The Korea Electrotechnology Research Institute (KERI) and the Korea Institute of Materials Science (KIMS) researchers have collaboratively developed a novel “spray drying technology-based high-performance dry electrode manufacturing technology” to produce high-capacity secondary batteries. The study was published in the Chemical Engineering Journal.
(Front row, left) Senior Researcher Jihee Yoon from KIMS and (Front row, right) Senior Researcher Insung Hwang from KERI successfully manufactured dry electrodes for high-capacity secondary batteries using the spray drying technique. Image Credit: Korea Electrotechnology Research Institute
Secondary battery electrodes are composed of “active materials” for energy storage, “conductive additives” to facilitate electricity flow, and “binders” acting as adhesives. These components are typically mixed using either a “wet process” involving solvents or a more environmentally friendly “dry process” that mixes solid powders without solvents.
The dry process is particularly attractive because it can increase the energy density of secondary batteries. However, achieving a uniform mixture of active materials, conductive additives, and binders in the dry process has historically presented significant challenges.
KERI and KIMS adapted “spray drying” technology, a method already proven for large-scale production in the food and pharmaceutical industries, for use in the dry process. Researchers at KIMS first created a liquid slurry of active materials and conductive additives, which was then sprayed into a high-temperature glass tube chamber.
The high temperature causes the solvent to evaporate rapidly, leaving behind a uniformly mixed composite powder of active materials and conductive additives. This process is analogous to the production of instant stick coffee, where the coffee concentrate is spray-dried with hot air to create a solid powder.
KERI researchers processed the composite powder produced via spray drying into high-capacity electrodes, leveraging their extensive knowledge in “dry-electrode processes.” The researchers mixed the composite with binders and subjected the mixture to “fibrillation,” a process where the binders are stretched into fine threads using specialized equipment.
This careful process allowed the “active materials-conductive additives-binders” to interweave more effectively, forming a precise structure. Finally, the mixture underwent “calendering,” where it was compressed into a thin film of uniform density, resulting in battery electrodes.
KERI and KIMS believe this advancement will enable the creation of higher-capacity secondary batteries by facilitating optimal mixing of internal materials. This will reduce the amount of conductive additives and correspondingly increase the space occupied by energy-storing active materials.
Through extensive experimentation, the joint research team significantly reduced the proportion of conductive additives from the 2-5% range reported in existing dry electrode literature to as low as 0.1%. They also achieved a world-leading active material content of 98%.
Furthermore, the dry electrodes produced using this method demonstrated an areal capacity of approximately 7 mAh/cm², double that of commercially available electrodes (2-4 mAh/cm²).
Senior Researcher Insung Hwang from KERI's Next Generation Battery Research Center highlighted the importance of the research, stating that the optimized combination of electrode materials can enhance energy density and performance and that this technology holds great promise for application in next-generation battery technologies such as solid-state and lithium-sulfur batteries.
Through follow-up research, we plan to reduce process costs, improve mass production capabilities, and increase technology maturity, with the goal of eventually transferring the technology to companies.
Jihee Yoon, Senior Researcher, Convergence and Composite Materials Research Division, Korea Institute of Materials Science
Both KERI and KIMS are government-supported research institutes operating under the National Research Council of Science & Technology (NST) of the Ministry of Science and ICT in Korea. This research, representing a successful example of collaboration between government-funded institutions, was a joint effort supported by NST's Creative Convergence Research Project and MOTIE's Machinery and Equipment Industry Technology Development Project.
Journal Reference:
Hwang, I., et al. (2025) A breakthrough in dry electrode technology for high-energy-density lithium-ion batteries with spray-dried SWCNT/NCM Composites. Chemical Engineering Journal. doi.org/10.1016/j.cej.2025.160159