Traditional Anode Research Articles

A Quasi‐Solid‐State Polyether Electrolyte for Low‐Temperature Sodium Metal Batteries

AbstractTaken the unlimited Na reservoir worldwide, battery technology based on Na‐ion chemistry poses as an ideal candidate for large‐scale energy storage systems. Especially, with metallic Na replacing traditional carbon anodes, it's able to maximize the energy density inexpensively. Nevertheless, sodium metal batteries (SMBs) face intrinsically poor stability due to their highly‐reactive nature, where low Coulombic efficiency and short lifetime are often witnessed. The situation can be further aggravated at low temperatures due to insurmountable kinetic barriers. Herein, a 1,3‐dioxolane‐based quasi‐solid‐state electrolyte (PDGE) is proposed with a high ionic conductivity of 3.68 mS cm−1 even at −20 ◦C for SMBs. Moreover, a weak solvation environment is tailored by PDGE, which possesses a high Na+ transference number of 0.7. Concurrently, the solid electrolyte interphase induced from PDGE presents inorganic Na2O, NaF as the major components, which offers accelerated Na+ diffusion and superior stability upon long‐term cycling. With such a quasi‐solid‐state electrolyte, the Na/Na3V2(PO4)3 full cell exhibits great stability over 1000 cycles at −20 ◦C. This study has significant implications to the development for SMBs under low‐temperature conditions.

A Novel Ejector with Water-Separator Function for Proton Exchange Membrane Fuel Cell System Based on a Transient 3D Model

The design and optimization of the hydrogen circulation system can improve the hydrogen utilization rate and overall system efficiency of the fuel cell system. The ejector and water separator are important parts of the design for the ejector-driven hydrogen circulation system. In this study, a novel ejector with water separation functionality is proposed based on a three-dimensional fluid transient simulation, which integrates the ejection and water separation functions in the traditional anode hydrogen circulation system. The separation efficiency of the novel ejector reaches 70.07% and 72.59% under low and high power, respectively, and the deviation is only about 3.47%. In addition, the entrainment ratios of 30 kW, 40 kW, and 50 kW have been improved by 12.54%, 8.04%, and 9.53%, respectively, through further optimization of the new ejector. The new ejector greatly simplifies the system structure while maintaining the original performance, which is innovative and beneficial to improving the power and energy density of the system.

Capacitive Ferrosoferric Oxide as an Anode to Enhance the Electrical Energy Output and Storage of Microbial Fuel Cells

Microbial fuel cells (MFCs) are electrochemical electricity generation devices that use microorganisms to degrade organic matter to produce electrical energy. The anode of microbial fuel cells (MFCs) is the carrier to which electrogenic microorganisms attach. However, traditional anodes do not have a storage function, which limits the application scope of microbial fuel cells. Effectively storing and utilizing the energy generated by MFCs is an important focus of ongoing research and is also key to realizing their effective application. A carbon felt film (CF) was used as the substrate, and a carbon felt film/ferrosoferric oxide (CF/Fe3O4) electrode was prepared by a hydrothermal method. In the power density test, the MFC system constructed with the CF/Fe3O4 electrode as a capacitive biological anode had a maximum power density of 5.09 W/m3, which was 4.43 times higher than that of the blank carbon felt film anode. In the charge–discharge test, the stored charge (Qs) released by the CF/Fe3O4 electrode was 157.12 C/m2 higher than that of the CF electrode after 45 min of charging–discharging. The modified ferrosoferric oxide anode was used in a microbial fuel cell to provide a scientific basis to construct microbial electrochemical systems with high power and energy storage functions.

Synergy of VN and Fe2O3 Enables High Performance Anodes for Asymmetric Supercapacitors.

Fe2O3 is one of the most common anode materials beyond carbons but suffers from unsatisfactory capacity and poor stability, which are associated with the insufficient utilization of active material and the structural instability caused by the phase transformation. In this work, we report an effective strategy to overcome the above issues through electronic structure optimization by constructing delicately designed Fe2O3@VN core-shell structure. The Fe2O3@VN/CC exhibits a much higher areal capacity of 254.8 mC cm-2 at 5 mA cm-2 (corresponding to 318.5 mF cm-2, or 265.4 F g-1) than the individual VN (48 mC cm-2, or 60 mF cm-2) or Fe2O3/CC (93.36 mC cm-2, or 116.7 mF cm-2), along with enhanced stability. Moreover, the assembled asymmetric supercapacitor devices based on Fe2O3@VN/CC anode and RuO2/CC cathode show a high stack energy density of 0.5 mWh cm-3 at a power density of 12.28 mW cm-3 along with good stability (80% capacitance retention after 14000 cycles at 10 mA cm-2). This work not only establishes the Fe2O3@VN as a high-performance anode material but also suggests a general strategy to enhance the electrochemical performance of traditional anodes that suffer from low capacity (capacitance) and poor stability.

Carbon resistant Ni1-xCux-BCZY anode for methane-fed protonic ceramic fuel cell

This research aims to develop a better carbon resistant anode compared to conventional Ni-BCZY anode for methane fueled protonic ceramic fuel cell (PCFC). Solid-state reaction process is used to prepare alloy Ni1-xCux-BCZY anode in PCFC. Ni is doped with Cu for better carbon resistance. Results show that, Ni0·9Cu0.1-BCZY anode calcined at 800 °C for 0.5 h exhibit an electrical conductivity of 2054 S/cm at 600 °C, which is 8.4% less than traditional Ni-BCZY anode. XPS, and Raman data show that Ni0·9Cu0.1-BCZY anode exhibit resistance to carbon deposition compared to traditional anode. The best carbon deposition resistance is observed for the Ni0·7Cu0.3-BCZY sample. This work demonstrates the suppression of carbon deposition and inhibition of anode deformation in methane fueled PCFC with Ni1-xCux-BCZY anode. This work is helpful for development of carbon-resistant materials for energy generation with solid oxide fuel cells.

AgInZnS quantum dots as anodic emitters with strong and stable electrochemiluminescence for biosensing application

Quantum dots (QDs) have become promising electrochemiluminescence (ECL) emitters with high quantum yield and size-tunable luminescence. However, most QDs generate strong ECL emission at the cathode, developing anodic ECL-emitting QDs with excellent performance is challenging. In this work, low-toxic quaternary AgInZnS QDs synthesized by a one-step aqueous phase method were used as novel anodic ECL emitters. AgInZnS QDs exhibited strong and stable ECL emission and a low excitation potential, which could avoid the side reaction of oxygen evolution. Furthermore, AgInZnS QDs displayed high ECL efficiency (ΦECL) of 5.84, taking the ΦECL of Ru(bpy)32+/tripropylamine (TPrA) ECL system as 1. Compared to AgInS2 QDs without Zn doping and traditional anode luminescent CdTe QDs, the ECL intensity of AgInZnS QDs was 1.62 times and 3.64 times higher than that of AgInS2 QDs and CdTe QDs, respectively. As a proof-of-concept, we further designed an “on-off-on” ECL biosensor for detecting microRNA-141 based on a dual isothermal enzyme-free strand displacement reaction (SDR), which not only to achieve the cyclic amplification of the target and ECL signal, but also to construct a switch of the biosensor. The ECL biosensor had a wide linear range from 100 aM to 10 nM with a low detection limit of 33.3 aM. Together, the constructed ECL sensing platform is a promising tool for rapid and accurate diagnosis of clinical diseases.

Influence of graphite Gibbs surface free energy on the initial viscosity and stability of traditional anode slurry in lithium-ion batteries

Influence of graphite Gibbs surface free energy on the initial viscosity and stability of traditional anode slurry in lithium-ion batteries

Investigation the Ni0·9Cu0·1TiO3-δ reforming layer for direct ethanol solid oxide fuel cells

When the solid oxide fuel cell uses ethanol as fuel, it is highly prone to cause carbon deposition and cell failure in the traditional Ni-based ceramic anode. Herein, Ni0·9Cu0·1TiO3-δ catalytic reforming layer is coated on the surface of the traditional Ni-based anode to address this issue. It has been shown that the reforming layer of Ni0·9Cu0·1TiO3-δ decomposes into Ni–Cu alloy and TiO2 under reducing atmosphere, which significantly improves the coking resistance performance of the anode. Cells with Ni0·9Cu0·1TiO3-δ layer have excellent electrocatalytic performance, and the maximum power density can reach 867 mW cm−2 at 800 °C using ethanol as fuel. Moreover, it doesn’t show significant degradation in the 50h stability test, proving that the Ni0·9Cu0·1TiO3-δ reforming layer has good coking resistance performance and electrocatalytic activity when used in direct ethanol solid oxide fuel cells.

Investigation of the Properties of Anode Electrodes for Lithium–Ion Batteries Manufactured Using Cu, and Si-Coated Carbon Nanowall Materials

The fabrication of high-capacity, binder-free Li–ion battery anodes using a simple and efficient manufacturing process was reported in this research. The anode material for lithium–ion batteries utilized is a combination of two-dimensional (2D) carbon nanowalls (CNWs) and Cu nanoparticles (improved rate performance and capacity retention) or Si (high capacity) nanoparticles. A methane (CH4) and hydrogen (H2) gas mixture was employed to synthesize CNWs on copper foil through microwave plasma-enhanced chemical vapor deposition (PECVD). The Cu or Si nanoparticles were then deposited on the CNW surface using an RF magnetron sputtering equipment with four-inch targets. To analyze the electrochemical performance of the LIBs, CR2032 coin-type cells were fabricated using anode materials based on CNWs and other components. It was confirmed that the Cu−CNW demonstrates improved rate performance, increased specific capacity, and capacity retention compared with traditional anodes. Additionally, CNW combined with Si nanoparticles has enhanced the capacity of LIB and minimized volume changes during LIB operation.

A Covalent Organic Framework as a Long‐life and High‐Rate Anode Suitable for Both Aqueous Acidic and Alkaline Batteries

AbstractAqueous rechargeable batteries are prospective candidates for large‐scale grid energy storage. However, traditional anode materials applied lack acid‐alkali co‐tolerance. Herein, we report a covalent organic framework containing pyrazine (C=N) and phenylimino (−NH−) groups (HPP‐COF) as a long‐cycle and high‐rate anode for both acidic and alkaline batteries. The HPP‐COF′s robust covalent linkage and the hydrogen bond network between −NH− and water molecules collectively improve the acid‐alkaline co‐tolerance. More importantly, the hydrogen bond network promotes the rapid transport of H+/OH−by the Grotthuss mechanism. As a result, the HPP‐COF delivers a superior capacity and cycle stability (66.6 mAh g−1@ 30 A g−1, over 40000 cycles in 1 M H2SO4electrolyte; 91.7 mAh g−1@ 100 A g−1, over 30000 cycles @ 30 A g−1in 1 M NaOH electrolyte). The work opens a new direction for the structural design and application of COF materials in acidic and alkaline batteries.

A Covalent Organic Framework as a Long-life and High-Rate Anode Suitable for Both Aqueous Acidic and Alkaline Batteries.

Aqueous rechargeable batteries are prospective candidates for large-scale grid energy storage. However, traditional anode materials applied lack acid-alkali co-tolerance. Herein, we report a covalent organic framework containing pyrazine (C=N) and phenylimino (-NH-) groups (HPP-COF) as a long-cycle and high-rate anode for both acidic and alkaline batteries. The HPP-COF's robust covalent linkage and the hydrogen bond network between -NH- and water molecules collectively improve the acid-alkaline co-tolerance. More importantly, the hydrogen bond network promotes the rapid transport of H+ /OH- by the Grotthuss mechanism. As a result, the HPP-COF delivers a superior capacity and cycle stability (66.6 mAh g-1 @ 30 A g-1 , over 40000 cycles in 1 M H2 SO4 electrolyte; 91.7 mAh g-1 @ 100 A g-1 , over 30000 cycles @ 30 A g-1 in 1 M NaOH electrolyte). The work opens a new direction for the structural design and application of COF materials in acidic and alkaline batteries.

Preparation of a SiO2 @Carbon Sphere/SiO2 -CNF Multilayer Self-standing Anode Prepared via an Alternate Electrospraying - Electrospinning Technique.

The development of flexible lithium-ion batteries (FLIBs) is restrained by traditional rigidity anodes. Carbon nanofiber (CNF) is a promising anode material owing to its high specific surface and superior ion transportation capability. However, the low amount of active material loaded on the CNFs and the poor stability during long cycling restrain their applications. Herein, a SiO2 @carbon sphere/SiO2 -CNF self-standing anode was prepared via alternate electrospraying-electrospinning. The SiO2 content of the anode was increased through the electrospraying SiO2 @carbon spheres layers, and the electrospun SiO2 -CNFs as robust layers enhanced the stability of the anode. The self-standing anode exhibited 633 mA h g-1 in the initial cycle and maintained a 70% Coulomb efficiency for 1000 cycles at a current density of 100 mA g-1 , which could be applied in FLIB and other electrochemical storage devices.

Dual Mechanism for Sodium based Energy Storage.

A dual-mechanism energy storage strategy isproposed, involving the electrochemical process of sodium ion battery (SIB) and sodium metal battery (SMB). This strategy is expected to achieve a higher capacity than SIB, and obtain dendrite-free growth of SMB with a well-designed anode. Here, self-constructed bismuth with "sodiophilic" framework and rapid ion transmission characteristics is employed as the sodium host (anode) integrating alloy/de-alloy and plating/stripping process that suppresses the dendrite growth and overcomes the limited capacity of traditional anode. Benefited from this, the capacity (capacity contributed by alloy and plating of sodium in total) of 2000mAhg-1 can be reached, which can retain up to 800h at 1Ag-1 . Also, the capacity of 3100mAhg-1 can be achieved that is ≈7.7 times than that of alloyed-bismuth (Bi). This work proposes a dual-mechanism strategy to tackle the dilemma of high-performance sodium (Na) storage devices, which opens a new avenue for the development of next-generation energy storage device.

High-entropy oxides: an emerging anode material for lithium-ion batteries.

High entropy oxides (HEOs) have gained significant attention in multiple research fields, particularly in reversible energy storage. HEOs with rock-salt and spinel structures have shown excellent reversible capacity and longer cycle spans compared to traditional conversion-type anodes. However, research on HEOs and their electrochemical performance remains at an early stage. In this highlight, we review recent progress on HEO materials in the field of lithium-ion batteries (LIBs). Firstly, we introduce the synthesis methods of HEOs and some factors that affect the morphology and electrochemical properties of the synthesized materials. We then elaborate on the structural evolution of HEOs with rock-salt and spinel structures in lithium energy storage and summarize the relationship between morphology, pseudocapacitance effect, oxygen vacancy, and electrochemical performance. In the end, we give the challenges of HEO anodes for LIBs and present our opinions on how to guide the further development of HEOs for advanced anodes.

Construction of 3D lithium metal anode using bi-functional composite separator: a new approach for lithium battery.

With the increasing use of Li batteries for storage, their safety issues and energy densities are attracting considerable attention. The Li metal battery (LMB) with limited capacity in the Li metal anode is one of ideal high energy-density systems due to eliminating the use of traditional anode, elevating the energy density of battery and reducing production costs. However, the side reactions between the electrolyte and metallic Li and the irreversible loss of lithium resources caused by the generation of "dead Li" will directly lead to the loss of battery capacity during the cycling process. Therefore, the cycle life of the LMB with limited capacity in the Li metal anode faces significant challenges. Herein, a bi-functional manganese oxide (MnO)/polypropylene/Li1+xAlxTi2-x(PO4)3 (LATP) composite separator is designed to construct a stable three dimensional (3D) Li metal in the surface of Cu foil for LMB. The MnO can dissolve in electrolytes with low concentration, which can be reduced to produce Mn and Li2O, functioning as nucleating seeds to induce sheet-like Li deposition. The sustainably released MnO also involves in the formation of solid electrolyte interphase (SEI) layer, which can be repaired promptly once damaged by the volume expansion of Li. The LATP coating layer is in situ transferred onto the sheet-like Li, acting as an artificial SEI layer for further protection. The constructed 3D Li metal anode with limited capacity shows improved cycle stability in LiFePO4 cell, which shows a capacity retention of 94.5% after 150 cycles. Our strategy, constructing stable 3D Li metal anode with bi-functional composite separator, will bring a new inspiration for developing high energy density LMB.

Investigation on carbon derived from casuarina bark using microwave activation for high performance supercapacitors

The activated carbon was obtained from casuarina bark skin (CBS). CBS were carbonized by 9 M concentrated sulfuric acid (H2SO4) and activated by a chemical activation process by adjusting the concentration of KOH in simple microwave pyrolysis. Obtained activated carbon sample has a defined surface area of about 4588 m2/g. In this study, the activator was KOH solution, is used to synthesise activated carbon from biomass.The activated carbon is created from casuarina bark skin in a 3 wt% KOH solution, and the resulting activated carbon material had a high specific capacitance of 333 F/g and a current density of 0.5 A/g. After 5000 cycles of testing, the produced activated carbon show extreme durability. According to the findings, biomass such as casuarina bark may be utilized to produce activated carbon, which can be used as a substitute for traditional anode materials in supercapacitor applications.

Enabling direct H2O2 electrosynthesis of 100 % selectivity at 100 mA cm−2 using a continuous flow sulfite/air fuel cell

Direct electrosynthesis of hydrogen peroxide from the air is a promising alternative to the complex and energy-intensive anthraquinone process but generally suffers a low productivity and high energy consumption now. Here we provide a direct synthesis strategy using a continuous flow sulfite/air fuel cell, where the traditional oxygen evolution anode is replaced by a sulfite depolarized anode. By optimizing the carbon catalyst and cell parameters for hydrogen peroxide electrosynthesis, the prototype cell can achieve 100 % selectivity at a current density of up to 100 mA cm−2 and retain the selectivity for > 50 h. Up to 23.12 g/L HO2–, the cell can be operated continuously at remarkable productivity of 1.86 mmol cm−2 h−1, where the energy consumption is only 1.96 kWh kg−1 HO2–. The maximum electrosynthesis HO2– concentration was 35.02 g L−1. As a win–win strategy, we apply the desulfurization solution from the ammonia flue gas desulfurization process as the anolyte, which not only enhances the direct electrosynthesis of hydrogen peroxide from the air but also recovers sulfur from flue gas to (NH4)2SO4 fertilizer.

Vanadium (oxy)nitride as a new category of anode for direct ammonia solid oxide fuel cells cells

Ammonia (NH3) is considered a potential energy carrier to be used as a fuel in energy conversion devices, such as solid oxide fuel cells (SOFCs). Nonetheless, in the presence of NH3, traditional Ni-containing anodes may suffer from poor chemical stability, resulting in its partial conversion to nickel nitride. We, therefore, propose a new composite anode for direct ammonia solid oxide fuel cells made of a metallic conducting phase, vanadium (oxy)nitride (VON), and an oxygen-ion conducting phase, (ZrO2)0.92(Y2O3)0.08 (YSZ). X-ray diffraction (XRD) reveals that the VON material is chemically compatible with YSZ. Good thermal stability was also shown under reducing conditions by thermogravimetry (TGA). Electrochemical impedance spectroscopy (EIS) showed that peak performing composition is composed of 50:50% vol of VON:YSZ at 850 °C, yielding comparable performance to that of previous reports on traditional Ni-YSZ cermets. The electrode mechanism under NH3 fuel was found to be similar to that of traditional Ni-based cermet compositions using hydrogen fuel, due to the predicted thermal decomposition of ammonia under the studied operation temperatures, i.e., ≥650 °C, while sensitivity to flow rate considerations was also highlighted. To the best of our knowledge, this work reports a completely new category of anodes for SOFC applications.

Higher Energy Density Mediated Lithium-Sulfur Flow Batteries

There is a need for safe, reliable, high-capacity storage for long duration energy storage. The low cost and high capacity of sulfur make Li-S batteries ideal for this purpose. However, sulfur has poor electrical conductivity and Li-S batteries are prone to polysulfide shuttling that decreases the battery life. Additionally, lithium metal cannot be cycled at high rates or dendritic growth is produced. We have previously addressed the issues with the S by combining aspects of a static Li-S battery with aspects of a redox targeting system and flow battery. With this system we demonstrated that fundamental Li-S chemistry and novel SEI engineering strategies can be adapted to the hybrid redox flow battery architecture, obviating the need for ion-selective membranes or flowing carbon additives, and offering a potential pathway for inexpensive, scalable, safe MWh scale Li-S energy storage. However, these tests were done at lab scale with low S loadings and limited charge rates, limiting both the energy and power density of the proof-of-concept system. In this study we present recent progress scaling up the system from 2.5 mgS cm-2 to over 50 mgS cm-2 and increasing the current density from 0.5 mA cm-2 to 10 mA cm-2 to decrease the charge/discharge time. The increase in S loading results in an increase in energy density and the increase in applied current increases the power density of the system.To scale up the flow cell we address limitations of the small-scale architecture including examining the flow field used with the catholyte and the structure of the Li metal anode. We first tested high surface area scaffolds in Swagelok cells to examine the effect of the increased effective surface area and seeding with lithiophilic materials, like ZnO, on Li metal deposition independent of the flow cell or S chemistry. Using a high effective surface area anode support enables us to increase the applied current density from 0.5 mA cm-2 to 10 mA cm-2 greatly increasing the charge/discharge speed. Furthermore, the addition of a lithiophilic seed layer decreases the nucleation overpotential and encourages uniform Li electrodeposition. A tailored flow field also improves the uniformity of Li deposition on the anode by improving the uniformity of the catholyte flow velocity. These improvements are first evaluated separately and then combined in a mediated Li-S flow battery where cycling rate and capacity retention are compared against a traditional planar Li anode and open flow field.Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

Primary Production of Aluminium and Its Alloys in Molten Salts with Oxygen Evolving Anodes: Overview

Carbon dioxide and other greenhouse gases are emitted during the production of primary aluminium through the Hall-Heroult process. Moreover, the process requires specific energy consumption of as high as 14.685 kWh/tonne of Al. There is an urgency to replace the existing process with a more environmentally and economically friendly process. One such process involves the use of inert anodes instead of traditional carbon anodes, where Al2O3 → 2Al + 1.5O2 occurs instead of 1.5C + Al2O3 → 2Al + 1.5CO2. The life span of inert anodes can be improved by using them at low operating temperatures, however, alumina solubility and dissolution rate decrease at low operating temperatures. Instead of using a traditional NaF-AlF3 molten solution, NaF-KF-AlF3 or KF-AlF3 could be used as low-temperature electrolytes. Introducing KF salt into the NaF-AlF3 mixture increases the alumina solubility and reduces the liquidus temperature of the molten salt. Another factor that affects the liquidus temperature of the mixture and alumina solubility in the electrolyte is the cryolite ratio , where M = Na or K (or both). It should be noted that the cells with AlF3-rich NaF electrolytes suffer with problems such as high cell voltage, low aluminium purity and unstable frozen side ledges. The addition of CaF2, MgF or LiF to the electrolyte mixture could improve the physical-chemical properties of the electrolyte. For instance, the addition of CaF2 to KF-AlF3 molten salts improves the electrical conductivity of the electrolyte. Specific energy consumption of the cell can be significantly reduced by using a vertical electrode cell with reduced anode-cathode distance (ACD). However, the major problem with low ACD is the contamination of reduced aluminium at cathode by anode products. This problem can be solved by using suspension electrolytes where the electrolyte contains excess about of Al2O3 in the electrolyte which obstructs the transportation of anode products into the aluminium diffusion layer on the cathode, thus maintaining high aluminium purity. In this paper, we summarise the developments obtained in designing the inert anode cells. We mainly focus on three main components: Inert anodes, wettable cathodes, and low-temperature electrolytes. The influence of additives on the properties of electrolytes will be discussed in detail. We also discuss the energy consumption, environmental impact and economic aspects of producing aluminium using vertical electrode cells.