A world-first technology has been developed by introducing a roll-to-roll compatible flash process into secondary battery electrode manufacturing, significantly suppressing the performance degradation of thick electrodes. This breakthrough presents a new possibility of reducing battery costs by minimizing inactive materials and simplifying the manufacturing process while increasing energy density and capacity, making batteries smaller and lighter.
The Korea Institute of Machinery and Materials (President Seog-Hyeon Ryu, hereinafter referred to as KIMM), an institute under the jurisdiction of the Ministry of Science and ICT, has developed an electrode activation technology utilizing an ultra-fast, large-area flash process to mitigate thick electrode degradation. Using the pilot-scale test bed, its compatibility with roll-to-roll (R2R) processes was successfully demonstrated. Thick electrodes offer advantages such as high energy density, fewer battery pack layers, a simplified structure, and increased manufacturing efficiency, leading to a drastic reduction in production costs. However, thick electrodes also face challenges, including increased resistance to lithium-ion and electron transport and limited electrolyte penetration, which lead to decreased overall electrochemical performance such as rate capability.
To address these issues, the research team introduced a flashlight irradiation process on thick electrodes for an instantaneous duration of less than one millisecond. The photothermal reaction triggered in this process instantly induces changes such as binder carbonization, interlayer expansion of active material (graphite), increased porosity, and an enlarged electrode-electrolyte interfacial area. These chemical and structural modifications enhance lithium-ion and electron transport while improving electrolyte penetration, ultimately suppressing the performance degradation of thick electrodes.
* Photothermal reaction refers to a process in which light energy is converted into heat energy.
By utilizing surface photothermal reactions, this technology prevents the entire thick electrode, including the current collector, from prolonged high-temperature exposure. This minimizes binder decomposition, preserving mechanical durability while also preventing oxidation-related thermal damage to the current collector. This technology is highly compatible with standard roll-to-roll manufacturing processes and is expected to be expandable to various electrode materials, including nickel-cobalt-manganese (NCM) cathodes.
Furthermore, the research team of KIMM is applying and evaluating the flash process in the electrode drying stage. It has been confirmed that the technology can significantly reduce the energy consumption and processing time required for electrode drying while simultaneously inducing electrode activation effects. Recently, in collaboration with lithium-ion battery equipment manufacturers, the team has been developing mass-production-scale facilities and conducting process evaluations.
The principal researcher Dr. Kyoohee Woo of KIMM stated that since flash-based electrode activation technology is a post-treatment process compatible with roll-to-roll manufacturing, it can be easily integrated into existing production lines and facilities Moving forward, the team aims to enhance the technology's maturity and continue testing and validation to facilitate its adoption by domestic lithium-ion battery manufacturers.
This research was supported by the Global Top Strategy Research Group (Market-Leading Next-Generation Lithium-Ion Battery Innovation Strategy Research Group) under the Ministry of Science and ICT and the Carbon-Reducing Medium and Large Lithium-Ion Battery Innovation Manufacturing Technology Development Project under the Ministry of Trade, Industry, and Energy. Recognized for its excellence, this study has been selected as the cover article for the February 2025 issue of Small Methods (Impact Factor: 10.7), a leading international journal in materials and chemistry.
