Anode Surface Research Articles

Constructing Dual Schottky Junctions for High‐Performance Zinc Anode

AbstractAqueous zinc ion batteries provide new solutions for achieving environmentally friendly and safe energy storage devices. Unfortunately, the further application is hampered by the growth of zinc dendrites caused by uneven zinc deposition, hydrogen evolution and other side interfacial reactions at the zinc anode. Herein, a multifunctional Bi‐Bi2O3 hybrid artificial interface layer is constructed on the surface of the zinc anode using an in situ conversion reaction. Among them, the Bi‐Bi2O3 Schottky structure not only significantly accelerates the migration of Zn2+ through its built‐in electric field, but also effectively improves the hydrogen evolution barrier (ΔGH*), thereby suppressing side reactions. Moreover, the Schottky contact formed between the interface layer and the metal zinc interface also regulates the electronic distribution state on the zinc surface and optimizes the deposition process of Zn2+, ensuring a more uniform and orderly zinc deposition process. Based on the synergistic effect of dual Schottky junctions, symmetric batteries achieve stable cycling for 2000 h under the conditions of 1.0 mA cm−2 and 1.0 mAh cm−2. The full cell assembled with α‐MnO2 as the cathode maintains capacity of 112.7 mAh g−1 after 1000 cycles at 1 A g−1 with a capacity retention rate of 84%.

Synergistic Long-Term Protection of Inorganic and Polymer Hybrid Coatings for Free-Dendrite Zinc Anodes.

Constructing an artificial solid electrolyte interface protective layer on the surface of the zinc anode is an effective strategy for addressing dendrite growth, passivation, and the hydrogen evolution reaction in aqueous zinc-ion batteries. This study introduces a robust interlayer composed of a polyvinyl butyral matrix decorated with SiO2 particles (PS). Adsorption of water by Si-OH on the surface of SiO2 leads to excellent hydrophilicity and accelerates the desolvation of ions. A highly stable and hydrophilic PS coating enhances ion migration and possesses ultralong protection ability, ensuring uniform ion deposition and a lower nucleation barrier. Anodes protected by the PS coating achieve long-term cycling stability of >4000 h at 2 mA cm-2 in symmetric cells. The assembled PS-Zn//NH4V4O10 full cells exhibit superior electrochemical performance, demonstrating their potential for practical applications in rechargeable zinc batteries.

Constructing a Multifunctional SEI Layer Enhancing Kinetics and Stabilizing Zinc Metal Anode

AbstractZn dendrite growth and parasitic reactions at the interface of zinc anode/electrolyte in aqueous zinc batteries severely hinder its lifespan in application. Herein, the zinc anode is effectively stabilized by introducing trace amounts of 4‐aminobutane‐1‐phosphate (ABPA) into the ZnSO4 electrolyte. The ABPA adsorbs onto the surface of zinc anode and then further decomposes to a high conductive organic/inorganic composite in situ SEI layer including amino, partial carbon chain, and zinc phosphate. In the SEI layer, the residual undecomposed carbon chain promotes the desolvation of Zn2+, the amino induces uniform Zn2+ plating and zinc phosphate facilitates the migration of Zn2+. Thus, this in situ SEI layer not only suppresses water‐related side reactions but also enhances the Zn2+ transport kinetics. As a result, Zn||Zn symmetric cell delivers an ultralong cycle life of over 13 000 cycles at 50 mA cm−2 and 1 mAh cm−2. A high average Coulombic efficiency of 99.72% is achieved in over 1000 cycles in Zn||Cu half‐cell. The Zn||I2 full cell delivers a high‐capacity retention of 91.42% after 40,000 cycles. Moreover, a 49 mAh Zn||I2 pouch cell maintains 80.28% capacity retention over 300 cycles and 61.22% after 1000 cycles.

Simultaneous Modulation on Solvation Shell and Electrode Interface for Reversible Zinc Anode Realized by a Mutiplefunctional Additive

AbstractThe inferior reversibility of Zn metal anode caused by undesired Zn dendrite and severe interfacial side reactions has to be addressed for the commercial application of Zinc ion batteries (ZIBs). Here, a multiple functional sodium benzaldehyde 2,4‐disulfonate(B24DADS) additives with various blocks of polar sulfonate group, Lewis basic aldehyde groups, and hydrophobic benzene ring is proposed to regulate the solvation structure of Zn2+, construct an H2O‐poor and zincophilic dual electric layer structure, and create a passive SEI on the Zn anode surface, thus restaining dendrite growth and interfacial side reactions. Furthermore, uniform deposition mechanics of the Zn are revealed by the synergistic effect of induced deposition, additive‐derived SEI formation, and texture regulation. In addition, Na+ can also limit the growth of zinc dendrites based on electrostatic shielding mechanisms. Therefore, the multifunctional B24DADS additive grants the anode to deliver remarkable electrochemical performance. Under critical test conditions (20 mA cm−2/20 mAh cm−2), the zinc provides superior long cycling (3700 h) with a low polarization voltage (0.02 V). B24DADS containing electrolyte is well matched with manganese dioxide cathode. This effort renders a promising way to explore advanced additives with unique molecular structures for addressing zinc dendrite growth and rampant side effects.

A tripartite synergistic optimization strategy for zinc-iodine batteries

The energy industry has taken notice of zinc-iodine (Zn-I2) batteries for their high safety, low cost, and attractive energy density. However, the shuttling of I3− by-products at cathode electrode and dendrite issues at Zn metal anode result in short cycle lifespan. Here, a tripartite synergistic optimization strategy is proposed, involving a MXene cathode host, a n-butanol electrolyte additive, and the in-situ solid electrolyte interface (SEI) protection. The MXene possesses catalytic ability to enhance the reaction kinetics and reduce I3− by-products. Meanwhile, the partially dissolved n-butanol additive can work synergistically with MXene to inhibit the shuttling of I3−. Besides, the n-butanol and I− in the electrolyte can synergistically improve the solvation structure of Zn2+. Moreover, an organic-inorganic hybrid SEI is in situ generated on the surface of the Zn anode, which induces stable non-dendritic zinc deposition. As a result, the fabricated batteries exhibit a high capacity of 0.30 mAh cm−2 and a superior energy density of 0.34 mWh cm−2 at a high specific current of 5 A g−1 across 30,000 cycles, with a minimal capacity decay of 0.0004% per cycle. This work offers a promising strategy for the subsequent research to comprehensively improve battery performance.

Biomineralization Inspired the Construction of Dense Spherical Stacks for Dendrite-Free Zinc Anodes.

Aqueous zinc-ion batteries (AZIBs) are considered to be one of the most promising energy storage systems due to their high degree of safety and low cost. However, the deposition of the uncontrolled zinc dendritic morphology on the surface of the Zn anode seriously reduces the cycle life of AZIBs. Herein, inspired by natural biomineralization, a uniform spherical zinc deposition is achieved via the addition of a biological macromolecule to the electrolyte. The proposed biological macromolecule makes Zn2+ undergo dense spherical deposition by regulating the relative growth rate of high-index planes of metal zinc, effectively avoiding the destruction from irregular zinc dendrites. The symmetric cell with the addition of such a biological macromolecule can be stably cycled for >3200 h at 1 mA cm-2 for 1 mAh cm-2. This work sheds light on expanding morphological regulation of metal deposition to spherical shapes for stable metal anodes in addition to a single-crystal plane control strategy.

Atomically Dispersed Ru Species Induced by Strong Metal-Support Interaction for Electrochemical Methane Reforming.

During the high-temperature oxygen evolution reaction for CO2 electrolysis in solid oxide electrolysis cells (SOECs), the key elementary process of O2- transfer is restricted by the high anodic oxygen pressure thermodynamically, thus requiring a high external voltage [open-circuit voltage (OCV)] to drive the electrolysis reaction. Herein, electrochemical CH4 reforming is introduced to the SOEC anode, which remarkably lowers the anodic oxygen pressure and OCV, finally reducing the energy demand from 3.12 to 0.11 kW h per cubic meter of CO. Meanwhile, atomically dispersed Ru species is anchored on the anode surface due to the strong metal-support interaction, which exhibits superior CH4 reforming activity (90% of CO selectivity) and stability (300 h) to the infiltrated Ru nanoparticles and doped Ru species in the bulk lattice at 600 °C. This work proposes an efficient strategy to boost the SOEC performance thermodynamically and produce value-added chemicals at both the cathode and anode of SOEC simultaneously.

Effects of anode geometry on DC magnetron sputtering of copper oxide films deposition

Abstract Effects of anode shape are examined in a custom-made DC magnetron sputtering system. Polycrystalline copper-oxide (CuO) films are deposited using wedge, ring and disc shaped anodes. Current–voltage (I-V) characteristics of the discharge were fitted with models of plasma discharge. Above 700 V a notable rise in average plasma impedance, from approximately 2kΩ to 7kΩ was observed. Scanning electron microscope (SEM) images reveal uniform and porous film growth. The deposition increased significantly with increasing the anode surface area due to decrease in gas density in cathode sheath. For all the anode shapes tested, the deposition rates were higher in magnetron sputtering compared to DC sputtering mode. X-ray diffraction (XRD) of the films deposited with the disk anode revealed polycrystalline films with predominant CuO phase. With increasing sputtering power, average crystallite size vary from 11 nm to 21 nm, dislocation density vary from approximately 8.4×〖10〗^(-3) nm-2 to 2.3×〖10〗^(-3) nm-2 and micro strain from approximately 3.3×〖10〗^(-3) to 1.7×〖10〗^(-3). This indicate that higher sputtering at higher powers produce higher quality films. Atomic force microscopy revealed that the rms roughness of the samples is about 4 nm.

Synergistic Regulation of Anode and Cathode Interphases via an Alum Electrolyte Additive for High‐Performance Aqueous Zinc‐Vanadium Batteries

AbstractA zinc (Zn) metal anode paired with a vanadium oxide (VOx) cathode is a promising system for aqueous Zn–ion batteries (AZIBs); however, side reactions proliferating on the Zn anode surface and the infinite dissolution of the VOx cathode destabilise the battery system. Here, we introduce a multi‐functional additive into the ZnSO4 (ZS) electrolyte, KAl(SO4)2 (KASO), to synchronise the in situ construction of the protective layer on the surface of the Zn anode and the VOx cathode. Theoretical calculations and synchrotron radiation have verified that the high‐valence Al3+ plays dual roles of competing with Zn2+ for solvation and forming a Zn−Al alloy layer with a homogeneous electric field on the anode surface to mitigate the side reactions and dendrite generation. The Al‐containing cathode–electrolyte interface (CEI) considerably alleviates the irreversible dissolution of the VOx cathode and the accumulation of byproducts. Consequently, the Zn||Zn cell with KASO exhibits an ultra‐long cycle of 6000 h at 2 mA cm−2. Importantly, the VOx cathodes (VO2, V2O5 and NH4V4O10) in the ZS−KASO electrolyte showed excellent cycling stability, including Zn powder||VO2 cells and Zn||VO2 pouch cells. Even better, the full cell exhibits excellent cycling stability at low negative/positive (N/P) ratio of 2.83 and high mass loading (~16 mg cm−2). This study offers a straightforward and practical reference for concurrently addressing challenges at the anode and cathode of AZIBs.

Effect of Chloride Ions on the Electrochemical Performance of Magnesium Metal‐Organic‐Frameworks‐Based Semi‐Solid Electrolytes

AbstractThe majority of research on magnesium (Mg) electrolytes has focused on enhancing reversible Mg deposition, often employing chloride‐containing electrolytes. However, there is a notable gap in the literature regarding the influence of chloride ions in semi‐solid Mg electrolytes. In this study, we systematically explore the impact of chloride ions on Mg deposition/dissolution on a copper (Cu) anode using a semi‐solid electrolyte composed of Mg‐based mixed metal‐organic frameworks, MgCl2 and Mg[TFSI]2. We separate the Mg deposition/dissolution process from changes in the anode's surface morphology In this respect, the morphological and compositional transformations in the electrolyte and electrode following galvanostatic cycling are meticulously investigated. Initial potential cycling reveals the feasibility of Mg deposition/dissolution on Cu electrodes, albeit with reduced reversibility in subsequent cycles. Extending the upper potential limit to 4.0 V vs. Mg/Mg2+ enhances Mg dissolution, attributed to chloride ions facilitating Cu surface dissolution. Our findings provide insights into optimizing semi‐solid electrolytes for advanced Magnesium battery technologies.

Anodic Dissolution Behavior of DD6 Nickel-Based Single Crystal Superalloy for Electrochemical Machining Applications

Abstract Nickel-based single crystal superalloys have been widely used in turbomachinery components. Electrochemical machining (ECM) is an essential method for shaping such high-performance alloys. Understanding the fundamentals of ECM for these alloys is crucial for the design and optimization of the process. This study investigated the anodic dissolution of DD6 nickel-based single crystal superalloy in concentrated NaCl and NaNO3 electrolytes under ECM conditions. Polarization curves showed a passive-transpassive transition behavior in both electrolytes. Galvanostatic experiments demonstrated unique current efficiency characteristics contradicting the empirical ECM knowledge. Surface analyses revealed that the anomalous current efficiency of >100% in the NaNO3 electrolyte results from the falling of γ’ phases from anodic surfaces due to the preferential dissolution of the γ matrix phase. The transition from selective to uniform dissolution with increased current density and reduced electrolyte flow velocity leads to decreased current efficiency in NaNO3 electrolyte. The removal of both γ and γ’ phases depends entirely on electrochemical dissolution in NaCl electrolyte, ensuring that current efficiency maintains a normal value. A schematical anodic interface model was proposed to describe the dissolution behavior.

Enhanced Organics Removal Using 3D/GAC/O3 for N-Containing Organic Pharmaceutical Wastewater: Accounting for Improved Biodegradability and Optimization of Operating Parameters by Response Surface Methodology

Pharmaceutical industry effluents often contain high concentrations of refractory organic solvents, chemical oxygen demand (COD), and total dissolved solids (TDSs). These wastewaters, including N-containing organic solvents known for their persistence and toxicity, pose significant environmental challenges. The study evaluated the efficacy of 3D/Granular Activated Carbon (GAC)/O3 treatment compared to linear process additions when treating real pharmaceutical wastewater, and revealed a 2.73-fold enhancement in COD mineralization. The process primarily involves the direct oxidation of monoprotic organic acids found in real pharmaceutical effluents, such as acetic and formic acid, crucially influencing mineralization rates. Optimal conditions determined via the response surface methodology were 125 g/L GAC, 30 mA/cm2, and 75 mg/L O3, achieving high total organic carbon (TOC) and COD removal efficiencies of 87.19 ± 0.19% and 89.67 ± 0.32%, respectively (R2 > 0.9), during verification runs. Current density emerged as the key parameter for organic abatement, aligning with the emphasis on direct oxidation at the anode surface. This integrated approach enhances biodegradability (BOD5/COD) and reduces acute toxicity associated with persistent N-containing solvents, demonstrating promising applications in pharmaceutical wastewater treatment.

Stable Dendrite‐Free Room Temperature Sodium‐Sulfur Batteries Enabled by a Novel Sodium Thiotellurate Interface

AbstractThe practical application of room‐temperature sodium‐sulfur (RT Na−S) batteries is severely hindered by inhomogeneous sodium deposition and notorious sodium polysulfides (NaPSs) shuttling. Herein, novel sodium thiotellurate (Na2TeS3) interfaces are constructed both on the cathode and anode for Na−S batteries to simultaneously address the Na dendritic growth and polysulfides shuttling. On the cathode side, a heterostructural sodium sulfide/sodium telluride embedded in a carbon matrix (Na2S/Na2Te@C) is rationally designed through a facile carbothermal reaction, where the Na2TeS3 interface will be in situ chemically obtained. Such an interface provides abundant electron/ion diffusion channels and ensures rich catalytic surfaces toward Na−S redox, which could significantly improve the utilization of active material and alleviate polysulfides shuttling in the cathode. On the anode side, the inevitable formation of soluble polytellurosulfides species will migrate on Na anode surface, finally constructing a compact and smooth solid‐electrolyte Na2TeS3 interphase (SEI) layer. Such electrochemical formed Na2TeS3 interface can significantly enhance ionic transport and stabilize Na deposition, thus realizing dendrite‐free Na‐metal plating/stripping. Benefitting from these advantages, an anode‐free cell fabricated with the Na2S/Na2Te@C cathode exhibits an ultrahigh initial discharge capacity of 634 mAh g−1 at 0.1 C, which could pave a new path to design high‐performance cathodes for anode‐free RT Na−S batteries.

Correlation between temperature distribution and changes in self-organized luminous pattern in an atmospheric pressure DC glow discharge with sheath gas flow

Abstract The self-organized luminous patterns observed above the anode surface in atmospheric-pressure DC glow discharges were changed by the composition of the gas flow. The patterns were observed not only with liquid anodes but also with metal anodes. Various pattern structures were observed by changing the helium gas flow rate in the core and the ambient oxygen gas flow rate supplied during the discharge. When the pattern formation was observed, the emission spectra and the radial spread of the positive column changed, and the voltage–current characteristic also changed. These results suggest that not only the anode surface but the entire discharge affects the pattern formation. Comparing the results for the liquid and metal anodes, the trends in the pattern formation and voltage–current characteristics were almost identical. The gas temperature in the discharge was also investigated in two different ways, by the laser-induced fluorescence spectroscopy of OH radicals and by Rayleigh scattering, showing in good agreement between both methods. Under the condition where the pattern formed, the gas temperature in the discharge was approximately 2500–3000 K and higher than that of the discharge without the pattern formation. Focusing on the gradient of the temperature distribution, the discharge with the pattern formation had a steeper gradient than that of the discharge without the pattern formation. It is suggested that not only the high temperature of the discharge but also the large gradient of the temperature change plays an important role in the pattern formation. The role of oxygen gas in the pattern formation may be the effect of increasing the temperature and altering the temperature gradient in the discharge rather than generating negative ions in the discharge.

Enhanced electricity generation and energy storage in a microbial fuel cell with a bimetallic-modified capacitive anode

Microbial fuel cells (MFCs) are energy conversion devices that utilize microorganisms attached to the electrode as catalysts for the oxidation of organic waste, thereby generating electricity. In this study, a two-step hydrothermal method was employed to prepare a CF/NiO/Fe3O4 capacitive composite anode by directly growing NiO on a carbon felt substrate as a metal framework to support the in-situ growth of Fe3O4. In this paper, electrochemical tests such as cyclic voltammetry and AC impedance were used to investigate the electrochemical performance of the modified anode. The two electrodes were characterized by SEM, EDS, XRD, FTIR, BET, TEM and SAED test. The MFCs with the CF/NiO/Fe3O4 anode exhibited significant improvements in generation of power and storage of energy performance, reaching a maximum power density of 9.29 W/m3, which has increased by 1.54-fold compared to CF/NiO anode. After charging/discharging for 60 min, the CF/NiO/Fe3O4 anode had a sum charge of 8532.07C /m2, which was a significant increase of 1868.82C/m2 compared to the CF/NiO anode. High-throughput sequencing analysis suggested that the proportion of electricity-generating microorganisms on the CF/NiO/Fe3O4 surface of the anode reached 86.03 %, which was higher than that on CF/NiO anode surface. The protein contents of the CF/NiO/Fe3O4 reached 71.03 mg/cm3. The application of capacitive materials in MFCs would allow the constructed MFCs to generate and store bioelectricity simultaneously.

Malic acid additive with a dual regulating mechanism for high-performances aqueous zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) are widely used in energy storage devices due to their high safety and low cost. However, the practical application of AZIBs is constrained by the formation of dendrites and the occurrence of severe side reactions. Herein, these problems are addressed by introducing malic acid (MA) as a multifunctional additive into electrolyte. Theoretical calculations, finite element simulations and experimental tests show that MA can adsorb on the surface of the Zn anode and change the solvated structure of Zn2+ and promote the desolvation of [Zn (H2O)6]2+, thus inhibiting the hydrogen evolution reaction (HER) and the generation of by-products, and promoting the uniform deposition of Zn. Additionally, benefiting from this dual effect of solvent structure and interface adsorption regulation, a high Coulombic efficiency of 99.83 % can be achieved for the Zn//Cu half cell in an electrolyte containing a small amount of MA, and an excellent lifetime of beyond 4000 h can be achieved in a Zn//Zn symmetric cell at 5 mA cm−2 and 1 mAh cm−2. Even under deep plating/stripping conditions (5 mA cm−2 and 5 mAh cm−2), it is still capable of stabling operation for 600 h. In addition, the Zn//V2O5 full cell with MA also exhibited higher capacity and better rate performance. The incorporation of MA improves the electrochemical performance of zinc ion batteries to a great extent relative to the pure ZnSO4 electrolyte.

Mechanism of the local destruction of the amorphous Ta2O5 layer on the surface of a tantalum anode

In the present work, a mechanism of the destruction of amorphous tantalum oxide Ta2O5 on the tantalum anode surface is suggested based on high absorption properties of tantalum. The data of analysis of the morphological peculiarities of the defective areas of the surface layers show that the destruction of the amorphous film occurs due to the growth of a pyramid-shaped defect; the pyramidal defect is not coherent with amorphous surface Ta2O5, and it is not a product of its crystallization. The nucleation and growth of the “pyramid” occurs due to the directed movement of oxygen during the oxidation of the tantalum surface along the grain boundaries to the region of triple junctions of the tantalum matrix with the subsequent local formation of crystalline Ta2O5. The suggested mechanism offig destruction can be realized when high-purity tantalum powders are used.

Simultaneous electrochemical removal of three microcystin congeners and sulfamethoxazole in natural water

Microcystins (MCs), frequently detected in freshwater ecosystems, have raised significant human health and ecological concerns. New approaches are being developed to control and remove MCs. In this study, we examined factors influencing the efficacy of electrochemical oxidation as a means of control. Anode material (Pt/Ti, Ta2O5-IrO2/Ti, SnO2-SbO2/Ti, boron-doped diamond (BDD)/Si), anode surface area ratios and solution volumes, initial pollutant concentrations, and the co-existing antibiotic sulfamethoxazole (SMX) were investigated. MCs and SMX were dissolved in filtered Taihu Lake water to simulate the natural aquatic environment. The results showed that non-active anodes, lower initial concentration of MC, larger surface area ratio of anode to cathode, and smaller ratio of reaction solution volume to anode surface area could promote the degradation target pollutants. Under optimal conditions in this study, the degradation rates of MC-LR, MC-YR, MC-RR, and SMX each reached more than 90% within 6 hours, and the removal efficiency of MC-YR was the highest among three congeners. The effect of SMX on the degradation of MC congeners depended mainly on their concentration differences, such that when the initial concentration of SMX was one to two orders of magnitude lower than microcystin, the presence of SMX would promote the degradation of MCs. In contrast, when the initial concentration of SMX was higher than that of microcystin by approximately an order of magnitude, sulfamethoxazole would inhibit the degradation of MCs by between 4.6% and 24.5%. Ultra-high-performance liquid chromatography tandem mass spectrometry analysis revealed that the three MC congeners were electrochemically degraded through aromatic ring oxidation, alkene oxidation, and bond cleavage on the ADDA (3-amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4,6-dienoic acid) side chain. Notably, the removal of MCs was accompanied by a decline in the hardness of the reaction water. This study provided insights into electrochemical degradation of microcystins and antibiotics in natural water, offering suggestions for its practical application.

Navigating highly reversible Zn metal anodes via a multifunctional corrosion inhibitor-inspired electrolyte additive

Uncontrolled dendrites growth and irreversible side reactions on the Zn anode have greatly shorten the lifespan of aqueous zinc-ion batteries (ZIBs), thereby hindering their application as promising energy storage devices. Herein, inspired by the use of corrosion and scale inhibitors in metal industry, sodium gluconate (SG) is proposed as a multifunctional electrolyte additive to improve the reversible plating/stripping behavior on Zn metal anodes by simultaneously modulating Zn anode-electrolyte interface and the Zn deposition behaviors. Combining theoretical calculations and experimental characterizations, it shows that SG can protect the Zn anode against the corrosion side reactions and suppress the random growth of dendritic Zn by absorbing on the Zn anode surface to form an artificial interface layer. Concomitantly, the gluconate anion reshapes the solvation shell of Zn2+, influencing the desolvation process of Zn2+ and disrupting the formation of active water. Furthermore, Na+ originating from SG suppresses the dendritic Zn development in the light of electrostatic shielding mechanism. Benefiting from these synergetic effects of SG additive, Zn metal anodes achieve exceptional reversibility with prolonged running lifetime and increased coulombic efficiency and the Zn||V2O5 full cell demonstrates outstanding cycle stability. This strategy is scalable and low-cost, developing a promising approach to advance high-performance ZIBs.

Effect of operating temperature on ammonia decomposition behavior and cell performance of direct ammonia solid oxide fuel cells

Direct ammonia solid oxide fuel cells (DA-SOFC) are regarded as a promising power generation technology. Nevertheless, the catalytic reaction of ammonia on the anode surface significantly affects DA-SOFC performance. This study explores the deterioration of DA-SOFC performance in the 550–700 °C and the interaction between NH3 decomposition and electrochemical reactions. The findings indicate that, at 550 °C, compared to H2, the reduction in power density of NH3 18.58% exceeds 4.56%t of NH3 d.s.g. (mixtures, 0.75H2 + 0.25N2). The anodic polarization impedance of NH3 exceeds that of H2 and NH3 d.s.g. by 51.1% and 28.9%, respectively. Cathode utilizing O2 has a dual impact on NH3 decomposition, at lower temperatures, oxidizing the anode's active site, decreasing NH3 decomposition rate, resulting in insufficient H2 supply, reducing electron transfer coefficient. Conversely, at higher temperatures, O2 promotes NH3 decomposition by boosting H2 consumption. However, more N2 is produced, increasing the concentration loss.