Hybrid Electrode Research Articles

A facile one-step route to synthesize of novel porous reduced graphene oxide@nickel sulfide (rGO@Ni3S2) core shell nanostructures for high-performance supercapacitor electrodes

In the last decade, there has been significant interest in the use of supercapacitors with high power density and cycle stability in a wide range of applications. Graphene-based hybrid electrodes are considered a very promising option for supercapacitors owing to the synergistic effects they exhibit. In this study, we provide a novel and efficient method for synthesising a core-shell nanocomposite consisting of reduced graphene oxide (rGO) wrapped around nickel sulphide (Ni3S2) using a one-step hydrothermal process. The resulting rGO@Ni3S2 composite exhibits excellent performance as a supercapacitor electrode while also being cost-effective. As a promising supercapacitor electrode, a relatively high specific capacitance of 1052.5 Fg−1 at current density of 1 Ag−1 in 1 mol.L−1 KOH aqueous solution, along with good cycling stability (with a 94.5 % retention rate after 10,000 cycles) were demonstrated for the rGO@Ni3S2 core shell composite electrode. In addition, excellent electrochemical performances were also demonstrated for the asymmetric supercapacitor (ASC) by using rGO@Ni3S2 as the cathode and activated carbon, respectively. The fabricated ASC showed with a high energy density of 61.9 Whkg−1 at the power density of 585.7 W kg−1. Such high performance of rGO@Ni3S2 core shell electrode can enrich the prospects for future practical applications in energy storage.

Synthesis and Characterization of Coconut-Derived Graphene Nano Sheet (GNS) and Its Properties in Nickel/GNS and Zinc/GNS Hybrid Electrodes

This study introduces a sustainable method of producing a graphene nano sheet (GNS) from coconut shells and investigates its application in GNS, Ni/GNS, and Zn/GNS electrodes for advanced energy storage devices. The GNS was synthesized in a scalable manner using a pyrolysis and impregnation technique, with its successful synthesis verified by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), Raman spectroscopy, and electrical conductivity measurement characterizations. The study highlights the enhanced performance of Zn/GNS electrodes, which outperform both pure GNS and Ni/GNS variants. This superior performance is attributed to the smaller particle size of Zn (mean = 2.356 µm) compared to Ni (mean = 3.09 µm) and Zn’s more favourable electron configuration for electron transfer. These findings demonstrate the potential of bio-derived GNS composites as efficient, high-performance electrodes, paving the way for more sustainable and cost-effective energy storage solutions.

On the Challenges to Develop Hybrid Faradaic‐Capacitive Electrodes Incorporating a Sacrificial Salt for Lithium‐ion Capacitors: The Case of Li3V1.95Ni0.05(PO4)3‐AC‐Li2C4O4

AbstractThe low capacity of activated carbon (AC) electrodes remains as one of the major limiting factors for the development of high energy density lithium‐ion capacitors (LICs). Hybridization of capacitive AC electrodes by incorporating faradaic materials into the electrode formulation could be performed to enhance the capacity of the overall device. However, this strategy requires an accurate electrode design to maximize the performance. In this work, Li3V1.95Ni0.05(PO4)3 (LVNP) was selected as faradaic material due to its compatibility with AC, showing high capacity, fast ionic diffusion, and relatively high conductivity. Various formulations and mass loadings have been studied to analyze the impact of incorporating LVNP into the positive electrode on the performance of the hybrid electrode. Moreover, for practical LIC applications, a sacrificial salt ‐dilithium squarate, Li2C4O4‐ was included in the hybrid electrode as a pre‐lithiation additive, developing a ternary electrode. The sacrificial salt oxidized releasing lithium ions, while the electrochemical performance of the hybrid positive electrode remained almost unaltered. Finally, a cycle life test combined with a post‐mortem analysis allows understanding the failure mechanisms of the electrode, suggesting the need of further improvements of the electrolyte and electrode‐electrolyte interface to develop long lifetime hybrid faradaic‐capacitive electrodes based on LVNP‐AC active materials.

Laser-Assisted Photo-Thermal Reaction for Ultrafast Synthesis of Single-Walled Carbon Nanotube/Copper Nanoparticles Hybrid Films as Flexible Electrodes.

The hybridization of single-walled carbon nanotubes (SWCNTs) and Cu nanoparticles offers a promising strategy for creating highly conductive and mechanically stable fillers for flexible printed electronics. In this study, we report the ultrafast synthesis of SWCNT/Cu hybrid nanostructures and the fabrication of flexible electrodes under ambient conditions through a laser-induced photo-thermal reaction. Thermal energy generated from the nonradiative relaxation of the π-plasmon resonance of SWCNTs was utilized to reduce the Cu-complex (known as a metal-organic decomposition ink) into Cu nanoparticles. We systematically investigated the effects of SWCNT concentration and output laser power on the structural and electrical properties of the SWCNT/Cu hybrid electrodes. The SWCNT/Cu electrodes achieved a minimum electrical resistivity of 46 μohm·cm, comparable to that of the metal-based printed electrodes. Mechanical bending tests demonstrated that the SWCNT/Cu electrodes were highly stable and durable, with no significant deformation observed even after 1000 bending cycles. Additionally, the electrodes showed rapid temperature increases and stable Joule heating performance, reaching temperatures of nearly 80 °C at an applied voltage of less than 3.5 V.

Chemical growth of Niobium-doped vanadium pentoxide on aminated graphene for all-solid-state asymmetric supercapacitors

In this investigation, niobium-doped vanadium pentoxide (Nb–V2O5) was grown on the surface of amine-functionalized graphene nanosheets (NH2-Gr) using an in-situ hydrothermal method and explored the hybrid material as a positive electrode for the fabrication of an all-solid-state asymmetric supercapacitor (ASC). We have used KOH-loaded poly(acrylonitrile-co-1-vinylimidazole) (KOH/P(AN-Co-VIM)) gel as a solid electrolyte-cum-separator and exfoliated graphene (XGnP) as a negative electrode in the ASC. The morphological analysis of the Nb–V2O5/NH2-Gr hybrid revealed homogeneous growth of Nb–V2O5 on NH2-Gr nanosheets, while surface analysis confirmed a large fraction of mesopores with large surface areas in the hybrid. The hybrid electrode achieved a high specific capacitance of 1141.1 F/g at 1 A/g with 80.3% capacitance retention even after a 10-fold increase in current density, a significantly higher performance than a pure Nb–V2O5 electrode. As-assembled solid-state ASC device delivered a high energy density of 79.39 Wh kg−1 at a power density of 280.3 W kg−1, even though it retained high energy density at a higher power density of 12 kW kg−1. The ASC exhibited slow a self-discharge rate owing to the suppression of Ohmic leakage by the use of KOH/P(AN-co-VIM) gel electrolyte. Thus, the as-synthesized Nb–V2O5/NH2-Gr hybrid is an ideal alternative candidate for future supercapacitors.

Enhancing Conductivity in Silicon Heterojunction Solar Cells with Silver Nanowire-Assisted Ti3C2Tx MXene Electrodes for Cost-Effective and Scalable Photovoltaics.

Silicon heterojunction (SHJ) solar cells have set world-record efficiencies among single-junction silicon solar cells, accelerating their commercial deployment. Despite these clear efficiency advantages, the high costs associated with low-temperature silver pastes (LTSP) for metallization have driven the search for more economical alternatives in mass production. 2D transition metal carbides (MXenes) have attracted significant attention due to their tunable optoelectronic properties and metal-like conductivity, the highest among all solution-processed 2D materials. MXenes have emerged as a cost-effective alternative for rear-side electrodes in SHJ solar cells. However, the use of MXene electrodes has so far been limited to lab-scale SHJ solar cells. The efficiency of these devices has been constrained by a fill factor (FF) of under 73%, primarily due to suboptimal charge transport at the contact layer/MXene interface. Herein, a silver nanowire (AgNW)-assisted Ti3C2Tx MXene electrode contact is introduced and explores the potential of this hybrid electrode in industry-scale solar cells. By incorporating this hybrid electrode into SHJ solar cells, 9.0 cm2 cells are achieved with an efficiency of 24.04% (FF of 81.64%) and 252 cm2 cells with an efficiency of 22.17% (FFof 76.86%), among the top-performing SHJ devices with non-metallic electrodes to date. Additionally, the stability and cost-effectiveness of these solar cells are discussed.

Synthesis and Characterization of Carbon Nano Sphere-doped Gd: Alpha Sb2O4 Nanostructure for High-Performance Energy Storage Applications

Background: To enhance the super capacitive properties of nanocomposites, the effective method is to combine carbon nanospheres with mesoporous structures with Gd3+:α-Sb2O4 inorganic nanocomposites (NC) to form hybrid electrodes. An as-prepared hybrid electrode material possesses increased energy density, high rate of reversibility and cyclic stability when incorporated in electrochemical cyclic voltammetric studies. Methods: In the present investigation, various wt % of C-nanospheres (Cx) (5 %, 10% and 20%) were decorated over Gd3+: α-Sb2O4 nanocomposites and were synthesized by coprecipitation method. XRD, SEM, EDX, UV-visible, and XPS are only a few of the analytical techniques used to describe the as-prepared hybrid nanocomposites. Electrochemical cyclic voltammetry was carried out in a 6 M KOH solution, three-electrode system. Results: The crystal structure and morphology of Cx: Gd3+@ α-Sb2O4 NC showed a mixed hexagonal phase and agglomerated tiny irregularly shaped morphology that appeared as the Cx concentration increased. Redshift in optical absorption peak appeared (near UV-edge), and the optical band gap (Eg) value increased from 3.53 eV to 3.65 eV. The electrochemical supercapacitor showed the highest specific capacitance of 989 F/g at the current density of 1 A/g for C20%:Gd3+@α-Sb2O4 NC compared with Cx:Gd3+@α-Sb2O4 (x = 5% and 10%) and undoped Gd3+:α-Sb2O4 NC. The change in phase angle and Rs value of 1.98 was attributed to the ideal supercapacitor properties. The cyclic stability after 5000 cycles with 79.71% capacitive retention was exhibited by C20%:Gd3+@α-Sb2O4 NC. Conclusion: The present research introduces ease of synthesis of hybrid electrode materials possessing high active surface area, increased energy density, high cyclic stability, and reversibility in an aqueous solution.

Controlled growth of redox-active polymer nanorods on MOF-derived activated nanoporous carbons: 3D reconstruction study and high-performance supercapacitor

Supercapacitors, which a energy storage systems, have been continuously studied because of their high power density and rapid charging-discharging capacity. Supercapacitors can be classified into pseudocapacitors and electric double-layer capacitors (EDLCs). The effective utilization of these two supercapacitor mechanisms is important for achieving high performance. In this study, highly nanoporous metal–organic framework (MOF)-derived carbon underwent chemical activation with potassium hydroxide to produce a high surface area. Subsequently, activated carbon was combined with a polyaniline (PANI) nanoarchitecture to introduce redox-active sites. Activated MOF-derived carbon provides a high specific surface area for EDLCs, and well-controlled PANI nanorods support large amounts of redox-active sites to achieve high capacitance. The aniline (ANI) concentration, growth time, acid, temperature, and ammonium persulfate (APS):ANI molar ratio were controlled to grow PANI nanorods without aggregation. At a scan rate of 5 mV/s, the capacitance of the PANI-ZIF-8-derived carbon composite reached 635.3 F/g, which was superior than that of ZIF-8-derived carbon (143.4 F/g). It also exhibited excellent durability during cycling, demonstrating that it can serve as a high-performance hybrid electrode material composed of carbon and polymer for supercapacitors.

Growth of WO3 nanostructure deposited on TiO2 nanotube arrays for electrochemical enzyme-free glucose sensor

In this study, a novel WO3-TiO2 hybrid nanostructure-based electrochemical non-enzymatic glucose biosensor has been developed. The anodization method was utilized to successfully produce TiO2 nanotubes on Ti6Al4V alloy functioning as substrates and WO3 nanomaterial decorate on the surface of TiO2 nanotubes (TNTs) deposited through electrochemical technique. The incorporation of WO3 on TNTs has resulted in a high electroactive surface and more degradation resistance in comparison to pure TNTs, resulting in enhanced electron transfer rate and electrode stability. High-resolution transmission electron microscopy (HR-TEM), field emission scanning electron microscopy (FE-SEM), and X-ray diffraction were used to investigate the crystalline structure and morphology of the WO3-TiO2 nanostructure. The electrochemical properties of the hybrid electrodes were investigated employing amperometry, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The hybrid electrode had a promising sensitivity (1228.12 μA/mM/cm2), low detection limit (0.19 mM), wide linear range (1.0–6.5 mM), and short response time (2-s). The sensors also demonstrated superior levels of reproducibility, repeatability, and stability.

Enhancing the electrochemical performance of supercapacitor electrodes using as-synthesized CuO and MOF-derived CuO nanostructures

Metal organic framework (MOF) have gained considerable attention in the field of energy storage and supercapacitors applications. Herein, we synthesized copper oxide (CuO) through the precipitation method and concurrently derived from the solvothermal prepared copper-benzene dicarboxylate (Cu-BDC) by calcination. The integration of MOF-derived nanostructures with traditional CuO to form a hybrid electrode material, has not been extensively explored. The synthesized materials were characterized using XRD, FTIR, XPS, BET and morphological analysis was conducted using SEM, affirming the composite's nature. Electrochemical impedance spectroscopy, galvanostatic charge-discharge, and cyclic voltammetry were used to evaluate the electrochemical properties of electrode material. With a specific capacitance of 691 F g-1 for CuO obtained from Cu-BDC (benzene dicarboxylic acid) and 236 Fg-1 for CuO via the precipitation method, measured at a scan rate of 5 mV/s in 6 M KOH was found to be the optimal performance solution for the electrode material. The mesoporous structures are crucial for their absorption ability and improved ion transport, resulting in optimized electrochemical performance. Finally, we demonstrate significant improvements in specific capacitance and cycling stability compared to pure CuO-based electrodes, highlighting the potential of this composite structure for advanced supercapacitor applications.

Bi2MoO6/MWCNTs-COOH/GCE electrochemical probe for ultrasensitively and selectively detecting antibiotic norfloxacin

Antibiotics have emerged as a class of contaminants of concern globally, raising widespread worry and unease, primarily because of their inappropriately use and endless migration in food chains. Electrochemical ultrasensitive and selective determination of norfloxacin (NOR) using bismuth-based bimetallic salt bismuth molybdate (Bi2MoO6) and carboxylated multi-walled carbon nanotube (MWCNTs-COOH) hybrid electrode as sensing platforms is presented hereby. The electrocatalytic ability of the electrodes was verified to be enhanced by the synergy effect of both Bi2MoO6 and MWCNTs-COOH using cyclic voltammetry and electrochemical impedance spectroscopy. Linear scan voltammetry was applied to detect NOR. The oxidation peak current was linearly correlated with NOR concentration of 0.03–10 μM and the low limit detection of the optimized method was 6.7 nM (S/N = 3). In addition, it was verified that Bi2MoO6/MWCNTs-COOH/GCE probe had good stability, reproducibility, repeatability and selectivity. The spiked recovery method for NOR in milk and lake water samples showed recoveries of 94.8 – 96.9% and 90.2 – 98.3%, respectively, which can be used to determine NOR in real samples with high sensitivity. The preparation of Bi2MoO6/MWCNTs-COOH/GCE provides a new prototype for probing NOR detection at nanomolar concentration and safeguarding antibiotic contamination in environmental and food chains.

Microwave-assisted synthesis of perovskite hydroxide-derived Co3O4/SnO2/reduced graphene oxide nanocomposites for advanced hybrid supercapacitor devices

The current article reports a facile, ultrafast, and cost-effective, solid-state microwave (MW) synthetic route for the conversion of perovskite hydroxide (CoSn(OH)6) to crystalline metal oxides (Co3O4 and SnO2) with the help of reduced graphene oxide (rGO) nanosheets. In a domestic MW oven, the Co3O4/SnO2/rGO (CSO-rGO) nanocomposite was synthesized within a quick reaction time of only 30 s. The study deeply focused on analyzing the surface morphology, metal oxide attachment on the surfaces of rGO nanosheets, the specific surface area, and the electrochemical performance of supercapacitor devices from the CSO-rGO nanocomposite. As a positive electrode for supercapacitors, the synthesized hybrid electrode displayed a good capacity (146.4C/g) and enhanced cycling stability (103.2 % after 15,000 cycles). Moreover, the corresponding aqueous hybrid supercapacitor device with MW-synthesized rGO as a negative electrode displayed a maximum energy density of 27 Wh/kg and promising cycling stability of 102.4 % after 10,000 cycles. As a whole, compared to the common time-consuming synthetic approaches, the MW-assisted synthetic approach is highly beneficial in terms of short reaction time, cost-effectiveness, and straightforwardness. The MW synthesis methodology employed in this study can be utilized for analogous composite electrodes that incorporate other layered conductive architectures in addition to metal oxides.

Achieving Non-Interfacial Blocking Zinc Ion Transport Based on MOF Derived Manganese Oxides and Amorphous Carbon Hybrid Materials.

How to coordinate electron and ion transport behavior across scales and interfaces within ion battery electrodes? The exponential increase in surface area observed in nanoscale electrode materials results in an incomprehensibly vast spatial interval. Herein, to address the problems of volume expansion, dissolution of cathode material, and the charge accumulation problem existing in manganiferous materials for zinc ion batteries, metal organic framework is utilized to form the architecture of non-interfacial blocking ~10 nm Mn2O3 nanoparticles and amorphous carbon hybrid electrode materials, demonstrating a high specific capacity of 361 mAh g-1 (0.1 A g-1), and excellent cycle stability of 105 mAh g-1 after 2000 cycles under 1 A g-1. The uniform and non-separated disposition of Mn and C atoms constitutes an interconnected network with high electronic and ionic conductivity, minimizing issues like structural collapse and volume expansion of the electrode material during cycling. The cooperative insert mechanism of H+ and Zn2+ are analyzed via ex-situ XRD and in-situ Raman tests. The model battery is assembled to present practical possibilities. The results indicate that MOF-derived carbonization provides an effective strategy for exploring Mn-based electrode materials with high ion and electron transport capacity.

Enhanced Electrohydrogenation of Cis,Cis-Muconic Acid to Trans-3-Hexenedioic Acid Using Hybrid Metal/Carbon Fiber Cathodes

Organic electrosynthesis is a long-known technique for diverse product development and efficient synthesis. With the recent rise of biomass as an alternative carbon and energy source, electrochemistry is further gaining popularity due to its inherently green and environmentally benign operating conditions. Electrochemical hydrogenation (ECH) reactions are particularly attractive for biomass conversion due to their ability to abstract hydrogen from water, tolerate biogenic impurities, and utilize Earth-abundant base metal electrodes. Moreover, the rate and selectivity of the reaction can be tubed by controlling the electrode material, operating potential/current density, and reactor design. However, the implementation of this decarbonized technology for chemical production is still hampered by low productivity and, as a result, unfavorable economics. cis,cis-Muconic acid (ccMA), a bioderived C6 diunsaturated diacid platform molecule, can be converted into commodity chemicals like caprolactam, adipic acid (AA), and terephthalic acid, with AA being of particular interest for the synthesis of nylon 6,6.1 Apart from various drop-in chemicals, ccMA can also be electrochemically upgraded to trans-3-hexenedioic acid (t3HDA), a potential bio-advantaged substitute for AA as the additional C=C bond in t3HDA can be leveraged to synthesize performance-advantaged polyamides.2,3 In this work, we investigated the electrohydrogenation of ccMA to t3HDA over Pb cathodes. We demonstrate that the reaction follows a radical-based pathway involving sequential electron transfer and hydrogen addition in solution to selectively produce t3HDA (100% selectivity). Next, we contacted the cathode with carbon felts (CF) to increase productivity. CF are often used in fuel cells and H2O2 electrolyzers due to their excellent conductivity, porosity for enhanced turbulence, and ability to tune the gas-liquid-solid three-phase interface. Following similar principles, we placed a CF (3mm. thickness) in contact with the Pb cathode to lower the charge transfer resistance (~3Ω) at the interface. The surface functionalities of carbon allowed us to further tune the hydrophobicity/hydrophilicity of our hybrid electrode. Molecular dynamics (MD) calculations provided critical insights into the role of surface functionalities and guided the optimal functionalization of CF’s surface. Combining reactor configuration with fine-tuning of the electrode’s microenvironment, we were able to achieve a 50x increase in t3HDA productivity reaching up to 20 g/cm2/day at a current density of 200 mA/cm2. We further replaced the kinetically sluggish oxygen-evolution reaction with the glucose oxidation reaction at the anode, allowing us to operate the electrolyzer at a lower cell potential.Overall, ECH represents a valuable alternative to thermochemical transformations for biomass upgrading. This work provides critical insights into reactor modifications for the scaled-up synthesis of bio-derived performance monomers via hybrid microbial electrosynthesis (HMES).

Li-Sn Alloyed Layer Containing Artificial SEI on Li-Metal Anode for Superior Lithium Metal Batteries: Development and Understanding of Anode/Electrolyte Interfacial Phenomena

Modern civilization and cutting-edge technologies and tools are highly dependent on energy storage devices and demand efficient and long-lasting high-energy-density storage devices. Lithium metal batteries have surpassed their competitors concerning energy density due to their inherent high specific capacity (3860 mAh/g) and the lowest electrochemical potential (-3.04 V vs. standard hydrogen electrode), proving to be one of the most favorable energy storage devices for smart and mobile gadgets, electric automobiles, grid storage, etc. However, safety-threatening and performance-decay challenges associated with lithium metal anodes, such as lithium dendrite formation, uncontrolled parasitic reactions between Li-metal and electrolyte, low coulombic efficiency, dead Li-formation, etc., restrict its employment in practical batteries. The root cause of the dendrite formation is poor Li-ion conductivity of bulk lithium metal, which results in an uneven electric field distribution, leading to non-uniform Li deposition/stripping upon repeated charge/discharge. Herein, a facile chemical reduction process is being opted to fabricate a highly Li-ion diffusive Li-Sn-based artificial SEI layer on the lithium metal surface to prevail over the above-mentioned issues. Therefore, upon careful concentration investigation of reactants, 25 mM precursor concentration (SnCl4 in EC: DMC in 1:1 volume ration) demonstrated the best electrochemical performance, revealing a cumulative capacity of over 700 mAh/cm2 at a current density of 1 mA/cm2 for 1 h in a symmetric cell. Physical characterizations (XRD and SEM-EDS) showed a thin layer containing Li-Sn alloys along with LiCl formed at the lithium metal surface. Possessing high Li-ion diffusivity, Li-Sn alloyed hybrid anode illustrated a gradual decrease in the charge transfer resistance on increasing the concentration, thus, lower overpotential in symmetric cells, in contrast to pristine Li-metal. However, an increase in the electrical resistance has been observed on increasing the precursor concentration due to the presence of the insulating LiCl phase in the protective layer. Moreover, in-situ optical microscopy demonstrated more uniform and on-surface Li-deposition for the hybrid electrode, whereas mossy and dendritic growth on bare Li-metal. Full cells prepared with Li-Sn alloyed anode against NMC532 cathode illustrated stable cycling up to 150 cycles; contrastingly, the cell with pristine Li-metal showed a drastic capacity fade just after 100 cycles, demonstrating the inclination towards safer lithium metal batteries.

3D Hybrid branched carbon/ZnO core-shell nanostructure as biosensor for sensitive and selective detection of glucose

Reliable glucose monitoring at physiological pH and clinical practical range is critical for appropriate diabetes management which remains one of a major health concern. Herein, we describe the construction of flexible and 3D hybrid electrode for glucose sensing by successful immobilization of the GOx on branched carbon/ZnO core–shell nanostructures electrode. The microstructure, morphology and device properties of glucose sensor was systemically characterized by using HRTEM, SEM, FT-IR, and electrochemical analysis. The branched carbon/ZnO core–shell nanostructure sensor showed reliable stability, selectivity and remarkable sensitivity (i.e., 32.48 (±0.04) µA mM−1 cm−2) for glucose in clinical range at physiological pH conditions. The mediator less direct electron communication between the electrode surface and the redox center (FADH & FAD) was also analyzed comprehensively, which concludes an efficient direct electron communication (DET). This enhanced DET can be attributed to the larger surface area provided by the branched carbon/ZnO core–shell nanostructure and also favorable orientation of GOx which allows close proximity of the redox center and the electrode surface. It is believed that such kind of sensors could provide an ideal platform for continuous glucose monitoring (CGM) device fabrication which could perform glucose sensing in real-time and in-vivo analysis.

Two-Dimensional Nanorod-Shaped Co(II) Coordination Polymer on Three-Dimensional Metallic Foam: A Hybrid Platform for Electrochemical Oxidation of Glucose.

This study unveils a novel electrochemical biosensor for monitoring glucose in biological fluids by employing nanorods of a cobalt-bispyridyl/dicarboxylate framework grown in a layer-by-layer manner on a highly porous nickel substrate. The hybrid microporous system has a bicatalytic effect on glucose oxidation due to the synergistic catalytic impact of the nickel and cobalt ions with varying oxidation states as electroactive sites. In addition, the controlled growth of inorganic-organic frameworks changes the mechanism of electron transfer from a diffusion-controlled process to an adsorption-controlled process, thus yielding a low onset oxidation potential (∼0.21 V/Ag-AgCl) and a high current intensity (∼1 mA) for the oxidation of glucose in alkaline media. A fast response time (∼2 s) and a reasonably high sensitivity (0.14 μA μM-1) within a broad linear range (40-360 μM) have determined the suitability and superiority of the hybrid electrode for glucose monitoring compared to many metal-organic-based biosensors. The facile fabrication process of the Co(II) coordination polymer/Ni substrate with a large surface area that benefits from the synergetic catalytic activity of nickel-cobalt hybrids may pave the way for the development of novel hybrid electrodes for biosensors and direct glucose fuel cells.

A Self‐Assembled Hybrid Electrode with Efficient Tandem Electrochemistry for Dissolution‐Shielding, Ultrafast‐Charging, and Record‐Lifespan Zinc‐Ion Batteries

AbstractThe design of electrode compatible with wide‐temperature, fast‐charging, and long‐lifespan aqueous zinc‐ion batteries is a great challenge that urgently needs addressing. However, the mismatch between runaway host dissolution and high interfacial hydrophilicity within electrode is a contradictory problem that restricts their electrochemical performance. In this report, take the typical vanadium diselendie (VSe2) host for example, by employing the natural polymer bacterial cellulose (BC) as the multifunctional mediator, a design paradigm of self‐assembly hybrid electrode with efficient tandem electrochemistry is presented. Theoretical and experimental research confirmed that such BC‐mediated hybrid structure exhibits multiple functions to well balance the cathode dissolution and storage kinetics. Impressively, such an electrode displayed an excellent rate capability (1–50 A g−1), and an unexpected record‐lifespan of 45 000 cycles. Beyond that, it also shows a good temperature‐tolerance ability, remaining the high specific capacities of 120 and 288 mAh g−1 (at 10 A g−1) after 3000 cycles at −25 and 50 °C, respectively. Note that such approach is also applicable to the high‐voltage platform MnO2 and I2 hosts, demonstrating its potential for universality. This discovery can provide a new design principle of robust electrode for advanced aqueous zinc‐ion batteries.

Design of highly stable Co3O4/RGO/CoFe2O4 hybrid nanocomposites with multiple nanointerfaces for enhanced supercapacitor performance

In this study, we developed a novel hybrid electrode nanomaterial composed of Co3O4, CoFe2O4, and reduced graphene oxide (RGO) for electrochemical supercapacitor applications. The hybrid nanocomposite of Co3O4/RGO/CoFe2O4 was prepared using a modified chemical oxidation process and the phase formation of the composites was evidenced by X-ray diffraction (XRD). The grain size for Co3O4 and CoFe2O4 was estimated as 12 nm and 22 nm. For Co3O4/CoFe2O4 the reduced grain size of 19 nm for CoFe2O4 was observed and further it was reduced with RGO up to 15 nm. The bare Co3O4 exhibited a hexagonal plate-like morphology, whereas the bare CoFe2O4 showed mostly a spherical morphology. The reduced saturation magnetization for the hybrid electrode material due to the non-magnetic fraction of Co3O4 and RGO was observed to be 21 emu/g compared to the bare CoFe2O4 (77 emu/g). The Co3O4/RGO/CoFe2O4 electrode exhibited enriched electroactive sites and enhanced diffusion pathways, achieving a high specific capacity of 235C g − 1 at 5 A g − 1 with excellent durability.. This work highlights the significant charge storage potential of the Co3O4/RGO/CoFe2O4 hybrid, making it a promising candidate for advanced energy storage systems.

Synthesis of CuO/NiO nanostructured hybrid electrode for supercapacitors

Supercapacitors employing copper metal oxides have garnered significant interest due to their substantial theoretical capacity and expansive active surface area. However, the performance of pure copper oxide electrode materials cannot meet the high demands currently placed on supercapacitors. In this study, a convenient, efficient, two-step electrodeposition method was utilized to develop micro/nanostructures of CuO/NiO on nickel foam. The synthetic strategy optimizes the capacitive performance of the composite by adjusting the deposition parameters during the growth of the NiO film.The CuO/NiO electrode can provide an area ratio capacitance of up to 1435.62 mF/cm2, the addition of NiO improves the area capacitance of the electrode material and the capacitance retention after cycling. In addition, the CuO/NiO composite material has been used to prepare solid-state symmetric supercapacitors, the device can reach a maximum energy and power density of 31.89 μWh/cm2 and 2099.76 μW/cm2, respectively. These results suggest that CuO/NiO electrodes exhibit promising potential as energy storage electrode materials.