Copper Foil Surface Research Articles

Corrosion resistance and forming mechanism of phytic acid conversion film on copper foil prepared by electrolysis

In this paper, the phytic acid conversion film was prepared on copper foil by electrolysis for the first time. Its morphology and chemical composition were characterized by SEM, EDS, FTIR and XPS, and its corrosion resistance was evaluated using electrochemistry. Finally, the formation mechanism of the phytic acid conversion film on the surface of copper foil and its corrosion resistance mechanism were revealed by quantum chemical calculations and molecular dynamics simulations. The results show that the phytic acid conversion film on the surface of copper foil prepared by electrolysis is uniform and dense. The electrochemical impedance value of copper foil in 3.5 wt% NaCl solution increased from 3956 Ω·cm2 to 24828 Ω·cm2 after the preparation of phytic acid conversion film, and the protection efficiency reached 91 %. During the electrolysis process, copper atoms are oxidized into copper ions, which can be coordinated with phytate ions to form negatively charged complexes. Under the action of electric field force, these complexes move toward the anode copper foil, and finally adsorbed on the surface of the anode copper foil to form phytic acid conversion film. The molecular dynamics show that the adsorption configuration of the phytic acid molecule on Cu(111) surface changed from perpendicular to parallel, and the binding energy increased from 234.87 kJ/mol to 354.23 kJ/mol after applying an electric field, Therefore, the phytic acid conversion film prepared on the surface of copper foil by electrolysis has good corrosion resistance. This study provides a new method for the rapid preparation of phytic acid conversion film with excellent performance on metal surface.

In-situ construction of high-performance artificial solid electrolyte interface layer on anode surfaces for anode-free lithium metal batteries

The electrochemical performance of lithium metal batteries (LMBs) was hampered by the uncontrolled growth of lithium (Li) dendrites. To address this issue, the extensive application of artificial solid electrolyte interphase (SEI) coatings on anode surfaces emerged as an effective solution. Electrospinning, as an innovative technique for fabricating artificial SEI layers on the surface of copper (Cu) foil, effectively mitigated Li volume strain during cycling. In this study, an electrospun organic–inorganic composite nanofiber membrane was in-situ fabricated on Cu foil, serving as an artificial SEI layer (CuWs) for anode-free LMBs (AF-LMBs) to enhance battery performance. Lithiophilic polyvinylpyrrolidone was used as the polymer matrix, and Cu nitrate served as the inorganic functional particles capable of in-situ redox reactions. The CuWs with their three-dimensional (3D) network structure accommodated electrode volume changes and suppressed Li dendrite growth during Li deposition and stripping. Additionally, CuWs facilitated the in-situ generation of Li nitrate (LiNO3), which helped stabilize SEI layer and enhance Li utilization. The release sites of LiNO3 on the nanofibers enabled the in-situ reduction of metallic Cu, providing nucleation sites for Li deposition and forming the 3D ion–electron hybrid conductive networks. This CuWs layer reduced interfacial resistance and nucleation barriers, promoting uniform Li+ distribution on the anode surface. Li-Cu cells incorporating CuWs exhibited remarkable cycling stability, enduring over 460 cycles at 1.0 mA cm−2 and 1.0 mAh cm−2 with an average Coulombic efficiency of over 98.6 %. In Li-poor cells, the LFP|PE|CuWs achieved stable cycling for more than 30 cycles at 1.0 C, with a capacity retention rate of 92.0 %. These findings demonstrated that the CuWs membrane significantly enhanced the electrochemical performance of Li-poor cells and provided a novel artificial SEI protective strategy for advanced AF-LMBs with high energy density.

In-situ formed Li2O and an artificial protective layer on copper current collectors to enhance the cycling stability of lithium metal anode batteries

In this study, we present a facile one-step method for the thermal treatment of commercial Cu foils, leading to the growth of Cu2O and CuO nanoparticles in an air atmosphere, resulting in the coating of an artificial protective layer on the copper foil surface. The as-prepared CuO/Cu2O nanoparticles exhibit a spherical morphology, providing ample active sites to improve uniform lithium plating and cyclic stability by building a highly stable In-situ Li2O-rich solid-electrolyte interphase (ISEI). The artificial solid-electrolyte interphase (ASEI) protective layer contains graphene oxide (GO) as a filler with PVDF-HFP and lithium Nafion polymers, enhances Li+ ion migration, which reduces volume expansion and stabilizes the interface, preventing unwanted side reactions between active lithium and electrolytes by facilitating controlled lithium deposition underneath. For integration into an anode-less full cell based on a 2032-type coin cell, alongside a lithium iron phosphate (LFP) cathode, the ISEI oxide layer was grown on a Cu foil electrode (denoted as Cu-30) via a thermal treatment at 320 °C in air for 30 min and coated ASEI (denoted as GO@Cu-30). This cell demonstrated remarkable electrochemical performance. After 250 cycles at 0.5C, it exhibited an outstanding capacity retention of 93.12 % with 99.92 % CE, significantly surpassing the performance of a bare Cu foil, which showed a capacity retention of only 9.54 % with CE of 98.77 %. This work highlights the potential of a simple thermally treated Cu foil as a current collector to overcome the Anode-less lithium metal battery (ALMB) challenges associated with high-energy-density demand.

Construction of chromium-free passivation film of pomelo peel extract on the surface of lithium-ion battery copper foil and study on anti-corrosion mechanism

Passivation treatment is the last key process to ensure the service life of copper foil for lithium-ion batteries. Although chromic anhydride commonly used in industry has an efficient passivation effect, it can threat human health and the environment. Herein, an environmentally friendly passivator is prepared from pomelo peel by a simple and economical solution extraction method, which makes copper foil have good anti-corrosion properties in air, chlorine-containing solution, and organic electrolyte. Electrochemical methods and X-ray photoelectron spectroscopy (XPS) confirm the potential of pomelo peel extractant (PP) to replace chromic anhydride as a passivating agent for copper foil. The interaction mechanism between PP and copper foil is analyzed by adsorption models, and the efficient passivation behavior of PP for copper foil is consistent with the Langmuir model. Density Functional Theory (DFT) calculations of the naringin (main component of PP) is performed to further reveal the protection mechanism of PP on copper foil. In addition, the copper foil treated by PP still has excellent electrochemical performance as lithium-ion battery current collector, indicating that the presence of PP not only protects the copper foil from corrosion, but also does not affect the conductivity of the copper foil. This research provides a new insight into the chrome-free passivation of copper foils, which is in line with the development concept of green production.

Effect of Different Surface States of Electrolytic Copper Foils on the Performance of Lithium-Ion Batteries

Currently, the field of lithium-ion batteries faces an urgent challenge, which is how to effectively inhibit the growth of dendrites, thereby improving the coulombic efficiency of plated/stripped lithium on copper foils and enhancing the cycling stability of the batteries. In this paper, the surface of copper foil is roughened by annealing post-treatment, which in turn improves the interfacial adhesion between the copper foil and the active material. This treatment helps the anode current collector to form a flat graphite electrode sheet and a uniform solid electrolyte interphase film, reducing the growth of lithium dendrites as well as extending the cycle life of the batteries. Among them, the annealed electrode exhibits extremely high roughness (0.533 μm) and elongation (9.91%), with the initial discharge capacity of the prepared lithium battery reaching as high as 384.22 mAh g−1. It also maintains good cycling performance at different rates, which confirms the gain effect of surface roughening on battery capacity.

Study on the corrosion resistance of new reticulated organic polymerized film on copper foil surface

In response to the policy of energy saving and emission reduction, the field of new energy vehicles is booming, and along with it, the technical requirements for lithium-ion batteries are becoming more and more stringent. Electrolytic copper foil, as the anode collector material of lithium batteries, seriously affects the progress of lithium technology, and electrolytic copper foil with high corrosion and oxidation resistance is the key to ensuring its performance. Experimentally, the BTA-Si passivation film layer was constructed on the surface of electrolytic copper foil by compounding benzotriazole (BTA) and silane coupling agent (JH-M902) with an easy-to-operate chemical impregnation method. The results of electrochemical analysis and characterization showed that JH-M902 hydrolyzed to produce Si-OH and then dehydrated and polymerized with Cu-OH to form Si-O-Cu or partially dehydrated and polymerized with each other to form Si-O-Si, which formed an intertwined organic reticulation film on the electrolytic copper foil. At the same time, BTA and copper oxides form a BTA-Cu complex, which is adsorbed and perpendicular to the copper foil. The combination of the two can not only make up for the gap in the organic mesh layer but also anchor the mesh layer, thus inhibiting its desorption in harsh external environments. Immersed in 3.5 wt% NaCl, the self-corrosion current density (icorr) of BTA-Si passivation film is only 1.115 × 10−7 A/cm2, and the corrosion inhibition rate as high as 99.56 %, which is far better than that of the single BTA and Si passivation film. In addition, the BTA-Si passivation film is smooth, dense, and thin, which significantly improves the corrosion resistance of copper foil without changing its original structure.

Preparation and photoelectric properties of photoanode based on N-TiO2 deposited on copper electrode

Reducing the photoresistance of a photoanode is one of the key points to improving the electron transfer rate of dye-sensitive solar cells. With TiO2 sol acting as the titanium source and urea serving as the nitrogen source, the N-doped TiO2 composite electrode material was prepared by electrodeposition on the surface of copper foil. The results show that the N-TiO2/Cu electrode prepared by electrodeposition doping at a voltage of 1.0 V has a low photoresistance and bias of 0.25 V difference with the Cu electrode under visible light. The photocurrent is increased by 270 % in comparison with that of the TiO2/Cu electrode. The N-TiO2/Cu electrode shows good photoresponsivity and has a good potential application in dye-sensitive solar cells.

Preparation of Ultra-thin Copper Foil with Low Profile and High Tensile Strength on Surface of 18-µm Carrier Copper Foil

Preparation of Ultra-thin Copper Foil with Low Profile and High Tensile Strength on Surface of 18-µm Carrier Copper Foil

A facile fabrication of an integrated electromagnetic interference shielding material with low electrical resistance based on silver particles/thermoplastic polyurethane composite@copper foil

As microelectronic technology advances, electronic devices have become faster and smaller. The electromagnetic radiation has negative effects on electronic device operation, how to eliminate the electromagnetic radiation has attracted much attention. Copper foil is the most commonly used and effective material for reducing electromagnetic radiation. In practical applications, it is necessary to use adhesive to fix it onto the surface of electronic devices. In this work, an integrated electromagnetic shielding material (AgPs/TPU@Cu hybrid film) was designed and prepared by a facile way, in which the mixture of silver particles (AgPs) and thermoplastic polyurethane (TPU) was cured to form a AgPs/TPU composite film on the surface of copper foil (Cu) by a one-pot heating press processing. The horizontal and vertical electrical resistances of AgPs/TPU composite film decreased to 0.2 Ω and 0.47 Ω at the AgPs loading of 38 wt%, respectively, and the corresponding thermal conductivity reached 0.81 W m−1 K−1. Moreover, the AgPs/TPU@Cu hybrid film at the AgPs loading of 38 wt% exhibited the maximum electromagnetic interference shielding effectiveness (EMI SE) value of 105 dB. This work provides valuable information about EMI shielding technologies for practical electronic applications.

Adsorption behavior and corrosion inhibition performance of tetrazolium derivatives on electrolytic copper foil surface

The development of chromate-based post-treatment methods has been limited mainly due to their toxicity, thus it is essential to explore environmentally friendly corrosion inhibitors for electrolytic copper foil. Herein, we evaluated three tetrazolium compounds (tetrazolium, 5-methyl-tetrazolium, and 5-amino-tetrazolium) as potential corrosion inhibitors for electrolytic copper foil, and explored their adsorption behavior onto the copper foil surface and their efficiency in inhibiting corrosion when exposed to a 3.5 wt% NaCl solution. Density functional theory calculations provide insights into the relationship between the molecular structure of the inhibitors and their corrosion inhibition efficiency. Furthermore, molecular dynamics simulations elucidate the adsorption behavior of these inhibitors on copper surfaces under solvation conditions. Notably, the 5-amino-tetrazolium molecule exhibits the most stable chemisorption on the Cu(111) surface. Finally, both electrochemical tests and antioxidation experiments confirm that ATZ is the most effective corrosion inhibitor with a corrosion inhibition efficiency (η) of 93.09%, consistent with theoretical predictions. This study highlights the potential application of the tetrazolium derivative 5-amino-tetrazolium in environmentally friendly and chromium-free post-treatment of electrolytic copper foil surfaces.

Thickness‐Dependence of 2D g‐C3N4 Artificial Interface Layers on Lithium Metal Deposition

AbstractConstructing artificial interfacial layers using 2D materials with tunable physicochemical properties is a promising strategy to fabricate high‐performance lithium (Li) metal anodes. However, their structural evolution during solid‐electrolyte interphase (SEI) formation and the thickness effects on charge transport remain elusive. Herein, 2D g‐C3N4 layers with varied thicknesses are developed on the surface of copper foil to evaluate the thickness effects of artificial SEI on Li metal deposition. It is demonstrated that a thin g‐C3N4 layer (≈2 nm) is rapidly decomposed and fractured under the impact of Li‐ion flux, while a thick g‐C3N4 layer (≈50 nm) impedes the transport of lithium ions and electrons simultaneously, hindering the Li metal deposition underneath. Notably, a g‐C3N4 layer with moderate thickness (≈10 nm) dominates in‐situ generation of stable g‐C3N4/Li3N hybrid artificial SEI and enables fast Li‐ion transport, which induces uniform Li deposition. The lithium electrode protected by the moderate‐thickness g‐C3N4 layer exhibits outstanding cycling stability with a high average Coulombic efficiency of ≈98.92% for over 380 cycles and enables stable cycling of full cell with 50% Li excess and lean electrolyte. This proof‐of‐concept study provides essential guidance for the application of 2D materials in constructing artificial SEI for Li metal anodes.

Bonding mechanism of laser joining of Poly-Ether-Ether-Ketone film which used for 5G antenna substrate to copper foil

The bonding of copper foil to Poly Ether Ether Ketone (PEEK) film has become a hotspot in research of the 5G RF (Radio Frequency) antenna substrate. In order to make the flexible copper clad laminates(FCCL) in the RF substrate thinner and more resistant to bending, there is an urgent need to replace the use of adhesive to join the copper foil to the PEEK film with a direct joining method. In this paper, a nanosecond laser was used to join the copper foil to the PEEK film effectively and the comprehensive property of joint was enhanced by the laser-textured grid on the surface of copper foil. The influence of textured grid on the adhesion work between copper foil and PEEK film was investigated. The interfacial morphology was observed and the result showed that molten PEEK completely filled the textured grid and formed a mechanical interlocking with copper. The complex reaction between Cu and PEEK was indicated by detecting the red-shift for the wave number of functional groups and the weak chemical bond between Cu and PEEK. Besides, the bonding mechanism was proved by density functional theory (DFT) calculation. The tensile shear strength of Cu/PEEK joint was significantly enhanced by laser texturing treatment, and the maximum force of joint with 0.4 mm-textured grid was increased by approximately 1.29 times compared to the untreated condition. This study proposes the use of nanosecond laser joining to replace the traditional use of adhesives to join copper foils to PEEK films.

Preparing CuBr particles onto the commercial copper foil surface to greatly boost the electrochemical performance of tin dioxide

Preparing CuBr particles onto the commercial copper foil surface to greatly boost the electrochemical performance of tin dioxide

Surface reconstruction of copper foil via electrochemical etching to proliferate CH4 production from CO2 electroreduction

Electrocatalytic CO2 reduction (eCO2R) to CH4 is a prospective approach for producing high value-added fuels. In this work, an effective approach was proposed by surface reconstruction using copper foil to facilitate eCO2R to CH4. The copper foil surface reconstruction was achieved via electrochemical etching in dilute phosphoric acid. Comprehensive characterizations suggested that the crystallinity and chemical binding energy states of the copper foil were well preserved after surface reconstruction, but the arrangement of copper atoms on the surface was adjusted. Etching time for 80 s was the most preferable condition, obtaining a uniform valley pattern structure with abundant grain boundaries, reporting the highest CH4 Faraday efficiency of 68.84% which was an order of magnitude higher compared to green foil counterpart. The relevant partial current density, CH4 production rate, and half-cell power conversion energy were measured to be −16.32 mA cm−2, 0.174 μmol s−1 cm−2, and 28.8% respectively from eCO2R at −1.3 V (vs. RHE). The in-situ ATR-IR spectroscopy confirmed that the surface reconstructed copper foil can significantly strengthen the adsorption of the *CO intermediate, facilitating its further hydrogenation to produce CH4 instead of dimerization to give C2 products. This work expanded the method of surface modification for copper foil via electrochemical etching and realized the regulation of geometric morphology on catalyst surface to obtain the desired performance for CO2 electroreduction reaction.

Fabrication of biomimetic anisotropic crescent-shaped microstructured surfaces by laser shock imprinting

Abstract The crescent-shaped microstructure bionic to the slip zone of the slippery zone of the carnivorous plant genus Nepenthes was fabricated on the surface of copper foil by laser shock imprinting (LSI). The microstructure of crescent-shaped grooves was initially fabricated on the surface of the micro-mold by etching, and then the microstructure was replicated on the surface of copper foil through plastic deformation under laser shock loading. Increasing the laser shock energy or the number of shocks can increase the degree of replication of the crescent-shaped microstructure, the height of the crescent-shaped microstructure, and the contact angle of water droplets on the surface. The wettability of the surface of the crescent microstructure is anisotropic and increases with an increase in offset distance. The anisotropy of the crescent-shaped microstructure causes the solid–liquid contact line in the direction of the bottom of the arc to become a long and approximately straight line. According to the rule that controlling LSI processing parameters can fabricate surfaces with different heights and wettability, a gradient wetting surface consisting of crescent-shaped microstructures was designed to achieve the directional spreading of droplets. By altering the distribution of crescent-shaped microstructures, a type-I flow channel with the ability to limit the spreading range of water droplets was fabricated.

Construction of Al-BTA passivation film on the surface of electrolytic copper foil and study of corrosion resistance mechanism

The use of chromates in copper foil metal passivation is becoming increasingly limited due to the emphasis on green production concepts. Thus, it is important to develop a chromium-free passivate that is both environmentally friendly and sustainable. Al(OH)3 passivation films were constructed on the surface of electrolytic copper foils by a simple impregnation method using NaAlO2 as the passivator, and it was found that the addition of a small amount of 1,2,3-benzene propyl triazole (BTA) could significantly improve the corrosion resistance of the passivation film. The passivation mechanism of the composite passivation film was investigated by electrochemical and related characterization tests. The results indicated that the self-corrosion current density (icorr) of the Al-BTA composite passivation film was reduced by two orders of magnitude to 4.375 × 10−7 A/cm2 compared to bare copper, which was better than that of the single aluminum-based passivation film at 5.562 × 10−6 A/cm2. In addition, the smooth and dense surface of the Al-BTA composite passivation film effectively blocked the erosion of corrosive media and protected the copper foil substrate, which has certain prospects for industrial applications.

Eco-friendly strategy for advanced recycling waste copper from spent lithium-ion batteries: Preparation of micro-nano copper powder

Massive spent lithium-ion batteries (LIBs) were emerged worldwide as a consequence of the extensive use in energy storage applications. The recovery of cathode electrode materials from spent LIBs has received great attention due to economic benefits, which has led to the neglect of the deep utilization of low-value copper current. The present study focuses on the selective crushing of copper foil and the preparation of micro-nano copper powders through eco-friendly leaching and reduction processes. The occurrence characteristics of copper in the anode material obtained by disassembling the battery after discharge pretreatment were first analyzed, SEM + EDS detection shows that graphite with thickness of tens of microns is attached to the surface of copper foil. Subsequently, the application of mechanical force promoted the graphite to detach from the collector, and the results indicate that significant selective crushing leads to the enrichment of copper foil in coarse-grained particles. Further, an ammonia leaching method was used to leach copper gently. The leaching kinetic behavior of copper foil particles with different particle sizes was analyzed. The diffusion controlled shrinking core model can accurately describe the leaching behavior of copper foil particles in leaching process. The activation energies of +2 mm, 2–1 mm, and 1–0.5 mm are 15.04 kJ/mol, 11.61 kJ/mol, and 8.21 kJ/mol, respectively. Undissociated graphite has negative impact on the leaching behavior, and reduction in the particle size of the copper foil can enhance the leaching behavior. Finally, the glucose and ascorbic acid system reducing reaction promotes the transformation of the copper ions in the leaching solution into regular shaped copper nanoparticles. SEM and XRD results show that high purity copper nanoparticles with hundreds of nanometers was successfully prepared. This study provides an eco-strategy and value-added recovery approach to address the challenges of full component utilization of spent LIBs.

Stannic oxide quantum dots constructed evenly alloyable layer stabilizing lithium metal batteries

Dendrite growth is still a problem that high energy density lithium metal batteries must face to commercialize. At present, the introduction of lithiophilic materials on the current collector has proved to be an effective strategy. However, most works are not conducive to the practical application of lithium metal batteries due to the neglect of the preparation cost and the excessive and uncontrollable modifier. Herein, stannic oxide (SnO2) quantum dots (QDs) were prepared by a simple dehydration reaction to construct a lithiophilic modification layer on the surface of copper foil. In addition, SnO2 QDs could induce uniform nucleation and growth of lithium ions at the quantum scale. More importantly, when the copper collector was modified by SnO2 QDs, the symmetric cell could cycle stably for 3200 h at a current density of 1 mA cm−2, which is better than other reports. LiFePO4 was employed as cathodic materials to fabricate a full battery, which delivered a capacity of 130.4 mAh g−1 with a capacity retention rate of 87.75% at 0.5 C for 200 cycles. Therefore, this work can be extended to practical applications, and help lithium metal batteries to be industrialized.

Characteristics of Graphene Growth at Different Temperatures from the Benzene Ring Structure in Coal Tar

A large number of aromatic substances can be found in so-called coal tar (containing >10,000 individual compounds), which is a mixture of heavy liquid fractions (dense viscous black liquor, tended to solidification) obtained after the pyrolysis of coal (solid product—coke, gas products, and light liquid products are also produced during the process). Volatile monocyclic aromatic hydrocarbons, which are naturally occurring in coal tar, can be exploited as premium raw materials for the production of graphene by chemical vapor deposition (CVD). Moreover, aromatic chemicals (compounds with benzene rings) can produce graphene at lower temperatures than other small-molecule gas feedstocks (for graphene growth via methane gas, the temperature must be at least 900 °C). The intermediate reaction mechanism involved in the creation of graphene from various temperature ranges of monocyclic aromatic hydrocarbons in benzene ring structures has long been a fascinating enigma. Accordingly, in this paper, we analyze the graphene growth pattern of benzene at different temperatures from 300 to 900 °C. For graphene synthesis in the lower temperature range (300~600 °C), analytical experiments show that benzene rings (almost) do not crack during the gas phase process. Thus, the structure of the benzene ring is directly coupled into graphene in the above temperature range. When benzene is more thoroughly transformed into tiny molecules that are deposited on the surface of copper foil at higher temperatures (700~900 °C), graphene is formed by a complex mixture of carbon sources, including gaseous small molecules (methane and ethane) and benzene. Based on the process above, we provide an alternative solution for the large-scale industrial preparation of graphene, with low energy consumption, via low-temperature synthesis of graphene by the CVD method using the coal tar carbon source at 500 °C, which is the optimal growth temperature of the benzene ring.

Multifunctional lithium compensation agent based on carbon edges catalysis and its application in anode-free lithium batteries

Lithium compensation agents, especially the self-sacrificing salts, can effectively compensate for the irreversible capacity loss of lithium-ion battery, but most lithium compensation materials only have the function of lithium compensation and their mechanisms are still unknown. In this study, a method for preparing multifunctional lithium compensation agent Li2C4O4 (lithium squarate) microspheres using spray drying to extend the cycle life of anode-free batteries is proposed, and the catalytic effect of the carbon edges on Li2C4O4 decomposition was evaluated. The Li2C4O4 microspheres can release additional capacity via decomposition and produce CO2 to improve the stability of the battery, as well as generate carbon bridges at the carbon edges to improve the rate performance of the battery. When it was applied to LiFePO4 battery system, the capacity increased from 60 mAh/g to 90 mAh/g at a current density of 10C. When applied to a Cu||LiFePO4 anode-free battery, an active lithium reserve layer formed on the surface of copper foil through Li2C4O4 decomposition, thus prolonging the cycling performance of the battery without any surface modification. After 40 turns at a current density of 0.1C, the cycling capacity retention was higher than 96%.