Researchers from Technische Universit?t Darmstadt, Universit?t Stuttgart, Justus-Liebig-Universit?t Giessen, and Universit?t des Saarlandes have developed a two-step recycling approach for all-solid-state Li-ion batteries (lithium ASSBs). The process, which uses citric acid as the leaching agent to separate and recover the individual components, is presented in an open-access paper in the journal ChemSusChem.

Flow chart of the recycling process. Waidha et al.

With the current global projection of over 130 million electric vehicles (EVs), there soon will be a need for battery waste management. Especially for all-solid-state lithium-ion batteries (lithium ASSBs), aspects of waste management and circular economy have not been addressed so far. Within such ASSBs, the use of solid-electrolytes like garnet-type Li6.5La3Zr1.5Ta0.5O12 (LLZTO) may shift focus on strategies to recover not only the transition metal elements but also elements like La/Zr/Ta.

—Waidha et al.

Applying the process to a model cell consisting of Li4Ti5O12 (LTO) anode, Li6.5La3Zr1.5Ta0.5O12 (LLZTO) garnet electrolyte and LiNi1/3Mn1/3Co1/3O2 (NMC) cathode, the researchers observed that by adjusting the concentration of citric acid, it was possible to separate the materials from each other without strong mixing of individual phases and also to maintain their principle performance characteristics.

Thus, they concluded, the process has a potential for upscaling and can guide towards considering separation capability of battery components in the development of lithium ASSBs.