Researchers at the University of California San Diego have actually enhanced their recycling procedure that restores abject cathodes from invested lithium-ion batteries. The brand-new procedure is more secure and utilizes less energy than their previous method in bring back cathodes to their initial capability and cycle efficiency.
Zheng Chen, a teacher of nanoengineering who is associated with the Sustainable Power and Energy Center at UC San Diego, led the task. The work was released in Advanced Energy Products.
“Due to the rapid growth of electric vehicle markets, the worldwide manufacturing capacity of lithium-ion batteries is expected to reach hundreds of gigawatt hours per year in the next five years,” Chen stated. “This work presents a solution to reclaim the values of end-of-life lithium-ion batteries after 5 to 10 years of operation.”
Chen’s group formerly established a direct recycling method to recycle and regrow abject cathodes. It renews lithium ions that cathodes lose over extended usage and restores their atomic structures back to their initial states. Nevertheless, that procedure includes pressurizing a hot lithium salt service of cathode particles to around 10 environments. The issue is this pressurizing action raises expenses and needs additional security preventative measures and unique devices, stated Chen.
So the group established a milder procedure to do the very same task at ambient pressure (1 environment). The secret was utilizing eutectic lithium salts—a mix of 2 or more salts that melts at temperature levels much lower than either of its elements. This mix of strong lithium salts produces a solvent-free liquid that researchers can utilize to liquify abject cathode products and bring back lithium ions without including any additional pressure in the reactors.
The brand-new recycling method includes gathering cathode particles from invested lithium ion batteries and then blending them with a eutectic lithium salt service. The mix is then heat dealt with in 2 actions: it is very first heated to 300 C, then it goes through a brief annealing procedure in which it is heated up to 850 C for a number of hours and then cooled naturally.
Researchers used the method to regrow NMC (LiNi0.5Mn0.3Co0.2), a popular cathode consisting of nickel, manganese and cobalt, which is used in much of today’s electrical cars.
“We made new cathodes from the regenerated particles and then tested them in batteries built in the lab. The regenerated cathodes showed the same capacity and cycle performance as the originals,” stated Yang Shi, the very first author who performed this work as a postdoctoral scientist in Chen’s laboratory at UC San Diego.
“In an end-of-life lithium-ion battery, the cathode material loses some of its lithium. The cathode’s crystal structure also changes such that it’s less capable of moving ions in and out. The recycling process that we developed restores both the cathode’s lithium concentration and crystal structure back to their original states,” Shi stated.
The group is tuning this procedure so that it can be used to recycle any kind of cathode products used in lithium-ion and sodium-ion batteries.
“The goal is to make this a universal recycling process for all cathode materials,” Chen stated. The group is likewise dealing with a procedure to recycle abject anodes, such as graphite along with other products.
Chen is likewise teaming up with UC San Diego nanoengineering teacher Shirley Meng, who is the director of the Sustainable Power and Energy Center, to determine subtle modifications in the cathode microstructure and regional structure utilizing high-resolution tiny imaging tools.