Small-Size Graphene-Enabled Corrosion-Resistant Ultra-Thin Copper Foils Fabricated by Direct-Current Electrodeposition

The corrosion degradation of ultra-thin copper foils remains a critical challenge for maintaining their long-term structural stability under aggressive electrochemical environments. In this work, small-size graphene (sGr) was incorporated into ultra-thin copper foils through a direct-current electrodeposition strategy to improve corrosion resistance. Compared with conventional graphene, the reduced graphene size facilitated a more uniform dispersion within the copper matrix and effectively regulated the surface morphology and crystallographic texture of the deposited copper foils. The resulting sGr/Cu composite foil exhibited reduced surface defects, enhanced (220) preferred orientation with a texture coefficient of 83.7%, and improved electrochemical corrosion resistance in 3.5 wt.% NaCl solution. Specifically, the sGr/Cu foil showed a more positive corrosion potential (−0.099 V), a lower corrosion current density (3.781 × 10−5 A·cm−2), and a higher charge transfer resistance (3789 Ω·cm2) compared with pure copper foil. The enhanced corrosion resistance was attributed to the synergistic effects of improved graphene dispersion, graphene-induced barrier effects, surface morphology optimization, and strengthened graphene/copper interfacial interactions. X-ray photoelectron spectroscopy analysis suggested the presence of Cu–O–C-related interfacial interactions, which may contribute to improved interfacial stability and corrosion protection. This work provides an effective strategy for designing corrosion-resistant ultra-thin copper foils through graphene size regulation and interface engineering.