Mechanical properties of commercial copper current-collector foils

Abstract

The functionality and reliability of the current collector (CC) are crucial to design and fabricate electrodes for Li-ion batteries because the CC serves as the bridge between external electronic and internal Li-ion transports. Therefore, understanding the mechanical behavior of CCs is of great importance for battery design and manufacturing. In this paper, we report the measured values of the elastic moduli of six commercial copper current-collector (CCC) foils. Measurements were performed using three techniques: a standard microtensile testing machine equipped with a laser sensor, dynamic mechanical analysis (DMA), and nanoindentation. For electrolytic copper (E-Cu) foils, we find elastic moduli of approximately 70 GPa, and for rolled copper (R-Cu) foils, we find elastic moduli of approximately 50 GPa. Values for yield strength and fracture strength of the foils were determined from load-deflection curves; the results are consistent with values recommended by the manufacturer. Crystalline structures, which influence values for the elastic moduli of the foils, were investigated by X-ray diffraction. Surface morphologies of the foils before testing and the fracture morphologies after testing were studied by scanning electron microscopy. Figure 4 Yield strength of CCC foils as a function of thickness Figure 5 Fracture strength of CCC foils as a function of thickness. The inset is the real picture of sample after microtensile test.

Longitudinal and Transversal Elasticity of Natural and Artificial Materials for Musical Instrument Reeds

“…The loading curves are shown in Figure 3 . For copper, we found an elasticity modulus of 121 GPa, with a literature value between 117 GPa and 133 GPa [ 10 , 11 , 12 ].…”

Solid‐State Lithium Batteries: Bipolar Design, Fabrication, and Electrochemistry

“…[39][40][41] A metallic current collector in LIBs in contact with the electrodes and a reactive fluorine-based non-aqueous electrolyte is considerably prone to corrosion. [45][46][47][48] The corroded current collector may cause uneven power delivery and/or to complete battery failure. Even though the corrosion phenomena in SSLBs are expected to be different from those in liquid electrolyte-based LIBs, the material requirements for BPs in SSLBs are more stringent than those for current collectors in monopolar LIBs.…”

“…In terms of electronic conductivity, chemical/electrochemical stabilities, mechanical properties, cost, and abundance, however, the choice is limited to the materials implemented in LIBs, e. g., Al, Cu, Ni, and alloys, including stainless steel and Inconel. [45][46][47][48] Al is an inexpensive, highly conductive material that is readily available in the form of a thin foil with high purity, and it is most widely utilized as a current collector for PEs. Al is usually covered with thin protective oxide films and hence exhibits high corrosion resistance at high potentials (~5.0 V vs. Li/Li + ) in various electrolyte systems.…”

“…In particular, one of critical issues of the bipolar SSLBs is the corrosion susceptibility of the BP exposed to large potential gradients, i. e., highly reductive (~0 V vs. Li/ Li + ) and highly oxidative (> 4.0 V vs. Li/Li + ) conditions on the NE and PE, respectively. [45][46][47][48] To circumvent this problem, multiple cells may be stacked in a "side-by-side" design in which only the edges of the BPs touch each other, thus leading to a reduced contact area. [42,49] However, this configuration is not considered "true"-bipolar, but rather "pseudo"-bipolar, which is beyond the scope of this review.…”

Current Collectors for Flexible Lithium Ion Batteries: A Review of Materials

“…It has been reported that the physical and chemical properties of the current collector can influence the performances of LIBs [5][6][7]. Copper foil current collectors show tensile strength over 245 MPa and elongation of 5% for thicknesses ranging from 12 to 35 µm [8]. Based on electrochemical analysis, aluminum foil is the most suitable current collector for the cathode [9].…”