Switching from gas-powered cars to electric vehicles is one way to reduce carbon emissions, but building the lithium-ion batteries that power those EVs can be an energy-intensive and polluting process itself. Now researchers at Dalhousie University have developed a manufacturing process that is cheaper and greener.
“Making lithium-ion cathode material takes a lot of energy and water, and produces waste. It has the biggest impact on the environment, especially the CO2 footprint of the battery,” says Dr. Mark Obrovac, a professor in Dalhousie University’s Departments of Chemistry and Physics & Atmospheric Science. “We wanted to see if there were more environmentally friendly and sustainable – and less expensive – ways to make these materials.”
Most electric vehicle batteries use lithium nickel manganese cobalt oxide (NMC), with the elements mixed in the crystal structure of the cathode. They are typically made by dissolving the elements in water then using the crystals that form when the elements come together as a solid. That process takes a lot of water – which then has to be treated to clean it – and energy, which is the main source of the cost and carbon footprint of the batteries. Using the Canadian Light Source (CLS) at the University of Saskatchewan, Obrovac and his team investigated whether they could use an all-dry process to get the same results while saving energy, water, and money.
Their work has been published in two papers, in ACS Omega and the Journal of the Electrochemical Society.
“We wanted to see, can you get the same quality if you take dry materials and combine them using simple processes that you’d find in any large-scale factory and heat them up,” he says. “And under what conditions can you do that to get commercial-grade material while cutting out the water and the waste?”
Cathodes made from dry materials are sometimes not as homogeneous as those made in water, so the team tried a variety of methods using different oxides and heating regimes under different temperatures and pressures to determine what worked best.
Read more on CLS website
Image: A student making lithium batteries in a glove box for the evaluation of new cathode materials.
Credit: CLS