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KAIST Uncovers the “Core Secret” of Energy Reactions—from Phone Charging to Hydrogen Production
<(From Left) Professor Hyungjun Kim, Ph.D candidate Dong Hyun Kim, Ph.D candidate Minho M. Kim, Ph.D candidate Junsic Cho, Professor Chang Hyuck Choi, Professor Seung-Jae Shin>
From smartphone charging to hydrogen production, the fundamental principles of energy technology have been revealed. Korean researchers have, for the first time, identified how molecular structures change within the ultra-small space called the “electric double layer” (a thin interface where the electrode and electrolyte meet; the electrode is a material through which electricity flows, and the electrolyte is a liquid through which ions move), where electrochemical reactions occur. This study opens a new path to simultaneously improve efficiency and performance in battery, hydrogen, and carbon-neutral technologies by reducing energy loss and selectively inducing desired reactions.
KAIST (President Kwang Hyung Lee) announced on the 3rd of May that a research team led by Professor Hyungjun Kim from the Department of Chemistry, in collaboration with Professor Chang Hyuck Choi from POSTECH (President Sung Keun Kim) and Professor Seung-Jae Shin from UNIST (President Jong Rae Park), has identified structural “phase transitions” (phenomena in which the state or arrangement of matter changes) occurring within the electric double layer. In particular, they revealed at the molecular level the cause of the phenomenon in which the pattern of electrical storage capacity (capacitance) changes from a “camel shape” to a “bell shape” depending on electrolyte concentration.
Electrochemical reactions occur within the ultra-small space called the “electric double layer,” where the electrode and electrolyte meet. In the field of electrochemistry, it has long been known that as electrolyte concentration increases, the capacitance curve changes from a “camel shape” with two peaks to a “bell shape” with a single peak, but the underlying cause had remained unexplained at the molecular level.
Through atomically precise simulations and experiments, the research team discovered that two key changes occur depending on the voltage applied to the electrode.
At the cathode, water molecules collectively realign in a uniform direction, while at the anode, anions (negatively charged particles) accumulate densely on the surface, forming a two-dimensional structure in a phenomenon known as “condensation.” These two processes each create peaks in the capacitance curve, and as electrolyte concentration increases, they merge into one, causing the curve to transition from a “camel” to a “bell” shape.
In simple terms, on one side, water molecules line up in an orderly fashion, while on the other side, ions gather densely. As the concentration increases, these two phenomena merge into one, and the graph changes from two peaks to a single peak.
In particular, the research team presented, for the first time in the world, a “phase diagram” that shows at a glance how the structure of the electric double layer changes depending on electrode potential (the voltage applied to the electrode) and electrolyte concentration. They also experimentally validated these theoretical predictions in real time using infrared spectroscopy (ATR-SEIRAS, an experimental technique that observes molecular movements in real time).
<Transition from a ‘camel-shaped’ to a ‘bell-shaped’ curve caused by changes in the electric double-layer structure>
In simple terms, they created a map that shows how structures change under different conditions and verified through experiments that the map is accurate.
Professor Hyungjun Kim stated, “This study is meaningful in that it provides the first understanding of the otherwise invisible, microscopic electrochemical reaction environment and opens the way to design it,” adding, “If we can precisely control phase transitions in the electric double layer, we will be able to accurately enhance the performance of energy technologies, such as increasing battery charging speed or maximizing hydrogen production efficiency.”
This study, with Minho Kim, a doctoral student in the Department of Chemistry at KAIST, and Dong Hyun Kim and Junsic Cho, doctoral students from the Department of Chemistry at POSTECH, as co-first authors, was published on March 7 in the international journal Nature Communications.
※ Paper title: “Electric double layer structure in concentrated aqueous solution,”
DOI: 10.1038/s41467-026-70322-5
This research was supported by the Samsung Future Technology Development Program, the InnoCore program of UNIST Hydro*Studio, and the National Research Foundation of Korea (NRF) through the Top-Tier Research Institution Collaboration Platform and Joint Research Support Program, as well as the Nano and Materials Technology Development Program.
2026.05.04 View 397 -
The Relentless Rain: East Asia's Recent Floods and What Lies Beneath
In just a month's time, East Asia witnessed torrential downpours that would usually span an entire season. Japan, battered by three times its usual monthly rainfall, faced landslides and flooding that claimed over 200 lives. Meanwhile, South Korea grappled with its longest monsoon in seven years, leaving more than 40 individuals dead or missing. But these events, as harrowing as they sound, are more than just weather anomalies. They're telltale signs, symptoms of a larger malaise that has gripped our planet.
Diving deep into these rain-soaked mysteries, a recently published paper in the journal Science Advances offers a fresh perspective. Led by a research team at the Korea Advanced Institute of Science and Technology (KAIST), Korea, the research unpacks the influence of human-induced climate changes on the East Asia Summer Monsoon frontal system.
Heavy summer rain has a significant impact on agriculture and industry, and can be said to be one of the greatest threats to human society by causing disasters such as floods and landslides, affecting the local ecosystem. It has been reported from all over the world that the intensity of summer heavy rain has changed over the past few decades. However, summer rain in East Asia is caused by various forms such as typhoons, extratropical cyclones, and fronts, and efforts to study heavy frontal rain, which account for more than 40% of summer rainfall, is still insufficient. In addition, because heavy rain is also influenced by natural fluctuations or coincidences in the climate system, it is not yet known to what extent warming due to human activities affects the intensity of heavy frontal precipitation.
An international joint research team consisting of eight institutions from Korea, the United States, and Japan, including KAIST, Tokyo University, Tokyo Institute of Technology, Chonnam National University, GIST, and Utah State University, confirmed the intensity of heavy rain caused by the weather fronts in East Asia using observation data for the past 60 years and found that the coast of southeastern China. It was found that the intensity of heavy rain increased by about 17% across the Korean Peninsula and Japan. To investigate the cause of these changes, the research team used the Earth Metaverse experiment, which simulated Earth with and without greenhouse gas emissions due to human activities, and found that heavy rain intensity was strengthened by about 6% due to greenhouse gas emissions, and the changes discovered were has succeeded for the first time in the world in showing that warming cannot be explained without the effects of human activities.
< Figure 1. (Left) Observed difference in frontal rainfall intensity (FRI) from the later (1991–2015) to the earlier periods (1958–1982) (Right) Visualization of the impact of anthropogenic warming on the intensity of heavy frontal rain analyzed using the Earth Metaverse experiment. >
"It's not just about connecting the dots," said Moon, the first author of the paper, "it's about seeing the larger pattern. Our data analysis reveals a clear and intensified trend in East Asia's frontal rainfall, one that's intertwined with human actions and increasingly harmful for lives and property."
One of the intriguing finds from the study is the mechanics behind this intensification. The team found increased moisture transport due to a warmer climate, which, when coupled with the strengthening of a gigantic weather system called the West North Pacific Subtropical High, results in enhanced frontal rainfall. It’s akin to the climate dialing up the volume on rain events. As the atmosphere warms, it holds more moisture, leading to heavier downpours when conditions are right.
Nobuyuki Utsumi, another voice from the team, makes the science accessible for all, saying, "Monsoon rain isn't just rain anymore. The frequency, the intensity, it's changing. And our actions, our carbon footprint, are casting a larger shadow than we anticipated."
While the devastating news of floods fills headlines, Professor Simon Wang of Utah State University, reminds us of the underlying importance of their study. "It's like reading a detective novel. To solve the mystery of these floods, one has to trace them back to their roots. This work hints at a future where such intense rain events aren't the exception but might become an everyday reality."
Hyungjun Kim, the principal investigator of the team throws in a note of caution, "Understanding this is just the first step. Predicting and preparing for these extremes is the real challenge. Every amplified rainfall event is a message from the future, urging us to adapt." So far, predicting rainfall intensity and locations remains a challenging task for even the most sophisticated weather models.
< Figure 2. Comparison of rates of change in Anthropocene fingerprints. The horizontal axis shows the long-term change slope of the Anthropocene fingerprint signal (1958 to 2015). Shows the probability distribution of slopes extracted from the non-warming experiment (blue) and the warming experiment (red). The vertical solid lines are the slope of the Anthropocene fingerprint signal extracted from observational data. >
The researchers say, “Facing climate change, the narrative of this new study is more than mere numbers and data. It's a story of our planet, our actions, and the rain-soaked repercussions we're beginning to face. As we mop up the aftermath of another flood, research like Moon's beckons us to look deeper, understand better, and act wiser.”
< Figure 3. Comparison of water vapor convergence and rate of change of the western North Pacific high pressure. Shows the gradient of change in water vapor convergence (horizontal axis) and the Northwestern Pacific-East Asia pressure gradient (vertical axis) extracted from warming (red) and non-warming (blue) experiments. Shows the distribution of slope changes of the two indices during the period 1958 to 1982 (P1) and 1991 to 2015 (P2). >
The results of this study were published on November 24 in Science Advances. (Paper title: Anthropogenic warming induced intensification of summer monsoon frontal precipitation over East Asia)
This research was conducted with support from the National Research Foundation of Korea's Overseas Scientist Attraction Project (BP+) and the Anthropocene Research Center.
2023.12.05 View 11167