Batteries are incredibly useful technologies and key to many sustainable technologies. Unfortunately, the chemicals in batteries pose a huge environmental problem themselves. But a new study by Xiao et al (2021) may have a solution or at least an improvement over the current situation.
Ultrasound is a relatively common imaging technology. It uses sound waves that travel into the area and then bounce back when they hit a boundary layer between different tissues or materials. Xiao et al used ultrasound to increase the mass transfer of metals in electric car batteries. Mass transfer is when you change the location of the masses. This can be done through processes like evaporation. In this case, the ultrasound waves create microbubbles which collapse and raise the temperature to around 5000 K. As a result of this change, the metals can be extracted more easily using milder acids like citric and acetic acids rather than the harsh chemicals like sulphuric acid that are currently used.
This method saw significantly more of the metals being reclaimed, an average of 97%, with fewer toxic chemicals. This bodes well because the extraction of these metals from natural sources often causes its own environmental degradation and has potential social implications. By reducing the need for harsh chemicals during recycling and improving recovery rates the environmental impact of electric cars may be improved significantly.