WARF TECHNOLOGIES

UW-Madison researchers have developed a new electrochemical method to recover Li from spent lithium-ion battery (LIB) materials as high purity Li-containing chemicals with a high yield in an efficient and environmentally benign manner. LiFePO4 is the most inexpensive, relatively non-toxic, and thermally stable cathode material that is widely used in electric vehicles (EVs). In a Li removal/recovery cell, Li+ is first leached from spent LiFePO4 electrodes in a phosphoric acid solution whose composition is optimized for efficient Li leaching (pH < 3). Then, Li+ and phosphate in the solution are selectively stored in a Li-storage electrode and a phosphate-storage electrode, respectively, by the operation of the Li removal cell. Once the electrodes are saturated with respective ions, they release these stored ions in a different solution whose pH (> 5) is adjusted so that the released Li+ and phosphate are precipitated as pure Li3PO4(s), which can be used to make new LiFePO4 electrodes. The operation of these cells proceeds at ambient pressure and temperature and produces Li3PO4 by a simple two-step process with minimal requirement of chemicals and minimal generation of waste.

For More Information About the Inventors

• Kyoung-Shin Choi

Tech Fields

• Clean Technology : Energy storage, delivery & resource efficiencies
• Clean Technology : Monitoring, remediation & waste reduction