Pyro- and hydrometallurgical processes or a combination of both have been widely established so far for the recycling of lithium-ion batteries. However, these methods are harmful for the environment e. g. due to high CO2 emissions. From these two, hydrometallurgy is a selective method to obtain the metals, yet, requires a large amount of chemicals. Reducing the amount of used chemicals is the aim of many researchers, but therefore understanding the mechanism of leaching is necessary.
To better understand leaching limitations, we show a solid phase investigation of leached LCO particles combining surface analysis (XPS and SEM) with bulk analysis methods (ICP-OES and XRD). Sulfuric acid is used as the leaching agent. LCO undergoes different structural phase transitions when leached with sulfuric acid due to strong delithiation, which stops further leaching processes. So, limitation of leaching and the occurring structural phase transitions with its lithium to cobalt ratio is connected to each other.