This method helps to recover 100 percent of aluminum and 98 percent of lithium in electric car batteries, while also reducing the loss of valuable raw materials such as nickel, cobalt and manganese.
Researchers at Chalmers University of Technology in Sweden have now come up with a new and efficient way to recycle metals from spent electric car batteries . This method helps to recover 100 percent aluminum and 98 percent lithium in electric car batteries.
Additionally, losses of valuable raw materials such as nickel, cobalt and manganese are reduced. The process does not require any expensive or harmful chemicals because the researchers use oxalic acid, an organic acid found in plants. This research has been published in the journal Separation and Purification Technology .
Lee Roquette, a researcher in the department of chemistry and chemical engineering at Chalmers University, says that, until now, no one has managed to find the perfect way to separate lithium as well as remove aluminum using oxalic acid. Because all batteries contain aluminum, we need to be able to remove it without damaging other metals.
In Chalmers University’s battery recycling lab, Rouquet and research coordinator Martina Petranikova show how the new method works. The laboratory uses material from car battery cells and fume cupboards. It takes the form of a finely ground black powder dissolved in oxalic acid, a transparent liquid.
Roquette gave the example of a mixer used in the kitchen, saying that it produces both powder and liquid. Although it seems as simple as making coffee, the exact process is a unique and recently published scientific breakthrough. By tweaking temperature, mixing and timing, researchers have come up with a remarkable new recipe to use oxalic acid, which is environmentally friendly and found in plants like rhubarb and spinach.
We need alternatives to inorganic chemicals, says Martina Petranikova, associate professor in the department of chemistry and chemical engineering at Chalmers University. One of the biggest hurdles in today’s processes is the removal of residual materials like aluminum. This is a unique approach that can provide new options to the recycling industry and help solve the problems hindering growth.
The aqueous-based recycling method is called hydrometallurgy. In conventional hydrometallurgy, all the metals in an EV battery cell are dissolved in an inorganic acid. Then, you remove “impurities” like aluminum and copper. Finally, you can recover valuable metals like cobalt, nickel, manganese and lithium separately.
Even though the amount of residual aluminum and copper is low, it requires multiple purification steps and each step in the process can cause loss of lithium. With the new method, the researchers reverse the order and recover lithium and aluminum first. Thus, they can reduce the wastage of valuable metals required to make new batteries.
The latter part of the process, in which the black mixture is filtered, is reminiscent of making coffee. While aluminum and lithium dissolve into liquid, other metals remain “solid.” The next step in the process is to separate the aluminum and lithium.
Because the metals have very different properties, we don’t think it would be difficult to separate them, says Rouquet. Our method is a promising new path for battery recycling, a path that certainly warrants further exploration. Petranikova says that, while this method can be scaled up, we hope it will be used in industry in the future.
Petranikova’s research team has spent several years conducting cutting-edge research into the recycling of metals found in lithium-ion batteries . The team has been involved in various collaborations with companies to develop electric car battery recycling.
