Current Collector For Lithium-ion Batteries Research Articles

Lightweight 3D-net Copper-Plated Polyimide Current Collector for Lithium-Ion Batteries.

Current collector (CC) is an indispensable constituent in lithium-ion battery (LIB). It plays an important role in supporting electrode materials and conducting electrons between the electrode materials and the external circuit. However, the density of metal CC is high and it hinders the lightweight development of LIB. In this work, lightweight three-dimensional (3D) CC was designed and prepared via a facile electroless plating method. The 3D copper-plated polyimide CC has a low areal density. The 3D structure of Cu-PI CC 2 can facilitate Li+ transfer between electrode materials and electrolyte owing to electrolyte can permeate through electrode. Moreover, the lithium titanate anode assembled with the 3D copper-plated polyimide Cu-PI CC 2 exhibited enhanced cycling and rate performance.

Electrochemical synthesis and carbon doping of nanostructured iron fluorides from the selection of metal current collectors in lithium-ion batteries

The use of materials that rely on conversion reactions as electrodes in lithium-ion batteries is extensively investigated due to their potential for enhanced capacity compared to traditional electrode materials. Iron fluorides, in particular, present a promising alternative in terms of specific capacity. However, these materials often face challenges related to low intrinsic conductivity. This issue is typically addressed in the literature by doping the active material with carbon particles and reducing the particle size of the active material. This study explores the feasibility of directly integrating conductive carbon from the substrate into the fluoride-based active material during the synthesis process. The synthesis employs a simple anodic method conducted directly on the chosen metallic substrate, which then functions as the current collector in the devices. This approach simplifies the synthesis process, reduces processing time, and eliminates the need for additives and binders at the conventional active material-current collector interface. Two FeF3 layers were electrochemically synthesized on steel substrates with different carbon contents. These layers were evaluated as cathode-active materials for rechargeable lithium-ion batteries. The influence of carbon on the conductivity of the conversion layer was assessed using Electrochemical Impedance Spectroscopy (EIS) with a model based on conductive porous electrodes. Morphological and thickness analyses of the layers showed a strong correlation between increased pore size and layer thickness and the carbon content in the metallic substrate. The optimal performance was observed with the layer on the substrate with higher carbon content. The electrochemical performance of the active material was further evaluated using electrochemical impedance spectroscopy and galvanostatic tests in pouch cells. The conversion layers derived from carbon steel exhibited reduced resistivity and enhanced specific capacitance and cyclability compared to layers formed on pure iron.

Fabrication and Characterization of Nanocrystalline and Nanotwinned Cu Foils By Electrodeposition

Because of the rise of electric vehicles, laptops, and smartphones in recent years, lithium-ion batteries play an important role in powering these electronic devices. As users become more attentive to battery lifespan and performance optimization for prolonged product utility, the selection of battery materials gains paramount significance. Copper, an integral conductor material within electronic devices, specifically functions as the anode current collector in lithium-ion batteries (LIBs). The anode electrode comprises a copper foil substrate coated with active materials, typically encompassing carbon-based materials and silicon-based materials. Although carbon-based materials, such as graphite, currently dominate the market, their relatively lower capacity prompts consideration of silicon-based materials as possessing substantial developmental potential.Nevertheless, silicon-based materials undergo volumetric expansion during charge and discharge processes, inducing pronounced swelling that may exert compressive forces on the copper foil, thereby elevating the risk of battery rupture. Consequently, the copper foil necessitates a requisite degree of strength to withstand these volumetric variations. Traditionally, copper foil fabrication relies on rolling techniques; however, it is hard to produce rolled Cu with thickness less than 10 mm. Therefore, electroplated copper foils have gradually emerged as the prevailing method in recent years. The purpose of strengthening is achieved by grain refinement, adding other metal impurities, and other strengthening methods. which causes the electrical conductivity to reduce. Nevertheless, nano-twinned copper can simultaneously increase the strength and avoid the problem of electrical conductivity decline. Nano-twinned copper is known to have high mechanical strength, good thermal stability, and resistance to electromigration.In this study, we employed the rotary electroplating technique to fabricate high-strength nanotwinned copper (NT-Cu) foils. By adjusting electroplating conditions through the incorporation of additives, we investigated the mechanical properties of copper foils. Copper foils electroplated at room temperature exhibited an ultimate tensile strength (UTS) of approximately 830 MPa and a yield strength (YS) of approximately 540 MPa. Compared with the regular copper foil plated under same condition, the UTS is increased by 70%, and the YS is increased by 50%. Moreover, the electroplated NT-Cu foil demonstrated good thermal stability, with the ultimate tensile strength decrease of only 1.54% following annealing for 1 hour at 100°C in a vacuum environment. After an annealing process at 200°C for 1 hour in a vacuum environment, the ultimate tensile strength decreased by approximately 8.74%.Additionally, electroplating experiments were conducted under both low and high-temperature conditions. The results revealed that copper foils electroplated at a low temperature of 10°C and low current density attained an ultimate tensile strength of 870 MPa, coupled with a yield strength of 560 MPa. In a high-temperature environment of 35°C, under high current density electroplating, the copper foils achieved an ultimate tensile strength of 845 MPa, reaching a yield strength of 540 MPa. These copper foils exhibited a fine-grained and nano-twinned microstructure, characterized by grains with dimensions less than 100 nm. Figure 1

Rotary Electrodeposition of High-Strength Nanotwinned Copper Foils

Due to the 2050 Net Zero Emissions becoming a major goal worldwide, electric vehicles have emerged as the future mainstream products. Among them, copper foils play a crucial role as the anode current collector in lithium-ion batteries (LIBs). Enhancing the strength and decreasing the thickness of copper foil are both important factors improving the lifespan of LIBs. The thickness of Cu foils can be reduced by rolling copper sheets, but it is challenging to achieve the required thinness below 10 micron for electronic applications. Direct current electroplating not only effectively increases the deposition rate but also reduces costs for thin Cu foils. In this study, we utilized a rotary direct current Cu-Ni co-electroplating method to enhance the mechanical strength of nanotwinned copper. The ultimate tensile strength (UTS) of nanotwinned copper-nickel alloy reached over 847.3 MPa (an increase of approximately 12.6 % compared to the maximum UTS of nanotwinned copper, which was 752.8 MPa) while maintaining excellent electrical conductivity similar to nanotwinned copper. Through potentiostat analysis, it was discovered that nickel ions inhibit copper growth, causing the reduction potential of copper to shift negatively, resulting in a decreased deposition rate and increased twin density. The nickel content, measured by ICP-MS, was found to be 0.467 ppm, suggesting that nickel acts as an impurity that refines grain size in copper foils. Therefore, this method not only significantly improves the strength of copper foils but also maintains low electrical resistance and low-cost characteristics. It provides a new material option for the anode current collector of the next-generation LIBs. Figure 1

Passivation and corrosion of Al current collectors in lithium-ion batteries

State-of-the-art lithium-ion batteries inevitably suffer from electrode corrosion over long-term operation, such as corrosion of Al current collectors. However, the understanding of Al corrosion and its impacts on the battery performances have not been evaluated in detail. The passivation, its breakdown, and corrosion of the Al resulted in the deterioration of the solid/solid interface and electrode integrity. Additionally, localized diffusion of F−/Al3+ brought the irreversible current detrimental to the Coulomb efficiency (1.14% loss). Eventually, the behavior led to extensive capacity damage (>20%) to battery performance until lifespan. During the battery cycling, the passivation layer greater than 20 nm was generated near the median voltage. When the charging voltage rose, the passivation layer was squeezed and deformed by the newly generated Al-F-O particles, resulting in stress corrosion cracks. The passivation layer peeled off, and the nano-passivation layer material was re-generated as the voltage continued to rise. The above results were repeated, and the Al matrix was continuously consumed. The passivity breakdown with localized corrosion was derived from ethylene carbonate adsorption, which was highly correlated to the charge voltages, especially at 4.4 V and 4.8 V. The results will serve as a benchmark for electrode corrosion of other advanced energy storage materials, which is crucial for electrode engineering and performance modulation using interfacial design.

Efficient and environmentally friendly separation and recycling of cathode materials and current collectors for lithium-ion batteries by fast Joule heating

Spent Li-ion batteries(LIBs) cathodes possess high recycling value. To improve subsequent recovery efficiency and product purity, separating the cathode materials from the aluminum foil is critical. However, traditional separation methods are characterized by high energy consumption, low recycling efficiency, and environmental pollution. This research presents a novel method that involves injecting Joule heat directly into the aluminum foil in the air, resulting in the melting and slight thermal decomposition of the PVDF binder, which reduces its adhesive properties. Owing to the difference in thermal expansion coefficients between the binder and aluminum foil, an instantaneous thermal stress was generated at the interface of the cathode materials and aluminum foil, resulting in a peeling force. This method enabled a rapid and efficient separation of lithium iron phosphate (LFP) and ternary Li-ion (NCM) battery cathode materials. The optimal separation conditions, separation mechanism, and properties of the recovered products were investigated thoroughly using high-speed camera imaging, temperature rise calculations, and microscopic characterization. This chemical-free method avoids the generation of wastewater and gas emissions. Under optimal experimental parameters, the separation efficiency and purity of cathode material reached 99 % and 99.7 %, respectively. Additionally, this method preserves both the structural integrity of the aluminum foil and the crystalline structure of the cathode materials, offering a new pathway for sustainable recycling of end-of-life LIBs.

Phytic-Acid-Modified Copper Foil as a Current Collector for Lithium-Ion Batteries

Electrolytic copper foil is ideal for use in the anode current collectors of lithium-ion batteries (LIBs) because of its abundant reserves, good electrical conductivity, and soft texture. However, electrolytic copper foil is prone to corrosion in electrolytes and weak bonding to the anode substance. Surface modification of copper foil is considered an effective method of improving the overall electrochemical performance of LIBs. In this study, a 5 nm thickness phytic acid (PA)-based film is constructed on electrolytic copper foil using a fast electrodeposition process (about 10 s). PA-treated copper foil (PA-Cu) displays an improved corrosion resistance in electrolytes because of a strong complexation between the PA and copper. It is found that PA-treated copper foil also bonds better with graphite particles compared with pristine copper foil. LIBs with PA-Cu foils as their current collectors exhibit enhanced cycling stability, improved capacity retention, and superior rate performance at both low and high current densities. Our study offers a novel avenue for the development of high-performance electrode current collector materials for LIBs.

Diameter dependent performance of silicon nanowire anodes grown on 3D current collectors for lithium-ion batteries

Si nanowires (Si NWs) with diameters tuned from ∼35 to 100 nm were directly grown on large-area (30 cm2) stainless-steel mesh (SSM) substrates via a facile vapour–liquid–solid approach.

Synthesis and Characterization of Ti3C2Tx Mxene for Flexible Current Collectors Fabricated through Inkjet Printing

Two-dimensional (2D) materials, as transition-metal carbides and/or nitrides (MXenes), have recently gained great attention due to their combination of electrochemical, electrical and mechanical properties, which can be tailored for the specific application by controlling the chemical composition. As a consequence, MXenes find applications in many fields as energy storage, sensing, photocatalysis and many more [1].MXenes are obtained by selective etching of a precursor layered material, known as MAX phase, and characterized by the general formula Mn+1XnTx, where M is a transition metal with n =1-4, X represents carbon and/or nitrogen atoms and Tx represents surface terminations of different nature (-O, -OH, -F and -Cl). The latter aspect is the one responsible for one important property related to the hydrophilicity of MXenes, which allows easy processing in water and/or solutions [2]. This aspect is particularly attractive for inkjet processing, as an easy water-based ink can be formulated. In addition, in aqueous solutions Ti3C2X flakes are negatively charged allowing the development of additive-free conductive inks.Ultimately, the MXenes extremely high conductivity is particularly attractive for final application as flexible current collector for lithium-ion batteries. The current collector can be considered as a bottleneck, especially when considering substrates selection, i.e. flexible/wearable substrates. Different silver or copper nanoparticles inks are commercially available, but they do require high curing temperatures, which are incompatible with plastic-based substrates, in order to reach the desired electrical conductivity. Another option is carbon-based inks, which despite being more cost-effective, they have limitations in terms of moderate electrical conductivity, which affects the Ohmic losses, and so the overall performance, of the battery device [3].Inkjet printing fabrication requires specific ink properties, in order to ensure a clogging-free condition, in terms of viscosity and surface tension of the ink. Generally, a clogging-free jetting is also forecast when particle size dimension is between 1/100 < d < 1/50 of the nozzle diameter [4]. This is a particularly meaningful aspect when considering MXene-based inks, as flake size should be finely controlled in order to avoid large or multilayered flakes, which can favor nozzle clogging. However, too small flakes can compromise the final electric conductivity.In this study, we provide an in-depth characterization of Ti3C2X MXene synthesis. The as-produced material will be characterized in terms of flake dimensions and electrical conductivity. IJP ink compatibility generally requires adjustments in terms of rheological and physical properties. Once chosen the optimal method, the Ti3C2X aqueous-based ink will be printed to obtain current collectors for lithium-ion batteries, which will be characterized from a morphological, electrical and electrochemical point of view. Preliminary study studies on inkjet printed full cell LTO/LFP were already obtained at the coin level. Flexible LTO/LFP full cell exploiting innovative Ti3C2X MXene current collector will be printed. Morphological and electrical analysis combined with an in-depth electrochemical characterization will be performed to demonstrate the battery device performances retention under different degrees of bending of the device.[1] M. Shekhirev, C. E. Shuck, A. Sarycheva, Y. Gogotsi, Progress in Materials Science 2021, 120, 100757.[2] K. Maleski, C. E. Ren, M.-Q. Zhao, B. Anasori, Y. Gogotsi, ACS Appl. Mater. Interfaces 2018, 10, 24491.[3] S. Uzun, M. Schelling, K. Hantanasirisakul, T. S. Mathis, R. Askeland, G. Dion, Y. Gogotsi, Small 2021, 17, 2006376.[4] Z. Tang, K. Fang, M. N. Bukhari, Y. Song, K. Zhang, Langmuir 2020, 36, 9481.

Development and Testing of Innovative Carbon Nanotubes/ Copper Composite Foils, Towards Lighter and Mechanically Improved Anode Current Collector for Lithium-Ion Batteries

Up to now, copper is an essential material for lithium-ion battery industry as preferential candidate for anode current collectors due to its high conductivity, low price, and electrochemical stability in the working potential range of the anodic electroactive material. However, such component, accounting for 8.1% of the battery total weight, does not participate in any energy storage processes. [1] Thus, the trend is in this industry is to decrease the weight as well as the thickness of the collector foil to optimize the gravimetric energy of the whole lithium-ion battery system. It is therefore of interest to explore the development of lighter current collectors with equal/improved mechanical and electrical properties.Nanocarbon materials such as Multi-Wall Carbon Nanotubes (MWCNTs) and Single-Wall Carbon Nanotubes (SWCNTs) display a combination of performances, namely high electrical conductivity, low density and high mechanical stability, of a high interests to be combined with copper as innovative lightweight current collectors. Such nanocarbon/copper composite represents a valid alternative to foster the rapid change the battery technology is undergoing.In 2013, Subramaniam et al. [2] reported the fabrication of a Copper /Carbon nanotubes (Cu-CNTs) composites with a similar specific conductivity than that of copper and an ampacity increased by two orders of magnitude. Moreover, Arai et al. have shown, by Electrochemical impedance analysis, that MWCNTs additive in a copper matrix can serve as preferential electron conduction pathway inside a Lithium-ion battery anode. [3]Recently, a new promising and scalable way to fabricate nanocarbon/copper composite has been demonstrated by our team. The process involved the coating of MWCNTs by a dispersing agent, namely the Polydopamine biopolymer, their spraying, and finally the electrochemical plating of metallic copper inside the porosity of the MWCNTs network.[4]Following similar approach, the present work exhibits the fabrication of a free standing MWCNTs/ Copper composite current collector foil of a thickness of 9 µm, a value reaching the industrial standards required by the Lithium-ion battery market players for the next generation cells.[5] Scanning Electron Microscopy and Transmission Microscopy have been used to investigate the interaction between the copper matrix and the carbonaceous reinforcement additive. Figure 1. displays a cross section of nanocarbon/copper composite obtain via Focused Ion Beam slicing, where homogeneous mixing of copper and carbon phases down to nanoscale is highlighted. Such experiments contribute to the understanding of the copper nucleation mode on modified MWCNTs which remains insufficiently controlled to this day.Nanoindentation technique and electromechanical tensile testing bench were combined to study the mechanical properties of such material to be used under mechanical stress as battery collector. In contrary to conventional indentation technique where the mechanical properties of micro-size area are probed, indentation at nanoscale allow the probing of the local mechanical heterogeneity of a composite material. Using such technique, the fabricated self-standing nanocarbon/copper composite was shown to display average hardness and Young modulus close to those of pure carbon (3.5 GPa and 152 GPa respectively).Electrochemical performances of the composite as anode battery collector are under test into pouch and coin-cells battery architecture. The adhesion strength between the electrode slurry and the nanocomposite substrate material is expected to be reinforced by the addition of a nanocarbon. A focus was made on the impact of the use of this new collector material on the cycling stability of typical Lithium-ion battery commercial mixture. Preliminary results indicate that the Cu/MWCNT composite is a promising current collector material to withstand the expansion/contraction imposed by the working cycles of a rechargeable Lithium-ion battery.[1] Zhu, P. Gastol, D. Marshall, J. Sommerville, R. Goodship, V. Kendrick, E. J Power Sources, 485, 229321 (2021)[2] Subramaniam, C. Yamada, T. Kobashi, K. Sekiguchi, A. Futaba, Yumura, D. N. Hata, K. Nat Commun,4, 2202 (2013).[3] Shimizu, M. Ohnuki, T. Ogasawara, T. Banno, Arai, S., RSC Advances, 9(38), 21939-21945 (2019)[4] Duhain, A. Guillot, J. Lamblin, G. Lenoble, D., RSC Advances,11(63), 40159-40172 (2020)[5] Copper Foil Market, Straits Research, 9.5.2.3.(2022)Figure 1. Scanning Electron Microscopy imaging of the cross section of MWCNTs/Copper composite with a thickness lower than 3 µm – 7kV acceleration, 45° tilt.. Figure 1

Thin-Film SiOx Coated Carbon Nanofibers As Stable Anodes for Lithium-Ion Batteries

With the increase in the capacity of cathode materials in lithium-ion batteries(LIBs), the demand for novel anode materials with high theoretical energy density is following. Up to now, many candidates have been reported; silicon-based composites are considered a prospective alternative due to their abundant reserves and high energy density. However, The primary disadvantage of Si, electrochemical irreversibility during the charge/discharge process, hinder widespread use.In this study, we adapted SiOx-coated carbon nanofibers (SiOx-CNFs) composite to the binder-free anode current collector for lithium-ion batteries. The composite has a structure where a thin amorphous SiOx (thickness ~100nm) is coated on the CNFs surface and is successfully synthesized by electrospinning and sputtering. This structure, surface SiOx-coated porous CNF, breaks through the significant drawback of Si-based composites, pulverization of Si element during the charge/discharge cycle. In addition to this, due to the structure of porous CNF, we achieved the curtail of electrode weight.Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD) analyses are carried out to confirm the morphology and crystallinity. Furthermore, with cyclic voltammetry analysis, fast reaction kinetics and excellent electrochemical reversibility are verified. The cycle test is also conducted to prove excellent capacity and cyclic stability.

Synthesis of Graphene / Copper Composite Thin Foils As Innovative Anode Current Collectors for Lithium-Ion Batteries

Lithium-ion batteries (LIB) are now considered as standard power storage units in laptops, mobile phones, and electric cars. Yet, they trigger important and constant R&D efforts to improve their energy density, lifespan, safety, and cost efficiency. Among LIB components, anodic copper current collector contributes to 8.1% of the total LIB weight [1]. In their ongoing quest to reduce the thickness of the anodic electrode foils, manufacturers face now a 6 µm thickness limitation due to mechanical issues (wrinkling and tearing) complicating their processing. In this context, using lighter materials with improved mechanical properties (with equal or improved thermal and electrical conductivity) compared to pristine copper is considered as an interesting solution to contribute to a further improvement of Lithium-Ion Batteries energy density.Owing to its high mechanical properties, high electrical and thermal conductivity, and low density [2], graphene and its derivates could be considered as promising materials to fabricate graphene / copper composites and achieve thinner / lighter current collectors. Such composites have already been successfully synthetised using copper electroplating with clear thermal and mechanical improvement [3].The work to be presented in this talk will describe a new and simple route for the fabrication of graphene nanoplatelets (GNPs) or graphene oxide (GO) / copper composites consisting of : (i) the dispersion of graphene derivates in ethanol, (ii) their spraying onto Titanium substrate, (iii) a post electroplating on the sprayed graphene materials. In case of GNPs, a prior functionalization by polydopamine biopolymer is performed to increase their hydrophilicity and allow their dispersion. The polydopamine polymerization mechanism is known in literature to be complex and not extensively understood. The investigations done to understand the functionalization of GNPs by polydopamine using different techniques like Transmission Electron Microscopy (TEM) and X-ray Photoemission Spectroscopy (XPS) will be shared. Moreover, the use of Helium Ions Microscopy coupled with Secondary Ions Mass Spectrometer (HIM-SIMS) has been chosen as an original and powerful technique to further study the conformation of polydopamine onto GNPs. Finally, we will present the fabrication of thin graphene oxide copper composite foils and their characterization using Scanning Electron Microscope (SEM). A special focus will be given on the comprehension of copper nucleation behaviour on Graphene materials that remains not well studied. Electrochemical techniques such as impedance and current transient nucleation and growth analysis is currently under testing.[1] Zhu, P. Gastol, D. Marshall, J. Sommerville, R. Goodship, V. Kendrick, E. J Power Sources, 485, 229321 (2021)[2] Fatemeh Farjadian et al. Recent Developments in Graphene and Graphene Oxide: Properties, Synthesis, and Modifications: A Review 5,10200-10219, Chemistry Europe (2020)[3] Song, G. et al.. One-step synthesis of sandwich-type Cu/graphene/Cu ultrathin foil with enhanced property via electrochemical route. Materials and Design, 191, 108629. (2020)

Thermoexpandable Microsphere-Coated Al Foil Current Collector for Lithium-Ion Batteries with Improved Safety

Thermoexpandable Microsphere-Coated Al Foil Current Collector for Lithium-Ion Batteries with Improved Safety

Review and New Perspectives on Non-Layered Manganese Compounds as Electrode Material for Sodium-Ion Batteries.

After more than 30 years of delay compared to lithium-ion batteries, sodium analogs are now emerging in the market. This is a result of the concerns regarding sustainability and production costs of the former, as well as issues related to safety and toxicity. Electrode materials for the new sodium-ion batteries may contain available and sustainable elements such as sodium itself, as well as iron or manganese, while eliminating the common cobalt cathode compounds and copper anode current collectors for lithium-ion batteries. The multiple oxidation states, abundance, and availability of manganese favor its use, as it was shown early on for primary batteries. Regarding structural considerations, an extraordinarily successful group of cathode materials are layered oxides of sodium, and transition metals, with manganese being the major component. However, other technologies point towards Prussian blue analogs, NASICON-related phosphates, and fluorophosphates. The role of manganese in these structural families and other oxide or halide compounds has until now not been fully explored. In this direction, the present review paper deals with the different Mn-containing solids with a non-layered structure already evaluated. The study aims to systematize the current knowledge on this topic and highlight new possibilities for further study, such as the concept of entatic state applied to electrodes.

Polymer@Cu composite foils with through-hole arrays as lightweight and flexible current collectors for lithium-ion batteries

The current collector is a critical component of lithium-ion batteries (LIBs). Herein, copper-coated polymer films (P@Cu) with through-hole arrays are developed lightweight and flexible current collectors. The through-hole arrays are created by laser drilling the polyimide film substrate. P@Cu composite current collectors are fabricated by electroless Cu deposition on polyimide films with through-hole arrays, which form three-dimensional conductive paths. As the anode current collector for LIBs, P@Cu exhibit a total electrode mass-specific capacity that is 54.58 % higher than that of the commercial Cu foil. Due to the polyimide substrate, the tensile deformation of P@Cu is 6.69 % higher than that of the commercial Cu foil. After 30,000 bending cycles, the conductivity of P@Cu is only reduced by 3.39 %, while the commercial Cu foil current collectors have broken by this point. The P@Cu composite foils with through-hole arrays are high-performance lightweight and flexible current collectors for LIBs.

Facile electrodeposition of copper layers on graphene film as high performance current collector for lithium-ion batteries

The increasing demand on high energy density and rate performance of lithium-ion batteries (LIBs) drives all battery components forward, including electrochemically inactive components. Herein, Cu coated graphene film (GF@Cu) is fabricated via electroplating method as a composite current collector with low areal density (3.44 mg cm−2), high electrical conductivity (3.25*107 S m−1), excellent thermal conductivity (836.20 W m−1K−1), and good weldability. By substituting Cu current collector with this lightweight GF@Cu in lithium-ion batteries, the graphite anode realizes an 246.01 % increasement of gravimetric capacity at 1C. The lithium-ion batteries equipped with GF@Cu current collector can also obviously improve the rate and cycling performance during charging/discharging at high current density by reducing the interfacial contact resistance and increasing the electrical and thermal conductivities.

Roll-to-Roll Scale Fabrication of High-Performance Graphene-Assembled Film Cathode Current Collectors for Lithium-Ion Batteries

Roll-to-Roll Scale Fabrication of High-Performance Graphene-Assembled Film Cathode Current Collectors for Lithium-Ion Batteries

Electroforming as a Novel One-Step Manufacturing Method of Structured Aluminum Foil Current Collectors for Lithium-Ion Batteries

Conventionally, cathode current collectors for lithium-ion batteries (LIB) consist of an aluminum foil generally manufactured by a rolling process. In the present work, a novel one-step manufacturing method of structured aluminum foil current collectors for lithium-ion batteries by electroforming is introduced. For this, a low-temperature chloride-based ionic liquid was used as an electrolyte and a rotating cylinder out of stainless steel as a temporary substrate. It was shown that the structure of the aluminum foils can be adjusted from dense and flat to three-dimensional by choosing an appropriate substrate rotation speed and current density. Scanning electron microscopy (SEM) and white light interferometry (WLI) were utilized to analyze the foils’ surface morphology, structure and topography. The SEM analysis of the aluminum foils showed that the rolling process produced a foil with small grains, while electrodeposition resulted in foils with different degrees of grain growth and seed formation. This was in total agreement with WLI results that revealed significant differences in terms of roughness parameters, including the peak-to-valley difference Rpv, the root-mean-square roughness Rq and the arithmetic mean roughness Ra. These were, respectively, equal to 6.8 µm, 0.35 µm and 0.279 µm for the state-of-the-art foil and up to 96.6 µm, 10.92 µm and 8.783 µm for the structured electroformed foil. Additionally, cyclic voltammetry (CV) of the aluminum foils was used to investigate their passivation behavior within the typical LIB cathode potential operation window. The strong decrease in the current density during the second cycle compared to the first cycle, where an anodic peak appeared between 4.0 and 4.4 V vs. Li/Li+, demonstrated that passivation occurs in the same manner as observed for commercial Al current collectors.

An electrochemically active textile current collector with a high areal capacity and a strong energy recovery effect using an interfacial interaction assembly

Conventional current collectors in lithium-ion batteries (LIBs) are generally nonactive components. However, enhancing their electroactive properties and increasing the electroactive surface area can significantly improve the areal energy performance of next-generation battery electrodes. Herein, we introduce an electrochemically active textile current collector that delivers high energy storage performance, achieved through interfacial interaction assembly-induced electroplating. We first prepared metal nanoparticle/multiwalled carbon nanotube multilayer-incorporated cotton textiles using complementary interaction-mediated layer-by-layer assembly, and subsequently electroplated them with Cu. The resulting textile exhibited a high areal capacity of ∼3.27 mA h cm−2 at 0.875 mA cm−2, excellent cycling stability, and a strong energy recovery effect, thanks to the synergistic contributions of the large active surface area of the fibril structure, the robust interfacial assembly, and the formation of a metal oxide NP/pseudocapacitive polymeric gel-like phase at the electrode/electrolyte interface. Moreover, when incorporating Li4Ti5O12 with a theoretical capacity of 175 mA h g − 1 into our textile current collector, the specific capacity and areal capacity of the LIB anode can be increased up to ∼573 mA h g − 1 and 8.60 mA h cm−2 (at 15 mg cm−2 LTO), respectively, outperforming those of previously reported LTO-based anodes.

Preparing ultra-thin copper foil as current collector for improving the LIBs performances with reduced carbon footprint

Adopting ultra-thin copper foil as the current collector is one of the most important strategies for improving the gravimetric energy density of lithium-ion batteries (LIBs), however, stumbled by the quality-control of physicochemical properties for ultra-thin foils. Herein, by utilizing combinative additives, the ≤ 4.5 µm ultra-thin electrolytic copper foil with appealing physicochemical properties is prepared, presenting very low Rz (surface roughness) of 1.74 µm and extraordinarily high tensile strength of 435.65 MPa. When being used as the current collector in LIBs, a high gravimetric energy density of 323.19 Wh/kg was achieved, outperforming both the commercial 9 µm candidate (205.81 Wh/kg) and the purchased 4.5 µm counterpart (310.48 Wh/kg). Also, decreasing the thickness of commercial copper foil (9 µm) to 4.5 µm demonstrates superiorities in both resources saving and environmental benignity, contributing to ∼32 million tons copper savings in 2030 and 40.6 % elimination in carbon footprint for copper foil preparation. The results herein can provide guidance for quality-controlled preparation of ultra-thin copper foil as well as new insights for resource savings and environmentally friendly manufacturing.