Foil Electrode Research Articles

Layer-by-Layer-Assembled Polyaniline/MXene Thin Film and Device for Improved Electrochromic and Energy Storage Capabilities.

Polyaniline (PANI) is an attractive electrochromic and storage material due to its reversible and sustainable electrochemical redox processes. However, the insufficient surface area and excessive charge intercalation after long-term cycling results in limited charge capacitance and unsatisfactory cycling stability. In this work, we demonstrate an innovative method to increase PANI's electrochromic and energy storage performance by incorporating MXene, to enhance electrochemical activity and reveal more active areas of ion/electron intercalation/deintercalation and charge transfer. The hydrogen bonds formed between N-H, C-H, and C-N of PANI and -OH and -O surface functional terminations of MXene further enhance the interface interaction. With substantial optical transmittance modulation and charge capacitance, excellent coloration efficiency, and outstanding durability, the PANI/MXene thin film demonstrates exceptional color-switching and energy storage characteristics. Furthermore, the sandwich device with a PANI/MXene thin film as the positive electrode and zinc foil as the negative electrode demonstrates exceptional electrochromic and Zn2+ storage capability. This work raises possibilities for next-generation intelligent energy conversion and storage technologies and offers fresh perspectives on the design of ionic devices.

Enhanced CO2 Electroreduction to ethylene on Cu nanocube coated with nitrogen-doped carbon shell in-situ electro-derived from metal-organic framework

Electrochemical CO2 reduction reaction (CO2RR) to ethylene is one of the most promising technologies to achieve efficient use of carbon resources and sustainable development, in which the development of an efficient and stable electrocatalyst is particularly important. In this work, we develop a catalyst in situ electro-derived from Cu-based MOF for CO2RR to ethylene. We prepared nano Cu-MOF by microwave synthesis and supported it on a Cu foil substrate as a working electrode (denoted as MOF/Cu foil). During in situ electrolysis, Cu-MOF was converted into a highly dispersed nitrogen-doped carbon-coated Cu nanocube (denoted as Cu-cube/CN), which inhibited particle agglomeration and enhanced active site exposure. At a potential of −1.15 V vs. RHE, the Faradaic efficiency (FE) of the Cu-cube/CN catalyst for ethylene is 49.6 %, significantly higher than that of the original Cu foil electrode and Cu-MOF supported on the gas diffusion layer (GDL) prepared working electrode (denoted as MOF/GDL). In situ attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) and density functional theory (DFT) calculations studies indicate that due to the electron-donating ability of the CN coating, the adsorption of *CO is enhanced, increasing the *CO coverage, lowering the reaction free energy of *CO dimerization, promoting C-C coupling and ethylene generation. This work provides new insights for the development of efficient and stable electrocatalysts for CO2RR-to-ethylene production.

Metal-Free Polymer-Based Current Collector for High Energy Density Lithium-Metal Batteries.

The energy density of lithium-metal batteries (LMBs) relies substantially on the thickness of the lithium-metal anode. However, a bare, thin lithium foil electrode is vulnerable to fragmentation due to the inhomogeneity of the lithium stripping/plating process, disrupting the electron conduction pathway along the electrode. Accordingly, the current collector is an integral part to prevent the resulting loss of electronic conductivity. However, the common use of a heavy and lithiophobic Cu current collector results in a great anode mass increase and unsatisfactory lithium plating behavior, limiting both the achievable specific energy and the cycle life of LMBs. Herein, a metal-free polymer-based current collector is reported that allows for a substantial mass reduction, while simultaneously extending the cycle life of the lithium-metal anode. The specific mass of the ultra-light, 10µm thick polymer-based current collector is only 1.03mg cm-2, which is ≈11% of a 10 µm thick copper foil (8.96mg cm-2). As a result, LMB cells employing this novel current collector provide a specific energy of 448Wh kg-1, which is almost 18% higher than that of LMBs using the copper current collector (378Wh kg-1), and a greatly enhanced cycle life owing to a more homogeneous lithium deposition.

Microstructure and properties of Mg/Ti joint welded by resistance spot welding with an aluminum interlayer

Magnesium alloy AZ31B and titanium TA2 were welded by resistance spot welding technology employing an interlayer of aluminum foil and asymmetric electrodes. The microstructure of the joint was observed, with an analysis conducted on the impact of welding current and welding time on the tensile shear load of the joint. During the welding process, the aluminum interlayer melted and blended with the molten magnesium alloy, leading to the formation of a eutectic layer consisting of Mg17Al12 and (Mg) in close proximity to the welding interface. As the increasing of welding current or the extending of welding time, there was an initial increase followed by a slight decrease in the tensile shear load of the AZ31B/TA2 joint. At a welding current of 16 kA, the tensile shear load of the joint achieved the maximum, which was approximately 6.48 kN. The findings suggest that it is effective to use an aluminum foil as an intermediary to regulate the metallurgical reaction at the interface and utilize nonsymmetrical electrodes for thermal compensation in the resistance spot welding between titanium and a magnesium alloy.

Comparison of the effect of different external electrodes on discharge plasma-assisted diffusion flame stabilization

To optimize the design of plasma injectors, the influence of different external electrodes on plasma-assisted flame stabilization was assessed by using a nonequilibrium plasma injector flame control setup. The electrical characteristics of the injector, flame structure parameters, flame intensity, discharge power, and cost-to-effectiveness ratio under different external electrodes (four mesh electrodes and one copper foil electrode) were analyzed using electrical and optical methods. The results show that reducing the mesh size of the external electrode leads to a decrease in breakdown voltage. Compared with a ceramic dielectric barrier-based injector, an injector with a quartz dielectric barrier produces a higher breakdown voltage under the same conditions. For the same actuation voltage, the discharge current increases as the mesh size of the external electrode decreases, and combustion is enhanced by the discharge plasma; therefore, it is better to adopt a smaller mesh hole size to realize good flame stabilization under a lower actuation voltage. However, under the studied working conditions, reducing the mesh hole size of the external electrode increases the cost-to-effectiveness ratio of plasma injector-based flame stabilization. Thus, considering the cost-to-effectiveness ratio and the weight of the injector, an external electrode with a larger mesh hole size should be chosen, which contradicts the above rule.

In-situ formed Li2O and an artificial protective layer on copper current collectors to enhance the cycling stability of lithium metal anode batteries

In this study, we present a facile one-step method for the thermal treatment of commercial Cu foils, leading to the growth of Cu2O and CuO nanoparticles in an air atmosphere, resulting in the coating of an artificial protective layer on the copper foil surface. The as-prepared CuO/Cu2O nanoparticles exhibit a spherical morphology, providing ample active sites to improve uniform lithium plating and cyclic stability by building a highly stable In-situ Li2O-rich solid-electrolyte interphase (ISEI). The artificial solid-electrolyte interphase (ASEI) protective layer contains graphene oxide (GO) as a filler with PVDF-HFP and lithium Nafion polymers, enhances Li+ ion migration, which reduces volume expansion and stabilizes the interface, preventing unwanted side reactions between active lithium and electrolytes by facilitating controlled lithium deposition underneath. For integration into an anode-less full cell based on a 2032-type coin cell, alongside a lithium iron phosphate (LFP) cathode, the ISEI oxide layer was grown on a Cu foil electrode (denoted as Cu-30) via a thermal treatment at 320 °C in air for 30 min and coated ASEI (denoted as GO@Cu-30). This cell demonstrated remarkable electrochemical performance. After 250 cycles at 0.5C, it exhibited an outstanding capacity retention of 93.12 % with 99.92 % CE, significantly surpassing the performance of a bare Cu foil, which showed a capacity retention of only 9.54 % with CE of 98.77 %. This work highlights the potential of a simple thermally treated Cu foil as a current collector to overcome the Anode-less lithium metal battery (ALMB) challenges associated with high-energy-density demand.

Chitin and Cellulose as Constituents of Efficient, Sustainable, and Flexible Zinc-Ion Hybrid Supercapacitors

A zinc-ion hybrid supercapacitor (ZIHS) is a prospective energy storage device featuring cost-effectiveness, operational safety, environmental friendliness, high-power performance, and satisfied energy density.1 The sustainability of this ZIHS technology is even improved by introducing biopolymer constituents into the cell construction.2 Herein, efficient, sustainable, and flexible ZIHSs employing polysaccharide (chitin- or cellulose-based) components are developed.3 Using green ionic liquid solvents, biopolymer-bound, activated carbon-based cathode materials and hydrogel biopolymer electrolytes containing conductive zinc salts are obtained. According to systematical characterization results, the prepared materials possess favorable functional properties. Biopolymer binders provide homogeneity and integrity within the electrode network and high adhesion to the surface of the current collector. Depending on the type of zinc salt, hydrogel biopolymer electrolytes display high ionic conductivity (up to 46 mS cm−1), expanded electrochemical stability window (up to ca. 2.8 V), and zinc dendrites growth suppression. Biopolymer components assembled with zinc foil electrodes operate efficiently in both coin and pouch ZIHS cell configurations, providing satisfactory energy (45–50 Wh kg−1) and high power (10–20 kW kg−1) density combined with excellent cycle stability. Moreover, these ZIHS pouch-type devices exhibit superior durability and flexibility, withstanding mechanical stress up to 150° bending states with at least 90% of capacitance retention. It suggests a prospect for their application in wearable electronics.4 References(1) Wang, Y.; Sun, S.; Wu, X.; Liang, H.; Zhang, W. Status and Opportunities of Zinc Ion Hybrid Capacitors: Focus on Carbon Materials, Current Collectors, and Separators. Nano-Micro Lett. 2023, 15 (1), 78.(2) Kasprzak, D.; Mayorga-Martinez, C. C.; Pumera, M. Sustainable and Flexible Energy Storage Devices : A Review. Energy & Fuels 2023, 37, 74–97.(3) Kasprzak, D.; Liu, J. Chitin and Cellulose as Constituents of Efficient, Sustainable, and Flexible Zinc-Ion Hybrid Supercapacitors. Sustain. Mater. Technol. 2023, 38, e00726.(4) Dubal, D. P.; Chodankar, N. R.; Kim, D. H.; Gomez-Romero, P. Towards Flexible Solid-State Supercapacitors for Smart and Wearable Electronics. Chem. Soc. Rev. 2018, 47 (6), 2065–2129. Figure 1. Graphical abstract of the research on biopolymer-based Zn-ion hybrid supercapacitors. Figure 1

Switching Reaction Pathways of CO2 Electroreduction by Modulating Cations in the Electrochemical Double Layer.

Tuning the selectivity of CO2 electroreduction reaction (CO2RR) solely by changing electrolyte is a very attractive topic. In this study, we conducted CO2RR in different aqueous electrolytes over bulk metal electrodes. It was discovered that controlled CO2RR could be achieved by modulating cations in the electrochemical double layer. Specifically, ionic liquid cations in the electrolyte significantly inhibits the hydrogen evolution reaction (HER), while yielding high Faraday efficiencies toward CO (FECO) or formate (FEformate) depending on the alkali metal cations. For example, the product could be switched from CO (FECO=97.3 %) to formate (FEformate=93.5 %) by changing the electrolyte from 0.1 M KBr-0.5 M 1-octyl-3-methylimidazolium bromide (OmimBr) to 0.1 M CsBr-0.5 M OmimBr aqueous solutions over pristine Cu foil electrode. In situ spectroscopy and theoretical calculations reveal that the ordered structure generated by the assembly of Omim+ under an applied negative potential alters the hydrogen bonding structure of the interfacial water, thereby inhibiting the HER. The difference in selectivity in the presence of different cations is attributed to the hydrogen bonding effect caused by Omim+, which alters the solvated structure of the alkali metal cations and thus affects the stabilization of intermediates of different pathways.

Switching Reaction Pathways of CO2 Electroreduction by Modulating Cations in the Electrochemical Double Layer

Tuning the selectivity of CO2 electroreduction reaction (CO2RR) solely by changing electrolyte is a very attractive topic. In this study, we conducted CO2RR in different aqueous electrolytes over bulk metal electrodes. It was discovered that controlled CO2RR could be achieved by modulating cations in the electrochemical double layer. Specifically, ionic liquid cations in the electrolyte significantly inhibits the hydrogen evolution reaction (HER), while yielding high Faraday efficiencies toward CO (FECO) or formate (FEformate) depending on the alkali metal cations. For example, the product could be switched from CO (FECO = 97.3%) to formate (FEformate = 93.5%) by changing the electrolyte from 0.1 M KBr‐0.5 M 1‐octyl‐3‐methylimidazolium bromide (OmimBr) to 0.1 M CsBr‐0.5M OmimBr aqueous solutions over pristine Cu foil electrode. In situ spectroscopy and theoretical calculations reveal that the ordered structure generated by the assembly of Omim+ under an applied negative potential alters the hydrogen bonding structure of the interfacial water, thereby inhibiting the HER. The difference in selectivity in the presence of different cations is attributed to the hydrogen bonding effect caused by Omim+, which alters the solvated structure of the alkali metal cations and thus affects the stabilization of intermediates of different pathways.

Ultrasonic vibration-assisted electrical discharge machining of enclosed microgrooves with laminated electrodes

An enclosed microgroove is a vital surface microstructure that is difficult to prepare on the surfaces of difficult-to-machine electrically conductive materials using conventional methods. Electrical discharge machining (EDM) is suitable for this task. It is obtained primarily through layer-by-layer scanning EDM with micro-column electrodes or reciprocating EDM with foil electrodes. However, owing to the small cross-sectional size of the electrodes, a stable machining process is challenging to achieve, which seriously reduces the machining efficiency. To solve these problems, this study proposed ultrasonic vibration-assisted EDM using a laminated electrode possessed strong anti-interference properties for enclosed microgrooves. The effects of ultrasonic vibration on the EDM of microgrooves with single foil and laminated electrodes were investigated. The results show that ultrasonic vibration could improve the machining efficiency of the two types of electrodes and significantly improve the profile quality of the microgrooves prepared using laminated electrodes. When the amplitude was 3 μm and the frequency was 30 kHz, the bottom sidewall corner radius of microgrooves machined by brass foils in laminated electrodes was 28 μm, the width, depth, and roughness of microgrooves machined by copper foils in laminated electrodes were approximately 78 μm, 229 μm and 0.7 μm, the material removal rate was 0.0072 mm3/min. Based on the optimized parameters, inverted “convex” microgrooves with fine consistency were successfully prepared using laminated electrodes on Ti–6Al–4V alloy surfaces. The machining time was reduced by 40% for each microgroove compared with using the single foil electrode. This study provides a new method for preparing complex microgrooves.

Preparation of oxygen vacancy-rich 3D-Ag nanosheet arrays electrodes for efficient CO2 reduction into CO through in situ oxidation-reduction

Enhancing the working current density is a great challenge that limits the practical applications of the CO2 electrochemical reduction. In this study, a facile method was developed to prepare 3D-Ag nanosheet arrays (3D-Ag NA) electrodes for efficient CO2 reduction into CO through in situ oxidation-reduction. The resulting electrodes exhibited high specific surface area and abundant oxygen vacancies. 3D-Ag NA on Ag foil electrode (3D-Ag NA/Ag) demonstrated a significantly enhanced current density of 25.9 mA/cm2 at −1.06 V vs. RHE in an H-cell, surpassing the performance of Ag foil, Ag nanoparticles and Ag2O nanoparticles electrodes. Moreover, 3D-Ag NA on low cost graphite (3D-Ag NA/C) showed a current density of 24.3 mA/cm2 at a remarkble low potential of −0.96 V vs. RHE. It was found that the formation of a dense Ag2O layer play a critical role in the establishing the 3D-Ag NA. Furthermore, CO2-TPD and DFT studies revealed that the 3D-Ag NA exhibited high CO2 adsorption capacity and low CO2 activation energy. This study presents a promising approach for scalable electrode preparation in the electrochemical reduction of CO2 to CO, enabling high current density and selectivity.

Silver nanoflake-mediated anode texture control enabling deep cycling of aqueous zinc-ion batteries

The escalating popularity of aqueous zinc-ion batteries has prompted substantial research efforts directed at mitigating zinc dendrites and parasitic reactions. Modifying Zn foil electrodes with Ag metal/alloy has emerged as an efficacious strategy owing to the exceptional zincophilicity and remarkable electrical conductivity of Ag. Nevertheless, previous studies predominantly rely on either 3D architectures or Ag nanowires/particles. The former approach may increase costs and compromise energy density, while the latter inadequately guides planar zinc deposition. In this work, Ag nanoflakes synthesized by a solution method are employed to control Zn anode texture through a facile drop-casting technique. The nanoflake morphology facilitates the horizontal arrangement of Ag modification layer, thereby readily promoting horizontal zinc deposition. It is also found that the Ag nanoflakes can improve electrolyte wettability, augment anti-corrosion ability, homogenize electric field, diminish nucleation overpotential, reduce desolvation activation energy, impede two-dimensional Zn2+ ion diffusion, reduce exchange current density, lower electrochemical impedances, and result in the formation of AgZn3 alloy. Correspondingly, the zinc stripping/plating reversibility is significantly improved, accompanied by considerably inhibited parasitic reaction, contributing to the realization of deep cycling for both Zn//Zn cell and Zn//MnO2 battery. This study unveils a viable morphology-tailored methodology to achieve dendrite-free characteristic.

An innovative aluminium foil electrode modified with Al nanoparticles and EDTA for lead detection in biological samples

This study presents a novel Aluminium foil-based electrode characterized by its affordability, flexibility, and ease of modification with carboxylic moiety-containing organic molecules. Upon foil modification with Aluminium nanoparticles and EDTA (AlNP-EDTA/AlE), the modified electrode exhibits remarkable activity in the oxidation of lead at potentials around −0.4 V. The lead signal is derived from the oxidation of lead deposited on the electrode surface using anodic stripping voltammetry (ASV). The addition of EDTA to AlNP/AlE increased the anodic peak current of lead by more than 500 %. The surface characterization of the electrode was performed by scanning electron microscopy (SEM) and infrared spectroscopy (IR), while its electroactive properties were evaluated by cyclic voltammetry (CV) and electrical impedance spectroscopy (EIS). Optimal operating parameters include pH 2.1, square-wave voltammetry (SWV) with an accumulation time of 60 s and an accumulation potential of −0.8 V. A low detection limit of 0.20 µmol/L and a relative standard deviation (RSD) of 3.0 % were achieved using five different electrodes. The effectiveness of AlNP-EDTA/AlE was further demonstrated with consistent results in biological samples spiked with Pb.

Tooth backlash inspired comb-shaped single-electrode triboelectric nanogenerator for self-powered condition monitoring of gear transmission

Gear transmissions are an integral part of most rotation machinery. Their abnormalities can affect the reliable operation of the equipment. Most sensors that monitor gear transmissions lack self-powered capability and have weak features due to the restricted mounting locations. In this study, the tooth backlash inspired triboelectric nanogenerator (TB-TENG) is proposed for self-powered condition monitoring of the gear transmissions. A series of comb-shaped copper foil electrodes is arranged on the non-load tooth sides to create a single-electrode TENG. Through the rational use of the tooth backlash space, the TB-TENG does not affect the tooth meshing or participate in the load transmission, ensuring both durability and structural compactness. The TB-TENG outputs are evaluated under various working conditions, structural optimizations, and different working environments based on the established TB-TENG test system. Consequently, the maximum output power density corresponding to the optimal resistance is obtained. Based on the output signal model, the effectiveness of the TB-TENG in self-powered condition monitoring is verified. Moreover, the denoising convolutional auto-encoder (DCAE) is trained based on the TB-TENG voltage signals, achieving a diagnostic accuracy of 98.4%, equivalent to accuracy based on vibration signals. The practical applicability of the proposed TB-TENG is demonstrated through deployment testing in an industrial parallel-gear transmission system. Specifically, TB-TENG can accurately monitor gear speed under variable speed conditions to assess operation stability and health status. Finally, the theoretical and experimental basis for the TB-TENG is provided with applications for self-powered condition monitoring.

Experimental study on electrode wear during the EDM of microgrooves with laminated electrodes consisting of various material foils

Electrode wear during electrical discharge machining (EDM) is inevitable, and tool electrodes of different materials exhibit different wear rates. Unlike a single-material tool electrode, for a laminated electrode consisting of various material foils (LE-VMF), the components suffer from significantly different amounts of wear and also influence each other in EDM, however, the form and cause of the wear are not clear. Thus, the LE-VMFs including symmetric and asymmetric LE-VMFs were prepared and used in EDM in this paper. The wear of foils in LE-VMFs and their mutual influence during the EDM process were investigated through experiments. The wear forms of a single foil electrode and a foil of the same material in the LE-VMF were also compared. The experimental results show that copper foil with a lower wear rate had a protective effect on an adjacent brass foil with a larger wear rate in the LE-VMF, while the protective effect of the brass foil in the symmetric LE-VMF was larger than that in the asymmetric LE-VMF. The closer the distance from the copper foil, the stronger was the protection effect and the smaller was the wear. In addition, the working surface of the brass foil in the LE-VMF did not show any concavity-like wear in the middle region of its thickness after EDM, as was the case for the single brass foil electrode, even if the thickness of the brass foil was greater than 150 μm.

Field‐representative evaluation of PID‐polarization in TOPCon PV modules by accelerated stress testing

AbstractPotential‐induced degradation‐polarization (PID‐p) can reduce module power, but how to project the extent to which PID‐p may occur in field conditions considering the factors of system voltage, condensed moisture, temperature, and illumination has not been clarified. Using tunnel oxide passivated contact (TOPCon) modules, this work demonstrates a method to test full‐size crystalline silicon PV modules for PID‐p to provide field‐representative results. In initial screening tests with positive or negative 1000 V electrical bias applied at 60°C for 96 h using Al foil electrodes on the glass surfaces, the module type exhibited reversible PID‐p only on the front face when the cell circuit was in negative voltage potential. No PID was detected on the rear after testing in either polarity. We then evaluated the PID‐p sensitivity on the front side under different UV irradiances while maintaining the glass surface wet to estimate real‐world susceptibility to PID‐p. The magnitude of the observed behavior was fit using a previously developed charge transfer and depletion by light model. Whereas power loss with −1000 V applied to the cell circuit at 60°C for 96 h in the dark was about 30%, testing the module front under 0.051 W·m−2 nm−1 at 340 nm UVA irradiation using fluorescent tubes, the mean degradation was only 3%. When the modules were tested in the dark for PID‐p with in situ dark current–voltage (I‐V) characterization, the thermal activation energy for degradation was 0.71 eV; for recovery in the dark, it was 0.58 eV. Whereas recovery from the degraded state at 60°C in the dark without voltage bias was 5% absolute in 38 h, rapid recovery of about 5% absolute was observed with 1000 W·s/m2 exposure at 25°C using a flash tester.

Magnetic Field Enhanced Oxygen Reduction Reaction via Oxygen Diffusion Speedup.

The mass-transfer of oxygen in liquid phases (including in the bulk electrolyte and near the electrode surface) is a critical step to deliver oxygen to catalyst sites (especially immersed catalyst sites) and use the full capacity of oxygen reduction reaction (ORR). Despite the extensive efforts of optimizing the complex three-phase reaction interfaces to enhance the gaseous oxygen transfer, strong limitations remain due to oxygen's poor solubility and slow diffusion in electrolytes. Herein, a magnetic method for boosting the directional hydrodynamic pumping of oxygen toward immersed catalyst sites is demonstrated which allows the ORR to reach otherwise inaccessible catalytic regions where high currents normally would have depleted oxygen. For Pt foil electrodes without forced oxygen saturation in KOH electrolytes, the mass-transfer-limited current densities can be improved by 60% under an external magnetic field of 435mT due to the synergistic effect between bulk- and surface-magnetohydrodynamic (MHD) flows induced by Lorentz forces. The residual magnetic fields are further used at the surface of magnetic materials (such as CoPt alloys and Pt/FeCo heterostructures) to enhance the surface-MHD effect, which helps to retain part of the ORR enhancement permanently without applying external magnetic fields.

Efficient and eco-friendly preparation of N/P/O co-doped porous carbon electrode for zinc-ion hybrid supercapacitors by laser carbonization

The incorporation of heteroatoms into carbon materials confers advantages in the development of electrode materials for zinc-ion supercapacitors with superior electrochemical performance. However, the conventional carbonization process requires a large thermal power input and is characterized by complexity, high costs, and lengthy reaction times. In this work, the phytic acid-doped polypyrrole (P-PPy) was carbonized via laser irradiation to synthesize N, P, O co-doped porous carbon (P-NOPC), wherein phytic acid served as the source of phosphorus and oxygen, while PPy served as the porous carbon precursor and nitrogen source. The formation of porous carbon can provide a large specific surface area for ion adsorption. The doping of heteroatoms improves the hydrophilicity of porous carbon electrodes and also improves the chemisorption capacity of carbon materials. The aqueous zinc-ion hybrid supercapacitor (ZHSC) based on 0.6P-NOPC9 positive electrode and zinc foil negative electrode has a discharge capacity of 148.0 mAh g−1 in a voltage window of 0.2–1.8 V at 0.1 A g−1, a high energy density (118.2 Wh kg−1) and long cycle life (capacity retention of 98.5% after 10,000 cycles). In addition, the capacity retention of the flexible quasi-solid-state ZHSC is 97.8% after 10,000 cycles. This study can provide a reference for the feasible design of porous carbon electrodes with high performance.

An azo functionalized anthraquinone as organic electrode materials for efficient pseudocapacitors with excellent cycling stability

Organic electrode materials (OEM) are attractive candidates for fabrication of pseudocapacitors (PSCs) to resolve the current problems related to low energy density and lower cycling stability. These problems can be effectively addressed by designing OEM electrode materials for PSC applications. Herein, we report the synthesis of 2,6-bis((E)-(4-hydroxyphenyl)diazenyl)anthracene-9,10-dione (AZOAQ) and utilized for fabrication of AZOAQ/graphene foil (GF) electrode. The two-electrode symmetric supercapacitor (SSC) cell made of the AZOAQ/GF show remarkably higher specific capacitance (Csp), excellent energy and power densities compared to reported OEMs. The SSC device made from AZOAQ/GF achieves specific capacitance (Csp) of 159.12 F g−1 at 0.5 A g−1 current density, remarkable than reported for SCs based on OEMs. The higher conductivity exhibited high energy density of 28.64 Wh kg−1 at power density of 1080.02 W kg−1. The SSC cell also displayed outstanding cycling stability with capacitance retention of 93.22 % after 10,000 galvanostatic charging/discharging (GCD) cycles. Furthermore, considering the simple molecular design for OEM electrode material, the proposed AZOAQ molecule would be an attractive, cheaper molecule for large-scale synthesis and fabricating organic electrodes for different energy storage applications in the future.

Suppressing Li dendrite by a guar gum natural polymer film for high‐performance lithium metal anodes

AbstractLithium dendrites pose a major hurdle for enhancing the energy density of lithium metal batteries, and the artificial solid electrolyte interface layer offers a potential solution. In this work, a cost‐effective and environmentally friendly guar gum film is applied to the artificial protective layer. The guar gum artificial solid electrolyte interface (SEI) layer formed naturally, enriched with OH and AOA groups, displayed exceptional electrochemical stability, and achieved an impressively high transference number of 0.88 for lithium‐ion movement. In symmetric cells, the Li@GG‐Cu anode displays remarkable cycling performance even during extended periods. This is evidenced by its ability to maintain a surface capacity of approximately 850 h (1 mA cm−2, 1 mAh cm−2). In addition, when utilizing a complete cell setup comprising a LiFPO4 cathode (weighing 1.5 mg cm−2) and anode coated with a guar gum film, the capacity retention of an impressive 96.2% showcases outstanding preservation of battery performance over time even after 700 cycles. This performance surpasses that of a lithium foil electrode (87.1%) and a copper anode with lithium deposition (0%). Our work exhibits a promising material for a novel configuration of artificial SEI, effectively stabilizing lithium metal anode.