The notion that a method used to produce instant coffee might, in the future, revolutionize the production of batteries might be whimsical, but that is what researchers at the Korea Electrotechnology Research Institute (KERI) and the Korea Institute of Materials Science (KIMS) have done. Through employing spray drying a process decades old in food and pharmaceutical applications they have cracked one of the big issues with mass-producing high-capacity secondary batteries: maintaining consistency in manufacturing dry electrodes.
Secondary battery electrodes consist of three major elements: electrical energy-storing active materials, electron-conducting additives, and binders that keep them all together. They have long been blended with the wet process, employing solvents. It is an effective process but environmentally questionable and restricts the energy density of batteries. The other, the dry process, is solvent-free and environmentally friendly but has not been able to provide a uniform blend of materials.
Breakthrough came when spray drying was applied in the dry process by KIMS researchers. They began by forming an active material-slurry with conductive additives, atomizing and spraying it into a hot chamber. The solvent evaporated quite quickly, but the composite powder of fine particles remained behind. KIMS Senior Researcher Jihee Yoon called the process a novel adaptation of a proven technique, and likened it to powdering instant coffee.
This innovation went beyond powder fabrication. Researchers at KERI, utilizing their dry-electrode process expertise, developed the composite powder into high-capacity electrodes. The composition was coated with binders and a technique referred to as fibrillation, whereby the binders were drawn into fibers, intertwining them closely with the active material and conductive additives. Such a complex process enabled effective mixing of the components together.
The final process was calendering, in which the materials were compressed into a flat, thin sheet. The final product was a dry electrode that achieved a record 98% content of active materials, a rate Senior Researcher Insung Hwang of KERI called “world-leading.” High active material content is directly proportional to battery capacity, and thus the achievement is a milestone.
The technology implications are enormous. The researchers managed to decrease the level of conductive additives in the electrodes from the typical 2-5% to 0.1%. This allowed room for extra active materials, effectively doubling the areal capacity of the electrodes to approximately 7 mAh/cm² compared to the 2-4 mAh/cm² of conventional electrodes. These breakthroughs can redefine the electric vehicle battery, consumer device, and renewable energy storage product performance standards.
Aside from its current uses, this technology has potential for batteries in the future. “The optimal combination of electrode materials can enhance energy density and performance,” said Hwang, and the technology is especially suited for next-generation battery types such as solid-state and lithium-sulfur batteries. These batteries are considered to be at the heart of the future of energy storage, with greater energy densities and better safety profiles.
The ecological advantage of the technology is equally significant. Through the elimination of the utilization of solvents during production, the spray drying technique greatly minimizes the ecological impact of battery production. This concurs with the efforts across the globe to make energy storage technology green, an action driven by the relocation of industries worldwide towards clean technologies.
The study has been in the international news, with the research appearing in the *Chemical Engineering Journal*, a leading refereed journal. Yoon explained that the team was dedicated to further developing the technology, adding, “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.”
Both KERI and KIMS are state-funded institutions under South Korea’s National Research Council of Science & Technology. Their partnership is proof of the prowess of cross-field collaboration in overcoming complex technical issues. In bringing together materials science and battery engineering expertise, they not only improved operating performance of secondary batteries but also established a new benchmark in eco-friendly manufacturing processes.
This milestone highlights the revolutionary possibilities of cross-industry technologies. What was simply a way of producing powdered coffee has now become the genesis toward securing green, high-capacity batteries. With consumer demand for the next energy storage generation still building, embracing such innovative means may be the beginning of a progressively greener and electrified future.
For more information regarding the research, this article. The technicalities of the spray drying process are discussed in more detail here, and its potential for use for next-generation batteries is explored in this resource.
