Full utilization of the high storage capacity of conversion electrode materials as tin oxide (SnO₂) in lithium‐ion batteries is hindered by the high volumetric expansion due to the high lithium storability which can lead to major cell damage and consequent safety issues. To overcome this issue, two promising approaches, nanostructures and buffer layers, are combined and evaluated. SnO₂ nanowires (NWs) are coated with an aluminum oxide (Al₂O₃) buffer layer to investigate the combination SnO₂–Al₂O₃. Strong differences in the crystallinity after cycling between the SnO₂/Al₂O₃ core/shell NW‐based heterostructure and uncoated SnO₂ NWs based on detailed structural analysis are shown via transmission electron microscopy (TEM) and determination of the elemental distribution of tin, oxygen, lithium, and aluminum via energy‐dispersive X‐Ray spectroscopy and energy‐filtered TEM in the as‐prepared and postmortem nanostructures. The core/shell NWs exhibit two different states after charge/discharge cycling, amorphous or crystalline, depending on the NW diameter; for the uncoated SnO₂ NWs, only an amorphous postmortem structure is found. Additionally, differences in the elemental distribution for the amorphous and crystalline postmortem SnO₂/Al₂O₃ core/shell NWs, especially for tin, are measured. Consequently, the structures and effects of the Al₂O₃ coating on the lithiation behavior of SnO₂ NW‐based heterostructures are discussed.