 | Dr. Hun Kim explores materials and interfacial chemistries for rechargeable batteries. His research integrates electrolyte design, composite-electrode engineering, interfacial chemistry, and cell-level engineering across Li-ion, Li-metal, Li-S, and all-solid-state batteries. One of his principal research areas is the development of composite cathode materials for high-energy all-solid-state batteries. In a study published in ACS Energy Letters (2023), he introduced an inorganic Li-ion-conducting interphase composed of polysulfido-intermediate species between sulfur and the sulfide solid electrolyte to overcome limitations associated with solid–solid contact. A small amount of a weakly polar solvent promoted controlled interfacial reactions during electrode preparation and was subsequently removed, improving the wettability, ionic contact, and mechanical integrity of the composite sulfur electrode. The resulting all-solid-state cell delivered a high areal capacity of 5.1 mAh cm−2 and operated for 250 cycles at 30 ºC. |
Building on this approach, in a study published in Advanced Energy Materials (2025), he developed a two-step electrode-processing strategy combining high-energy ball milling with mild mixing through an entirely dry process. This strategy creates intimate solid-solid interfaces by generating ion-conducting interfacial species and continuous Li-ion conduction pathways throughout the thick sulfur electrodes. The resulting all-solid-state cell achieved a high areal capacity of 10.1 mAh cm−2 and retained 92.0% of its initial capacity after 150 cycles at 30 ºC. Together, these studies establish a continuing research direction from molecular-level materials science to the practical engineering of solid-state sulfur electrodes.
Dr. Kim has also investigated cell-level mechanical strategies for durable lithium-metal batteries. In another study published in ACS Energy Letters (2023), he combined a boehmite-coated separator with controlled external compression to promote dense and uniform lithium deposition while mitigating microcrack formation in the Ni-rich cathode and suppressing pressure-induced short circuits.
The resulting high-energy stacked lithium-metal cell, with an areal capacity exceeding 4 mAh cm−2, retained 82.0% of its initial capacity after 500 cycles. This work was subsequently featured by Nature Energy in a Research Highlight entitled “Coating and compressing,” which emphasized the combined roles of interfacial coating and mechanical pressure in enabling durable lithium-metal batteries with carbonate-based electrolytes.
Beyond these representative achievements, Dr. Kim’s research includes electrolyte-solution engineering for Li-ion and Li-metal batteries paired with Ni-rich layered cathodes. He employs complementary electrochemical, spectroscopic, microscopic, and thermal-analysis methods to connect material design with interfacial reactions and degradation behavior. Furthermore, he aims to develop stable battery chemistries tailored to the local climate, while leveraging data-driven approaches to investigate degradation behavior.
His research directions are summarized below.
1. Functional Electrolytes for Li-ion and Li-metal Batteries
His group develops functional electrolyte solutions for wide-voltage/temperature range Li-ion batteries and Li-metal batteries by tuning solvents, salts, additives, and solvation structures.
2. Composite Materials for All-Solid-State Batteries
His group designs composite electrode materials and electrolyte membranes for sulfide-based all-solid-state batteries using Ni-rich NCM/NCA and Chalcogen-based CAMs (S, Li2S, Se, and SeS2).
3. Electrolyte-Electrode Interface Design and Characterization
His group investigates how electrolyte and electrode components affect the electrode-electrolyte interface, and how these interactions influence material, electrode, and cell degradation, using electrochemical and surface-sensitive characterization techniques.
4. New Battery Chemistries and Advanced Electrode Processing
His group explores new battery chemistries and advanced electrode-processing methods. The group is not limited to a specific battery chemistry and pursues any promising approach toward safe, high-energy batteries.