Stable Current Collector Research Articles

Li2ZnCu3 modified Cu current collector to regulate Li deposition

Rationally designing a current collector that can maintain low lithium (Li) porosity and smooth morphology while enduring high‐loading Li deposition is crucial for realizing the high energy density of Li metal batteries, but it is still challengeable. Herein, a Li2ZnCu3 alloy‐modified Cu foil is reported as a stable current collector to fulfill the stable high‐loading Li deposition. Benefiting from the in‐situ alloying, the generated numerous Li2ZnCu3@Cu heterojunctions induce a homogeneous Li nucleation and dense growth even at an ultrahigh capacity of 12 mAh cm‐2. Such a spatial structure endows the overall Li2ZnCu3@Cu electrode with the manipulated steric hindrance and outmost surface electric potential to suppress the side reactions during Li stripping and plating. The resultant Li||Li2ZnCu3@Cu asymmetric cell preserves an ultrahigh average Coulombic efficiency of 99.2% at 3 mA cm‐2/6 mAh cm‐2 over 200 cycles. Moreover, the Li‐Li2ZnCu3@Cu||LiFePO4 cell maintains a cycling stability of 87.5% after 300 cycles. After coupling with the LiCoO2 cathode (4 mAh cm‐2), the cell exhibits a high energy density of 407.4 Wh kg‐1 with remarkable cycling reversibility at an N/P ratio of 3. All these findings present a doable way to realize the high‐capacity, dendrite‐free, and dense Li deposition for high‐performance Li metal batteries.

Li2ZnCu3 Modified Cu Current Collector to Regulate Li Deposition.

Rationally designing a current collector that can maintain low lithium (Li) porosity and smooth morphology while enduring high-loading Li deposition is crucial for realizing the high energy density of Li metal batteries, but it is still challengeable. Herein, a Li2ZnCu3 alloy-modified Cu foil is reported as a stable current collector to fulfill the stable high-loading Li deposition. Benefiting from the in situ alloying, the generated numerous Li2ZnCu3@Cu heterojunctions induce a homogeneous Li nucleation and dense growth even at an ultrahigh capacity of 12 mAh cm-2. Such a spatial structure endows the overall Li2ZnCu3@Cu electrode with the manipulated steric hindrance and outmost surface electric potential to suppress the side reactions during Li stripping and plating. The resultant Li||Li2ZnCu3@Cu asymmetric cell preserves an ultrahigh average Coulombic efficiency of 99.2 % at 3 mA cm-2/6 mAh cm-2 over 200 cycles. Moreover, the Li-Li2ZnCu3@Cu||LiFePO4 cell maintains a cycling stability of 87.5 % after 300 cycles. After coupling with the LiCoO2 cathode (4 mAh cm-2), the cell exhibits a high energy density of 407.4 Wh kg-1 with remarkable cycling reversibility at an N/P ratio of 3. All these findings present a doable way to realize the high-capacity, dendrite-free, and dense Li deposition for high-performance Li metal batteries.

New Mn Electrochemistry for Rechargeable Aqueous Batteries: Promising Directions Based on Preliminary Results

Aqueous batteries with metal anodes exhibit robust anodic capacities, but their energy densities are low because of the limited potential stabilities of aqueous electrolyte solutions. Current metal options, such as Zn and Al, pose a dilemma: Zn lacks a sufficiently low redox potential, whereas Al tends to be strongly oxidized in aqueous environments. Our investigation introduces a novel rechargeable aqueous battery system based on Mn as the anode. We examine the effects of anions, electrolyte concentration, and diverse cathode chemistries. Notably, the ClO4‐based electrolyte solution exhibits improved deposition and dissolution efficiencies. Although stainless steel (SS 316 L) and Ni are stable current collectors for cathodes, they display limitations as anodes. However, using Ti as the anode resulted in increased Mn deposition and dissolution efficiencies. Moreover, we evaluate this system using various cathode materials, including Mn‐intercalation‐based inorganic (Ag0.33V2O5) and organic (perylenetetracarboxylic dianhydride) cathodes and an anion‐intercalation‐chemistry (coronene)‐based cathode. These configurations yield markedly higher output potentials compared to those of Zn metal batteries, highlighting the potential for an augmented energy density when using an Mn anode. This study outlines a systematic approach for use in optimizing metal anodes in Mn metal batteries, unlocking novel prospects for Mn‐based batteries with diverse cathode chemistries.

Laser-Printed Photoanode: Femtosecond Laser-Induced Crystalline Phase Transformation of WO3 Nanorods for Space-Efficient and Flexible Thin-Film Solar Water-Splitting Cells.

Despite its potential for clean hydrogen harvesting, photoelectrochemical (PEC) water-splitting cells face challenges in commercialization, particularly related its harvesting performance and productivity at an industrial scale. Herein, a facile fabrication method of flexible thin-film photoanode for PEC water-splitting to overcome these limitations, based on laser processing technologies, is proposed. Laser-induced graphene, a carbon structure produced through direct laser writing carbonization (DLWC), plays a dual role: a flexible and stable current collector and a substrate for the hydrothermal synthesis of tungsten trioxide (WO3) nanorods (NRs). To facilitate water-splitting, a femtosecond-pulsed laser (fs laser) is focused on the WO3 NRs, converting their crystalline phase from pristine orthorhombic to monoclinic structure without thermal damage. With NiFe layered double hydroxide (LDH) catalyst, the flexible thin-film photoanode exhibits good PEC performance (1.46mAcm-2 at 1.23 VRHE) and retains ≈90% of its performance after 3000 bending cycles. With its excellent mechanical properties, the flexible photoanode can be operated in various shapes with different curvatures, enabling space-efficient PEC water-splitting by loading larger photoanode within a given space. This study is expected to contribute to the advancement of large-scale solar water-splitting cells, introducing a new approach to enhance H2/O2 production and expand its application range.

Role of Interface Strain and Chemo-Mechanical Effects during Electroplating in Sodium Metal Battery Anodes.

In this study, we demonstrate that elastic strain applied to a current collector can influence the overall thermodynamic and kinetic picture of sodium metal electrodeposition and hence the performance of a sodium metal battery. To controllably study the role of strain in electrochemical performance, we utilize NiTi foil as a stable current collector, nucleation interface, and superelastic material. Our findings demonstrate that a locked-in elastic tensile strain near 8% results in 40 mV lower onset potential for sodium electrodeposition, 19% decrease in charge transfer resistance, and 20% lower cumulative sodium loss, among other effects. These performance improvements are correlated primarily to the control of the irreversible behavior in the first few minutes of electroplating. Given the prevalence of strain buildup in commercial battery cell configurations, our work highlights that strained current collector interfaces can result in significant long-term chemo-mechanical performance outcomes broadly relevant to sodium and other metal battery design considerations.

Development of Electroactive and Stable Current Collectors for Aqueous Batteries

The need for low-cost, high-safety batteries for large-scale energy storage applications has sparked a surge in research of rechargeable aqueous batteries. While most research efforts are focused on the development of electrolyte formulations and electrode materials, it appears that the current collector impact on the battery performance is frequently overlooked. Even though the current collector is traditionally thought of as an inactive battery component, it is included in the battery energy density calculations, making its activation desirable. Furthermore, poor current collector selection can cause irreversible side reactions, resulting in rapid cell efficiency decay. Herein we propose a new approach to design current collectors that makes use of anodized Ti. The redox-active anodized Ti significantly improves the overall anode capacity and provides effective inhibition of hydrogen formation on the electrified interface. The use of TiO2 particles on an anodized Ti current collector in an aqueous electrolyte solution resulted in capacity of 130 mAh g−1 and exceptional capacity retention of 99% after 1000 cycles. Although the concept of active current collectors needs to be refined before it can be implemented in commercial cells, our findings indicate that this approach could be useful for improving overall cell performance without requiring significant changes to its configuration.

Achievement of high energy carbon based supercapacitors in acid solution enabled by the balance of SSA with abundant micropores and conductivity

Wide potential window and stable current collector that are high concerned with the energy density and durability respectively of an aqueous based energy storage device have always been big challenges. Herein, flexible and self-standing carbon fiber fabric with high surface area of 951 m2 g−1 and high conductivity (HSHC-CFF) are synthesized via a facile heat treatment process. When served as supercapacitive electrode directly in 1 M H2SO4, a high specific capacitance of 255 F g−1 (3.32 F cm−2, 127.7 F cm−3) at 0.5 A g−1 is achieved, which means a high area normalized capacitance of 26 μF cm−2 that is in the range of theoretical values speculated from the electric double-layer mechanism is realized. Importantly, operation window of the HSHC-CFF film is high close to 1.8 V (−0.6–1.2/1.15 V vs Ag/AgCl), resulting in a high energy density of 16 Wh kg−1 at 160 W kg−1 for a symmetric cell when considering the mass of two electrodes. Meanwhile, the high performance is maintained and even better along cycling of over 20,000 cycles (the capacitance rises to 118% of the initial value). A mechanism of micropore (∼0.7 nm) induced dehydration process of electrolyte cations and linear counter-ions’ accommodation in the pores is proposed, which is supposed to contribute to the high normalized capacitance and wide operation window.

Embossed aluminum as a current collector for high-rate lithium cathode performance

Al foil carefully prepared via an anodization process followed by chromate-phosphate treatment is evaluated for use as a current collector for a cathode powder prepared by the conventional electrode coating method. The formation of an embossed surface on the current collector imparts hydrophilic properties, thereby enhancing the adhesion capabilities of the cathode active material. In Li-ion cells where LiCoO2 is employed as the active cathode material, the embossed Al foil is an electrochemically stable current collector when in contact with other cell components during the charge–discharge processes. This also produces a notable decrease in the polarization associated with the electrical disconnection between the active material and the Al current collector, which ultimately results in a stable cycle life at high current densities.

Development of stable current collectors for large area dye-sensitized solar cells

The substrate sheet resistance effect in a large area dye-sensitized solar cell (DSC) device is still the main factor responsible for low energy conversion efficiencies. In this work, current collectors made of metal lines were applied by magnetron sputtering on a transparent conducting glass substrate. The introduction of these metal lines enabled a decrease in the sheet resistance from 7.26Ω·□−1 to 2.52Ω·□−1, by depositing an optimized 1.0μm tungsten thick layer on the top of 1.5μm thick molybdenum lines. These Mo/W lines withstanded long-term stability when in contact with iodide/triiodide redox couple. Large area dye-sensitized solar cells with 36cm2 of active area were assembled and the power conversion efficiency increased from 0.54% to 1.62% when ten metal lines were applied in both electrodes. As a final design, Mo/W lines were only applied onto the counter-electrode and protected with an indium-tin oxide layer; the resulting device showed a power conversion efficiency of 3.43%, compared with the reference efficiency of 2.38%.

Iron supported C@Fe3O4 nanotube array: a new type of 3D anode with low-cost for high performance lithium-ion batteries

Rational design and engineering of materials and/or structures for novel electrodes leading to next-generation lithium-ion batteries with high energy and power densities is a major challenge to the ever-growing needs of the electronic and automobile industries. To tackle this issue, we have designed a new type of 3D anode by anodization of iron foil to form a highly ordered Fe3O4 nanotube array directly on a low-cost current collector (Fe foil) followed by carbonization of pre-adsorbed glucose on the nanotube array at 500 °C. In such an electrode, each part plays its desired role, with the Fe foil being a low cost and stable current collector, Fe3O4 working as a high-capacity active material, and the carbon coating forming an electron conducting network and stable solid electrolyte interface. High capacity (1020 μA h cm−2 at 20 μA cm−2) and high rate capability (176 μA h cm−2 at 1000 μA cm−2) were achieved in this newly designed electrode. Overall, the results described in this work provide a promising route to facile and large-scale production of a low-cost 3D composite electrode with enhanced electrochemical performance.

Development of a Silver Based Stable Current Collector for Solid Oxide Fuel Cell Cathodes

ABSTRACTLong term stability has been a crucial issue for the future applications of the solid oxide fuel cells (SOFCs). Current collectors for the cathodes have been among the most vulnerable components of the SOFCs due to their operation in oxidizing atmospheres at relatively high temperatures. Ag and Ag based LSM (lanthanum-strontium manganite) composites were studied to develop highly stable and low-cost current collectors compatible with other fuel cell components. In this study, no degradation was observed in the electrical conductivity and the porous microstructure of the Ag-LSM composite current collectors after 600 hours of operation at 800oC in air.

The electrowinning of lithium from chloride-carbonate melts

It is shown that lithium can be electrowon from a lithium chloride-carbonate electrolyte with current efficiencies as high as 90 pct from cells where the catholyte and anolyte are separated by a porous diaphragm and lithium carbonate is fed to the anolyte. The reduction of carbonate ions at the cathode was kept to a minimum by the porous diaphragm. The primary product of the reaction of carbonate ions with the carbon anode was carbon dioxide. Various cell designs were investigated, and a packed-bed anode consisting of a graphite tube containing a bed of graphite particles showed the greatest promise in providing a dimensionally stable current collector with preferential consumption of the bed material.