- Photocatalysis-based Prompt and Complete Removal of Trace Amount of Alcohol in Water Alcohols are used to remove impurities on the surface of semiconductors or electronics during the manufacturing process, and wastewater containing alcohols is treated using reverse osmosis, ozone, and biological decomposition. Although such methods can lower the alcohol concentration in wastewater, they are ineffective at completely decomposing alcohols in wastewater with a low alcohol concentration. This is because alcohol is miscible in water, making it impossible to completely separate from alcohol using physical methods, while chemical or biological treatments are highly inefficient. For this reason, wastewater with a low alcohol concentration is primarily treated by diluting it with a large amount of clean water before its discharge. The Korea Institute of Science and Technology (KIST, President Seok-Jin Yoon) has announced that a research team led by Dr. Sang Hoon Kim and Dr. Gun-hee Moon of Extreme Materials Research Center developed a photocatalyst that can completely decompose a trace amount of alcohol in water within a short duration by adding a very trace amount of copper to iron oxide, which is used as a catalyst during the advanced oxidation process. The research team employed Fenton oxidation that uses oxidizing agents and catalysts during the advanced oxidation process for water treatment. Usually alcohols were used as reagents to verify radical production during Fenton oxidation in other advanced oxidation process (AOP) studies, they were the target for removal from semiconductor wastewater in this research. This water treatment technology is expected to dramatically reduce the cost and water resources invested into the treatment of semiconductor wastewater. In the past, clean water with a volume 10 times higher than that of the wastewater under treatment was required for dilution of the wastewater in order to reduce the alcohol concentration of 10 ppm in the wastewater to less than 1 ppm. If the photocatalyst developed by the KIST is used for water treatment, water resources can be saved. The research team applied the photocatalyst to wastewater from a semiconductor factory to prove that alcohol decomposition levels similar to those observed in the laboratory could be achieved in industrial practice. “As large-scale semiconductor production lines are established, we expect that there will be a rapid increase in the demand for the treatment of semiconductor wastewater,” said Dr. Kim. “The results of our research will provide a solution to effectively treat semiconductor wastewater using less resources and at a lower cost,” he added. Image [Figure 1] Mechanism of Isopropyl alcohol (IPA) decomposition during photo-Fenton oxidation using the developed catalyst

Hydrogen is considered a future clean energy source, and thus, building infrastructure and developing core technologies for hydrogen production, storage, transportation, and utilization has attracted significant attention. Among the various hydrogen storage methods, metal hydride-based hydrogen storage systems are considered the safest method to store hydrogen. The Korea Institute of Science and Technology (KIST, President Seokjin Yoon), headed by Dr. Dong Won Chun and Dr. Jin-Yoo Suh, the research teams of the Energy Materials Research Center, and Prof. Kyu Hyoung Lee from the Yonsei University (President Seoung-Hwan Suh), along with their research team, succeeded in the real-time monitoring of the dehydrogenation of metal hydride composites made of Mg and Fe with high nanometer-scale resolution. The joint research team observed the transition of hydrogen atoms from their initial state inside a metal hydride solid to the gaseous state as they move from the outside and calculated the amount of hydrogen that remains inside the metal hydride after the dehydrogenation process. Meanwhile, physical properties of metal hydride were investigated by observing nano-sized samples through an electron microscope; therefore, the reliability of results is questionable. However, the researchers verified that the same phenomenon is reproduced in an experiment when the nano-sized sample (100 nm) is compared with bulk-sized metal hydrate samples (several mm) produced for commercialization. By minimizing sample damage caused by the electron beam, it is possible to observe the movement of hydrogen within the metal, bringing a new phase in the development of hydrogen storage. Dr. Chun said "Hydrogen, with atomic number 1, has one electron and one proton, so it is difficult to observe its movement at the current level of technology, which analyzes the signal of electrons or protons. The research team has introduced a new methodology to observe hydrogen movement within solids. We will apply this technology to the new national challenge of developing solid hydrogen storage systems to build a safe hydrogen storage infrastructure. The final goal is to make hydrogen energy widely available in our daily lives." The research was supported by the Ministry of Science and ICT (Minister Jong-Ho Lee) and was carried out as a major KIST project and as a mid-career researcher project by the National Research Foundation of Korea. The results were published in the latest issue of “Advanced Functional Materials”, a specialized journal on materials and energy. Figure 1. Real-time analysis of hydrogen atom movement and metal hydride dehydrogenation process. Figure 2. Quantification results of hydrogen mobility through observation of hydrogen inside metal hydride. Journal : Advanced Functional Materials Title : Real-Time Monitoring of the Dehydrogenation Behavior of a Mg2FeH6-MgH2 Composite by In Situ Transmission Electron Microscopy 2022.07.19. DOI: https://doi.org/10.1002/adfm.202204147

- Utilization of new two-dimensional materials as thin as a single atomic layer - Development of semiconductor devices that operate at low energy like human synapses The Korea Institute of Science and Technology (KIST, President Yoon Seokjin) announced that the research team of Dr. Joon Young Kwak at the Artificial Brain Convergence Research Center developed a new two-dimensional insulator material synthesis technology with a new element composition ratio, as well as a high-performance and low-power artificial synaptic semiconductor device using this new material, through joint research with Professor Ki-beom Kang's team at the Korea Advanced Institute of Science and Technology (KAIST) and Dr. Taek-mo Jeong's team at the Korea Research Institute of Chemical Technology (KRICT). With the recent increase in the proportion of video and image data, the processing of unstructured data is drawing attention as a key factor in the development of future artificial intelligence (AI) systems. In line with this trend, to overcome the excessive power consumption and limited information processing performance of the current widely used von Neumann computing structure, a “neuromorphic system” that can process and learn information with high efficiency and low power consumption is emerging as a next-generation semiconductor system. Neuromorphic systems mimic the human brain to increase computing performance while reducing power consumption. To implement this, it is necessary to develop high-performance next-generation semiconductor devices that can precisely simulate “synapses” that regulate the connection strength between neurons according to the input signals. Silicon-based semiconductor devices, which are predominantly used at present, consume much more energy than biological synapses, and have physical limitations in simulating a highly integrated system similar to a real nervous system. For this reason, research is actively being conducted to realize high-performance artificial synaptic devices by applying the properties of materials such as oxides and organic/inorganic materials. In addition, newly emerging two-dimensional materials are very thin at the atomic level, which gives them a great advantage in high integration of semiconductor devices. They have superior performance compared to existing silicon materials, such as fast switching speed and charge transfer speed, due to their unique characteristics. The joint research team developed a synaptic device based on a new 2D insulator material and a heterojunction structure of a 2D semiconductor, enabling electrons to move efficiently even at low energy. Using these physical characteristics, they succeeded in developing an artificial synaptic device that shows uniform synaptic connection strength change and operates with an energy of about 15 fJ, which is similar to the actual energy consumption of human synapses. In addition, synaptic connection strength can be maintained for a short or long time depending on the number and intensity of external stimuli, enabling more precise simulation of human brain functions. The research team attempted artificial intelligence learning based on the developed high-performance two-dimensional artificial synaptic device, and the classification accuracy of handwritten digit image data (MNIST) was about 88.3%, confirming the possibility of application to actual neuromorphic systems. Dr. Kwak of KIST said, “As the importance of research on high-efficiency new materials that can be used as substitutes for silicon in the development of next-generation semiconductors is growing, synaptic devices based on the heterojunction structure of semiconductors and the new two-dimensional insulator material presented in this study should have excellent competitiveness in implementing high-level neuromorphic hardware that can accurately simulate brain behavior." This research was carried out with the support of a KIST institutional research program, the Next-Generation Intelligent Semiconductor Technology Development Project of the National Research Foundation of Korea, and the New Concept PIM Semiconductor Leading Technology Development Project of the National Institute of Information and Communications Technology Evaluation. The research results were published in the latest issue of the international journal Advanced Materials (IF: 32.086). [Core Figure (Main)] Characteristics of the low-power, high-performance artificial synapse (left) and image classification learning accuracy test (right) of the new 2D-material-based artificial synaptic device developed by the research team. [Reference figure] Synthesis technology developed by the research team and structure and analysis of the new 2D material.

Due to unusual weather conditions caused by global warming, countries around the world have been suffering from disasters such as extreme heat waves, droughts, and floods in recent years, raising a sense of crisis. Meanwhile, Korean researchers have developed a new catalyst material to realize the resourceization of carbon dioxide, one of the causes of greenhouse gases that cause global warming. Korea Institute of Science and Technology (KIST, President Yoon Seokjin) announced that the team of Dr. Hyung-Suk Oh and Dr. Woong Hee Lee at the Clean Energy Research Center developed a nickel sulfide catalyst used to convert carbon dioxide, the main culprit of greenhouse gases, into carbon monoxide, which is used as a raw material for industries. When the catalyst was applied to the actual conversion systerm, the carbon dioxide conversion performance was three times or more than that of the existing nickel single atom catalyst. Carbon dioxide accounts for most of the substances that cause global warming and has the greatest impact on the greenhouse effect. Through an electrochemical reduction reaction, carbon dioxide can be converted into useful compounds such as carbon monoxide, ethylene, antacid, and methanol. Therefore, research to collect, utilize, and store carbon dioxide is being actively carried out. In particular, carbon monoxide (CO) is a very important basic raw material in the industry. Since carbon monoxide is very chemically unstable, it is mainly used as a reducing agent in the chemical, metal and electronic industries. It also has the highest economic value among chemical materials that can be made of carbon dioxide because of its high production compared to energy input. Research on converting carbon dioxide into carbon monoxide has been based on presioud metal catalysts such as expensive silver and gold. For full-scale commercialization, the development of inexpensive catalyst materials is the key. A nickel(Ni)-based single atom catalyst has been developed as an alternative to a precious metal catalyst, but there is a limit to the conversion rate of carbon dioxide, that is, the maximum current amount, being low. The KIST research team proposed a relatively inexpensive nickel sulfide catalyst and applied it to an actual system to confirm that its performance was high. It was known that only nickel in a single atomic state can be used for carbon dioxide conversion, and nickel catalysts in other metalic states are not possible. However, the research team confirmed though operando analysis that the nickel sulfide catalyst exhibits high electrochemical carbon dioxide conversion activity by simulating the electroninc structure of the single atomic nickel catalyst during the reaction. In addition, it has been confirmed that power efficiency (Faradaic efficiency 3) is also improved by more than three times (70%) compared to the existing nickel monatomic catalyst (22%) Dr. Oh of KIST said, "The nickel sulfide catalyst material, which was simulated by analyzing the reaction and behavior of the nickel single atom catalyst in real time, was born through an original catalyst research and development method called electronic structure imitation. The significance of the study is that it presented new possibilities for developing various low-cos catalysts." He also said, "We plan to make efforts to quickly commercialize nickel sulfide catalysts through follow-up studies such as long-term durability in the future." With the support of the Ministry of Science and ICT (Minister Lee Jong-ho), this study was conducted as a KIST institutional program, 'Carbon to X Project', and a 'Creative Convergence Research Project' by the National Science and Technology Research Association (Chairman Kim Bok-cheol). It was also published in the latest issue of Advanced Energy Materials, an international journal in the field of energy and environment (IF: 29.698, the top 2.464% in the field of JCR).

- KIST discovered critical variables to maximize the performance of artificial synaptic devices - Green light for next-generation neuromorphic system development Neuromorphic computing system technology mimicking the human brain has emerged and overcome the limitation of excessive power consumption regarding the existing von Neumann computing method. A high-performance, analog artificial synapse device, capable of expressing various synapse connection strengths, is required to implement a semiconductor device that uses a brain information transmission method. This method uses signals transmitted between neurons when a neuron generates a spike signal. However, considering conventional resistance-variable memory devices widely used as artificial synapses, as the filament grows with varying resistance, the electric field increases, causing a feedback phenomenon, resulting in rapid filament growth. Therefore, it is challenging to implement considerable plasticity while maintaining analog (gradual) resistance variation concerning the filament type. The Korea Institute of Science and Technology (KIST, President Yoon Seok-jin), led by Dr. YeonJoo Jeong’s team at the Center for Neuromorphic Engineering, solved the limitations of analog synaptic characteristics, plasticity, and information preservation, which are chronic obstacles regarding memristors, neuromorphic semiconductor devices. He announced the development of an artificial synaptic semiconductor device capable of highly reliable neuromorphic computing. The KIST research team fine-tuned the redox properties of active electrode ions to solve small synaptic plasticity hindering the performance of existing neuromorphic semiconductor devices. Furthermore, various transition metals were doped and used in the synaptic device, controlling the reduction probability of active electrode ions. It was discovered that the high reduction probability of ions is a critical variable in the development of high-performance artificial synaptic devices. Therefore, a titanium transition metal, having a high ion reduction probability, was introduced by the research team into an existing artificial synaptic device. This maintains the synapse’s analog characteristics and the device plasticity at the synapse of the biological brain, approximately five times the difference between high and low resistances. Furthermore, they developed a high-performance neuromorphic semiconductor that is approximately 50 times more efficient. Additionally, due to the high alloy formation reaction concerning the doped titanium transition metal, the information retention increased up to 63 times compared with the existing artificial synaptic device. Furthermore, brain functions, including long-term potentiation and long-term depression, could be more precisely simulated. The team implemented an artificial neural network learning pattern using the developed artificial synaptic device and attempted artificial intelligence image recognition learning. As a result, the error rate was reduced by more than 60% compared with the existing artificial synaptic device; additionally, the handwriting image pattern (MNIST) recognition accuracy increased by more than 69%. The research team confirmed the feasibility of a high-performance neuromorphic computing system through this improved the artificial synaptic device. Dr. Jeong of KIST stated, “This study drastically improved the synaptic range of motion and information preservation, which were the greatest technical barriers of existing synaptic mimics.” “In the developed artificial synapse device, the device’s analog operation area to express the synapse’s various connection strengths has been maximized, so the performance of brain simulation-based artificial intelligence computing will be improved.” Additionally, he mentioned, “In the follow-up research, we will manufacture a neuromorphic semiconductor chip based on the developed artificial synapse device to realize a high-performance artificial intelligence system, thereby further enhancing competitiveness in the domestic system and artificial intelligence semiconductor field.” Image [Figure 1] Concept image of the article [Figure 2] Example of visual information processing technology using the artificial synaptic device, confirming that the error rate is reduced by more than 60% by improving the device performance [Figure 3] Photographs of (a) Solar Energy Collector, (b) Membrane Distillation System

- A protein crucial to synaptic function in brain tissues of patients with Huntington’s disease (HD) was discovered to have decreased function by researchers at KIST Huntington’s disease (HD) is a hereditary brain disease caused by a mutation in the huntingtin gene. HD is a neurodegenerative disease without a cure that, after the onset of the disease at around 40 years of age, causes changes in personality and symptoms of dementia along with uncontrollable convulsive movements, ultimately leading to death. It is known that such HD symptoms are caused by the destruction of brain cells in the striatum due to problems occurring in synapses that are crucial to brain function during the progression of the disease. However, the specific mechanism behind brain dysfunction during the progression of HD has not been fully elucidated. The research team lead by Dr. Jihye Seong and Dr. Hoon Ryu, principal researchers at the Brain Science Institute (BSI) of Korea Institute of Science and Technology (KIST, President Seokjin Yoon), was said to have found significantly reduced activity of focal adhesion kinase (FAK) proteins that play an important role in neurite motility and proper synapse formation in the brain tissues of patients with HD. Activated FAK proteins play an important role in brain function as they are essential in neurite motility and proper synapse formation. The KIST research team identified a significant reduction in FAK activity in HD cells and mouse models, as well as brain tissues of HD patients. These results were also verified through accurate measurements of FAK activity in live cells using a fluorescence resonance energy transfer (FRET)-based biosensor. Phosphatidylinositol 4,5-biphosphate (PIP2), a phospholipid found in the cell membrane, is essential for the activation of FAK proteins. Using super-resolution structured illumination microscopy, the research team found that PIP2 in HD cells was unusually strongly bound to the mutant huntingtin protein, inhibiting proper distribution of PIP2 throughout the cell membrane. This abnormal distribution of PIP2 inhibits FAK activation, which hinders proper synaptic function, causing brain dysfunction in the early stages of HD. Dr. Seong said, “The pathological mechanisms of synaptic dysfunction in patients with Huntington’s disease revealed through this study could be utilized as a therapeutic target for the treatment of brain dysfunction.” Dr. Ryu said, “Because the results of this study show the pathological mechanisms found in actual brain tissues of patients with HD, I believe it has a greater significance in suggesting a new therapeutic target for human degenerative brain diseases.” Image [Figure 1] Differences in FAK activation and neuronal protrusion formation in brain tissues of normal and Huntington's disease patients [Figure 2] Inhibition of FAK activation due to abnormal distribution of phospholipid caused by mutant huntingtin

- KIST identified lithium ion migration pathways by using a self-designed one-stop battery analysis platform - The mechanism of anode material expansion/deterioration was confirmed… Proposing a new direction for material design to ensure stability and high-efficiency Amid global efforts towards carbon neutrality, automakers all over the world are actively engaged in research and development to convert internal combustion engine vehicles into electric vehicles. Accordingly, competition to improve battery performance, which is at the heart of electric vehicles, is intensifying. Since their commercialization in 1991, lithium-ion batteries have held a dominant market share in most market segments, from small home appliances to electric vehicles, thanks to continuous improvement in energy density and efficiency. However, some phenomena occurring within such batteries are still not well understood, such as the expansion and deterioration of the anode material. The Korea Institute of Science and Technology (KIST, President Seok-Jin Yoon) announced that its team led by Dr Jae-Pyoung Ahn (Research Resources Division) and Dr Hong-Kyu Kim (Advanced Analysis and Data Center) has succeeded in the real-time observation of the expansion and deterioration of the anode material within batteries due to the movement of lithium ions. The performance and lifespan of lithium-ion batteries are generally known to be affected by various changes that occur in the internal electrode materials during the charging and discharging processes. However, it is, difficult to monitor such changes during operation because major battery materials, such as electrodes and electrolytes, are instantly contaminated when exposed to the air. Therefore, accurate observation and analysis of structural changes in the electrode material during lithium ion migration is the most important factor in improving performance and safety. In a lithium-ion battery, the lithium ions move to the anode during charging and move to the anode during discharging. The KIST research team succeeded in real-time observation of a silicon–graphite composite anode, which is being studied for its commercial use as a high-capacity battery. Theoretically, the charging capacity of silicon is 10 times higher than that of graphite, a conventional anode material. However, the volume of silicon nanopowders quadruples during the charging process, making it difficult to ensure performance and safety. It has been hypothesized that the nanopores formed during the mixing of the constituents of silicon–graphite composites can accommodate the volume expansion of silicon during battery charging, thereby changing the battery volume. However, the role of these nanopores has never been confirmed by direct observation with electrochemical voltage curves. Using a self-designed battery analysis platform, The KIST research team directly observed the migration of lithium ions into the silicon–graphite composite anode during charging, and identified the practical role of the nanopores. It was found that lithium ions migrate sequentially into the carbon, nanopores, and silicon in the silicon–graphite composite. Furthermore, the research team noted that the nano-sized pores tend to store lithium ions (fore-filling lithiation) before the lithium-silicon particles (Si lithiation), while the micro-sized pores accommodate the volume expansion of silicon as previously believed. Therefore, the research team suggests that a novel approach that appropriately distributes micro- and nano-sized pores to alleviate the volume expansion of silicon, thereby improving the safety of the material, is necessary for the design of high-capacity anode materials for lithium-ion batteries. “Just as the James Webb Space Telescope heralds a new era in space exploration, the KIST battery analysis platform opens new horizons in material research by enabling the observation of structural changes in electric batteries,” said Dr Jae-pyeong Ahn, head of KIST Research Resources Division. "We plan to continue the additional research necessary for driving innovations in battery material design, by observing structural changes in battery materials that are not affected by atmospheric exposure." he said. This work was supported by the Ministry of Science and ICT (Minister Jong-Ho Lee) as part of the Nano Material Source Technology Development Project of the Korea National Research Foundation (NRF), and the Creative Convergence Research Project of the Korea National Research Council of Science and Technology (NST). The research results were published in the latest issue of the ‘ACS Energy Letters (IF: 23.991, top 3.21% of JCR), an international academic journal in the field of batteries. [Figure 1] Schematic diagram of KIST Battery Analysis Platform [Figure 2] Scanning Electron Microscopy (SEM) images of lithium migration

- KIST develops membrane distillation methods using hydrothermal and solar energy - The goal is to maximize system efficiency through customized membrane distillation technologies for regional climate characteristics Clean water is essential for human survival. However, less than 3% of fresh water can be used as drinking water. According to a report published by the World Meteorological Organization, there is scarcity of drinking water for approximately 1 billion people worldwide, which is expected to rise to 1.4 billion by 2050. Seawater desalination technology, which produces fresh water from seawater, could solve the problem of water scarcity. At the Korea Institute of Science and Technology (KIST, President: Seok-Jin Yoon), a research team led by Dr. Kyung Guen Song from the Center for Water Cycle Research, have developed a hybrid membrane distillation module that combines solar energy with hydrothermal heat pumps to reduce thermal energy consumption during the desalination process. Reverse osmosis and evaporation methods are relatively common seawater desalination processes; however, these methods can operate only at high pressures and temperatures. In comparison, the membrane distillation method produces fresh water by utilizing the vapor pressure generated by the temperature difference between the flowing raw water and treated water separated by a membrane. This approach has the advantage of low energy consumption, as fresh water can be generated at pressures of 0.2–0.8 bar, which is lower than atmospheric pressure, and temperatures of 50–60℃. However, large scale operation requires more thermal energy. Thus, research studies are required to reduce the use of thermal energy for commercial operation. The membrane distillation involves simultaneous mass and heat (energy) transfer. It is divided into a direct contact membrane distillation (DCMD) and an air gap membrane distillation (AGMD) based on the modes applied to the treated water side of membrane to generate vapor pressure differences, which are the driving force. For high energy supply, the mode of producing water by direct contact of raw water of high temperature and treated water of low temperature to the membrane surface (i.e., DCMD) is beneficial. In contrast, for low energy supply, the efficiency is greater if the heat transmitted (heat loss) is reduced by air gaps, rather than direct contact between raw water and processed water (see Figure 1). Thus, the mode that generate water by condensing over a cold surface and which maintain air gaps between the membrane and the condensation surface (i.e., AGMD) are preferred. The KIST Research Team developed a hybrid desalination technology by conducting on-site tests for 1 month to compare the system performance and economy using solar energy and hydrothermal heat pumps. When the system operated in parallel with solar energy, production increased by 9.6% (see Figure 2) and energy usage was reduced by 30% (see Figure 3) compared to the membrane distillation method using only hydrothermal heat pumps. In addition, comparison of the consumption of thermal energy depending on the presence of solar energy showed that the efficiency of the membrane distillation plant process increased by up to 17.5% when solar energy was used as an additional heat source. According to Dr. Song, “The hybrid desalination technology we developed can be considered a method to supply water to some industrial complexes and island areas facing water scarcity as it can reduce the energy consumption required to generate fresh water. We expect this technology to be applied to significant water supply facilities in the Middle East and Southeast Asia where the annual solar radiation quantity is 1.5 times that in Korea." He added, “Membrane distillation is not significantly affected by raw water quality, so it will be possible to supply drinking water to areas where raw water quality became heavily contaminated due to water pollution and areas where heavy metal detection is high." Image [그림 1] Comparison of Production Volume and Efficiency for Different Membrane Distillation Compositions [그림 2] Comparison of Specific Energy Consumption (SEC) and Gain Output Ratio (GOR) with Weather in Hybrid Systems [그림 3] Photographs of (a) Solar Energy Collector, (b) Membrane Distillation System

- Self-reporting and self-healing coatings similar to human skin - High re-usability of coating reduces waste generation by maintaining functionality Skin-like polymeric coatings are applied to the surfaces of automobiles, ships, and buildings to protect them from the external environment. As it is difficult to determine whether the currently used coatings are already damaged or not, these non-reusable coatings must be regularly replaced, leading to a large amount of waste generation and high disposal costs. The Korea Institute of Science and Technology (KIST, President Seok-Jin Yoon) announced that Dr. Tae Ann Kim’s team at the Soft Hybrid Materials Research Center has developed a polymeric coating wherein the damaged area changes color, enabling immediate detection and high temperature self-healing. Existing studies on damage-reporting and self-healing polymeric coatings involve the use of extremely small capsules containing functional agents. However, these capsules cannot be used again for subsequent damage detection and self-healing if broken. The KIST research team has developed a thermoset polymer that can recover its original chemical structure after being disrupted by an external stimulus, thereby allowing this material to self-report damage and self-heal multiple times. In this study, a mechanochromic molecule, which changes color when an external force is applied due to a specific bond cleavage, and a thermoset polymer containing a molecule that can be separated and re-formed by temperature were synthesized. When a force is applied to a mechanochromic molecule, a certain bond is broken, thus changing into a form that can exhibit color. The damaged part of the synthesized polymeric coating changed to purple. When a temperature of 100 °C or higher was applied, the material became processable and was physically healed and became colorless. The research team used molecular dynamics simulations to predict and confirm that only certain desired chemical bonds are selectively cleaved when a mechanical force is applied to yield a colored structure; the functionality was implemented by synthesizing the actual coating agent. The novel multifunctional polymeric coating developed herein can be extensively used in automotive, marine, defense, timber, railway, highway, and aerospace industries, and can significantly contribute toward the reduction of industrial waste. In addition, it can be used as an artificial skin for robots, such as humanoids, since its functionality is similar to that of skin and it does not require an external energy source. Dr. Tae Ann Kim of KIST said, “This study reports a method for the simultaneous realization of damage detection and self-healing technology without any external agents such as capsules.” He added, “However, even if repeated self-healing is possible, it cannot be used permanently. Therefore, additional research is underway to transition materials that have reached their lifespan into materials that are harmless to the environment or convert them into a re-cyclable form.” [Image] [Fig. 1] Schematic of mechanochromic and self-healing thermosets [Fig. 2] Mechanochromic and self-healing coatings on diverse substrates

- Expected to replace lithium-based energy storage systems that have a high risk of explosions with aqueous zinc batteries. Successful growth and optimization of zinc metal anodes through low-cos and ecofriendly electroplate processes. Most energy storage systems (ESSs) have recently adopted lithium-ion batteries (LIBs), with the highest technology maturity among secondary batteries. However, these are argued to be unsuitable for ESSs, which store substantial amounts of electricity, owing to fire risks. The instability of the international supply of raw materials to construct LIBs has also emerged as a crucial concern. By contrast, aqueous zinc-ion batteries (AZIBs) use water as the electrolyte, which fundamentally prevents battery ignition. Furthermore, the price of zinc, the raw material, is only one-sixteenth of that of lithium. The research team led by Dr. Minah Lee at the Energy Storage Research Center in the Korea Institute of Science and Technology (KIST; President Seok-Jin Yoon) announced that they had succeeded in developing a technology for manufacturing “high-density zinc metal anodes,” which is key to commercializing AZIBs. This manufacturing technology is expected to act as a catalyst for the mass production of AZIBs because zinc metal anodes with high energy density and long lifespan can be produced through a simple electroplating process by using low-cost and ecofriendly solutions. In theory, because AZIBs utilize two electrons per ion, they are advantageous in terms of volumetric energy density relative to alkali metal-ion batteries. If the capacity of the zinc metal used as the anode for making the battery does not exceed twice that of the cathode, it is possible to realize an energy density comparable to that of the LIBs commercialized today. Furthermore, even if the capacity of the zinc metal reaches five times that of the cathode, it is still competitive in that it is similar to that of sodium-ion batteries, which are attracting attention as the next generation of batteries owing to their low cost and material abundance. However, zinc metal anodes restrict the energy density and lifespan of AZIBs because of the irregular growth of nanoparticles during battery operation. A low zinc metal particle density and a large surface area in the anode accelerate corrosion with the electrolyte, thus depleting the active zinc metal and the electrolyte. Existing studies have typically used zinc metals that were 20 times thicker than what was required to counteract the lifespan limitations; paradoxically, this led to an inevitable decline in energy density and cost competitiveness, the biggest strengths of AZIBs. Thus, the team led by Dr. Minah Lee at the KIST controlled the microstructure of zinc metal anodes to reduce the prevalence of the side reactions that induce the decline in energy density and lifespan of AZIBs. The team adopted a deep eutectic solvent (DES) solution, which can be easily synthesized at room temperature, was to construct the compact zinc anodes. This DES solution is composed of choline chloride and urea mixed at a mole ratio of 1:2; the mixture becomes a liquid complex with a melting point of 12 °C. The researchers confirmed that a zincophilic copper–zinc alloy layer spontaneously forms between the zinc and copper current collectors within the DES, enabling high-density zinc particles to grow. The researchers succeeded in using this discovery to develop an electroplating process that allows zinc metals to grow densely and evenly in the low-cost and ecofriendly DES solution. Application of the manufactured zinc metal anode to an aqueous zinc battery system showed that the corrosion reactions are effectively suppressed, and the capacity is maintained at more than 70% after more than 7000 repeated charges and discharges. This result is exceptional relative to those of similar existing studies that utilized thin zinc, and the values far exceed the charging and discharging lifespans (1000–2000 times) of commercial LIBs. Dr. Minah Lee of the KIST stated, “We were able to develop a core technology for commercializing AZIBs that can solve the fire safety issue of ESSs, which is the biggest obstacle to the provision and expansion of renewable energy.” She added, “We expect that this compact zinc anode manufacturing technology will open the way for the mass production of AZIBs by combining a particularly economical and ecofriendly DES solution with an electroplating process already widely used throughout the industry.” - Image Unlike zinc particles, which are irregularly formed in a conventional aqueous electrolyte and induce corrosion, zinc grown in a DES solution is tight and uniform and maintains a stable structure even after charging and discharging in an aqueous electrolyte