, particularly their susceptibility to drying out and mechanical degradation under demanding operating conditions.

At Frontis Energy, we are convinced that the synergistic interplay of enhanced proton transport pathways, improved water retention, and superior thermomechanical stability makes this composite membrane a promising candidate for robust and efficient next-generation fuel cells.

Nicotera, et al. 2025 Enhanced electrochemical performance and thermomechanical stability of nafion/sulfonated clay-carbon nanotube nanocomposite membranes for high-performance fuel cells under challenging conditions. Materials for Renewable and Sustainable Energy 14, 48, DOI: 10.1007/s40243-025-00325-7.

Image: Pixabay

Posted on December 1, 2025February 24, 2026 by admin

Stability of anion exchange membranes for electrolysis

DOI: 10.13140/RG.2.2.18396.65927

Energy security and climate change are among the greatest challenges of our time. To reduce dependence on fossil fuels, renewable energy sources are emerging as key solutions for sustainable energy production. To this end, scalable solutions are essential for storing and transporting renewable energy. Hydrogen produced in water electrolyzers and reconverted into electricity in fuel cells can help balance the seasonal variability of renewable energy.

Fuel cells have the potential to significantly contribute to the decarbonization of the transport sector. Transport of people and goods accounts for almost one‑third of global greenhouse gas emissions. Despite this potential, the widespread adoption of modern fuel cells and electrolyzers remains limited due to high investment costs. This is mainly due to expensive noble‑metal catalysts and perfluorinated proton exchange membranes.

This challenge has sparked growing interest in anion exchange membranes. Under alkaline conditions, they offer several advantages:

Use of non‑noble metal catalysts thanks to non‑corrosive conditions
More sustainable membrane materials

However, there are hurdles to their introduction, particularly their short lifetime under alkaline conditions and oxidative stress. The formation of hydrogen peroxide and hydroxyl radicals under alkaline conditions is responsible for the accelerated degradation of polymer membranes. Investigation radical‑induced degradation of anion exchange membranes is therefore of central importance.

Hence, efficient radical generation in the laboratory is required. Current methods such as thermal decomposition or UV activation of hydrogen peroxide are inefficient and prone to side reactions, limiting their relevance to real operating conditions. Immersion in oxygen‑saturated alkaline solutions has provided useful insights, but cannot distinguish between natural membrane degradation and radical‑accelerated breakdown.

Radioactivity and electromagnetic pulse radiation allow precise control of radical formation but require expensive, specialized infrastructure. Affordable and practical solutions are needed to study radicals under realistic laboratory conditions.

Researchers from SINTEF in Norway and ETH Zurich have addressed this challenge. They introduced adapted photochemical methods to generate radicals and study their influence on the stability of anion exchange membranes independently of other degradation processes. The results were recently published in Membranes.

By irradiating aqueous potassium nitrite solutions or titanium oxide suspensions with UV light at 365 nm, hydroxyl radicals or a combination of hydroxyl and superoxide radicals were successfully generated. Tests on three commercial anion exchange membranes – PiperION®‑40 (PiperION), FM‑FAA‑3‑PK‑75 (Fumasep), and PNB‑R45 (Polynorbornene) – showed clear differences in durability. As expected, thinner, non‑reinforced membranes degraded faster than thicker, reinforced ones, likely due to the limited penetration depth of highly reactive radicals.

Both methods proved to be practical, affordable, and accessible tools for evaluating the stability of anion exchange membranes against radical attack. Photochemical radical generation was thus a viable way to study radical‑induced degradation under controlled conditions. The nitrite‑based approach selectively generated hydroxyl radicals, while titanium oxide suspensions produced both hydroxyl and superoxide radicals. Longer irradiation intensified membrane damage, clearly demonstrating the critical role of radicals in membrane decomposition. Experiments at pH 10 enabled differentiation between natural and radical‑driven causes.

Beyond laboratory use, both methods are also of industrial relevance. Combined with low‑cost laboratory equipment, they provide widely applicable and reproducible tools for evaluating commercial and prototype anion exchange membranes. By reducing costs and extending durability tests under realistic conditions, the development of robust anion exchange membranes for fuel cells and electrolyzers can be accelerated.

Frontis Energy is part of the mission to provide cost‑effective solutions for the development of efficient energy conversion technologies. In doing so, we strengthen the global transition to clean, resilient, and sustainable energy systems.

Solyom, et al., 2025, Photochemical methods to study the radical-induced degradation of anion-exchange membranes. Membranes, 15, 305. DOI: 10.3390/membranes15100305

Posted on June 30, 2025January 15, 2026 by zoba

Electrolytic water splitting for binders in building material

DOI: 10.13140/RG.2.2.23827.54564

The oceans are rich in magnesium resources, which that could be used in the production of construction materials. Sorel cement (magnesium cement), for example, can be used in interior building applications as an alternative to screed. Extracting magnesium from seawater traditionally requires a highly energy-intensive calcination process to isolate magnesium oxide (magnesia). The innovative method of electrolysis-controlled water splitting can bypass this process, significantly reducing CO₂ emissions.

To obtain the precursor of magnesia, magnesium hydroxide (Mg[OH]₂), an alkaline solution must be produced. While previous research has investigated electrochemical methods for hydroxide production, few studies have combined efficient alkali synthesis with the direct precipitation of magnesium hydroxide to make magnesia for low-carbon cement. This critical knowledge gap in optimizing energy and material efficiency has now been addressed.

A new study led by a research team at Columbia University used electrochemical water splitting at low voltages (1.6–2.0 V). Hydroxide ions (OH⁻) were generated from seawater through hydrogen production. This led to the direct precipitation of magnesium hydroxide. The findings were recently published in the journal Desalination. This new approach reduces energy intensity by 52–78%. Normally, the energy consumption per ton of MgO is 0.56 MWh. With the new method, carbon emissions per ton of magnesia can be reduced by up to 0.41 tons of CO₂.

To further improve production efficiency, the nanostructure of magnesium hydroxide was optimized using urea as a crosslinker. This enhanced its reactivity, porosity, and specific surface area. At an optimal urea concentration of 0.2 mol/L, magnesia particles exhibited excellent binding properties. The researchers attributed this to the sealing effects of rosette-shaped dypingite and rod-shaped nesquehonite. According to the authors, the formation of these minerals facilitates CO₂ incorporation and enhances carbonate hardening.

Advances in symmetric electrochemical systems, as demonstrated in this study, result in up to a 78% reduction in energy demand for the production of alkaline solutions. This gives these methods the potential to serve as viable alternatives to traditional processes. The further optimization of electrodes and electrolytes represents a pioneering approach to the carbon-neutral production of building materials and alkalis. Additionally, this method highlights how construction material manufacturing can efficiently lead to large-scale CO₂ mineralization. As a result, the greenhouse gas can be permanently removed from the atmosphere.

The industrial scaling of electrochemical alkali production can reduce operating costs, minimize environmental impact, and improve the properties of low-carbon building materials. The economic aspects of this manufacturing process are particularly noteworthy, as the demand for efficient binding materials continues to grow.

At Frontis Energy, we are committed to promoting sustainable and economically viable energy solutions. Research like this provides valuable insights and innovations to support such sustainable advancements.

Chu. Yang, Unluer, 2025, Energy-efficient calcination-free Mg cement recovered from desalination brine, Desalination, Volume 610, 118928, 10.1016/j.desal.2025.118928.

Image: Pixabay

Posted on April 11, 2025January 15, 2026 by zoba

From waste heat to ultrapure water: A new technology transforming renewable hydrogen

DOI: 10.13140/RG.2.2.36620.17281

Hydrogen (H₂), produced using renewable energy, has emerged as a possible alternative to fossil fuel. This versatile molecule can serve as an energy carrier, an efficient storage solution, and a sustainable feedstock for transportation, chemical processing, and energy systems worldwide.

Unlike fossil fuels, hydrogen produces no harmful emissions when used. It can be generated using electrolyzers running on renewable energy and abundant water as feedstock. It then becomes a renewable and sustainable energy source, reducing reliance on depleting fossil fuel reserves, helping combat climate change. Consequently, hydrogen production has become a key priority on the political agenda of numerous countries.

However, the water used in electrolyzers must be ultrapure in order to protect the electrodes of electrolyzers from poisoning and avoid chloride oxidation to chlorine. Abundant seawater adds several challenges when directly fed to electrolyzer plants for hydrogen production, making highly pure water, specifically ultrapure water, an expensive necessity. Ultrapure water is produced in a series of steps, including pretreatment to remove suspended solids and desalination to eliminate salts, organics, and colloidal particles. Polishing techniques such as deionization, degasification, and ultraviolet treatment are then used to achieve the required quality. Among these processes, desalination is particularly critical for removing most impurities.

Reverse osmosis, especially seawater reverse osmosis, is a widely used desalination technology but has notable drawbacks, such as requiring high-pressure operation (high energy consumption), intensive pretreatment, and producing concentrated brine, which can harm marine ecosystems when discharged. Membrane distillation has gained attention as an alternative for producing high-quality water and supporting recovery applications. It operates at lower temperatures and has the ability to utilize waste heat.

Membrane distillation is a thermal separation process where a vapor pressure difference across a hydrophobic membrane causes liquid particles to phase change and pass through as gas. Operating at ambient pressure and utilizing low-temperature heat sources (<90 °C), membrane distillation offers significant advantages. However, research on membrane distillation as a viable alternative to reverse osmosis for ultrapure water production remains limited, particularly in areas such as module design and techno-economic analysis.

A group of researchers at the Fraunhofer Institute for Solar Energy Systems (ISE) in Freiburg, Germany, has explored the potential of membrane distillation as a cost- and energy-efficient alternative to reverse osmosis for producing ultrapure water for proton exchange membrane (PEM) electrolyzers. The findings were recently published in the Desalination Journal. They introduced membrane distillation as a possible alternative to reverse osmosis for ultrapure water production. But here is the twist: the membrane distillation system ingeniously taps into waste heat from a 5 MW proton exchange membrane electrolyzer, transforming what would typically be an efficiency liability into an asset for sustainability. So far, their results are impressive—membrane distillation not only produces exceptional distillate (<3 μS/cm) but does so at a cost ranging from €2.33 to €2.85 per ton of distillate, compared to reverse osmosis’s €2.80 to €5.51. Using membrane distillation, seawater desalination could be 50% or more cheaper.

Economic analyses highlight that membrane distillation’s cost-effectiveness is driven by its low electrical energy requirements and optimized short-channel module design. Its impressive energy efficiency, enabled using low-grade thermal energy, establishes membrane distillation as a highly versatile and environmentally friendly solution that aligns seamlessly with the vision for renewable hydrogen production. This study positions membrane distillation as more than just an alternative to reverse osmosis: it is a smarter and greener approach to ultrapure water production.

Their findings have the potential to reshape the industrial approach to ultrapure water production. By demonstrating an efficient use of waste heat and providing a more economical solution, it offers industries a pathway to lower operational costs while advancing sustainability. This aligns particularly well with sectors striving for greener operations, such as renewable hydrogen production and other energy-intensive applications. Moreover, the adoption of membrane distillation could catalyze innovation in system design and integration, encouraging industries to optimize processes and reduce dependence on traditional, energy-intensive methods. This shift can contribute to broader sustainability goals and improve the economic feasibility of renewable energy initiatives.

At Frontis Energy, we are committed to advancing sustainable and green energy solutions by embracing innovative technologies like membrane distillation, bringing us closer to a sustainable future.

Schwantes et al. 2025 Thermally driven ultrapure water production for water electrolysis – A techno-economic analysis of membrane distillation, Desalination, Volume 608, 118848, DOI: 10.1016/j.desal.2025.118848.

Image: Pixabay

Posted on March 18, 2025January 15, 2026 by zoba

Unlocking the potential of conducting polymers for sustainable water treatment and energy solutions

DOI: 10.13140/RG.2.2.13132.07045

Carbon based materials have a broad range of applications such as energy storage and conversion, electronics, nanotechnology, water purification, and catalysis. They are made of an element which is available everywhere.

In recent times, the electrochemical features of carbon-based electrodes are being enhanced by using conducting polymers. Carbon cloth, woven from carbon microfibers, serves as a promising carbon-based electrode, which acts as a durable and cost-effective medium for facilitating electrochemical reactions that degrade pollutants and improve water quality. These electrodes, notable for their mechanical flexibility, strength, and cost-effectiveness, are employed in processes such as electrochemical oxidation, microbial fuel cells, and other advanced wastewater treatment technologies.

Due to a few limitations of pristine carbon cloth electrodes such as low specific capacitance and limited wettability associated with its inherent hydrophobicity, scientists conduct research to improve the modern electrodes. For instance, since wettability is crucial for for immersing the electrode surface in liquid and ensuring interaction with contaminants, enhancing it is always beneficial for the process. Improving the performance of carbon cloth electrodes could lead to more efficient treatment, faster reaction times, and better overall performance.

A research group at San Diego State University undertook the task of addressing these limitations by making conformal conducting polymer films on carbon fibers via oxidative chemical vapor deposition (oCVD) method. They recently published their results in the Advanced Material Interface Journal. With antimony pentachloride (SbCl₅) as the oxidant, they developed a highly uniform coating of poly(3,4-ethylenedioxythiophene) (PEDOT) on three-dimensional porous fibers. The oCVD technique ensures uniform coatings while preserving the geometric and functional properties of the carbon cloth, making it a promising approach for enhancing electrochemical performance.

The PEDOT-coated carbon cloth electrodes achieved a remarkable improvement in specific capacitance and pseudocapacitance compared to pristine carbon cloth. Depending on the deposition temperature, the oCVD PEDOT-coated electrodes showed a 1.5- to 2.3-fold enhancement in specific capacitance. Notably, the electrode fabricated at a deposition temperature of 80 °C exhibited the highest specific capacitance and superior electrochemical performance. Adjusting the deposition temperature to optimize performance can help tailor carbon cloth electrodes for specific wastewater treatment needs.

The investigation underscores the effectiveness of the oCVD method in addressing the limitations of carbon cloth electrodes and expanding their potential applications in wastewater treatment and electrochemical energy storage devices. Furthermore, the researchers showed that PEDOT-coated carbon cloth can be applied as supercapacitors, where flexibility and high capacitance are critical. It should be noted that the study not only showcases significant advancements in material design but also open new avenues for optimizing electrode performance for diverse applications.

Overall, the findings emphasize the growing potential of advanced electrode technologies in addressing industrial challenges. By improving the functionality of carbon-based electrodes through novel material coatings, industries can achieve more efficient and tailored solutions for both wastewater treatment and energy storage. The ability to fine-tune electrode properties to meet specific requirements offers a pathway toward the development of highly efective and cost-efficient technologies, which could be a game-changer for sectors focused on sustainability and resource management. As these innovations continue to evolve, they have the potential to significantly improve operational efficiency and environmental impact across various industries. For example, in wastewater treatment, electrochemical processes such as electrocoagulation, electrooxidation, or electroreduction are often used to remove contaminants.

At Frontis Energy, we believe that improvements and customization can aid in designing electrodes tailored to specific contaminants or types of wastewater.

Heydari Gharahcheshmeh and Chowdhury, 2024, Enhancing Capacitance of Carbon Cloth Electrodes via Highly Conformal PEDOT Coating Fabricated by the OCVD Method Utilizing SbCl5 Oxidant, Advanced Materials Interfaces, 11, 2400118. DOI: 10.1002/admi.202400118.

Image: Pixabay

Posted on June 22, 2024 by admin

Producing liquid bio-electrically engineered fuels from CO₂

At Frontis Energy we have spent much thought on how to recycle CO₂. While high value products such as polymers for medical applications are more profitable, customer demand for such products is too low to recycle CO₂ in volumes required to decarbonize our atmosphere to pre-industrial levels. Biofuel, for example from field crops or algae has long been thought to be the solution. Unfortunately, they require too much arable land. On top of their land use, biochemical pathways are too complex to understand by the human brain. Therefore, we propose a different way to quickly reach the target of decarbonizing our planet. The procedure begins with a desired target fuel and suggests a microbial consortium to produce this fuel. In a second step, the consortium will be examined in a bio-electrical system (BES).

CO₂ can be used for liquid fuel production via multiple pathways. The end product, long-chain alcohols, can be used either directly as fuel or reduced to hydrocarbons. Shown are examples of high level BEEF pathways using CO₂ and electricity as input and methane, acetate, or butanol as output. Subsequent processes are 1, aerobic methane oxidation, 2, direct use of methane, 3 heterotrophic phototrophs, 4, acetone-butanol fermentation, 5, heterotrophs, 6, butanol direct use, 7, further processing by yeasts

Today’s atmospheric CO₂ imbalance is a consequence of fossil carbon combustion. This reality requires quick and pragmatic solutions if further CO₂ accumulation is to be prevented. Direct air capture of CO₂ is moving closer to economic feasibility, avoiding the use of arable land to grow fuel crops. Producing combustible fuel from CO₂ is the most promising intermediate solution because such fuel integrates seamlessly into existing urban infrastructure. Biofuels have been explored intensively in recent years, in particular within the emerging field of synthetic biology. However tempting the application of genetically modified organisms (GMOs) appears, non-GMO technology is easier and faster to implement as the required microbial strains already exist. Avoiding GMOs, CO₂ can be used in BES to produce C₁ fuels like methane and precursors like formic acid or syngas, as well as C₁₊ compounds like acetate, 2-oxybutyrate, butyrate, ethanol, and butanol. At the same time, BES integrate well into urban infrastructure without the need for arable land. However, except for methane, none of these fuels are readily combustible in their pure form. While electromethane is a commercially available alternative to fossil natural gas, its volumetric energy density of 40-80 MJ/m³ is lower than that of gasoline with 35-45 GJ/m³. This, the necessary technical modifications, and the psychological barrier of tanking a gaseous fuel make methane hard to sell to automobilists. To produce liquid fuel, carbon chains need to be elongated with alcohols or better, hydrocarbons as final products. To this end, syngas (CO + H₂) is theoretically a viable option in the Fischer-Tropsch process. In reality, syngas precursors are either fossil fuels (e.g. coal, natural gas, methanol) or biomass. While the former is obviously not CO₂-neutral, the latter competes for arable land. The direct conversion of CO₂ and electrolytic H₂ to C₁₊ fuels, in turn, is catalyzed out by electroactive microbes in the dark (see title figure), avoiding food crop competition for sun-lit land. Unfortunately, little research has been undertaken beyond proof of concept of few electroactive strains. In stark contrast, a plethora of metabolic studies in non-BES is available. These studies often propose the use of GMOs or complex organic substrates as precursors. We propose to systematically identify metabolic strategies for liquid bio-electrically engineered fuel (BEEF) production. The fastest approach should start by screening metabolic databases using established methods of metabolic modeling, followed by high throughput hypothesis testing in BES. Since H₂ is the intermediate in bio-electrosynthesis, the most efficient strategy is to focus on CO₂ and H₂ as direct precursors with as few intermediate steps as possible. Scalability and energy efficiency, economic feasibility that is, are pivotal elements.

First, an electrotrophic acetogen produces acetate, which then used by heterotrophic algae in a consecutive step.

The biggest obstacle for BEEF production is lacking knowledge about pathways that use CO₂ and electrolytic H₂. This gap exists despite metabolic databases like KEGG and more recently KBase, making metabolic design and adequate BEEF strain selection a guessing game rather than an educated approach. Nonetheless, metabolic tools were used to model fuel production in single cell yeasts and various prokaryotes. In spite of their shortcomings, metabolic databases were also employed to model species interactions, for example in a photo-heterotroph consortium using software like ModelSEED / KBase (http://modelseed.org/), RAVEN / KEGG and COBRA. A first systematic attempt for BEEF cultures producing acetate demonstrated the usability of KBase for BES. This research was a bottom-up study which mapped existing genomes onto existing BEEF consortia. The same tool can also be employed in a top-down approach, starting with the desired fuel to find the required organisms. Some possible BEEF organisms are the following.

Possible pathways for BEEF production involving Clostridium, 3, or heterotrophic phototrophs, 7, further processing by yeasts

Yeasts are among the microorganisms with the greatest potential for liquid biofuel production. Baker’s yeast, (Saccharomyces cerevisiae) is the most prominent example. While known for ethanol fermentation, yeasts also produce fusel oils such as butane, phenyl, and amyl derivate aldehydes and alcohols. Unlike ethanol, which is formed via sugar fermentation, fusel oil is synthesized in branched-off amino acid pathways followed by aldehyde reduction. Many enzymes involved in the reduction of aldehydes have been identified, with alcohol dehydrogenases being the most commonly observed. The corresponding reduction reactions require reduced NADH⁠ but it is not known whether H₂ produced on cathodes of BES can be involved.
Clostridia, for example Clostridium acetobutylicum and C. carboxidivorans, can produce alcohols like butanol, isopropanol, hexanol, and ketones like acetone from complex substrates (starch, whey, cellulose, etc. ) or from syngas. Clostridial metabolism has been clarified some time ago and is different from yeast. It does not necessarily require complex precursors for NAD⁺ reduction and it was shown that H₂, CO, and cathodes can donate electrons for alcohol production. CO₂ and H₂ were used in a GMO clostridium to produce high titers of isobutanol. Typical representatives for acetate production from CO₂ and H₂ are C. ljungdahlii, C. aceticum, and Butyribacterium methylotrophicum. Sporomusa sphaeroides produces acetate in BES. Clostridia also dominated mixed culture BESs converting CO₂ to butyrate. They are therefore prime targets for low cost biofuel production. Alcohols in clostridia are produced from acetyl-CoA. This reaction is reversible, allowing acetate to serve as substrate for biofuel production with extracellular energy supply. Then, energy conservation, ATP synthesis that is, can be achieved from ethanol electron bifurcation or H₂ oxidation via respiration. While possible in anaerobic clostridia, it is hitherto unknown whether electron bifurcation or respiration are linked to alcohols or ketone synthesis.
Phototrophs like Botryococcus produce C₁₊ biofuels as well. They synthesize a number of different hydrocarbons including high value alkanes and alkenes as well as terpenes. However, high titers were achieved by only means of genetic engineering, which is economically not feasible in many countries due to regulatory constrains. Moreover, aldehyde dehydration/deformylation to alkanes or alkenes requires molecular oxygen to be present. Also the olefin pathway of Synechococcus depends on molecular oxygen with the cytochrome P₄₅₀ involved in fatty acid decarboxylation. The presence of molecular oxygen affects BES performance due to immediate product degradation and unwanted cathodic oxygen reduction. In contrast, our own preliminary experiments (see title photo) and a corrosion experiment show that algae can live in the dark using electrons from a cathode. While the enzymes involved in the production of some algal biofuels are known (such as olefin and aldehyde deformylation), it is not known whether these pathways are connected to H₂ utilization (perhaps via ferredoxins). Such a connection would be a promising indicator for the possibility of growing hydrocarbon producing cyanobacteria on cathodes of BES and should be examined in future research.
At Frontis Energy we believe that a number of other microorganisms show potential for BEEF production and these deserve further investigation. To avoid GMOs, BES compatible co-cultures must be identified via in silico metabolic reconstruction from existing databases. Possible inter-species intermediates are unknown but are prerequisite for successful BES operation. Finally, a techno-economical assessment of BEEF production, with and without carbon taxes, and compared with chemical methods, will direct future research.

Posted on November 29, 2023November 29, 2023 by admin

Alternating catholyte flow improves microbial electrosynthesis start-up

Microbial electrolysis is a technology that uses living microorganisms as electro-catalysts in electrolysis cells. The technology can be used for wastewater treatment. Earlier, we proposed that microbial electrolysis be used to decentralize wastewater treatment and biogas production. Since this is a process that converts CO₂ into organic compounds using electricity it can also be used for CO₂ valorization. Besides methane, such electrolysis cells produce compounds such as acetic acid (vinegar), caproic acid, and others. It is then called microbial electrosynthesis.

However, the main problem with microbial electrolysis and electrosynthesis is the long start-up time. The start-up time is the time required for the microorganisms to form a biofilm on the electrode surface and to start producing the desired products. It can range from several weeks to several months, depending on the operating conditions and the type of microorganisms. This long start-up time limits the feasibility and the scalability of microbial electrosynthesis, as well as its economic and environmental benefits.

Now, scientists of the Wageningen University in the Netherlands presented new research, which aimed to reduce the start-up time of microbial electrosynthesis. By using a novel technique that involves alternating the direction of the catholyte flow through a three-dimensional electrode they were able to reduce the startup time to only ten days. They hypothesized that this technique enhances mass transfer and biofilm formation, and thus accelerates the CO₂ reduction and the product formation. This was a start-up time reduction of 50%, compared to a conventional flow-through electrode.

The alternating electrolyte flow also reduced the power consumption to 136 kWh per kg of hydrogen. After 60 days, the local hydrogen concentration at the cathode was at a maximum of 600 μM, which indicates a better mass transport and thus a more active biofilm. The researchers speculated that the alternating catholyte flow improved mass transport, because the hydrogen could be better distributed over the cathode layers. In addition, the researchers think that alternating the flow refreshed potential “dead zones” in the cathode chamber.

The pH in the catholyte was 5.8–6.8 and in optimal range for electrosynthetic microorganisms. Production of short and medium chain fatty acids was linked to the presence of microorganisms identified as Peptococcaceae and Clostridium sensu stricto 12 species. Hydrogenotrophic methanogenesis was also observed and was linked to Methanobrevibacter. The latter is a typical constituent of microbial electrolysis cells that use higher intermediate hydrogen concentrations for electrosynthesis at the cathode.

However, there are limitations of the technique, such as the energy efficiency, the product selectivity, and the scalability of microbial electrosynthesis. Such limitations are typical for bench top experiments. We are therefore looking forward to see an industrial application of this new method.