The time required to make particles and prepare for the next cathode batch drops from as many as a few days to 12 hours. The hydrothermal synthesis method is also much faster, said ORNL lead researcher Rachid Essehli. “This novel process offers the key advantage of moving the cathode industry to cleaner and more cost-competitive production while putting less burden on our environment,” said ORNL’s Ilias Belharouak, the principal investigator for the project.

The ethanol is safer to store and handle than ammonia, and afterward it can be distilled and reused. Instead of continuously stirring cathode materials with chemicals in a reactor, their hydrothermal synthesis approach crystalizes the cathode using metals dissolved in ethanol.

ORNL researchers report in the Journal of Power Sources that they have developed a cleaner, cheaper, more efficient method for making a new class of high-capacity cathode material without cobalt. Using the toxic chemical increases costs, heightens health and environmental concerns, and wastes large amounts of water to reduce acidity. For example, high nickel concentration has led to the widespread use of a chemical mixing method for cathode production that requires large quantities of ammonia for corrosive reactions. The balance of other metals common in cathodes can also make the manufacturing process longer and more hazardous. The availability of cobalt is not the only complication. This dependence on foreign sources poses risks to American manufacturing supply chains and transportation infrastructure. The first obstacle is a reliance on cobalt, a rare metal mined and refined abroad. However, traditional processing presents challenges. The drive toward decarbonization and the demand for electric cars has increased the focus on sustainably producing energy-dense cathodes. Ions move from anode to cathode through the electrolyte in a reaction that converts chemical energy to electrical energy. Lithium-ion batteries - used in products from appliances to cell phones, as well as in most electric vehicles - are composed of a cathode and an anode with an electrolyte in between. The result is a more affordable battery from a faster, less wasteful process that uses less toxic material. Researchers at the Department of Energy’s Oak Ridge National Laboratory have developed a new method for producing a key component of lithium-ion batteries.

Lithium battery cathode material