- 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

- KIST increases charge and discharge efficiency with magnesium metal chemical activation process - Expected to commercialize magnesium secondary batteries by utilizing non-corrosive general electrolyte A research team led by Dr. Minah Lee of the Energy Storage Research Center at the Korea Institute of Science and Technology(KIST) has developed a chemical activation strategy of magnesium metal that enables efficient operation of magnesium batteries in common electrolytes that are free of corrosive additives and can be mass-produced. While the demand for lithium-ion batteries is exploding due to the rapid growth of the electric vehicle and energy storage system(ESS) markets, the supply and demand of their raw materials such as lithium and cobalt are mostly dependent on specific countries, and thus there are great concerns about securing a stable supply chain. For this reason, research on next-generation secondary batteries have been actively conducted, and secondary batteries utilizing magnesium, which is abundant in the earth's crust, are gaining attention. [Figure 1] COMPARISON OF ELECTROCHEMICAL REVERSIBILITY OF MAGNESIUM METAL BEFORE AND AFTER CHEMICAL ACTIVATION Magnesium secondary batteries can be expected to have a high energy density because they utilize Mg2+, a divalent ion instead of monovalent alkali metal ions such as lithium. The highest energy density can be obtained by directly utilizing magnesium metal as a anode, of which volumetric capacity is about 1.9 times higher than lithium metal. [Figure 2] Cycling performance of activated magnesium metal Despite these advantages, the difficulty of efficiently charging and discharging magnesium metal due to its reactivity with electrolytes, has hindered its commercialization. KIST researchers have developed a technology to induce a highly efficient charge and discharge reaction of magnesium metal, opening the possibility of the commercialization of magnesium secondary batteries. In particular, unlike previous studies that utilized corrosive electrolytes to facilitate the charging and discharging of magnesium, the researchers utilized a common electrolyte with a similar composition to existing commercial electrolytes, enabling the use of high-voltage electrodes and minimizing corrosion of battery components. [Figure 3] (Left) Lithium metal, (middle) Magnesium metal with the equivalent capacity as the left lithium metal but smaller in size, (right) Magnesium anode immersed in chemical activation solution The team synthesized an artificial protective layer with a novel composition based on magnesium alkyl halide oligomers on the magnesium surface by a simple process of dipping the magnesium metal to be used as the anode into a reactive alkyl halide solution prior to cell assembly. They found that selecting a specific reaction solvent facilitated the formation of nanostructures on the magnesium surface, which in turn facilitated the dissolution and deposition of magnesium. Based on this, they suppressed unwanted reactions with electrolytes and maximized the reaction area through nanostructuring to induce highly efficient magnesium cycling. By applying the developed technology, the overpotential can be reduced from more than 2 V to less than 0.2 V when charging and discharging magnesium metal in a common electrolyte without corrosive additives, and the Coulombic efficiency can be increased from less than 10% to more than 99.5%. The team demonstrated stable charging and discharging of activated magnesium metal more than 990 cycles, confirming that magnesium rechargeable batteries can operate in conventional electrolytes that can be mass-produced. "This work provides a new direction for the existing magnesium secondary battery research, which has been using corrosive electrolytes that prevent the formation of interfacial layers on magnesium metal surfaces," said Dr. Minah Lee of KIST. "It will increase the possiblity of low-cost, high-energy-density magnesium secondary batteries based on common electrolytes suitable for energy storage systems (ESS).“ ### 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 funded by the Ministry of Science and ICT (MSIT) through the KIST Major Project and the National Research Foundation of Korea (NRF) Mid-Career Researchers Program, and the results were published in the latest issue of ACS Nano (IF:18.027, JCR top 5.652%), an international journal in the field of nanomaterials. Journal : ACS Nano Title : Reversible magnesium metal cycling in additive-free simple salt electrolytes enabled by spontaneous chemical activation Publication Date : 8-May-2023 DOI : https://doi.org/10.1021/acsnano.2c08672

- Substantially reducing the amount of platinum and iridium used in water electrolysis devices - Reducing iridium usage to one-tenth of current levels while maintaining high performance Green hydrogen, which produces hydrogen without the use of fossil fuels or the emission of carbon dioxide, has become increasingly important in recent years as part of efforts to realize a decarbonized economy. However, due to the high production cost of water electrolysis devices that produce green hydrogen, the economic feasibility of green hydrogen has not been very high. However, the development of a technology that drastically reduces the amount of rare metals such as iridium and platinum used in polymer electrolyte membrane water electrolysis devices is opening the way to lower production costs. [Figure 1] (A) CATALYST SHAPES MADE WITH CONVENTIONAL TECHNOLOGY (RED-IRIDIUM CATALYST/GREEN-PLATINUM) A research team led by Dr. Hyun S. Park and Sung Jong Yoo of the Hydrogen and Fuel Cell Research Center at the Korea Institute of Science and Technology (KIST) announced that they have developed a technology that can significantly reduce the amount of platinum and iridium, precious metals used in the electrode protection layer of polymer electrolyte membrane water electrolysis devices, and secure performance and durability on par with existing devices. In particular, unlike previous studies that focused on reducing the amount of iridium catalyst while maintaining the structure that uses a large amount of platinum and gold as the electrode protection layer, the researchers replaced the precious metal in the electrode protection layer with inexpensive iron nitride having large surface area and uniformly coated a small amount of iridium catalyst on top of it, greatly increasing the economic efficiency of the electrolysis device. The polymer electrolyte membrane water electrolysis device is a device that produces high-purity hydrogen and oxygen by decomposing water using electricity supplied by renewable energy such as solar power, and it plays a role in supplying hydrogen to various industries such as steelmaking and chemicals. In addition, it is advantageous for energy conversion to store renewable energy as hydrogen energy, so increasing the economic efficiency of this device is very important for the realization of the green hydrogen economy. In a typical electrolysis device, there are two electrodes that produce hydrogen and oxygen, and for the oxygen generating electrode, which operates in a highly corrosive environment, gold or platinum is coated on the surface of the electrode at 1 mg/cm2 as a protective layer to ensure durability and production efficiency, and 1-2 mg/cm2 of iridium catalyst is coated on top. The precious metals used in these electrolysis devices have very low reserves and production, which is a major factor hindering the widespread adoption of green hydrogen production devices. [Figure 2] Schematic of the electrode fabrication process for this development To improve the economics of water electrolysis, the team replaced the rare metals gold and platinum used as a protective layer for the oxygen electrode in polymer electrolyte membrane hydrogen production devices with inexpensive iron nitride (Fe2N). To do so, the team developed a composite process that first uniformly coats the electrode with iron oxide, which has low electrical conductivity, and then converts the iron oxide to iron nitride to increase its conductivity. The team also developed a process that uniformly coats an iridium catalyst about 25 nanometers (nm) thick on top of the iron nitride protective layer, reducing the amount of iridium catalyst to less than 0.1 mg/cm2, resulting in an electrode with high hydrogen production efficiency and durability. The developed electrode replaces the gold or platinum used as a protective layer for the oxygen generating electrode with non-precious metal nitrides while maintaining similar performance to existing commercial electrolysis units, and reduces the amount of iridium catalyst to 10% of the existing level. In addition, the electrolysis unit with the new components was operated for more than 100 hours to verify its initial stability. "Reducing the amount of iridium catalyst and developing alternative materials for the platinum protective layer are essential for the economical and widespread use of polymer electrolyte membrane green hydrogen production devices, and the use of inexpensive iron nitride instead of platinum is of great significance," said Dr. Hyun S. Park of KIST. "After further observing the performance and durability of the electrode, we will apply it to commercial devices in the near future." The research was supported by the Ministry of Trade, Industry and Energy (Minister Lee, Chang-Yang) and KIST Major Projects, and the results were published online in the latest issue of the international scientific journal Applied Catalysis B:Environmental (IF: 24.319, top 0.926% in JCR). ### 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 conducted through the KIST Major Projects supported by the Ministry of Science and ICT (Minister Lee Jong-ho), and the results were published online in the latest issue of the international scientific journal Applied Catalysis B:Environmental (IF: 24.319, top 0.926% in JCR). Journal : Applied Catalysis B:Environmental Title : High-performance water electrolyzer with minimum platinum group metal usage : Iron nitride-iridium oxide core-shell nanostructures for stable and efficient oxygen evolution reaction Publication Date : 9-March-2023 DOI : https://doi.org/10.1016/j.apcatb.2023.122596

- A KIST research team succeeds in the development of a simplified CO2 conversion process without a CO2 capture process - Outperforms conventional CO2 conversion technology in terms of economic feasibility and environmental impact The issue of achieving the target of net-zero CO2 emissions has emerged as a matter of future survival of mankind, with the impact of climate change causing a palpable sense of crisis in the everyday lives of people. The technology of Carbon dioxide Capture Utilization and Storage(CCUS), one of the methods for achieving net-zero CO2 emissions has drawn attention as an innovative technology for reducing CO2 emissions. CCUS is the very technology for which Elon Musk, the CEO of Tesla Inc., announced his funding of $100 million in prize money over four years starting in 2021. However, the high energy consumption required in the process of purification, pressurization, separation, and reuse of CO2 poses a challenge to the industrial application of these technologies in practice. The research team led by Drs. Ung Lee and Da Hye Won at the Clean Energy Research Center, Korea Institute of Science and Technology (KIST, President Seok Jin Yoon), announced that they succeeded in developing a process for producing high-value-added synthesis gas (syngas) by direct electrochemical conversion of CO2 captured using a liquid absorbent. The research achievement is expected to provide a cost-effective solution for CCUS technology, which has restricted wider applications of the technology. [Figure 1] Schematic diagram comparing the novel CO2 utilization technology(the proposed reaction swing absorption(RSA) pathway) with conventional CCU pathways The CO2 conversion process developed by the research team utilizes the CO2 captured in a liquid absorbent; in this way, the conventional CCU pathways with complex and energy-consuming processes of purification and pressurization of CO2 for pure gaseous CO2 production are no longer needed. For this reason, the proposed method outperforms the conventional CCUS technology, with superior cost-effectiveness and enhanced effect of reducing CO2 emissions. In addition, since unreacted CO2 is still captured in the liquid absorbent, there is no need for an additional separation process with syngas, a product from the pathway; another advantage is that the ratio of hydrogen to CO in the syngas can be more easily controlled. [Figure 2] Simplified CO2 conversion process Also, the research team was able to maximize the efficiency of the direct CO2 conversion in the liquid phase by conducting experiments for selecting the best absorbent, optimizing the catalyst, designing electrochemical reactor as well as testing long-term stability. In addition, simulation studies with numerical modeling of the industrial-scale process were also carried out to examine the feasibility of commercialization of the developed process. Furthermore, through techno-economic analysis and life cycle assessment, it is estimated that the newly developed CO2 conversion process will be able to reduce production costs by 27.0% and CO2 emissions by 75.7% compared to the conventional CCUS technology. [Figure 3] Schematic of the novel electrochemical CO2 reduction technology(RSA pathway) In addition, the proposed technology demonstrated an equivalent level of competitive price when compared to the current market price of chemicals dominated by fossil fuel-based technologies. In particular, in the case of syngas, the production cost was reduced by 27.02% compared to the conventional process (reduction of the production cost from $0.89/kg to $0.65/kg, and CO2 emissions from 1.13kg CO2/kg to 0.27kg CO2/kg. If the developed CO2 conversion process is applied to a major CO2 emission source such as a thermal power plant, the proposed technology is expected to be able to produce high-value chemicals such as ethylene at a low cost while reducing CO2. Dr. Da Hye Won, a senior research scientist at KIST, reported, “The significance of the proposed technology lies in that we have achieved technological progress in the efficient production of high-concentration syngas through the electrochemical process by utilizing captured CO2.” Dr. Ung Lee, the principal research scientist at KIST, commented, “We expect that the proposed technology will be applicable to a range of electrochemical conversion systems that utilize CO2, and we plan to move onto the next stage of continuous process demonstration and verification as well as technology transfer to business entities in the future.” ### 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 conducted as a part of the “Carbon to X project for the production of useful materials” with the support of the Ministry of Science and ICT (Minister Lee Jong-Ho), and the results were published in Nature Communications (IF 17.694, JCR 7.432%), a world-renowned scientific journal, on December 5, 2022. Journal : Nature Communications Title : Toward economical application of carbon capture and utilization technology with near-zero carbon emission Publication Date : 5-Dec-2022 DOI : https://doi.org/10.1038/s41467-022-35239-9

- Revealed the principle that gaseous materials cause densification of proton ceramic electrolytes - One step closer to commercializing protonic ceramic electrolysis cells for green hydrogen production Green hydrogen production technology is absolutely necessary to finally realize the hydrogen economy because unlike gray hydrogen, green hydrogen does not generate large amounts of carbon dioxide in the production process. Green hydrogen production technology based on solid oxide electrolysis cells (SOEC), which produce hydrogen from water using renewable energy, has recently attracted attention because it does not generate pollutants. Among these technologies, high-temperature SOECs have the advantage of excellent efficiency and production speed. The protonic ceramic cell is a high-temperature SOEC technology that utilizes a proton ceramic electrolyte to transfer hydrogen ions within material. These cells also use a technology that can reduce operating temperatures from 700 ℃ or more to 500 ℃ or less, thereby reducing system size and price and improving long-term operation reliability by delaying deterioration. However, it has been difficult to enter the commercialization stage because the key mechanism responsible for sintering protonic ceramic electrolytes at relatively low temperatures during the cell manufacturing process has not been specifically identified. Dr. Ho-Il Ji, Dr. Jong-Ho Lee, and Dr. Hyungmook Kang's research team at the Energy Materials Research Center, Korea Institute of Science and Technology (KIST, President Yoon Seok Jin), announced that they have increased the possibility of commercialization by identifying this electrolyte sintering mechanism: a next-generation high-efficiency ceramic cell that had not previously been identified. The research team designed and conducted various model experiments based on the fact that the transient phase generated on the electrode during the electrolyte-electrode sintering process affects the densification of the electrolyte. They discovered for the first time that supplying the electrolyte with a small amount of gaseous sintering aid material from the transient phase promotes sintering of the electrolyte. Gaseous sintering aids are extremely rare and technically difficult to observe; therefore, the hypothesis that the densification of the electrolyte in proton ceramic cells is caused by vaporized sintering aids has never been proposed. The research team verified the gaseous sintering aid using computational science and confirmed that the reaction did not impair the unique electrical properties of the electrolyte. Thus, the design of the core manufacturing process of proton ceramic cells is expected to be possible. Dr. Ji of KIST said, "Through this research, we have come one step closer to developing the core manufacturing process for protonic ceramic cells. We plan to conduct research on the manufacturing process of large-area, high-efficiency proton ceramic cells in the future." He also mentioned that, "If large-area technology is successfully developed, it will be possible to produce pink hydrogen in connection with next-generation nuclear technology as well as green hydrogen in connection with renewable energy, which will lead to the commercialization of ceramic cells and accelerate the realization of the hydrogen economy." This research was conducted under major KIST projects, the New Renewable Energy Technology Development Project by the National Research Foundation of Korea, supported by the Ministry of Science and ICT (Minister Jong-ho Lee), and the New Renewable Energy Technology Development Project by the Korea Institute of Energy Technology Evaluation and Planning, which is supported by the Ministry of Trade, Industry, and Energy (Minister Chang-yang Lee). The research results were published in the latest issue of ACS Energy Letters (IF: 23.991, top 3.211% in the JCR field), an international journal in the field of energy. Journal: ACS Energy Letters Title: An Unprecedented Vapor-Phase Sintering Activator for Highly Refractory Proton-Conducting Oxides Publication Date: 21-Oct-2022 DIO: https://doi.org/10.1021/acsenergylett.2c02059 The principle of accelerating electrolyte densification in the proton ceramic cell manufacturing process

- Complete replacement of existing petrochemical-based solvents with environmentally friendly solvents - Production of economically secured and environmentally friendly biofuels and renewable chemicals in a ‘one-pot process’ Biomass refers to biological organisms, including plants, that synthesize organic matter utilizing solar energy and animals that use these plants as food. Biomass also includes resources that can be converted into chemical energy. To achieve carbon neutrality by 2050, substantial efforts have been made worldwide to develop biorefinery technology that can replace fossil fuels with biofuels. However, the conventional biofuel production process involves the use of highly toxic solvents, which are mainly derived from petroleum causing environmental and economic concerns. Dr. Kwang Ho Kim’s research team at the Clean Energy Research Center of Korea Institute of Science and Technology (KIST, President Seok Jin Yoon) developed a green solvent that can completely replace conventional petrochemical-based solvents while maximizing the efficiency of biofuel production. The researchers announced that it is now possible to produce sustainable and economically secured biofuels. After screening various solvent candidates, the KIST research team synthesized a green deep eutectic solvent that is also biocompatible with microorganisms during the fermentation process. The synthesized eutectic solvents were systematically analyzed by advanced nuclear magnetic resonance spectroscopy and computational analysis. The ‘one-pot process’ based on the newly developed solvent maximized the production efficiency of high-purity biofuels and biochemicals by integrating three to four complex existing processes into one consolidated process. It was also announced that the one-pot process that uses environmentally friendly solvents is sustainable, does not emit pollutants, does not require washing water, and allows for the reuse of solvents. Dr. Kim of KIST said, “By overcoming the uneconomical problems currently being faced by the biorefinery industry via the development of green solvents and maximization of biofuel production process efficiency, Korea will be able to take the lead in the ‘Race to Zero’ by developing this sustainable technology.” This research was supported by by the KIST and the National Research Foundation of Korea (Minister Jong Ho Lee). This collaborative research was conducted between the University of British Columbia, State University of New York, National Institute of Forest Science of Korea and Korea Military Academy. The research results were published in the latest issue of Green Chemistry (Impact Factor: 11.034), an international journal in the energy and environment field and were selected as the back cover. One-pot process for producing biofuels and biochemicals from biomass using environmentally friendly eutectic solvents Title: One-pot conversion of engineered poplar into biochemicals and biofuels using biocompatible deep eutectic solvents Journal: Green Chemistry DOI: https://doi.org/10.1039/D2GC02774G