Despite the tremendous progress made towards understanding the alloying and dealloying mechanisms in new lithium-ion battery anode materials like silicon and tin, the large volumetric changes that are intrinsic to these materials seem difficult to overcome in the absence of additional coating or nano-structuring methods that inherently increase cost and decrease capacity. Thus, the most likely candidate to replace graphite in the future may not be that which has the absolute highest capacity, but one that has an optimal balance between cost, capacity and processing complexity. Aluminum has significant advantages over other alloy anodes because of its low cost, high abundance, and wide variety of film and foil processing options. If the high theoretical capacity of aluminum (ca. 1 Ah/g or 2.7 Ah/cm3) can be even partially realized, it would be a significant improvement over conventional carbon-based anode materials. Despite the great promise of aluminum as an anode material in lithium-ion batteries, it typically suffers from fast capacity fading upon cycling. Unfortunately, the depth of knowledge concerning the degradation mechanisms of aluminum-based anode electrodes is still scarce. In this work, aluminum and aluminum-based alloys are used to investigate the lithiation, delithiation, and degradation mechanisms in this industrially-friendly materials system. Various in situ and ex situ microscopy methods are employed, along with conventional electrochemical cycling and characterization techniques, to investigate the phase transformations associated with the Al-Li system, in particular from the α-phase (Al) to the β-phase (AlLi), during charging and discharging. Furthermore, substrate curvature methods are used which allow for quantitative insights into the mechanical properties of the film as a function of lithium content. Scanning electron microscopy investigations of the surface morphological evolution of the aluminum-based thin-film electrodes indicate that irreversible damage depends more on the depth of discharge than on the volume contraction during delithiation [1]. These results suggest that aluminum-based anodes may be highly suitable for future lithium-ion battery anodes and implications for commercially available aluminum foils as anode materials will be discussed. [1] M. H. Tahmasebi, D. Kramer, R. Mönig, and S. T. Boles, “Insights into Phase Transformations and Degradation Mechanisms in Aluminum Anodes for Lithium-Ion Batteries,” J. Electrochem. Soc., vol. 166, no. 3, pp. A5001–A5007, 2019.