Highly (111) Textured Copper Foils with High Hardness and High Electrical Conductivity by Pulse Reverse Electrodeposition

Abstract

The present article reports the pulse reverse electrodeposition of highly ͑111͒ textured freestanding copper foils, in an additive-free electrolyte, exhibiting hardness as high as 2.2-2.7 GPa with an electrical conductivity equal to that of bulk copper. The short anodic pulse applied and the absence of organic additives allowed the formation of highly dense foils with room-temperature stability in terms of mechanical and electrical properties. The process involves a fast electrodeposition method with a deposition rate of 25-50 m/h. The ͑111͒ texture and twin boundaries contribute to the high hardness and better electrical conductivity of the copper foils.

Controllable Crystallographic Texture in Copper Foils Exhibiting Enhanced Mechanical and Electrical Properties by Pulse Reverse Electrodeposition

“…During the deposition, development of (111) texture is also favored at large current densities applied at low temperatures due to 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 10 minimization of the surface/interfacial energy during growth process. Our previous study has also revealed that (111) texture is favorable at high current densities with short forward pulses and short reverse pulses 31 . In addition, low deposition temperatures are suggested in order to minimize the surface and interfacial energies, for twin boundary formation, good surface properties and to reduce the usage of additives 67 .…”

“…In order to evaluate this, the copper foils are stored at room temperature for six months. Subsequently hardness of these foils was measured and it was found that the hardness has decreased by only 5% in comparison to its as-deposited value 31 . This constancy of hardness at room temperature is probably due to the absence of grain growth 68 .…”

“…Lu et al, and Chen et al, reported about 10 times increase in the strength compared to that of bulk copper, while an electrical resistivity of 1.75±0.02×10 -6 Ω-cm was achieved by pulse electrodeposition (PED) with (101) texture 1,49 . Preparation of highly (111) textured copper foils with high hardness and electrical conductivity by PRED has been reported by us previously 31 . In the present paper, for the first time we report a novel approach involving a rapid PRED technique in order to manipulate the (111), (100) and (101) textures, CSLΣ3 coherent twin boundaries and the grain size in order to obtain enhanced hardness and required electrical properties in copper using an additive-free electrolyte.…”

“…Numerous research efforts have been devoted towards the preparation of copper foils with high hardness and electrical conductivity. As part of these studies, highly textured and twinned copper foils with enhanced mechanical and electrical properties were synthesized by electrodepositionusing DC and PED techniques 23,[30][31][32][33][34][35][36][37] (various reports on usage of DC and PED to deposit copper in various forms with varied microstructure and texture are summarized in supporting information).…”

Mechanical properties of commercial copper current-collector foils

“…Note that the 35-µm-thick R-Cu CC foil shows a texture-like structure formed along a certain direction because it only has a strong peak in the (220) plane. According to the results of Sarada et al 24 , the foils with a strong peak in the (111) plane had high electrical conductivity, which is the key factor for use as CC in LIBs. This may be a reason why most commercial industries often select E-Cu foils and not R-Cu foils for anode CCs.…”