The Korea Electrotechnology Research Institute announced on the 7th that it has developed a method to create high-capacity secondary batteries using spray-drying technology in collaboration with the Korea Institute of Materials Science. Spray-drying technology is used in the production of coffee mixes.
Secondary battery electrodes are made by mixing active materials that store electrical energy, conductive materials that facilitate electrical flow, and binders that act as adhesives. The mixing methods include a wet process that utilizes solvents and a dry process that produces solid powders without solvents. The dry process can increase energy density compared to the wet process, but it has the limitation of making it difficult to mix the active materials, conductive materials, and binders uniformly.
The research team applied the spray-drying technique to the dry process. They mixed active materials and conductive materials in liquid form and then sprayed them inside a high-temperature chamber made of glass tubes. This causes the solvent to evaporate immediately due to the high temperature inside the chamber, leaving only the composite powder of active materials and conductive materials. This process is similar to that of coffee mix production, where coffee concentrate is sprayed while adding hot air to obtain only solid form powder.
The research team mixed the active material and conductive material powders with the binder and then conducted a fiberization process using specialized equipment to stretch the binder into strands. This allows for the precise mixing of active materials, conductive materials, and binders, according to the research team. They manufactured the battery electrodes by creating thin films from the combination of active materials, conductive materials, and binders.
The research team reduced the conductive material content in secondary batteries from 2-5% to 0.1%. The active material content, which directly correlates to battery capacity, reached 7 mAh/cm², double that of commercial electrodes (2-4 mAh/cm²). The research findings were published in the chemical journal 'Chemical Engineering Journal.' Senior researcher Hwang In-sung from the Korea Electrotechnology Research Institute noted that this is a technology applicable to next-generation batteries such as all-solid-state batteries and lithium-sulfur batteries.