3D Current Collector Research Articles

Synergistic effect of modest pores and lithiophilic surface on 3D current collectors for stable Li metal anodes

The increasing demand for high energy density battery systems has accelerated the development of lithium metal batteries, and it is imperative to seek strategies for alleviating the large volume change and inhibiting dendrite growth of the Li metal anode. 3D porous anode current collectors cooperated with surface modification have been considered as effective methods. Herein, we develop 3D porous Cu with modest pores by powder metallurgy method, combined with surface modification by lithiophilic Ag nanoparticles. The obtained ingenious porous structure ensures the reduction of local current density when served as the Li anode current collector, while the Ag nanoparticle layer provides numerous lithiophilic nucleation sites. Smooth and uniform Li plating morphologies are confirmed on the PM Cu@AgNP electrode surface, and the PM Cu@AgNP-Li symmetric cell presents a stable cycle of 1600 h, which effectively inhibits the Li dendrite growth. When coupled with the LiFePO 4 cathode, the assembled full cell exhibits superb capacity retention and stability for 600 cycles at 0.5 C. This facile and rational strategy with synergistic effect of modest pores and surface lithiophilicity provides a way to achieve highly stable Li metal anodes for next-generation Li batteries. • Powder metallurgy method is introduced to prepare the Li metal anode current collector. • Synergistic effect of the structure and lithiophilicity makes stable Li anode. • An average pore size of 21.2 µm is modest for the porous current collector. • Surface Ag nanoparticles significantly reduce Li nucleation overpotential.

Built‐In Stable Lithiophilic Sites in 3D Current Collectors for Dendrite Free Li Metal Electrode

Stable lithiophilic sites in 3D current collectors are the key to guiding the uniform Li deposition and thus suppressing the Li dendrite growth, but such sites created by the conventional surface decoration method are easy to be consumed along with cycling. In this work, carbon fiber (CF)-based 3D porous networks with built-in lithiophilic sites that are stable upon cycling are demonstrated. Such heterostructured architecture is constructed by the introduction of zeolitic imidazolate framework-8-based nanoparticles during the formation of the 3D fibrous carbonaceous network and the following annealing. The introduced Zn species are found to be re-distributed along the entire individual CF in the 3D network, and function as lithiophilic sites that favor the homogenous lithium nucleation and growth. The 3D network also presents a multi-scale porous structure that improves the space utilization of the host. The corresponding symmetric cells adopting such 3D anode demonstrate excellent cycling performance, especially at a high rate (300 cycles at 10mAcm-2 with a capacity of 5mAhcm-2 ). A full cell with LiFePO4 cathode shows a capacity retention of 98% after cycling at 1C for 300 cycles. This method provides an effective design strategy for 3D hosting electrodes in dendrite-free alkali metal anode applications.

Preparation of a Honeycomb-like FeNi(OH/P) Nanosheet Array as a High-Performance Cathode for Hybrid Supercapacitors

Polymetallic transition metal phosphides (TMPs) exhibit quasi-metallic properties and a high electrical conductivity, making them attractive for high-performance hybrid supercapacitors (HSCs). Herein, a nanohoneycomb (NHC)-like FeNi layered double hydroxide (LDH) array was grown in situ on 3D current collector nickel foam (NF), which is also the nickel source during the hydrothermal process. By adjusting the amount of NaH2PO2, an incomplete phosphated FeNi(OH/P) nanosheet array was obtained. The optimized FeNi(OH/P) nanosheet array exhibited a high capacity up to 3.6 C cm−2 (408.3 mAh g−1) and an excellent long-term cycle performance (72.0% after 10,000 cycles), which was much better than FeNi LDH’s precursor. In addition, the hybrid supercapacitor (HSC) assembled with FeNi(OH/P) (cathode) and polypyrrole (PPy/C, anode) achieved an ultra-high energy density of 45 W h kg−1 at a power density of 581 W kg−1 and an excellent cycle stability (118.5%, 2000 cycles), indicating its great potential as an HSC with a high electrochemical performance.

Powder metallurgical 3D nickel current collectors with plasma-induced Ni3N nanocoatings enabling long-life and dendrite-free lithium metal anode

Building three-dimensional (3D) current collectors is a promising strategy to surmount the bottlenecks of lithium metal anodes (LMAs), but the regulation methodology of a 3D current collector has seldom been considered comprehensively concerning both skeleton architectures and surface coatings. Herein, a robust porous 3D nickel skeleton (NS) with lithiophilic Ni3N nanocoatings (Ni3N@NS) is synthesized via an integrative route of powder metallurgy/plasma-enhanced nitridation technics. The facile powder metallurgical method facilitates the adjustment of NS architectures toward sufficient electrolyte adsorption and even current density distribution, while the followed plasma-enhanced chemical vapor deposition (PECVD) method can induce compact Ni3N nanocoatings on NS, which reduces the Li nucleation overpotential, accelerates the Li-ion transfer, and facilitates a highly reversible oriented texture of Li deposition morphology owing to the dense and homogenous deposition of Li into the pores. The optimized Ni3N@NS current collector shows a high averaged Coulombic efficiency (CE) of 98.8% over 350 cycles, a prolonged lifespan of 1000 h (at 2 mA cm−2) in symmetrical cells, together with the significant performance in full cells. The ingenious methodology reported in this work can also be broadly applicable for the controllable production of other 3D skeletons with nitride nanocoatings for various applications.

Regulating the Li Nucleation/Growth Behavior via Cu2O Nanowire Array and Artificial Solid Electrolyte Interphase toward Highly Stable Li Metal Anode.

Lithium (Li) metal has been considered to be the most promising anode material for next-generation rechargeable batteries. Unfortunately, the hazards induced by dendrite growth and volume fluctuation hinder its commercialized application. Here, a three-dimensional (3D) current collector composed of a vertically aligned Cu2O nanowire that is tightly coated with a polydopamine protective layer is developed to solve the encountered issues of lithium metal batteries (LMBs). The Cu2O nanowire arrays (Cu2O NWAs) provide abundant lithiophilic sites for inducing Li nucleation selectively to form a thin Li layer around the nanowires and direct subsequent Li deposition. The well-defined nanochannel works well in confining the Li growth spatially and buffering the volume change during the repeated cycling. The PDA coatings adhered onto the outline of the Cu2O NWAs serve as the artificial solid electrolyte interface to isolate the electrode and electrolyte and retain the interfacial stability. Moreover, the increased specific area of copper foam (CF) can dissipate the local current density and further suppress the growth of Li dendrites. As a result, CF@Cu2O NWAs@PDA realizes a dendrite-free morphology and the assembled symmetrical batteries can work stably for over 1000 h at 3 mA cm-2. When CF@Cu2O NWAs@PDA is coupled with a LiFePO4 cathode, the full cells exhibit improved cycle stability and rate performance.

Forming Solid-Electrolyte Interphases with Rich Grain Boundaries on 3D Lithiophilic Skeleton for Low-Temperature Lithium Metal Batteries

Rational design of the current collector along with further constructing solid electrolyte interphases (SEI) shows great promise to achieve uniform lithium (Li) deposition, specifically at low temperature. Here we report a Li 2 O-Ni based SEI layer with rich grain boundaries formed on the three-dimensional (3D) Ni-NiO current collector for stabilizing Li metal anodes. Different from two-dimensional (2D) substrates, the lithiophilic 3D substrates with porous structures exhibit high binding affinity to Li and provide enough space for volume fluctuation, leading to uniform Li deposition. The grain boundaries between Li 2 O (111) and Ni (111) in the SEI layer display a low diffusion barrier of Li + , facilitating Li + transport through the interface. As a result, Li||NCM811 full cells using 3D Ni-NiO display an excellent cycling stability with capacity retention of 80.8% after 160 cycles under harsh conditions, i.e., a limited Li supply (N/P = 2.4) and a high areal capacity (4.0 mAh cm −2 ). Even at low temperature of -30°C, Li||NCM811 full cells with 3D Ni-NiO exhibit a large areal capacity of 3.2 mAh cm −2 and apparently enhanced cycle life with limited Li anode (N/P = 1.2) compared with non-lithiophilic 3D current collectors. Graphical Abstract .

TiN nano arrays on nickel foam prepared by multi-arc ion plating for fast-charging supercapacitors

Physical vapor deposition (PVD) technologies have been widely used to produce metal nitride films on planar substrate for electrode of ultrafast charging supercapacitors. However, planar electrode structure greatly limits the energy density of device. This work, for the first time, employs multi-arc ion plating (MAIP) to efficiently prepare titanium nitride (TiN) nano arrays on 3D current collector (i.e., nickel foam). The array morphology, composition, crystal structure, electrical and electrochemical properties of TiN as a function of working pressure are investigated. The optimized electrode exhibits a large specific capacitance of 90.18 F g−1 and a good stability with capacity loss of 11.9% after 10,000 charge-discharge cycles at 1 A g−1. The assembled symmetrical supercapacitor can achieve a high energy density of 4.72 Wh kg−1 with a power density of 800 W kg−1 under current density of 1 A g−1. The general findings open a new and promising strategy in facile and efficient fabrication of electrode materials towards ultrafast charging supercapacitors.

Compact 3D Metal Collectors Enabled by Roll‐to‐Roll Nanoimprinting for Improving Capacitive Energy Storage (Small Methods 4/2022)

Front Cover In article number 2101539, Xiangming Li, Jinyou Shao, and co-workers demonstrate a roll-to-roll nanoimprinting method to deform flat aluminum foils into 3D current collectors with hierarchical microstructures. The 3D current collector significantly reduces the contact resistance by an order of magnitude, which comprehensively improves the electrochemical performance of the supercapacitor. The method can be extended to other systems that involve microstructured metal interfaces, such as batteries.

Application of electrodeposited Cu-metal nanoflake structures as 3D current collector in lithium-metal batteries

Since uncontrolled lithium (Li) dendrite growth and dendrite-induced dead Li severely limit the development of Li metal batteries, 3D Cu current collectors can effectively alleviate these problems during Li plating/stripping. Herein, one-step galvanostatic electrodeposition method is employed to fabricate a new current collector on Cu foam decorated with large-scale and uniform 3D porous Cu-based nanoflake (NF) structures (abbreviated as 3D Cu NF@Cu foam). This 3D structure with large internal surface areas not only generates lithophilic surface copper oxides and hydroxides as charge centers and nucleation sites for Li insertion/extraction, but also endows abundant space with interlinked NFs for buffering the cell volume expansion and increasing battery performance. As a result, Li-deposited 3D Cu NF@Cu foam current collector can realize stable cycling over 455 cycles with an average Coulombic efficiency of 98.8% at a current density of 1.0 mA cm−2, as well as a prolonged lifespan of >380 cycles in symmetrical cell without short-circuit, which are superior to those of blank Cu foam current collector. This work realizes Li metal anode stabilization by constructing 3D porous Cu NFs current collectors, which can advance the development of Li metal anode for battery industries.

Constructing 3D Porous Current Collectors for Stable and Dendrite‐Free Lithium Metal Anodes

AbstractLithium metal batteries (LMBs) are considered promising candidates for the next‐generation rechargeable batteries due to the ultrahigh theoretical specific capacity (3860 mAh g−1) and the lowest negative electrochemical potential (−3.040 V versus the standard hydrogen anode) of lithium metal. However, the practical application of LMBs has been hindered by various serious challenges, especially the low cycling stability of lithium anodes due to the uncontrolled growth of lithium dendrites, unstable solid–electrolyte interphase, and excessive volume change of lithium metal. 3D lithium metal anodes with reduced local current density and alleviated volume expansion can be used to improve the safety performance of LMBs. The design of various 3D structures is therefore critical to achieve high‐performance lithium metal anodes. This review summarizes recent advances of several important 3D porous structures such as foam structures, parallel arrays, interweaved structures, coiled structures, Janus structures, gradient structures, and alloy frameworks for stable and dendrite‐free lithium metal anodes. The constructing strategies and modification methods of 3D lithium metal anodes are discussed in detail. The design and construction of novel 3D porous current collectors are expected to provide promising opportunities for the next‐generation of high‐energy‐density LMBs.

Au-coated carbon fabric as Janus current collector for dendrite-free flexible lithium metal anode and battery

Composite lithium metal anodes with three-dimensional (3D) conductive fabric present great potential to be used in high-energy-density flexible batteries for next-generation wearable electronics. However, lithium dendrites at the top of the fabric anode increase the risk of separator piercing and, therefore, cause a high possibility of short circuits, especially when undergoing large mechanical deformation. To ensure the safe application of the flexible lithium metal batteries, we herein propose a 3D Janus current collector by a simple modification of the bottom side of carbon fabric (CF) with a lithiophilic Au layer to construct highly flexible, stable, and safe Li metal anodes. The Janus Au layer can guide an orientated deposition of Li to the bottom of the CF. The lithium dendrite problem can be largely alleviated due to the lithium-free interface between the anode and separator, and meanwhile, the porous upper skeleton of the CF also provides large space to buffer the volume expansion of lithium metal. The resulting composite lithium metal anode exhibits a significant improvement in the life cycle (∼two fold) compared to the traditional top deposition of lithium metal. More importantly, assembled full batteries using the Janus anode structure exhibit high stability and safety during severe mechanical deformation, indicating the opportunity of the orientated deposition strategy to be used in future flexible and wearable electronics.

Laser-assisted mask-free patterning strategy for high-performance hybrid micro-supercapacitors with 3D current collectors

Planar micro-supercapacitors (MSCs) as a promising energy storage device have been widely used in portable, wearable, and implantable electronics. However, the energy density is still limited by the plane configuration and relatively low loading of electrode active material. Here, we reported a facile approach to fabricate the interdigitated current collectors architecture by direct laser engraving of nickel (Ni) foams, followed by electrodeposition of pseudocapacitive materials for fabricating all-solid-state 3D MSCs devices. The fabricated hybrid AMSC (Ni foam-MnO2//Ni foam-PPy) presented a large areal capacitance of 59.29 mF/cm2 at 1 V/s and excellent capacity retention of 95.6% after 10,000 cycles. Moreover, the hybrid Ni foam-based AMSC exhibited a high areal energy density range from 42.99 to 77.94 μWh/cm2 with a corresponding power density range from 0.272 to 6.818 mW/cm2. This prototype of laser-assisted all-solid-state AMSC demonstrates the potential of Ni foam-based energy storage devices applications for 3D MSCs that require high energy density.

Open-Source CFD Elucidating Mechanism of 3D Pillar Electrode in Improving All-Solid-State Battery Performance.

All‐solid‐state batteries (ASSBs) have become an important technology because of their high performance and low‐risk operation. However, the high interface resistance and low ionic conductivity of ASSBs hinder their application. In this study, a self‐developed electrochemical model based on an open‐source computational fluid dynamics platform is presented. The effect of contact area reduction at the electrode/solid‐state electrolyte interface is investigated. Then, a new conceptual 3D structure is introduced to circumvent the existing barriers. The results demonstrate that the discharge time is shortened by over 20% when the area contact ratio reduces from 1.0 to 0.8 at 1 C‐rate, owing to the increased overpotential. By adopting the new 3D pillar design, the energy density of ASSBs can be improved. However, it is only when a 3D current collector is contained in the cathode that the battery energy/power density, capacity, and material utilization can be greatly enhanced without being limited by pillar height issues. Therefore, this work provides important insight into the enhanced performance of 3D structures.

Synergizing Conformal Lithiophilic Granule and Dealloyed Porous Skeleton toward Pragmatic Li Metal Anodes

Li metal is regarded as one of the most promising anodes for next‐generation rechargeable batteries. Nonetheless, infinite volume change and severe dendrite growth impede its practicability. To date, unremitting efforts have been devoted to stabilizing Li metal anode via the rational design of 3D current collectors. In this sense, optimizing Li nucleation behavior plays a pivotal role in alleviating the dendrite formation. Herein, a practically viable route is devised by in situ crafting lithiophilic CuSe granules on the dealloyed Cu skeleton (D‐Cu@CuSe). Persuasive electrochemical analysis and systematic theoretical calculation disclose the underlying Li nucleation mechanism on the CuSe overlayer. Impressively, the D‐Cu@CuSe‐Li symmetric cell can sustain a stable plating/stripping operation over 1000 h at a high depth of discharge at 62.5%. More crucially, when paired with high‐loading sulfur cathodes, D‐Cu@CuSe‐Li||S batteries harvest advanced areal capacity and stable cycling performance even under stringent working conditions of low negative‐to‐positive (N/P) (≈2) and electrolyte‐to‐sulfur (8 μL mgs−1) ratios. Overall, a fresh perspective into rationalizing current collector design is afforded, which extends Li utilization and cycling durability in the pursuit of pragmatic Li metal anodes.

Compact 3D Metal Collectors Enabled by Roll-to-Roll Nanoimprinting for Improving Capacitive Energy Storage.

Reducing the contact resistance between active materials and current collectors is of engineering importance for improving capacitive energy storage. 3D current collectors have shown extraordinary promise for reducing the contact resistance, however, there is a major obstacle of being bulky or inefficient fabrication before they become viable in practice. Here a roll-to-roll nanoimprinting method is demonstrated to deform flat aluminum foils into 3D current collectors with hierarchical microstructures by combining soft matter-enhanced plastic deformation and template-confined local surface nanocracks. The generated 3D current collectors are inserted by and interlocked with active electrode materials such as activated carbon, decreasing the contact resistance by at least one order of magnitude and quadrupling the specific capacitance at high current density of 30 A g-1 for commercial-level mass loading of 5mg cm-2 . The 3D current collectors are so compact that they have a low volume percentage of 7.8% in the entire electrode film, resulting in energy and power density of 29.1Wh L-1 and 12.8kW L-1 , respectively, for stack cells in organic electrolyte. Furthermore, roll-to-roll nanoimprinting of metal microstructures is low-cost, high-throughput, and can be extended to other systems that involve the microstructured metal interface, such as batteries and thermal management.

Bifunctional 3D Graphite@Ni-Fe foam negative current collector toward stable liquid metal battery

Negative current collectors play vital roles in the electrochemical performance of liquid metal batteries (LMBs). Employing a three-dimensional (3D) current collector is an effective approach to host molten lithium and reduce the effective current density. The Ni-Fe foam is a frequently used 3D current collector for the negative electrode. However, the corrosion of molten lithium towards the Ni-Fe foam skeleton devastates the 3D structure of the current collector and so deteriorates seriously the electrochemical performance of LMB. To enhance the corrosion resistivity, herein, the graphite layer coated Ni-Fe foam (Graphite@Ni-Fe) is prepared by the chemical vapor deposition method. The prepared scaly-like graphite layer plays a bifunctional role in chemistry, preventing corrosion as an effective barrier and improving remarkably the surface lithiophilicity of Ni-Fe foam. The assembled Li||Bi batteries with Graphite@Ni-Fe foam as negative current collector exhibit stable cycling performance with capacity retention of 98.10% and high Coulombic efficiencies over 98.3% at 0.4 A cm−2 over 100 cycles at 500 °C. More importantly, outstanding rate capability is achieved and almost no capacity degradation is observed upon current density change from 0.2 to 2.0 A cm−2. This work highlights the importance of the lithiophilicity and the corrosion resistance ability of the negative current collectors for LMBs.

A surface-nitridized 3D nickel host for lithium metal anodes with long cycling life at a high rate.

Three dimensional (3D) metal structures such as nickel (Ni) and copper (Cu) frames have long been regarded as a good host for lithium (Li) metal. However, Li deposition on different metals often causes obvious over-potential, affecting the electrode performance in lithium metal batteries. Here, a Ni-N-O interface was created by surface nitridation to the Ni micro-particles, which were made into 3D current collectors. The directly grown Ni3N created a thin and lithiophilic layer containing dense Li nucleation sites. The homogeneous distribution of amorphous Ni3N and NiO at the interface allowed for a fast transfer of both electrons and ions, and thus facilitated smooth and even plating/stripping of lithium. High cycling stability and rate capability were simultaneously achieved. The 3D Li@N-Ni anode exhibited an extremely low voltage hysteresis of ∼10 mV over 850 h in a symmetric cell. The full battery paired with LiFePO4 achieved steady cycling at 5C for 1500 cycles, with coulombic efficiency constantly higher than 99.2% and an average capacity loss of 0.027 mA h g-1 per cycle, demonstrating a rational strategy for the design and fabrication of efficient lithium anodes for practical applications.

Remedies to Avoid Failure Mechanisms of Lithium-Metal Anode in Li-Ion Batteries

Rechargeable lithium-metal batteries (LMBs), which have high power and energy density, are very attractive to solve the intermittence problem of the energy supplied either by wind mills or solar plants or to power electric vehicles. However, two failure modes limit the commercial use of LMBs, i.e., dendrite growth at the surface of Li metal and side reactions with the electrolyte. Substantial research is being accomplished to mitigate these drawbacks. This article reviews the different strategies for fabricating safe LMBs, aiming to outperform lithium-ion batteries (LIBs). They include modification of the electrolyte (salt and solvents) to obtain a highly conductive solid–electrolyte interphase (SEI) layer, protection of the Li anode by in situ and ex situ coatings, use of three-dimensional porous skeletons, and anchoring Li on 3D current collectors.

Porous Carbon Nanosheets Armoring 3D Current Collectors toward Ultrahigh Mass Loading for High-Energy-Density All-Solid-State Supercapacitors.

The in situ growth of active materials on 3D current collectors (such as Ni foams) presents facile and efficient access to high-performance supercapacitors. However, the low surface area of current collectors limits the mass loading, microstructure, and capacitive performance of active materials thereon. Herein, we develop a novel surface modification with hierarchical N-rich carbon nanosheets on Ni foams via a simple sol-gel method. At the same time, its favorable effects on mass loading and utilization are demonstrated using NiCoMn-carbonate hydroxide (NCM) as a model active material. Specifically, the carbon modification greatly boosts the current collector's specific surface area and enables the growth of dense NCM nanoneedles with controllable mass loading ranging from 5.2 to 23.1 mg cm-2. Meanwhile, the correlation between mass loading and utilization is systematically studied, which shows the well-maintained energy storage efficiency due to the conducive surface modification. As a result, excellent performance with the ultrahigh area-specific capacity of 19.36 F cm-2 at 2 mA cm-2 in the three-electrode configuration and remarkable area-specific energy density of 1352 μW h cm-2 in the solid-state asymmetric device can be achieved, demonstrating a prospective pathway toward facile and effective current collector designs for high-energy/power-density supercapacitors.

Quantitatively Designing Porous Copper Current Collectors for Lithium Metal Anodes

Lithium metal has been an attractive candidate as a next-generation anode material. Despite its popularity, stability issues of lithium in the liquid electrolyte and the formation of lithium whiskers have kept it from practical use. Three-dimensional (3D) current collectors have been proposed as an effective method to mitigate whiskers growth. Although extensive research has been done, the effects of three key parameters of the 3D current collectors, namely the surface area, the tortuosity factor, and the surface chemistry, on the performance of lithium metal batteries remain elusive. Herein, we quantitatively studied the role of these three parameters by synthesizing four types of porous copper networks with different sizes of well-structured micro-channels. X-ray microscale computed tomography (micro-CT) allowed us to assess the surface area, the pore size and the tortuosity factor of the porous copper materials. A metallic Zn coating was also applied to study the influence of surface chemistry on the performance of the 3D current collectors. The effects of these parameters on the performance were studied in detail through Scanning Electron Microscopy (SEM) and Titration Gas Chromatography (TGC). Stochastic simulations further allowed us to interpret the role of the tortuosity factor in lithiation. The optimal range of the key parameters is thereby found for the porous coppers and their performance is predicted. Using these parameters to inform the design of porous copper anodes for Li deposition, Coulombic efficiencies (CE) of up to 99.63% are achieved, thus paving the way for the design of effective 3D current collector systems.