- Lithium serves an unparalleled role for high energy-density storage applications and is vital for the continued advancement of the world economy. However, global supply is heavily reliant on lithium deposits situated in select locations, creating unpredictability in the price and concerns for the sustained production of the resource. Additionally, future demands for applications in the small electronics, automotive, and renewable energy industries threaten to place further strain on the lithium supply. Thus, the implementation of lithium battery recycling methods is critical meet this expected surge in demand for lithium-based battery technologies. Several economic obstacles and safety considerations have halted the advancement of these necessary recycling techniques. A prominent barrier to recycling efforts revolves around the reactivity of active lithium compounds that remain in used lithium batteries. As a result, significant safety precautions must be taken when handling and transporting lithium-based batteries, adding to the costs associated with recycling methods. Current research has been dedicated to developing a passivation method for the remaining active lithium in used cells, seeking to lower the classification, and subsequently the costs, associated with these materials. Analytical techniques, which quantify the amount of active lithium separate from compounds associated with passivation, require development to prove the functionality of passivation methods. This study focuses on two potential chemistries, a redox titration with triiodide and a pH titration with a strong acid, which serve as cost-effective and robust methods for quantifying active lithium. Lithium was determined to be a suitable reductant for triiodide to iodide by UV/vis analysis, with the characteristic triiodide peaks disappearing over time when in the presence of lithium metal. However, significant drawbacks resulting from the large difference in molar masses between lithium and triiodide and the competing reductant properties of copper, a common material used for anode current collectors, render the method impractical for quantifying the amount of active lithium in lithium batteries. Preliminary studies for the pH titration exhibited positive results, with repeated success in using sulfuric acid to accurately measure the amount of lithium hydroxide and lithium methoxide present in solution, which would result from the reaction of lithium metal with water and methanol, respectively. Unforeseen circumstances, however, halted the continuation of the pH titration method development and further studies around potential contaminants and undesired reactions must be conducted to determine the feasibility of the technique.
Key Words: Lithium Content, Lithium Battery Recycling, Lithium Quantification, pH Titration, Redox Titration