EV battery cathode recycled with less energy and hazardous chemicals

Their method uses organic acid such as ascorbic acid as a leaching agent and has been tested on cathode material from a first-generation Nissan Leaf battery cell. 

The results of this testing, published today (October 20, 2023) in ChemRxiV, demonstrated that ascorbic acid selectively leaches low-value electrode material (lithium manganese oxide), and leaves the higher-value nickel and cobalt-based material in a solid state.

Currently, battery recycling concentrates on recovering elements by dissolving battery cathodes using strong acids, which present disposal challenges. It relies also on the initial shredding of the batteries, which combines components and creates a mixture of chemistries that can only be separated by chemical processes.  

The new leaching method was developed by Professor Peter Slater, Professor Paul Anderson, and Dr Laura Driscoll from Birmingham’s School of Chemistry and has been patented by Birmingham University Enterprise. Their research is part of the ReLiB (Recycling and Reuse of EV Lithium-ion Batteries) project, a multi-institution consortium of researchers funded by the Faraday Institution and led by Birmingham University.

In a statement, Professor Slater said: “Battery chemistry, and cathode chemistry in particular, is constantly evolving to meet the demand for greater energy density. However, battery recycling has remained relatively static, and has focused on breaking down the cathodes into their individual element components particularly when recycling mixed chemistries, which loses a lot on the internal value of the cathode material.

“The challenge with recycling mixed chemistries is to separate out the low and high-value materials. Our method removes the low-value material, while leaving the high-value material in a solid state, so it can be directly recycled, maintaining its high value.” 

The research team started their research by looking at what is going into recycling chains. They chose a battery from a Nissan Leaf, as this car was the first mass-market electric vehicle, and both cars and batteries will be among the first to enter recycling chains, and the recycling industry.  

Professor Slater said: “Our method will reduce the cost and number of steps to recover cathode materials, so they can be remanufactured and put back into new batteries, with minimal environmental footprint.” 

The research team is now working on scaling up this approach, and is looking for long-term partners for pilot studies, deliver this technology to existing infrastructure, or collaborate on further research to develop the system.