Highly Selective Extraction of Lithium from Spent NCM Cathode Powder Reconstructive Electrode by Acid-Free Electrochemical Process

The environmentally friendly and efficient recovery of valuable metals from spent lithium-ion batteries (LIBs) can mitigate environmental pollution and enhance resource utilization efficiency. This study proposed a process for coating spent NCM cathode powder (LiNi x Co y Mn z O2) on graphite sheets for the electrochemical leaching of lithium. Direct electrooxidation method for leaching from the prepared electrode sheets can achieve the selective leaching rate of Li+ close to 100% in Na2CO3 solution. In addition, the electron transfer mechanism was investigated during the electrooxidation process. Under optimal conditions, the same electrolyte solution was electrolyzed 40 times to enrich lithium by replacing fresh electrode sheets. Since there was almost no leaching of other metals, there was no need to add precipitants to obtain battery-grade Li2CO3 through evaporation and concentration. This strategy not only circumvents the risk of secondary pollution caused by the use of a large number of leaching agents but also shortens the lithium recycling process.