“All organic solvents eliminated” ... Korea University (KU) and Seoul National University develop a “fully dry” battery process

[Financial News] South Korean researchers have developed a fully solvent-free electrode manufacturing technology that can dramatically reduce battery production costs and prevent environmental pollution.
A joint research team led by Professor Seung-ho Yoo of KU’s Department of Chemical and Biological Engineering and Professor Young-eun Sung of Seoul National University said on the 26th that it had developed a dry-process technology that uses no organic solvents at any stage of battery electrode manufacturing.
Wet processes using liquid organic solvents have traditionally been used to mix electrode materials and attach them to metal plates when making lithium-ion batteries, which store electricity. However, drying and recovering the solvents requires enormous amounts of electricity and costly equipment. Dry processes that eliminate solvents have been studied to overcome this problem, but one limitation remained: liquid solvents were still needed at the bonding-layer stage to firmly attach the electrodes to the metal plates.
The research team addressed this problem by using indium, a metal with a low melting point of around 156.6°C, as an adhesive. They coated a current-carrying copper plate with a thin layer of indium, placed the electrode material on top, and applied heat and pressure. The indium first melted slightly, then seeped into every nook and cranny of the tiny voids inside the electrode, bonding it firmly to the current collector without deforming its shape.
The fully dry electrodes produced this way showed stronger adhesion than electrodes made using the conventional wet-bonding method. They retained 91.3% of their initial performance even after 150 charge-discharge cycles, and also operated stably without short-circuiting in tests using actual pouch-type batteries.
KU Professor Seung-ho Yoo said, “Bonding technology that takes advantage of differences in the melting points of metals is the key to maximizing the bonding stability of dry electrodes,” adding, “It will help accelerate the scale-up of battery manufacturing processes that use no organic solvents at all and the commercialization of high-performance batteries.”
The findings were published in the online edition of Advanced Energy Materials, a world-renowned journal in the field of energy materials. 

[email protected] Man-ki Kim Reporter