- Development of a CCU process for formic acid production with both economic and environmental viability - Expected to expedite the commercialization of CCU through the world's largest-scale demonstration CCU (Carbon Capture & Utilization), which captures CO2 and converts it into useful compounds, is crucial for rapidly transitioning to a carbon-neutral society. While CCS (Carbon Capture & Storage), which only involves CO2 storage, has entered the initial commercialization stage due to its relatively simple process and low operational costs, CCU has only been explored at the research level due to the complexity of conversion processes and high production costs of compounds. Dr. Lee Ung's team at the Clean Energy Research Center of the Korea Institute of Science and Technology (KIST, Director Oh Sang Rok) announced the development of a novel CCU process that converts CO2 into formic acid. Formic acid, an organic acid, is a high-value compound used in various industries such as leather, food, and pharmaceuticals. Currently formic acid retains a large market consuming around one million tons annually, which is expected to grow in the future owing to its potential use as a hydrogen carrier. Moreover, it has a higher production efficiency compared to other CCU-based chemicals, as it can be produced from a single CO2 molecule. The research team selected 1-methylpyrrolidine, which exhibited the highest CO2 conversion rate among various amines mediating formic acid production reactions, and optimized the operating temperature and pressure of the reactor containing a ruthenium (Ru)-based catalyst, thereby increasing the CO2 conversion rate to over twice the current level of 38%. Furthermore, to address the excessive energy consumption and formic acid decomposition issues during CO2 separation from air or exhaust gases and formic acid purification, the team developed a simultaneous capture-conversion process that directly converts CO2 captured within the amine without separating it. As a result, they significantly reduced the formic acid production cost from around $790 per ton to $490 per ton while mitigating CO2 emissions, compared to conventional formic acid production. To evaluate the commercialization potential of the developed formic acid production process, the research team constructed the world's largest pilot plant capable of producing 10 kg of formic acid per day. Previous CCU studies were conducted on a small scale in laboratories and did not consider the product purification process required for large-scale production. However, the research team developed processes and materials to minimize corrosion and formic acid decomposition, and optimized operating conditions that led to successful production of formic acid with a purity exceeding 92%. The team plans to complete a 100 kg per day pilot plant by 2025 and conduct process verification, aiming for commercialization by 2030. Success in process verification with the 100 kg pilot plant is expected to enable transportation and sales to demand companies. Dr. Lee Ung stated, "Through this research, we have confirmed the commercialization potential of our process that converts CO2 to formic acid, which is a huge breakthrough considering that most CCU technologies are being conducted at lab-scale." He further expressed his intention to contribute to achieving the country's carbon neutrality goal by accelerating the commercialization of CCU. . [Figure 1] Process for Formic Acid Production via Carbon Dioxide Conversion Flowchart of the process (above) for producing formic acid through the conversion of newly developed carbon dioxide (CO2) using Carbon Capture & Utilization (CCU) technology, and pilot-scale process verification data (below). [Figure 2] Pilot-Scale Demonstration Process Producing 10kg of Formic Acid per Day A depiction of the pilot-scale demonstration process in operation. It consists of a reaction section, separation section, recycling, and vacuum systems, enabling stable continuous operation and enhancing commercialization potential. ### KIST was established in 1966 as the first government-funded research institute in Korea. KIST now strives to solve national and social challenges and secure growth engines through leading and innovative research. For more information, please visit KIST’s website at https://eng.kist.re.kr/ This research was supported by the Ministry of Science and ICT (Minister Lee Jong-Ho) as part of KIST's major projects and the Carbon-to-X project (2020M3H7A1098271). The research results were published in the latest issue of the international journal "Joule" (IF 39.8, JCR top 0.9%).

- Development of Durability Evaluation Technique Reflecting Solar Output Variability for Green Hydrogen Production Devices - Guidelines for Developing Core Components for Green Hydrogen Production via Water Electrolysis As green hydrogen gains attention as a future clean energy carrier, the question of which renewable energy to utilize as an energy source becomes increasingly important. Among them, solar energy has the advantage of being available everywhere on Earth, with low dependence on natural topography. However, fluctuations in solar output and generation due to factors such as season and weather lead to repetitive increases and decreases in power, posing a challenge of damaging components of production devices. Therefore, precise evaluation of the durability of devices under power fluctuations is crucial for determining the optimal timing for component replacement and developing new materials. Dr. Bora Seo's research team from the Hydrogen and Fuel Cell Research Center at the Korea Institute of Science and Technology (KIST), led by Director Yoon Seok-jin, has developed a durability evaluation technique for green hydrogen production devices with step durations as short as one second, utilizing actual solar irradiance data. This represents the application of the shortest step duration among developed techniques, enabling the most accurate simulation of fluctuations in actual solar energy output. To increase the applicability of solar energy to green hydrogen production devices, a reliable durability evaluation technique is required. However, existing durability evaluation methods have not accurately reflected solar output variability, relying solely on simple methods such as periodic cycling or constant maintenance of current and voltage. Additionally, there have been no standardized evaluation criteria for assessing the durability of core materials for water electrolysis under power fluctuation conditions. The research team has developed a simulation method that converts irradiance values into current densities using actual solar irradiance data obtained from solar panels, and using water electrolysis stack data. This has dramatically shortened the step duration from 10 seconds to 1 second, allowing fluctuations in solar output to be accurately reflected. Moreover, based on the newly developed durability evaluation technique, the team has proposed key indicators for the material development of green hydrogen production devices. Standardized analysis methods for assessing performance degradation of materials such as catalysts and electrolyte membranes, as well as indicators of performance degradation such as catalyst leaching amount, fluoride release rate, and thickness of passivation layer have been newly proposed. These guidelines can be utilized for the development of materials and components to improve the durability and performance of green hydrogen production devices. The developed durability evaluation technique can diagnose the precise condition and predict the remaining lifespan of solar-based green hydrogen production devices, facilitating efficient equipment investment and enhancing competitiveness in materials and components. This technology is expected to be applicable to assessing the performance of green hydrogen production devices based on other renewable energies such as offshore wind and tidal power. Dr. Seo stated, "This research achievement marks the first attempt to evaluate the durability of green hydrogen production devices by reflecting solar output variability most closely to reality," adding, "This can contribute to efficient equipment investment and enhancement of competitiveness in materials and components for green hydrogen production systems." [Figure 1] Comparison of Solar-Based Durability Evaluation Techniques with Constant Current and Cyclic Current Methods [Figure 2] Degradation Analysis of Key Materials for Water Electrolysis Before and After Solar-Based Durability Evaluation [Figure 3] Durability Evaluation Experiment Reflecting Solar Output Variability for Green Hydrogen Production Devices ### KIST was established in 1966 as the first government-funded research institute in Korea. KIST now strives to solve national and social challenges and secure growth engines through leading and innovative research. For more information, please visit KIST’s website at https://eng.kist.re.kr/ This research was supported by the Ministry of Science and ICT (Minister Lee Jong-ho) through KIST's major projects and the Ministry of Trade, Industry and Energy (Minister Ahn Dae-keun) through the Materials and Components Technology Development Project (20022451). The research results have been published in the prestigious international journal "Energy & Environmental Science" (IF 32.5, JCR top 0.4%) in the field of environmental energy.

- Overcoming the durability limits of bifunctional catalysts for simultaneous hydrogen and oxygen production - Presenting large area reactor drive technology for commercialization of electrochemical systems Dr. Hyung-Suk Oh and Dr. Woong-Hee Lee of the Clean Energy Research Center at the Korea Institute of Science and Technology (KIST), in collaboration with POSTECH and Yonsei University, have developed a methodology to improve the reversibility and durability of electrodes using bifunctional platinum-nickel alloy catalysts with an octahedral structure that exhibits both oxygen reduction and generation reactions. Bifunctional catalysts are a new generation of catalysts that simultaneously produce hydrogen and oxygen from water using a single catalyst. Currently, electrochemical systems such as water electrolysis technology and CCU (carbon dioxide capture and utilization) utilize separate catalysts for both electrodes, resulting in a high unit cost of hydrogen production. On the other hand, bifunctional catalysts that can be synthesized in a single production process are attracting attention as a technology that can reduce production costs and increase the economic efficiency of electrochemical energy conversion technologies. However, the problem with bifunctional catalysts is that after each electrochemical reaction that generates hydrogen and oxygen, the performance of other reactions decreases due to structural changes in the electrode material. Therefore, in order to commercialize bifunctional catalysts, it is important to secure reversibility and durability that can maintain the catalyst structure for a long time after the reaction. To enhance the reversibility and durability of the bifunctional catalyst, the team synthesized alloy catalysts with different structures by mixing platinum and nickel, which have high performance in oxygen reduction and generation reactions, respectively. The experimental results showed that the nickel-platinum interaction was most active in the octahedral structure, and the alloy catalysts performed more than twice as well as the platinum and nickel monoliths in oxygen reduction and generation reactions. The researchers identified platinum oxide generated during the repeated generation reaction of the alloy catalyst as the cause of the performance degradation and developed a structure restoration methodology to reduce platinum oxide to platinum. The team confirmed through transmission electron microscopy that the methodology restored the catalyst's shape, and in large-area reactor experiments for commercialization, the team succeeded in restoring the catalyst shape and more than doubled the run time. The team's bifunctional catalysts and structure recovery methodology are expected to accelerate the commercialization of unitized renewable fuel cells (URFCs) technology by replacing the separate catalysts for oxygen evolution and reduction reactions with bifunctional catalysts. URFCs that can produce both hydrogen and electricity can lower production costs by reducing the input of expensive catalysts while maintaining performance. "The technology to improve the reversibility and durability of catalysts has provided a new direction for the development of bifunctional catalysts, which is an important technology for electrochemical energy conversion systems," said Hyung-suk Oh, lead researcher at KIST. "It will contribute to the commercialization and carbon neutrality of electrochemical systems such as URFCs in the future.“ [Fig 1] Unitized Renewable Fuel Cells operation schematic [Fig 2] Structural changes of platinum at each reaction step using X-ray photoelectron spectroscopy and in-situ X-ray absorption spectroscopy [Fig 3] In-situ X-ray absorption spectroscopy instrumentation schematic ### KIST was established in 1966 as the first government-funded research institute in Korea. KIST now strives to solve national and social challenges and secure growth engines through leading and innovative research. For more information, please visit KIST’s website at https://eng.kist.re.kr/ This research was supported by the Ministry of Science and ICT (Minister Lee Jong-ho) under the 'KIST Institutional Program', 'Carbon to X Project' (2020M3H7A109822921), and 'Creative Convergence Research Project' (CAP21013-100) of the National Research Council of Korea (Chairman Kim Bok-cheol). The results were published in the latest issue of the prestigious international journal 'Advanced Energy Materials' (IF: 27.8, top 2.5% in JCR) and were selected for the back cover image. Journal : Advanced Energy Materials Title : Activity restoration of Pt-Ni octahedron via phase recovery for anion exchange membrane-unitized regenerative fuel cells Publication Date : 2024.01.12. DOI : https://doi.org/10.1002/aenm.202302971

- Computational science-based high-voltage stable solid electrolyte material design principles suggested - Anticipating commercialization of next-generation lithium all-solid-state batteries with high energy density and no fire risk Researchers are actively working on non-flammable solid electrolytes as a safer alternative to liquid electrolytes commonly found in lithium-ion batteries, which are vulnerable to fires and explosions. While sulfide-based solid electrolytes exhibit excellent ionic conductivity, their chemical instability with high-voltage cathode materials necessary for high-energy-density batteries has impeded their commercial viability. Consequently, there has been a growing interest in chloride-based solid electrolytes, which are stability in high-voltage conditions due to their strong bonding properties. The Korea Institute of Science and Technology (KIST; President: Dr. Seok-Jin Yoon) announced that a KIST-LLNL joint research team led by Dr. Seungho Yu of the Energy Storage Research Center, Dr. Sang Soo Han of the Computational Science Research Center, and Dr. Brandon Wood of Lawrence Livermore National Laboratory (LLNL) has developed a fluorine substituted high-voltage stable chloride-based solid-state electrolyte through computational science. LLNL is a leading national laboratory under the U.S. National Nuclear Security Administration, renown for its excellent supercomputing facilities. Since 2019, KIST and LLNL have been conducting collaborative research in the field of secondary batteries. To improve the high-voltage stability of chloride-based solid electrolyte (Li3MCl6), the research team proposed the optimal composition and design principle of chloride-based solid electrolyte (Li3MCl5F) substituted with fluorine(F), which has strong chemical bonding ability. For the proposed strategy to improve the high-voltage stability of chloride-based solid electrolytes by KIST, LLNL contributed by utilizing their cutting-edge supercomputing resources for calculations and subsequent experimental validations were conducted at KIST. The collaborative research team adopted a cost-effective and time-saving strategy, wherein computational science guides the initial material design, followed by rigorous laboratory validation. The chloride-based solid electrolyte synthesized based on the design principle proposed by the research team was applied to an all-solid-state battery to evaluate its electrochemical stability under high-voltage conditions. Impressively, it showed high-voltage stability exceeding 4 V, comparable to that of commercial lithium-ion batteries with liquid electrolytes. Accordingly, fluorine(F)-substituted chloride-based solid electrolytes are expected to replace sulfide-based solid electrolytes that are unstable at high voltages, accelerating the commercialization of all-solid-state batteries. The Korea-U.S. Joint Research Team will conduct follow-up research on the synthesis process of the material, alongside the optimization of electrode and cell manufacturing processes. These concerted efforts aim to hasten the commercialization of all-solid-state batteries. In the event of successful commercialization, the U.S.-Korea team will be able to capture the market for solid-state electrolytes, a key component of all-solid-state batteries, in the U.S., one of the largest consumers of secondary batteries such as ESS(Energy Storage System) and electric vehicles. "This work provides a new design principle for fluorine-substituted high-voltage stable chloride-based solid-state electrolytes, which will accelerate the commercialization of high-energy-density next-generation lithium all-solid-state batteries without fire hazards," said Dr. Seungho Yu of KIST. "This was a systematic, internationally collaborative study that provided computational science-based design principles for the development of a new solid-state electrolyte and validated them experimentally," said Dr. Brandon Wood of LLNL. [Figure 1] High-Voltage Stable Solid-State Electrolytes Design Strategies [Figure 2] Overview of KIST-LLNL International Cooperation Research ### KIST was established in 1966 as the first government-funded research institute in Korea. KIST now strives to solve national and social challenges and secure growth engines through leading and innovative research. For more information, please visit KIST’s website at https://eng.kist.re.kr/ This research was supported by the Ministry of Science and ICT (Minister Lee Jongho) through the KIST Major Project and Climate Change Response Technology Development Project, the Ministry of Trade, Industry and Energy (Minister Ahn Deokgeun) through the Lithium-based Next Generation Secondary Battery Performance Improvement and Manufacturing Technology Development Project, and the Automotive Industry Core Technology Development Project. The research was published in the latest issue of ACS Energy Letters (IF 22.0, top 3.6% in JCR), an international journal in the field of energy materials. Journal : ACS Energy Letters Title : Fluorine-Substituted Lithium Chloride Solid Electrolytes for High-Voltage All-Solid-State Lithium-Ion Batteries Publication Date : 2024.01.12. DOI : https://doi.org/10.1021/acsenergylett.3c02307

- Developing nanocatalysts that do not degrade at high temperatures above 600 degrees Celsius - More than doubling green hydrogen production with high-temperature water electrolysis cells Green hydrogen can be produced through water electrolysis technology, which uses renewable energy to split water into hydrogen and oxygen without emitting carbon dioxide. However, the production cost of green hydrogen is currently around $5 per kilogram, which is two to three times higher than gray hydrogen obtained from natural gas. For the practical use of green hydroten, the innovation in water electrolysis technology is required for the realization of hydrogen economy, especially for Korea where the utilization of renewable energy is limited owing to geographical reasons. Dr. Kyung Joong Yoon’s research team at the Energy Materials Research Center of the Korea Institute of Science and Technology (KIST) has developed a nanocatalyst for high-temperature water electrolysis that can retain a high current density of more than 1A/cm2 for a long time at temperatures above 600 degrees. While the degradation mechanisms of nanomaterials at high temperatures have been elusive thus far, the team identified the fundamental reasons of abnormal behavior of nanomateirals and successfully resolved issues, eventually improving performance and stability in realistic water electrolysis cells. The electrolysis technology can be classified into low- and high-temperature electrolysis. While low-temperature electrolysis operating at temperatures below 100 degrees Celsius has long been developed and is technologically more mature, high-temperature electrolysis operating above 600 degrees Celsius offers higher efficiency and is considered as a next-generation technology with a strong potential for further cost-down. However, its commercialization has been hindered by the lack of thermal stability and insufficient lifetime owing to high-temperature degradation, such as corrosion and structural deformation. In particular, nanocatalysts, which are widely used to improve the performance of low-temperature water electrolyzers, quickly deteriorate at high operating temperatures, making it difficult to effectively use them for high-temperature water electrolysis. To overcome this limitation, the team developed a new nanocatalyst synthetic techniques that suppresses the formation of harmful compounds causing high temperature degradation. By systematically analyzing the nanoscale phenomena using transmission electron microscopy, the researchers identified specific substances causing severe structural alterations, such as strontium carbonate and cobalt oxide and successfully removed them to achieve highly stable nanocatalysts in terms of chemical and physical properties. When the team applied the nanocatalyst to a high-temperature water electrolysis cell, it more than doubled hydrogen production rate and operated for more than 400 hours at 650 degrees without degradation. This technique was also sucessfully applied to a practical large-area water electrolysis cell, confirming its strong potential for scale-up and commercial use. "Our newly developed nanomaterials achieved both high performance ans stability for high-temperature water electrolysis technology, and it can contribute to lower the production cost of green hydrogen, making it economically competitive with gray hydrogen in the future," said Dr. Kyungjoong Yoon of KIST. "For commercialization, we plan to develop automated processing techniques for mass production in cooperation with industry cell manufacturers." [Figure 1] Manufacturing process and evaluation results of high temperature water electrolysis cell with nanomaterials ### KIST was established in 1966 as the first government-funded research institute in Korea. KIST now strives to solve national and social challenges and secure growth engines through leading and innovative research. For more information, please visit KIST’s website at https://eng.kist.re.kr/ This research was supported by the Ministry of Science and ICT (Minister Lee Jong-ho) through the KIST Major Project and Climate Change Response Technology Development Project (2020M1A2A2080862), and the results were published in the latest issue of the Chemical Engineering Journal (IF 15.1, top 3.2% in JCR), an international journal in the field of chemical engineering. Journal : Chemical Engineering Journal Title : In situ synthesis of extremely small, thermally stable perovskite nanocatalysts for high-temperature electrochemical energy devices Publication Date : 2023.10.24. DOI : https://doi.org/10.1016/j.cej.2023.146924

- New findings reveal how degradation of all-solid-state batteries occurs at the cathode under low-pressure operation - Clues to accelerate commercialization of all-solid-state batteries Often referred to as the ‘dream batteries’, all-solid-state batteries are the next generation of batteries that many battery manufacturers are competing to bring to market. Unlike lithium-ion batteries, which use a liquid electrolyte, all components, including the electrolyte, anode, and cathode, are solid, reducing the risk of explosion, and are in high demand in markets ranging from automobiles to energy storage systems (ESS). However, devices that maintain the high pressure (tens of MPa) required for stable operation of all-solid-state batteries have problems that reduce the battery performance, such as energy density and capacity, and must be solved for commercialization. Dr. Hun-Gi Jung and his team at the Energy Storage Research Center at the Korea Institute of Science and Technology (KIST) have newly identified degradation factors that cause rapid capacity degradation and shortened lifespan when operating all-solid-state batteries at pressures similar to those of lithium-ion batteries. Unlike previous studies, the researchers confirmed for the first time that degradation can occur inside the cathode as well as outside, showing that all-solid-state batteries can be operated reliably even in low-pressure environments in the future. [Figure 1] Comparison of cathode volume changes in all-solid-state cells under low-pressure operated In all-solid-state batteries, the cathode and anode have a volume change during repeated charging and discharging, resulting in interfacial degradation such as side reaction and contact loss between active materials and solid electrolytes, which increase the interfacial resistance and worsen cell performance. To solve this problem, external devices are used to maintain high pressure, but this has the disadvantage of reducing energy density as the weight and volume of the battery increase. Recently, research is being conducted on the inside of the all-solid-state cell to maintain the performance of the cell even in low-pressure environments. [Figure 2] Schematic image of cathode degradation in all-solid-state battery under low-pressure operation The research team analyzed the cause of performance degradation by repeatedly operating a coin-type all-solid-state battery with a sulfide-based solid electrolyte in a low-pressure environment of 0.3 MPa, similar to that of a coin-type Li-ion battery. After 50 charge-discharge cycles, the NCM cathode layer had expanded in volume by about two times, and cross-sectional image analysis confirmed that severe cracks had developed between the cathode active material and the solid electrolyte. This newly revealed that in addition to the interfacial contact loss, cracking of the cathode material and irreversible cathode phase transformation are the causes of degradation in low-pressure operation. Furthermore, after replacing the lithium in the cathode with an isotope (6Li) to distinguish it from the lithium present in the solid electrolyte, the team used time-of-flight secondary ion mass spectrometry (TOF-SIMS) to identify for the first time the mechanism by which lithium consumption in the cathode contributes to the overall cell capacity reduction. During repeated charge-discharge cycles, sulfur, a decomposed product of the solid electrolyte, infused the cracks in the cathode material to form lithium sulfide, a byproduct that is non-conductive. This depleted the active lithium ions and promoted cathode phase transformation, reducing the capacity of the all-solid-state batteries. [Figure 3] The front cover image By clearly identifying the cause of the degradation of all-solid-state batteries in low-pressure operating environments, these analytical methods provide a clue to solving the problem of poor cycling characteristics compared to conventional lithium-ion batteries. If this problem is solved, it is expected that the economics of all-solid-state batteries can be secured by eliminating external auxiliary devices, which have been a major cause of rising production costs. "For the commercialization of all-solid-state batteries, it is essential to develop new cathode and anode materials that can be operated in a pressure-free or low-pressure environment rather than the current pressurized environment," said Dr. Hun-Gi Jung of KIST. "When applying low-pressure-working all-solid-state batteries to medium and large-scale applications such as electric vehicles, it will be expected to make full use of established lithium-ion battery manufacturing facilities." ### KIST was established in 1966 as the first government-funded research institute in Korea. KIST now strives to solve national and social challenges and secure growth engines through leading and innovative research. For more information, please visit KIST’s website at https://eng.kist.re.kr/ This research was supported by the Korea Institute of Science and Technology institutional program funded by the Ministry of Science and ICT of Korea (Minister Lee Jong-ho), by the Development Program of Core Industrial Technology funded by the Ministry of Trade, Industry and Energy (Minister Bang, Moon Kyu), and by the Technology Development Program to Solve Climate Changes funded by the National Research Foundation (President Lee, Kwang-bok). The research results were published as a front cover article in the latest issue of Advanced Energy Materials (IF 27.8, top 2.5% in JCR), an international journal in the field of energy materials. Journal : Advanced Energy Materials Title : New Consideration of Degradation Accelerating of All-Solid-State Batteries under a Low-Pressure Condition Publication Date : 27-Oct-2023 DOI : https://doi.org/10.1002/aenm.202301220

- Automatic conversion of hydrogen gas into water makes batteries safer - A breakthrough technology for the commercialization of cheaper, safer aqueous rechargeable batteries This summer, the planet is suffering from unprecedented heat waves and heavy rainfalls. Developing renewable energy and expanding associated infrastructure has become an essential survival strategy to ensure the sustainability of the planet in crisis, but it has obvious limitations due to the volatility of electricity production, which relies on uncertain variables like labile weather conditions. For this reason, the demand for energy storage systems (ESS) that can store and supply electricity as needed is ever-increasing, but lithium-ion batteries (LIBs) currently employed in ESS are not only highly expensive, but also prone to potential fire, so there is an urgent need to develop cheaper and safer alternatives. A research team led by Dr. Oh, Si Hyoung of the Energy Storage Research Center at the Korea Institute of Science and Technology (KIST) has developed a highly safe aqueous rechargeable battery that can offer a timely substitute that meets the cost and safety needs. Despite of lower energy density achievable, aqueous rechargeable batteries have a significant economic advantage as the cost of raw materials is much lower than LIBs. However, inveterate hydrogen gas generated from parasitic water decomposition causes a gradual rise in internal pressure and eventual depletion of the electrolyte, which poses a sizeable threat on the battery safety, making commercialization difficult. [Figure 1] CAUSES OF HYDROGEN GENERATION AND INCESSANT ACCUMULATION WITHIN THE CELL IN THE AQUEOUS RECHARGEABLE BATTERIES Until now, researchers have often tried to evade this issue by installing a surface protection layer that minimizes the contact area between the metal anode and the electrolyte. However, the corrosion of the metal anode and accompanying decomposition of water in the electrolyte is inevitable in most cases, and incessant accumulation of hydrogen gas can cause a potential detonation in long-term operation. [Figure 2] Proposed strategy for securing safety of the aqueous rechargeable batteries via water-regeneration To cope with this critical issue, the research team has developed a composite catalyst consisting of manganese dioxide and palladium, which is capable of automatically converting hydrogen gas generated inside the cell into water, ensuring both the performance and safety of the cell. Manganese dioxide does not react with hydrogen gas under normal circumstances, but when a small amount of palladium is added, hydrogen is readily absorbed by the catalysts, being regenerated into water. In the prototype cell loaded with the newly developed catalysts, the internal pressure of the cell was maintained well below the safety limit, and no electrolyte depletion was observed. [Figure 3] Role of composite catalysts in activating water-regeneration chemical reaction The results of this research effectively solves one of the most concerning safety issues in the aqueous batteries, making a major stride towards commercial application to ESS in the future. Replacing LIBs by cheaper and safer aqueous batteries can even trigger a rapid growth of global market for ESS. "This technology pertains to a customized safety strategy for aqueous rechargeable batteries, based on the built-in active safety mechanism, through which risk factors are automatically controlled." said Dr. Oh, Si Hyoung of KIST. "Moreover, it can be applied to various industrial facilities where hydrogen gas leakage is one of major safety concerns (for instance, hydrogen gas station, nuclear power plant etc) to protect public safety." ### KIST was established in 1966 as the first government-funded research institute in Korea. KIST now strives to solve national and social challenges and secure growth engines through leading and innovative research. For more information, please visit KIST’s website at https://eng.kist.re.kr/ This research was supported by the Ministry of Science and ICT (Minister Lee Jong-ho) through the Nano Future Material Source Technology Development Project and the Mid-Career Researcher Support Project, and the results were published on August 1 in the international journal Energy Storage Materials (IF 20.4). Journal : Energy Storage Materials Title : Highly safe aqueous rechargeable batteries via electrolyte regeneration using Pd-MnO2 catalytic cycle Publication Date : 1-August-2023 DOI :https://doi.org/10.1016/j.ensm.2023.102881

- Suggested use of carbon in water electrolysis, which has been neglected due to corrosion issues - Using carbon supports and low-cost catalysts enables superior electrolysis performance and durability According to the International Energy Agency (IEA), global hydrogen demand is expected to reach 530 million tons in 2050, a nearly six-fold increase from 2020. Currently, the primary method of hydrogen production involves the reaction of natural gas and water vapor, resulting in what is known as 'gray hydrogen' due to its carbon dioxide emissions, constituting around 80% of total hydrogen production. In contrast, green hydrogen is produced through water electrolysis using electricity, without emitting carbon dioxide. However, a challenge lies in the inevitable use of expensive precious metal catalysts, such as iridium oxide. [Figure 1] Image of nickel-iron-cobalt layered double hydroxide supported on hydrophobic crystalline carbon and image of crystalline carbon A research team led by Dr. Yoo Sung Jong of the Hydrogen and Fuel Cell Research Center at the Korea Institute of Science and Technology (KIST) have succeeded in significantly reducing the cost of green hydrogen production by implementing an anion exchange membrane water electrolysis device with excellent performance and durability by introducing a carbon support. Carbon supports have been utilized as supports for various electrocatalysts due to their high electrical conductivity and specific surface area, but their usage has been limited because they readily oxidize to carbon dioxide in water electrolysis conditions, specifically at high voltages and in the presence of water. [Figure 2] Time-dependent-lapse transmission electron micrograph images of nickel-iron-cobalt layered double hydroxide synthesis on carbon support, high resolution scanning TEM and EDS elemental mapping images The team synthesized a nickel-iron-cobalt layered double hydroxide material, a significantly cheaper alternative to iridium, on a hydrophobic carbon support and used it as an electrocatalyst for the oxygen evolution reaction in anion exchange membrane electrolysis. The catalyst showed excellent durability due to the layered structure facing a hydrophobic carbon support and a nickel-iron-cobalt layered double hydroxide catalyst. In terms of carbon corrosion, it was found that the generation of carbon dioxide during the corrosion process was reduced by more than half, primarily because of decreased interaction with water, a key factor in carbon corrosion. It was found that the carbon dioxide generated during the corrosion process was less than half due to the reduced interaction with water, which causes corrosion of carbon. [Figure 3] Electrochemical activity evaluation of nickel-iron-cobalt layered double hydroxide and single cell test results As a result of performance evaluation, it is found that the newly developed supported catalyt achieved a current density of 10.29 A/cm-2 in the 2 V region, exceeding the 9.38 A/cm-2 current density of commercial iridium oxide. demonstrated long-term durability of about 550 hours. We also confirmed a correlation between electrolysis performance and the hydrophobicity of carbon, showing for the first time that the support's hydrophobicity can significantly affect the water electrolysis device's performance. "The results of this research confirm the applicability of water electrolysis devices on carbon supports, which have previously been limited in use due to corrosion problems, and it is expected that water electrolysis technology can grow to the next level if the research focused on catalyst development is expanded to various supports." "We will strive to develop various eco-friendly energy technologies, including green hydrogen production," said Dr. Yoo Sung Jong Yoo in KIST. ### KIST was established in 1966 as the first government-funded research institute in Korea. KIST now strives to solve national and social challenges and secure growth engines through leading and innovative research. For more information, please visit KIST’s website at https://eng.kist.re.kr/ This research was supported by the Ministry of Science and ICT (Minister Lee Jong-ho) through the KIST Major Project and Nano and Material Technology Development Project, and the Korea Energy Technology Assessment Institute(Director Kwon Ki-young) Renewable Energy Core Technology Development Project, and the results were published on August 1 in the international journal Energy & Environmental Science (IF 32.5, top 0.4% in JCR). Journal : Energy & Environmental Science Title : Realizing the Potential of Hydrophobic Crystalline Carbon as a Support for Oxygen Evolution Electrocatalysts Publication Date : 16-June-2023 DOI : https://doi.org/10.1039/d3ee00987d

- Tailoring the molecular structure of organic carbonates in commercial electrolytes reduces the fire hazard of batteries - Nonfluorinated, nonflammable electrolytes present a viable route to achieving thermally stable high-performance batteries The Korea Institute of Science and Technology(KIST, President Seok-Jin Yoon) announced that a collaborative research team led by Dr. Minah Lee of the Energy Storage Research Center, Professor Dong-Hwa Seo of the Korea Institute of Science and Technology(KAIST), and Drs. Yong-Jin Kim and Jayeon Baek of the Korea Institute of Industrial Technology(KITECH) has developed a nonflammable electrolyte that does not catch fire at room temperature by tailoring the molecular structure of linear organic carbonate to prevent fire and thermal runaway in lithium-ion batteries. As the use of medium and large-scale lithium-ion batteries in electric vehicles and energy storage systems(ESS) expands, concerns about fires and explosions are growing. Fires in batteries occur when batteries are short-circuited due to external impacts, abuse or aging, and the thermal runaway phenomenon accompanied by a serial exothermic reactions makes it difficult to extinguish the fire and poses a high risk of personal injury. In particular, the linear organic carbonate used in commercial electrolytes for lithium-ion batteries has a low flash point and easily catches fire even at room temperature, which is a direct cause of ignition. [Figure 1] MOLECULAR DESIGN STRATEGY FOR HIGH-FLASHPOINT ELECTROLYTE AND COMPARISON OF ROOM TEMPERATURE IGNITION PROPERTY Until now, in order to reduce the flammability of the electrolyte, Intensive fluorination in the solvent molecules or highly concentrated salts has been widely adopted. As a result, the lithium-ion transport in the electrolyte was reduced or those were incompatible with commercial electrodes, limiting their commercialization. By simultaneously applying alkyl chain extension and alkoxy substitution to the diethyl carbonate(DEC) molecule, a typical linear organic carbonate used in commercial lithium-ion battery electrolytes, the researchers developed a new electrolyte, bis(2-methoxyethyl) carbonate(BMEC), with enhanced flash point and ionic conductivity by increasing intermolecular interactions and the solvation ability. The BMEC solution has a flash point of 121°C, which is 90°C higher than that of the conventional DEC solution, and thus is not ignitable in the temperature range for conventional battery operation. BMEC can dissociate lithium salt stronger than its simple alkylated counterpart, dibutyl carbonate(DBC), solving the problem of slower lithium ion transport when reducing flammability by increasing intermolecular interaction. As a result, it retains more than 92% of the original rate capability of the conventional electrolyte while significantly reducing the fire hazards. [Figure 2] Nail-penetration test results of 4Ah pouch cells using conventional and new electrolyte In addition, the new electrolyte alleviated 37% of combustible gas evolution and 62% of heat generation than those of the conventional electrolyte. The research team demonstrated the stable operation of 1Ah lithium-ion batteries over 500 cycles by combining the new electrolyte with a high nickel cathode and a graphite anode. They also conducted a nail-penetration test on a 70% charged 4Ah-level Li-ion battery and confirmed the suppressed thermal runaway. [Figure 3] (Left) Electrolyte of a commercial lithium-ion battery (DEC) and a new electrolyte (BMEC) developed by a joint research team from KIST, KITECH, and KAIST (right). Dr. Minah Lee of the KIST stated, "The results of this research provide a new direction for designing nonflammable electrolytes, which has been inevitably sacrificed the electrochemical property or economic feasibility." "The developed nonflammable electrolyte has cost competitiveness and excellent compatibility with high-energy density electrode materials, so it is expected to be applied to the conventional battery manufacturing infrastructure. Ultimately, it will accelerate the emergence of high-performance batteries with excellent thermal stability." Dr. Jayeon Baek of KITECH stated, "The BMEC solution developed in this research can be synthesized by transesterification using low-cost catalysts and easily scaled up. In the future, we will develop the synthesis method using C1 gas (CO or CO2) to enhance its eco-friendliness further." ### KIST was established in 1966 as the first government-funded research institute in Korea. KIST now strives to solve national and social challenges and secure growth engines through leading and innovative research. For more information, please visit KIST’s website at https://eng.kist.re.kr/ This research was supported by the the National Research Council of Science & Technology and the Mid-Career Research Progam of the National Research Foundation of Korea grant by the Korea government Ministry of Science and ICT(Minister Jong-Ho Lee). The research result was published in the latest issue of Energy & Environmental Science (IF 32.5, JCR top 0.4%), an international journal in the field of energy and environmental science. Journal : Energy & Environmental Science Title : Molecularly engineered linear organic carbonates as practically viable nonflammable electrolytes for safe Li-ion batteries Publication Date : 12-July-2023 DOI : https://doi.org/10.1039/d3ee00157a

- Developing a new type of fuel cell utilizing three-dimensional structures - Solving water management issues by improving the structure of the fuel cell's electrode layer, electrolyte membrane, and transport layer A research team led by Dr. Yoo Sung Jong of the Hydrogen and Fuel Cell Research Center at the Korea Institute of Science and Technology (KIST) has developed a fuel cell technology with high stability over a long period of time and improved power density compared to conventional fuel cells by introducing three-dimensional structure control technology. A three-dimensional structure is a three-dimensional arrangement of electrode layers, electrolyte membranes, and transport layers, which are necessary components for fuel cell operation, and are closely related to fuel cell performance. [Figure 1] Schematic representation of various applications of fuel cells utilizing 3D structures Fuel cells are a technology that utilizes hydrogen, the most abundant element on Earth, to generate electricity, and are attracting attention as a clean energy source that can overcome the limitations of charging speed and storage capacity of secondary batteries. Among the various types of fuel cells, polymer electrolyte membrane fuel cells (PEMFCs) have a high potential for commercialization because they can deliver power quickly and operate at relatively low temperatures. However, the water generated inside them during long-term operation reduces their durability and performance, hindering their commercialization. [Figure 2] Designing polymeric membranes using imprinting technology to improve fuel cell performance The research team developed a three-dimensional structured electrode control technology based on a multiscale architecture to manage water generation within PEMFCs. This technology combines structures of different sizes to improve the performance of fuel cells, and this study shows that designing electrode layers with multidimensional structures of one and three dimensions can solve the problem of performance degradation due to overgenerated water while utilizing existing catalysts and electrolyte membranes. Furthermore, by patterning the surface of the three-dimensional electrolyte membrane with a single or multi-layer structure, the researchers were able to reduce the resistance and increase the electrochemically active surface area in the fuel cell, resulting in the mechanical strength of the fuel cell has improved and the power density of the fuel cell has increased by more than 40% compared to the previous one. The research team also developed a three-dimensional structure of the transport layer with improved mass transfer properties due to pore gradients and humidified gas diffusion. Using the high surface stress of the electrolyte membrane, the researchers found that the crack due to stretching in the electrode layer act as efficient channels for the water generated inside the cell, resulting in an 18% increase in maximum power density compared to conventional fuel cells without cracks. [Figure 3] Optimization of electrode gaps to improve water management in fuel cells "Using a three-dimensional structure, it is possible to maximize the utilization of various catalysts, which was difficult with the existing fuel cell structure, and to stably manage the generanted water in PEMFCs" said Dr. Yoo sung jong of KIST. "In the future, we expect to be able to apply new three-dimensional structures that are totally different from conventional simple structures to fuel cells for hydrogen vehicles or power generation." ### KIST was established in 1966 as the first government-funded research institute in Korea. KIST now strives to solve national and social challenges and secure growth engines through leading and innovative research. For more information, please visit KIST’s website at https://eng.kist.re.kr/ The research was supported by the Ministry of Science and ICT (Minister Lee Jong-ho) under the KIST Major Project and the Nano and Materials Technology Development Project, and the results were published in the latest issue of the international journal Advanced Materials (IF 32.086, JCR top 2.51%). Journal : Advanced Materials Title : Multiscale Architectured Membranes, Electrodes, and Transport Layers for Next-Generation Polymer Electrolyte Membrane Fuel Cells Publication Date : 23-June-2023 DOI : https://doi.org/10.1002/adma.202204902