Copper–tin porous hybrid microstructures formed via dynamic hydrogen bubble templating and electroless deposition. Part I: preparation, anodic behavior, and chemical composition

Abstract Free-standing copper–tin hybrid porous layers are fabricated by combining the dynamic hydrogen bubble template technique with electroless tin deposition. The characteristic morphology of the porous copper microstructure and its homogeneity on a large scale are preserved after the Sn deposition, ensuring optimal ionic transport throughout the layer when applied as an anode for rechargeable batteries. The hybrid material shows a highly oxidized near-surface chemical composition. However, the XPS depth profiling reveals a significant presence of metallic tin, accompanied by considerable amounts of elemental copper within the bulk. These findings indicate depletion of the Sn phase along the layer thickness and alloy formation between both elements. The electrochemical characterization revealed two main oxidation regions, at low potential (E = − 0.38 V), associated with the formation of Sn(II) and at high potential (around − 0.1 – 0 V), corresponding to Sn-Cu dealloying and further Sn(II) oxidation. XPS analysis corroborates these results, indicating the formation of a passive SnO x layer during the anodic potential polarization, partial Sn dissolution, and dealloying of the Sn-Cu intermetallic structure. The electrode fabrication approach allows the possibility for adjusting the pore size, regulation of Sn quantity, and further chemical modification of the interface, which would benefit the application of this material type for advanced electrochemical energy storage. Graphical Abstract