Application Of Anodes Research Articles

Vacuum Evaporation Plating Enabling ≤ 10µm Ultrathin Lithium Foils for Lithium Metal Batteries.

Lithium (Li) metal is widely recognized as a viable candidate for anode material in future battery technologies due to its exceptional energy density. Nevertheless, the commercial Li foils in common use are too thick (≈100µm), resulting in a waste of Li resources. Herein, by applying the vacuum evaporation plating technology, the ultra-thin Li foils (VELi) with high purity, strong adhesion, and thickness of less than 10µm are successfully prepared. The manipulation of evaporation temperature allows for convenient regulation of the thickness of the fabricated Li film. This physical thinning method allows for fast, continuous, and highly accurate mass production. With a current density of 0.5mAcm-2 for a plating amount of 0.5mAhcm-2, VELi||VELi cells can stably cycle for 200h. The maximum utilization of Li is already more than 25%. Furthermore, LiFePO4||VELi full cells present excellent cycling performance at 1C (1C = 155mAhg-1) with a capacity retention rate of 90.56% after 240 cycles. VELi increases the utilization of active Li and significantly reduces the cost of Li usage while ensuring anode cycling and multiplication performance. Vacuum evaporation plating technology provides a feasible strategy for the practical application of ultra-thin Li anodes.

Development of an in situ polymerized artificial layer for dendrite‐free and stable lithium metal batteries

AbstractSevere lithium dendrite issues bring a significant challenge for the practical application of Li metal anodes. In this study, a scalable spray‐coating method is used to in situ construct an organic/inorganic composite interfacial layer including Li‐Zn alloy and lithium polyacrylate on the surface of lithium metal. The Li‐Zn alloy exhibits favorable lithiophilic and high Li+ diffusion coefficient, whereas highly elastic lithium polyacrylate is a Li+ conductor and provides excellent mechanical properties. Finally, the ZA‐Li||ZA‐Li cell shows stable cycling for over 1800 h with 1 mA cm−2 at 2 h per cycle, which demonstrates a pronounced inhibition of lithium dendrite growth. Based on the above merits, this work would open a new avenue to develop advanced artificial interfacial layer with multiple capabilities for high‐performance lithium metal batteries.

A Liquid Alloy Anode for the Electrolytic Reduction of Uranium Oxide in Molten Lithium Chloride

Abstract A cost-effective anode material for uranium oxide electrolytic reduction in lithium chloride is still in deficiency. In this work, the application of liquid lithium-bismuth alloy anode was investigated. In the LiCl electrolyte at 923 K, UO2 was reduced electrochemically in cathode, while Li-Bi alloy served as counter electrode. Partial reduction of UO2 was verified by X-ray powder diffraction when the cathode potential was intentionally controlled above the lithium reduction potential. In contrast, when the precipitation of lithium metal was intentionally controlled, the reduction of UO2 was significantly improved. The charge transfer coefficient of UO2/U reaction was also calculated. Regeneration of Li-Bi alloy in LiCl-Li2O through electrolysis was proposed. Carbon, gold, and platinum had been investigated as anode materials. According to the potential variation curve, lithium was not effectively reduced into bismuth as in pure LiCl when oxygen ion was present in the molten salt. These three materials failed to demonstrate advantage in the regeneration of Li-Bi alloy.

Porous carbon-coated silicon composites for high performance lithium-ion batterie anode

With the rapid development of silicon-based lithium-ion battery anode, the commercialization process highlights the importance of low-cost and short-flowproduction processes. The porous carbon/silicon composites (C/Si) are prepared by one-step calcination using zinc citrate and nano-silicon as the primary raw materials at a temperature of 950 °C. In this composite, silicon nanoparticles are coated with a porous carbon shell with an average pore diameter of 4.49nm, which improves the structural stability and electrochemical performance of the anode. Density-functional theory calculations show that the porous carbon enhances the electrical conductivity, facilitates the interlayer migration of Li-ion, and strengthens the gain effect of stress on conductivity. Additionally, stress further reduces the diffusion barriers of Li-ion. The porous C/Si anode demonstrates outstanding specific capacity and rate capability, maintaining a stable specific capacity of 1170 mAh/g at a current density of 0.2 A g−1 after 100 cycles and retaining a reversible specific capacity of 944 mAh/g even at a charging current density of 2 A g−1. The carbon/silicon anode materials prepared using this strategy present a streamlined manufacturing process and exceptional performance, as well as avoiding the post-washing step, providing a pathway toward the scalable application of silicon-based anodes.

Construction of an artificial zinc alloy layer toward stable zinc-metal anode

Aqueous zinc-ion batteries (AZIBs) present a promising option for next-generation batteries given their high safety, eco-friendliness, and resource sustainability. Nonetheless, the practical application of zinc anodes is hindered by inevitable parasitic reactions and dendrite growth. Here, zinc alloy layers (i.e., ZnCo and ZnFe alloys) were rationally constructed on the zinc surface by chemical displacement reactions. The alloying process exposes more (002) planes of the ZnCo anode to guide the preferential and dendrite-free zinc deposition. Furthermore, the ZnCo alloy layer not only effectively inhibits water-induced side reactions but also accelerates electrode kinetics, enabling highly reversible zinc plating/stripping. As a result, the ZnCo anode achieves a Coulombic efficiency of 99.2% over 1300 cycles, and the ZnCo symmetric cell exhibits a long cycle life of over 2000 h at 4.4 mA cm−2. Importantly, the ZnCo//NH4V4O10 full cell retains a high discharge capacity of 218.4 mAh g−1 after 800 cycles. Meanwhile, the ZnFe-based symmetric cell also displays excellent cycling stability over 2500 h at 1.77 mA cm−2. This strategy provides a facile anode modification approach toward high-performance AZIBs.

A simple and effective approach to relieve stress and enhance cyclability of Si-based materials toward high-energy lithium-ion batteries

Silicon-based materials are promising anodes to keep up with the demands for next-generation lithium-ion batteries in the coming decades owing to their ultrahigh theoretical capacities. However, the severe volume changes and mechanical fractures during cycling greatly hinder their way to commercialization. So far, it still remains a great challenge to develop advanced Si-based electrodes with high mechanical stability and remarkable electrochemical properties. In this work, we propose a simple and effective strategy to encapsulate Si@SiOx particles into B, N co-doped carbon nanotubes (BNCNTs) to develop Si@SiOx@BNCNT electrode for enhanced lithium storage. The SiOx layer upon Si particle is designed to mitigate the volume expansion of Si and maintain the particle integrity. Finite element analysis demonstrates that BNCNTs with high mechanical strength can further relieve the internal stress induced by Si expansion upon lithiation. The double restraint effect from SiOx layers and BNCNTs on the Si particles contributes to excellent resistance to structural degradation, enabling high stability and desirable electrochemical performance of Si@SiOx@BNCNT electrode. This strategy provides great opportunities for the practical application of Si-based anodes in high-energy lithium-ion batteries.

Synergistically enhanced LiF–rich protective layer for highly stable silicon anodes

Silicon (Si) is considered as one of the most promising anode materials with an extremely high specific capacity (3579 mAh/g), which is beyond the limit of conventional graphite anodes in lithium (Li) ion batteries (LIBs). However, large volume changes during the lithiation/delithiation process and formation of an unstable solid electrolyte interface (SEI) layer hinder the practical application of Si anodes. To address these issues, constructing a stable protective layer at the interface between anode and electrolyte is a desirable strategy. In this study, a LiF-rich SEI inducing protective layer (LPL) comprising aluminum fluoride (AlF3) and poly(acrylic acid) (PAA) is introduced onto Si anode to construct a stable LiF–rich SEI layer and mitigate the volume changes of the Si anodes during cycling. Owing to the synergetic effects of AlF3 and PAA, a LiF-rich SEI layer with robust physicochemical properties is uniformly formed on the Si anode. As a result, the LPL coated Si (LPL@Si) anodes exhibit outstanding electrochemical properties in Li metal cell tests. In addition, a full-cell prepared with the LPL@Si anode and LiNi0.8Co0.1Mn0.1O2 as a cathode exhibits an excellent cycling performance and mitigated volume changes, demonstrating the potential of this strategy to protect the Si anodes for the development of high-energy–density LIBs.

Stabilizing Solid Electrolyte Interphase on Liquid Metal Via Dynamic Hydrogel-Derived Carbon Framework Encapsulation.

Eutectic gallium-indium liquid metal (EGaIn-LM), with a considerable capacity and unique self-healing properties derived from its intrinsic liquid nature, gains tremendous attention for lithium-ion batteries (LIBs) anode. However, the fluidity of the LM can trigger continuous consumption of the electrolyte, and its liquid-solid transition during the lithiation/de-lithiation process may result in the rupture of the solid electrolyte interface (SEI). Herein, LM is employed as an initiator to in situ assemble the 3D hydrogel for dynamically encapsulating itself; the LM nanoparticles can be homogeneously confined within the hydrogel-derived carbon framework (HDC) after calcination. Such design effectively alleviates the volume expansion of LM and facilitates electron transportation, resulting in a superior rate capability and long-term cyclability. Further, the "dual-layer" SEI structure and its key components, including the robust LiF outer layer and corrosion-resistant and ionic conductive LiGaOx inner layer are revealed, confirming the involvement of LM in the formation of SEI, as well as the important role of carbon framework in reducing interfacial side reactions and SEI decomposition. This work provides a distinct perspective for the formation, structural evolution, and composition of SEI at the liquid/solid interface, and demonstrates an effective strategy to construct a reliable matrix for stabilizing the SEI.

Driving inward growth of lithium metal in hollow microcapsule hosts by heteroatom‐controlled nucleation

AbstractThe application of Li metal anodes in rechargeable batteries is impeded by safety issues arising from the severe volume changes and formation of dendritic Li deposits. Three‐dimensional hollow carbon is receiving increasing attention as a host material capable of accommodating Li metal inside its cavity; however, uncontrollable and nonuniform deposition of Li remains a challenge. In this study, we synthesize metal–organic framework‐derived carbon microcapsules with heteroatom clusters (Zn and Ag) on the capsule walls and it is demonstrated that Ag‐assisted nucleation of Li metal alters the outward‐to‐inward growth in the microcapsule host. Zn‐incorporated microcapsules are prepared via chemical etching of zeolitic imidazole framework‐8 polyhedra and are subsequently decorated with Ag by a galvanic displacement reaction between Ag+ and metallic Zn. Galvanically introduced Ag significantly reduces the energy barrier and increases the reaction rate for Li nucleation in the microcapsule host upon Li plating. Through combined electrochemical, microstructural, and computational studies, we verify the beneficial role of Ag‐assisted Li nucleation in facilitating inward growth inside the cavity of the microcapsule host and, in turn, enhancing electrochemical performance. This study provides new insights into the design of reversible host materials for practical Li metal batteries.

Superhydrophilic 3D amorphous/crystalline heterostructure: Nanosheets-assembled CoMoP-FexP/NF as efficient bifunctional electrodes for alkaline water splitting

To push forward the hydrogen energy technology, it is crucial to develop a highly active catalyst for the application of water splitting. Nevertheless, many electrocatalysts suffer from functional limitations, making them unsuitable for both anode and cathode applications. Therefore, the utilization of bifunctional electrocatalysts is necessary to overcome this limitation. In this study, we have reported a bifunctional CoMoP-FexP/NF catalyst with favorable electrocatalytic performance toward hydrogen evolution reaction/oxygen evolution reaction (HER/OER). Balanced amorphous/crystalline heterophase endows CoMoP-FexP/NF with more exposed active sites. In addition, the superhydrophobic nature of CoMoP-FexP/NF helps to improve the contact with electrolyte. Following conditional optimization, CoMoP-FexP/NF requires only an overpotential of 85.6 mV to achieve a current density of 10 mA cm−2 for HER, and 249.6 mV for a current density of 20 mA cm−2 for OER. A water-splitting electrolyzer comprising CoMoP-FexP/NF requires a low cell voltage of 1.56 V to achieve a current density of 10 mA cm−2. This study provides valuable insights into designing bifunctional electrocatalysts and replacing noble metallic materials to enhance hydrogen production from water splitting.

Interfacial Ru centers coupling with oxygen vacancies in VO-RuO2@CA hybrid aerogel boosts acidic water oxidation

The exploitation of highly active, cheap cost and durable electrocatalyst for acidic water oxidation reaction still presents a major technological and scientific challenge in proton exchange membrane water electrolysers (PEMWEs). Herein, a hybrid aerogel of oxygen defect-rich RuO2 nanoparticles coupling with carbon (VO-RuO2@CA) was designed to promote their activity and stability during acid water oxidation. The optimized VO-RuO2@CA achieves an ultralow overpotential of 207 mV at 10 mA cm−2 for acidic water oxidation and sustains a prominent long-term stability during the 30 h chronopotentiometry test in 0.5 M H2SO4. Furthermore, VO-RuO2@CA exhibits high mass activities of 186.5 mA mgRu−1 and TOF values of up to 2.07 s−1 at an overpotential of 300 mV, being 17.7 and 4.8 times higher than commercial RuO2, respectively. Theory calculations and experimental results verify that the oxygen vacancies (VO) could significantly weaken the binding energy of O* with respect to OOH* for the interfacial Ru centers between RuO2 and carbon, rendering the increase of the intrinsic water oxidation activity and resistance to over-oxidation for RuO2. This research provides a novel pathway to explore remarkably efficient 3D porous hybrid aerogel electrocatalysts toward anodic electrocatalysts applications in PEMWEs.

Investigation on the application of platinum anode towards direct electrochemical reduction of solid metal oxides in CaCl2–CaO melt

Investigation on the application of platinum anode towards direct electrochemical reduction of solid metal oxides in CaCl2–CaO melt

Petaloid bimetallic metal-organic frameworks derived ZnCo2O4/ZnO nanosheets enabled intermittent lithiophilic model for dendrite-free lithium metal anode

The application of lithium metal anode (LMA) is hindered by its poor cycle life which could be caused by lithium dendrite and critical volume change during cycling. Our group previously proposed an intermittent lithiophilic model for three-dimensional (3D) composite LMA, however, the lithium electrodeposition behavior was not discussed. To verify this model, this work proposed a facile design of a petaloid bimetallic metal–organic frameworks (MOFs) derived ZnCo2O4/ZnO (ZZCO) nanosheets modified carbon cloth (CC), i.e. CC@ZZCO, as a 3D host to achieve the intermittent deposition of lithium (Li). The material characterizations, density functional theory (DFT) calculations, lithium electrodeposition behaviors, and the electrochemical tests were investigated and the intermittent lithium deposition behavior was firstly confirmed. Thanks to the intermittent lithiophilic model, the composite LMA enabled a prolonged lifespan of 1500 h in a symmetrical cell under challenging conditions of 5 mA h cm−2 and 5 mA cm−2, and can maintain stable at 10C with an ultrahigh specific capacity of 110 mAh/g. Furthermore, it can also be coupled with a LiNi0.5Co0.2Mn0.3O2 (NCM523) and a high surface load of LiFePO4 (LFP) cathode (11.5 mg cm−2). This research might open a window for the understanding of the Li deposition behavior and pave the way to develop other alkali-metal-ion batteries.

Iron-doped cross-linked puffed carbon as capacitive anode for the enhancement of bioelectron storage capacity in microbial fuel cells

Microbial fuel cell (MFC) can utilize the metabolism of electroactive microorganisms to remove organic pollutants from wastewater, and the application of capacitive anodes can enhance the power generation capacity of MFC and the energy storage capacity of bioelectronics. This research aimed to create a capacitive anode with a large specific surface area and excellent electrical conductivity. To achieve this aim, iron-doped cross-linked puffed carbon (CPC–Fe) was prepared for the modification of carbon cloth (CC) substrates by a simple one-step expansion carbonization method using FeCl3·6H2O and maltose as raw materials. The surface structure characterization confirms the successful incorporation of Fe atoms, with Fe3O4 accounting for 79.61%. Fe3O4 exhibits excellent specific capacitance characteristics and can also serve as a good conductor for the transmission or reception of electrons generated by electroactive bacteria. Furthermore, the mesoporous volume of CPC-Fe significantly increases, which contributes to the enhancement of the specific capacitance of material and the improvement of charge storage capacity. Based on these advantages, the maximum power density of MFC equipped with CPC-Fe/CC anode reaches 1850.50 mW m−2. The CPC-Fe/CC bioanode has a cumulative total charge of 1076.02 C m−2, showing good capacitive behaviour and exhibiting a significant enrichment effect on Geobacter species. This study demonstrates that the regulation of extracellular electron transfer (EET) process based on bioelectronic reception steps can not only enhance the power generation performance of MFC, but also effectively improve the energy storage capacity of MFC, which offers significant knowledge for the development of electrode design in other bioelectrochemical systems.

Fluidized Bed Chemical Vapor Deposition on Hard Carbon Powders to Produce Composite Energy Materials.

Herein, we report a general route for the uniform coating of hard carbon (HC) powders via fluidized bed chemical vapor deposition. Carbon-based fine powders are excellent substrate materials for many catalytic and electrochemical applications but intrinsically difficult to fluidize and prone to elutriation. The reactor was designed to achieve as much retention of powders as possible, supported by a computational fluid dynamics study to assess the hydrodynamic behavior for varying gaseous flow rates. Solutions of the tin seleno- and thio-ether complexes [SnCl4{nBuSe(CH2)3SenBu}] and [SnCl4{nBuS(CH2)3SnBu}] were used as single source precursors and injected at high temperature into a fluidized bed of HC powders under nitrogen flow. The method allowed for the synthesis of HC-SnSx-SnSe2 composites at the gram scale with potential applications in electrocatalysis and sodium-ion battery anodes.

Unravelling the deposition of Zn and Sn as corrosion inhibitor on aluminum (Al) surface for Al-air battery application with sodium chloride electrolytes

Recently, Aluminum (Al) has been extensively developed as an anode material for Al-air batteries. High corrosion rate and slow kinetic reactions of Al in anode application drive the recent research to coat with other more noble metals. Therefore, the primary objective of this work is identifying the effect of zinc (Zn) and tin (Sn) coating on high purity Al surface for electrochemical properties improvement. The employed method of metal oxide coating was electrodeposition process. The structural and morphological of electrodeposition was investigated by scanning electron microscopy (SEM). The surface of Zn-Al was finer than Sn–Al. Additionally, the observed cracks on the surface were analyzed and interpreted as indicative of mixed metal oxide (MMO) coating behavior. In electrochemical performance, the Zn–Al half-cell exhibits a consistent open circuit potential value of −0.94 V. This value is the most stable compared with other variables. Remarkably, the discharge time that represents full-cell of Zn–Al and N-doped carbon-based cathode performance was about 14 h, which is nearly fourteen orders compared with Al variables that can only sustain in an hour. The electrodeposition also contributes to enhancing the specific capacity from 40.763 m Ah g−1 to become 324.627 mAh g−1. In line with other measurements, the corrosion rate with linear polarization measurement placed Zn–Al with the smallest corrosion rate, that is 3.71 × 10-5 mm/year. All the electrochemical measurements used 3.5 % NaCl as the model of seawater electrolytes. This finding could be a reliable option of aluminum air battery development on larger scale in the future.

Multi-dimensional assembly of ZnO nanodots in the reticular carbon nanofibers for high-performance lithium-ion batteries

Due to the high theoretical specific capacity, abundant resources, easy availability, and environmental amicability, zinc oxide (ZnO) has been regarded as a promising alternative for lithium-ion battery anode. However, the further application of ZnO anode is still faced with great challenges such as huge volume transformation and intrinsic low conductivity. Herein, we propose a simple strategy for the preparation of ZnO/carbon clusters (∼50 nm) which are assembled with uniformly distributed ZnO nanodots (∼5 nm) in the three-dimensional carbon nanofibers (ZnO/CNFs) through an electrospinning and subsequent carbonization process using gallic acid-zinc coordination polymer (GAZ) as precursor. The multi-dimensional assembly of ZnO nanodots and reticular formation of conductive carbon network can effectively alleviate the volume change of ZnO anode during long-term cycling process and promote the fast transfer of electrolyte ions/electrons, greatly improving the rate and cycle performance. As a result, the ZnO/CNFs electrode exhibits excellent rate performance of 375.3 mAh g−1 at 2 A g−1 and long cycling stability with capacity retention of 92% over 600 cycles at 1 A g−1. These features indicate that the systematic combination of electrospinning and metal-organic coordination polymers have significant promise for the construction of high-performance metal derivative anodes.

Graphene–Encapsulated Si@C with Dual Carbon Layer Structure as High‐Performance Anode Materials for Lithium–Ion Batteries

AbstractSilicon–based materials are among the highly promising anode candidates for Li–ion batteries owing to their excellent theoretical energy density. However, the huge volume variation makes the application of silicon anode in lithium–ion batteries be full of challenge. Herein, high–performance Si@C@rGO composites anode for lithium–ion batteries are successfully prepared by graphene oxide (GO) uniformly encapsulating resorcinol–formaldehyde resin (RF) coated silicon nanoparticles. The RF‐derived carbon layer can prevent the silicon from direct contact with the electrolyte. Furthermore, the continuous conductive graphene network not only improves the overall electrical conductivity of the composite material, but also can be reversibly deformed with the volume change of silicon during the charging and discharging process, thus greatly improving the structural stability of the anode. The optimal Si@C@rGO‐2 composite provides a high specific capacity of 743.9 mAh g−−1 after 300 cycles at a current density of 1 A g−1. Meanwhile, the material also exhibits good rate performance, showing a good reversible capacity of 719.5 mAh g−1 even at a high current density of 2 A g−1. In addition, this simple and low‐cost strategy of Si@C@rGO anode can provide a design reference for the further development of anode materials in lithium–ion batteries.

Two‐Alloys‐Layer Modified Current Collector toward the Efficient Plating/Stripping of Sodium in Ester‐Based Electrolyte

AbstractSodium metal anode is considered the most promising alternative to lithium due to its cost‐effectiveness and widespread availability. To realize its practical applications, numerous strategies have been devised in metallic Na and electrolyte to enhance the cycle life. However, the improvements in 2D current collector in ester‐based electrolyte remain limited. Herein, a two‐alloys‐layer modified current collector (Na15Sn4/Cu6Sn5/Cu) has been constructed through electrodeposition and sodiation processes. The Na15Sn4/Cu6Sn5 alloys‐layer guarantees the dense plating of Na and establishes a credible connection between Na and substrate. The failure of sodium anode is attributed to the depletion of ester‐based electrolyte resulting from their side reactions, which could be mitigated on Na15Sn4 surface. Thus, the asymmetric cell, containing merely 100 µL electrolyte, achieves efficient Na plating/stripping for 110 times with an average Coulombic efficiency of 94.9%, which is superior than those reported using excessive fluorine‐rich electrolytes. The full cell consisting of an anode with 3 mAh cm−2 of Na on Na15Sn4/Cu6Sn5/Cu and a Na3V2(PO4)3 cathode demonstrates a capacity retention rate of 96% after 200 cycles at 1.0 C. By improving the Coulombic efficiency solely through the modified copper foil, this work provides a new route for the practical application of Na anode in ester‐based electrolytes.

Amorphous Anode Materials for Fast-charging Lithium-ion Batteries.

Fast-charging technology is set to revolutionize the field of lithium-ion batteries (LIBs), driving the creation of next-generation devices with the ability to get charged within a short span of time. From the anode perspective, it is of paramount importance to design materials that can withstand continuous Li+ insertion/deinsertion at high charging rates and still remain unaffected by factors such as mechanical fractures, electrolyte side reactions, polarisation, lithium plating and heat generation. Herein, the recent advancements in the design of amorphous materials as anodes for fast-charging LIBs have been discussed. While the development of this particular class of materials for application in high-rate anodes has been paid limited attention in recent literature, it holds immense promise for improving the fast-charging capabilities. This concept summarizes the recent strides made in this emerging field, outlining the strategies employed in the design of amorphous anodes and emphasizing the crucial role played by the amorphous nature in achieving fast-charging performance. Further, the successive initiatives that can be undertaken to drive the progress of amorphous materials for fast charging LIBs have also been detailed, which could potentially improve their commercial viability.