Microwave Pre-Treatment of Spent Lithium-Ion Battery Electrode Materials: Mass Loss and Morphological Response

The growing volume of spent lithium-ion batteries has increased the need for simple and effective pre-treatment steps that improve material liberation before downstream recycling. In this study, dismantled electrode materials recovered from spent commercial lithium-ion battery cells were subjected to microwave pre-treatment after removal of the casing and separator. Microwave irradiation was conducted at 440, 620 and 800 W for exposure times of 5, 10 and 20 minutes (min). The response of the electrode materials was evaluated using percentage mass loss and visual morphological assessment of delamination, powder formation, foil distortion and structural fragmentation. Mass loss ranged from 4.36 to 12.14%, depending on the microwave condition. At 440 W, mass loss remained within a narrow range of 5.05 to 5.35%, indicating mild thermal action and early removal of readily volatile constituents. At 620 W, mass loss decreased slightly with increasing residence time, which is attributed to the heterogeneous distribution of electrode constituents in the dismantled material. At 800 W, mass loss increased from 5.04% at 5 min to 12.14% at 20 min, showing a stronger thermal response and greater removal of volatile or organic fractions. However, visual inspection showed that the most severe condition also promoted brittleness, wrinkling and thermal distortion of the electrode fragments. The results indicate that microwave pre-treatment can assist the physical disintegration and partial liberation of spent battery electrode materials, but treatment severity must be controlled to avoid excessive thermal damage. For conservative material preservation, 440 W for 20 min gave visible delamination with limited foil distortion, while 800 W for 10 min provided greater mass reduction but with a higher risk of thermal damage. The study provides a process screening basis for selecting microwave pre-treatment windows before flotation, leaching or other recovery operations.