High-performance Electrode Materials Research Articles

A sustainable solution: Conversion of distillers' grains waste into high-performance supercapacitor electrode materials for energy storage applications

The development of cost-effective biomass-derived carbon with good electrochemical properties is crucial for advancing energy storage devices sustainably. One feasible approach to producing supercapacitor electrode materials is the conversion of heteroatom-rich biomass waste into heteroatom self-doped hierarchical porous carbons with favorable electrochemical properties. In this study, distillers' grains with abundant crude fiber and protein were utilized as precursors to prepare N, S self-doped hierarchical porous carbon, which presents a high specific surface area of 3642.87 m2 g−1. The N, S doping could improve the interfacial wettability of electrode materials and enhance the pseudocapacitive effect of the materials. In three-electrode system, the carbon delivered a high capacitance of 347 F g−1 at 1 A g−1. Symmetrical capacitors assembled with PVA/KOH gel electrolytes delivered an ultrahigh energy density of 11.29 Wh kg−1 at a power density of 250 W kg−1. This strategy provides a practical, low-cost, and renewable design approach of carbon electrode for high-performance supercapacitors.

Nickel-molybdenum bimetallic sulfide decorated biomass derived carbon support for high performance asymmetric supercapacitor application

Biomass - derived carbon electrode material with a porous structure is widely used in supercapacitor applications, which can improve electron transfer and shorter ion diffusion pathways. In this work, the garlic peel biomass carbon (GPBC), NiMo3S4(NMS) and garlic peel biomass carbon decorated with NiMo3S4 (GPBC/NMS) composite were prepared through a in situ two-step hydrothermal method. The synthesized materials were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM), energy dispersive x-ray spectroscopy (EDS), Transmission electron microscopy techniques (TEM), Raman spectroscopy and Brunauer-Emmett-Teller (BET) techniques were used to analyze the structure, morphology and specific surface areas and X-ray photoelectron spectroscopy (XPS). The prepared bimetallic metal sulfide on a biomass - derived carbon namely the GPBC/NMS composite is used in supercapacitor application. The GPBC/NMS composite electrode exhibits good cycle performance with high specific capacity of 304C/g at current density of 1 A/g in a 3 M KOH electrolyte solution. The electrochemical performance of the GPBC/NMS//GPBC asymmetric supercapacitor device produces an excellent energy density 45.5 Wh kg−1 at a power density of 1125 W kg−1 in the 1.6 V operating potential window. The GPBC/NMS//GPBC also exhibits 93 % retention of its initial capacitance after the 10,000 GCD cycle performance. The above results demonstrate a new way of developing high performance electrode materials for energy storage applications.

Phytic acid as an eco-friendly phosphorus source in the synthesis of phosphorus-doped NiCo2O4 for supercapacitor electrodes

This study explores the synthesis of nickel-cobalt bimetallic precursors using phytic acid (PA) as a phosphorus source and their application as supercapacitor electrodes. Through high-temperature annealing, these precursors were converted into phosphorus-doped nickel-cobalt bimetallic oxides (NCO) with certain defects. The morphologies and particle size of NCO can be easily adjusted by the amount of PA. Compared to the undoped nickel-cobalt bimetallic oxides, the phosphorus-doped materials exhibited significantly enhanced electrochemical activity and specific capacitance. The optimized electrode exhibits the highest specific capacitance of 1075 F·g−1 at a current density of 1 A·g−1. The asymmetric supercapacitor assembled together with activated carbon can deliver a relatively high energy density of 39.8 Wh·kg−1 at a power density of 696 W·kg−1. Additionally, this paper provides a detailed discussion on the impact of phosphorus doping on the performance of supercapacitor electrodes and the potential of PA as an eco-friendly phosphorus source in the synthesis of high-performance electrode materials.

Supercapacitors and triboelectric nanogenerators based on electrodes of greener iron nanoparticles/carbon nanotubes composites

The development of supporting materials based on carbon nanotubes (CNTs) impregnated with iron nanoparticles via a sustainable and green synthesis employing plant extract of Punica granatum L. leaves was carried out for the iron nanoparticle modification and the following impregnation into the carbon nanotubes composites (CNT-Fe) that were also coated with polypyrrole (CNT-Fe + PPy) for use as electrode for supercapacitor and triboelectric nanogenerators. The electrochemical characterization of the materials by cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) assays revealed that the CNT-Fe + PPy gave rise to better performance due to the association of double-layer capacitance behavior of carbon derivative in association with the pseudocapacitance contribution of PPy resulting in an areal capacitance value 202 mF/ cm2 for the overall composite. In terms of the application of electrodes in triboelectric nanogenerators, the best performance for the composite of CNT-Fe + PPy was 60 V for output voltage and power density of 6 μW/cm2. The integrated system showed that the supercapacitors can be charged directly by the nanogenerator from 0 to 42 mV in 300 s. The successful green synthesis of iron nanoparticles on CNT and further PPy coating provides a feasible method for the design and synthesis of high-performance SCs and TENGs electrode materials. This work provides a systematic approach that moves the research front forward by generating data that underpins further research in self-powered electronic devices.

Controllable synthesis of porous NiSe2 nanowires to boost energy storage performance for supercapacitors

Porous nanowires can improve energy storage performance due to their fascinating one-dimensional architecture, and large exposed surface areas. Developing high-performance porous electrode materials is essential for enhancing the energy storage performance of supercapacitors. In this study, porous NiSe2 nanowires (NWs) with abundant nanocavities were obtained by treating α-Ni(OH)2 NWs with Se powder under an Ar atmosphere. The amount of Se powder had a significant impact on the specific surface (SS) and capacitive performance. Compared to NiSe2–100 and NiSe2–300, NiSe2–200 exhibited the highest SS and pore volume of 83.8 m2 g−1 and 0.463 cm3 g−1, respectively. The NiSe2–200 electrode achieved a maximum specific capacity of 653.3C g−1 at 0.25 A g−1, attributed to its highly accessible surface, abundant active sites, and short charge transfer path. Additionally, the assembled NiSe2–200//activated carbon hybrid supercapacitor (NiSe2–200//AC HSC) delivered high specific capacitance (88.3 F g−1 at 1.0 A g−1), remarkable specific energy (35.4 Wh kg−1 at 850 W kg−1), and robust cycling durability. Furthermore, a homemade NiSe2–200//AC HSC successfully powered a clock for about 8 min. This study not only provides a simple method for preparing porous NiSe2 NWs but also shows its promising application in HSCs.

Progress on Copper-Based AnodeMaterials for Sodium-Ion Batteries.

Fossil fuels have clearly failed to meet people's growingenergy needs due to their limited reserves, potential pollution of the environment, and high costs.The development of cleaner, renewable energy sources as well as secondary batteries for energy storage is imminent, in a modern society where energy demand is soaring. Sodium-ion batteries (SIBs) have become the focus of large-scale energy storage systems as a promising alternative to lithium-ion batteries. The development of SIBs relies on the construction of high performance electrode materials. The design of low cost and high performance anode materials is a key link in this regard. Copper-based anodes are characterised by high theoretical capacity, abundant reserves, low cost and environmental friendliness. A variety of copper-based anode materials, which include cobalt oxides, sulfides, selenides and phosphides, have been synthesised and evaluated in the scientific literature for sodium storage. In detail, the preparation methods, response mechanisms, strengths and weaknesses, the relationship between morphology structure and electrochemical performance are discussed, as well as highlighting strategies to improve the electrochemical performance of copper-based anode materials. Finally, we offer our perspective on the challenges and potential for the development of copper-based anodes as a means of developing practical and high performing SIBs.

Tuning the thermo-mechanical synergies effect of solid oxide fuel cells with negative thermal expansion NdMnO3 in La0.6Sr0.4Co0.2Fe0.8O3-δ-based symmetric electrode

Solid oxide fuel cells (SOFCs) are efficient and clean energy conversion devices, but one of the major challenges for their marketization is the instability of different component materials under high temperature operating conditions. The existence of a certain internal stress gradient between materials with different thermal expansion characteristics in the process of SOFCs from low temperature assembly to high temperature use is the main reason of this instability, leading to the inability of SOFCs to repeat start-stop and the rapid decay of long-term stability performance. To improve these problems, a creative concept of fuel cell interface overall regulation is proposed, simplifying the complex interface between different components of SOFCs into a unified and adjustable quasi-zero difference thermal expansion interface. The composite of high catalytic activity electrode material and high stability negative thermal expansion material is used for electrolyte support structure symmetrical cell, which makes the whole cell “sandwich” structure thermally and mechanically compatible. As a concept verification, the classic high catalytic performance electrode material La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF), Gd0.2Ce0.8O2-δ (GDC) and NdMnO3 (NM) negative thermal expansion material with high chemical stability and mechanical stability were composited in equal proportions to form LSCF@GDC&NM electrode as the symmetrical electrode. After equal proportion compositing, the thermal expansion curve of LSCF@GDC&NM material can highly coincide with the thermal expansion curve of GDC, making the single cell with LSCF@GDC&NM electrode can withstand 25 power thermal cycles without significant performance decay, achieving 442 mW cm−2 at 800 °C and maintaining stably for 140 h without any degradation. These results show that using negative thermal expansion material to regulate electrode strategy is expected to make a whole zero difference thermal fuel cell configuration.

Iodine intercalation-assisted alkali activation constructs coal-based porous carbon for high-performance supercapacitors

Supercapacitors have the advantages of fast charging and discharging speeds, high power density, long cycle life, and wide operating temperature range. They are widely used in portable electronic equipment, rail transit, industry, military, aerospace, and other fields. The design and preparation of low-cost, high-performance electrode materials still pose a bottleneck that hinders the development of supercapacitors. In this paper, coal was used as the raw material, and the coal-based porous carbon electrode material was constructed using the iodine intercalation-assisted activation method and used for supercapacitors. The CK-700 electrode exhibits excellent charge storage performance in a 6 M potassium hydroxide (KOH) electrolyte, with a maximum specific capacitance of 350 F/g at a current density of 0.5 A/g. In addition, it has an excellent rate performance (310 F/g at 1 A/g) and cycle stability (capacitance retention up to 91.7 % after 30000 cycles). This work provides a method for realizing high-quality, high-yield and low-cost preparation of coal-based porous carbon, and an idea for improving the performance of supercapacitors.

High Capacity and Fast Kinetics Enabled by Metal-Doping in Prussian Blue Analogue Cathodes for Sodium-Ion Batteries.

Prussian blue analogues (PBAs) have gained tremendous attention as promising low-cost electrochemically-tunable electrode materials, which can accommodate large Na+ ions with attractive specific capacity and charge-discharge kinetics. However, poor cycling stability caused by lattice strain and volume change remains to be improved. Herein, metal-doping strategy has been demonstrated in FeNiHCF, Na1.40Fe0.90Ni0.10[Fe(CN)6]0.85·1.3H2O, delivering a capacity as high as 148 mAh g‒1 at 10 mA g‒1. At an exceptionally high rate of 25.6 A g‒1, a reversible capacity of ~55 mAh g‒1 still can be obtained with a very small capacity decay rate of 0.02% per cycle for 1000 cycles, considered one of the best among all metal-doped PBAs. This exhibits the stabilizing effect of Ni doping which enhances structural stability and long-term cyclability. In situ synchrotron X-ray diffraction reveals an extremely small (~1%) change in unit cell parameters. The Ni substitution is found to increase the electronic conductivity and redox activity, especially at the low-spin (LS) Fe center due to inductive effect. This larger capacity contribution from LS Fe2+C6/Fe3+C6 redox couple is responsible for stable high-rate capability of FeNiHCF. The insight gained in this work may pave the way for the design of other high-performance electrode materials for sustainable sodium-ion batteries.

Home-made chemical vapor deposition-based synthesis of binder-free nanostructured magnesium-molybdenum-sulfide electrode materials for supercapacitor application

Molybdenum disulfides (MoS2) is considered as promising electrode materials (E-M) for high electrochemical performance (ECP) of lithium-ion batteries and supercapacitors due to their layered nanostructures. Herein, MoS2, MgS and hetrostructure MgS/MoS2 E-Ms comprising of nano-particles/sheets/needles like structures are synthesized on Nickel foam (Ni–F) by a simple home-made chemical vapor deposition (CVD) technique. The XRD analysis confirmed the formation of MoS2, MgS and MgS/MoS2 polycrystalline E-Ms growing along different directions. The FESEM analysis is confirmed that the addition of MgS layer over the surface of MoS2 change the surafce morphology from nano-particles to nano-needles. The change in structural and microstructural features is indicated the appearance of defects, micro-strain and dislocations density which are fruitful for excellent ECP. The cyclic voltammetry analysis is indicated the pseudocapacitive nature of the synthesized E-Ms. The maximum specific capacitance values for MoS2/Ni–F, MgS/Ni–F and MgS/MoS2/Ni–F E-Ms are 1273, 1688 and 3934 F/g at 1 A/g respectively. Moreover, the addition of MgS layer over MoS2/Ni–F is revealed the excellent cyclic stability of 98.76 % at current density of 10 A/g after 4000 cycles, energy density values are ranged from 79 to 136 W h/kg with homologous power density of 250–2500 W/kg and very small charge transfer resistance. The simulations of Power's Law and Dunn's model is confirmed that the excellent ECP is due to both capacitive and diffusive controlled contributions of heterostructured MgS/MoS2/Ni–F E-Ms. Additionally, MgS/MoS2/Ni–F E-Ms have both battery and pseudocapacitive nature due to unique nano-needles like morphology. The excellent electrochemical properties of MgS/MoS2/Ni–F E-Ms substantiate their potential applications in portable energy storage devices.

Magnetic field-assisted electrodeposition of ZnCo2O4-rGo nanoelectrodes for enhanced supercapacitor performance

To investigate a convenient, rapid, and environmentally friendly method for the preparation of supercapacitor electrode materials to enhance supercapacitor performance, this study achieved the successful synthesis of ZnCo2O4-rGo (ZCG) nanomaterial electrodes on a nickel foam substrate. These electrodes were then assembled into supercapacitors using Magnetic field-assisted Electrodeposition (MFAED) technology. The surface morphology and structure characterization analysis revealed that the ZCG-4 material exhibited a mesoporous layered nanosheet structure. Moreover, they exhibited a significant specific active surface area of 155.7 m2/g and showed excellent adhesion to the nickel foam substrate. The electrochemical properties of the ZCG nanoelectrode material were studied in a 1 M KOH aqueous solution. The results revealed that the ZCG-4 nanoelectrode displayed low electrochemical impedance (Rs 0.23 Ω, Rct 1.36 Ω, and Zw 0.99 Ω) and a high specific capacitance of 2672 Fg−1. Furthermore, at a current density of 3 Ag−1, the electrode maintained good capacity retention (2672 Fg−1–2529 Fg−1, 94.6 %). Moreover, it retained a significantly high specific capacitance of 1339 Fg−1 even after 6000 cycles under a current density of 20 Ag−1. The supercapacitor assembled with ZCG-4 electrodes exhibits good electrochemical performance, possessing a high capacitance of 5.8F/cm2 at a current density of 1 mA/cm2. Moreover, the ZCG-4 supercapacitor demonstrates outstanding cyclic performance, maintaining 86 % capacity retention following 6000 charge–discharge cycles at a high current density of 30 mA/cm2. The mechanism of magnetic field electrodeposition for preparing ZCG has also been explained using magnetohydrodynamics theory. At a magnetic field strength of 6 T, the ion migration speed is 1.7 × 10−5 m/s, and the addition of the magnetic field effectively increases this speed. An effective magnetic field electrodeposition approach was thus proposed in this investigation to enable the synthesis of high-performance electrode materials and capacitors by combining metal oxide and rGo.

Synthesis of Co@CoO/C by Micro-Tube Method and Their Electrochemical Performances

Lithium-ion batteries (LIBs) are promising secondary batteries that are widely used in portable electronic devices, electric vehicles and smart grids. The design and synthesis of high-performance electrode materials play a crucial role in achieving lithium-ion batteries with high energy density, prolonged cycle life, and superior safety. CoO has attracted significant attention as a negative electrode material for lithium-ion batteries due to its high theoretical capacity and abundant resources. However, its limited conductivity and suboptimal cycling performance impede its potential applications. The study proposes a novel micro-tube reaction method for the synthesis of Co@CoO/C, utilizing Kapok fiber as a template with a special hollow structure. The microstructure and composition of the samples were characterized using X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). After conducting electrochemical performance tests, it was discovered that at a current density of 100 mA/g and within the range of 0.01∼3.0V for 50 charge and discharge cycles. Co@CoO/C composite negative electrode exhibits a reversible lithium insertion specific capacity of 499.8 mAh/g and keep a discharge capacity retention rate of 97.6%. The greatly improved lithium storage and stability performance of Co@CoO/C composite anode is mainly attributed to the synergistic effect between Co@CoO nanoparticles and the kapok carbon microtubule structure.

Nitrogen-doped porous carbon derived from cross-cutting bamboo for high-performance supercapacitors by one-pot ball milling method

In this work, Nitrogen-doped cross-cut KOH-activated porous carbon (NCKC) was obtained through a simple and effective fabrication process. Cross-cut bamboo, KOH, and urea are mixed through a one-pot ball milling strategy. The obtained sample (NCKC) has a high specific capacitance in the three-electrode test (367 F·g−1 at 0.2 A· g−1), and maintains a satisfactory specific capacitance of 183 F·g−1 at a high current of 50 A·g−1. Moreover, an aqueous supercapacitor based on NCKC with 1 M Na2SO4 as the electrolyte can provide an outstanding specific energy of 31.1 W h kg−1 with a specific power of 200 W·kg−1, without any noticeable reduction in capacity even after 40,000 cycles. This is attributed to the fact that NCKC has an abundant hierarchical pore structure. The cross-cutting process can shorten natural pores origin from bamboo native structures, and facilitate hydrophilicity in the resulting porous carbon. The results reveal that the synergistic effect of cross-cutting process, ball milling, and N-doping in carbon enhanced the electrochemical performance of carbon remarkably. The results show such one-pot ball milling method simplifies the preparation process and is of great interest for the innovation and application of high-performance electrode materials.

Novel Electrospun Sn-Based Composite Cathodes Exhibiting Extended Cycle Life for Hybrid Magnesium-Lithium Batteries.

In this study, we present a strategic approach for the structural design and composite modification of one-dimensional Sn-based nanocomposites to enhance the overall electrochemical performance of hybrid magnesium-lithium batteries (MLIBs), which are emerging as promising successors to lithium-ion batteries. By using electrospinning technology, we successfully synthesized NST-SnO2, NST-SnO2-NiO, Sn-CNF, and Ni3Sn2-CNF composite cathodes, as well as analyzed the synthesis mechanism of the four Sn-based cathodes. The 100-cycle testing at a current density of 500 mA·g-1 revealed that NST-SnO2 maintained a discharge specific capacity of 129.8 mA h·g-1 with a retention rate of 90.76%, while NST-SnO2-NiO achieved a higher capacity of 147.4 mA h·g-1 and an 88.05% retention rate. Notably, Sn-CNF and Ni3Sn2-CNF exhibited initial discharge capacities of 66.7 and 79.6 mA h·g-1, respectively, coupled with exceptional cycle stability, evidenced by retention rates of 104.19 and 102.38%. The remarkable cycling stability observed in these novel cathodes is attributed to their robust structural integrity, thus demonstrating the potential for an extended cycle life in MLIBs. This work provides significant advancement in the development of high-performance electrode materials for next-generation hybrid magnesium-lithium energy storage systems.

Hydrogels and Carbon Nanotubes: Composite Electrode Materials for Long-Term Electrocardiography Monitoring.

This paper presents methods for developing high-performance interface electrode materials designed to enhance signal collection efficacy during long-term (over 24 h) electrocardiography (ECG) monitoring. The electrode materials are fabricated by integrating commercial ECG liquid hydrogels with carbon nanotubes (CNTs), which are widely utilized in dry-electrode technologies and extensively discussed in the current scientific literature. The composite materials are either prepared by dispersing CNTs within the commercial liquid hydrogel matrix or by encasing the hydrogels in macroscopic CNT films. Both approaches ensure the optimal wetting of the epidermis via the hydrogels, while the CNTs reduce material impedance and stabilize the drying process. The resulting electrode materials maintain their softness, allowing for micro-conformal skin attachment, and are biocompatible. Empirical testing confirms that the ECG electrodes employing these hybrid hydrogels adhere to relevant standards for durations exceeding 24 h. These innovative hybrid solutions merge the benefits of both wet and dry ECG electrode technologies, potentially facilitating the extended monitoring of ECG signals and thus advancing the diagnosis and treatment of various cardiac conditions.

Ligand regulation and capacitive properties of nickel based pyrazole trinuclear copper cluster organic framework

Traditional metal organic framework (MOF) hinders its application as high-performance electrode materials for supercapacitors due to the limited electron transfer efficiency and conjugation of its ligand molecules. Therefore, in this article, highly electrochemical active pyrazole trincore-copper cluster derivatives as the core unit were covalently assembled by Schiff base reaction with organic linkers of different structures to obtain a series of structurally different electroactive ligands. It was found that ligands with multiactive metal chelation site structure with polydentate carboxylate linker and aromatic extension showed high coordination ability and high degree of conjugation. The nickel-based MOF synthesized with this novel electroactive ligand exhibited a high specific capacitance of 1804 Fg−1 at a current density of 1 Ag−1. At a power density of 747.25 W kg−1, the maximum energy density of the assembled asymmetric supercapacitor assembled with Cu-PyAc-Am2Ac-Ni is 58.95 Wh kg−1 with cycling stability of 88.95 % after 5000 charges and discharges. This means that Cu-PyAc-Am2Ac-Ni is a promising electrode material for supercapacitors.

Design of high-performance transition metal sulfide electrode materials and its application in supercapacitors

In this paper, the starting point is to create a large surface area, multi-metal cooperative composite material, and then add lithium to enhance the capacitance of the material to build a high-performance and high-stability electrode material. The CoMnLi hydroxide is synthesized on the metal organic framework Ni-BTC, and the composite is vulcanized as Ni-BTC@CoMnLiS using a solvent-thermal process. Moreover, the electrochemical properties electrode materials prepared under different conditions are investigated. It is eventually discovered that the electrode material prepared using water as a solvent having the best electrochemical performance at a reaction time of 6 h, and it is named Ni-BTC@Co2.13Mn1.78LiS4.52#6 (N@CMLS#6). The N@CMLS#6 electrode material has a high specific capacity (1040C g−1, 1 A g−1) and an eminent cycling stability (87.94 %, 10,000 cycles). In addition, the asymmetric supercapacitors devices (N@CMLS#6//AC) exhibit large energy density (82.14 W h kg−1, 800 W kg−1) and good cycle life (85.62 % of the original capacity after 10,000 charge-discharge cycles). Connecting two asymmetric supercapacitors (ASC) devices in series may light up tiny Light Emitting Diode (LED) lights, demonstrating its practical utility.

Work-function-prompted interfacial charge kinetics in hierarchical heterojunction flexible electrode for efficient capacitive deionization

The growing challenge of water scarcity has spurred extensive research into the development of advanced freestanding pseudocapacitive electrode materials. These electrodes, characterized by their controlled morphology, mechanical complexity, and enhanced desalination capabilities, are advancing water treatment technologies. Additionally, electrodes with interfacially influenced heterostructures demonstrate substantial potential to enhance electrochemical kinetics. However, their widespread adoption is hindered by intricate synthesis procedures and the necessity for multiple discrete components. Herein, the report introduces a cohesive approach that utilizes electrospinning and carbonization to create a freestanding, hierarchically porous nitrogen-doped carbon nanofiber network encapsulating FeNi3 alloy (FeNi3@CNFs) for desalination applications. The method enhances the interfacial effect, mitigates volume changes during sodium ion adsorption and desorption, and improves interfacial stability. By capitalizing on structural and compositional advantages, the novel FeNi3@CNFs electrode delivers outstanding electrochemical properties, including a high desalination capacity (46.47 mg g−1 at 1.2 V), rapid desalination rate (0.77 mg g−1 min−1), and enhanced cyclic durability. Computational analysis via Density Functional Theory shows that the work function prompts a surface charge redistribution at the FeNi3@CNFs heterojunction, optimizing the surface electronic structure and reducing the energy barrier for adsorption. The modification significantly boosts the diffusion kinetics of sodium adsorption. The study delineates a comprehensive methodology for fabricating high-performance heterostructured electrode materials that are effective for capacitive deionization.

Optimization of Desalination Efficiency and Exploratory Applications of TiO2 Active Site Electrode Enhanced by Activated Carbon and Tween 80 in Capacitive Deionization Technology.

Capacitive deionization (CDI) is an emerging desalination technology for seawater desalination. The development of high-desalination and long-life electrode materials is a research focus in the global water treatment field. In this experiment, Tween T80 was used as a surface activator, and a modified electrode was prepared by facilitating the deposition of TiO2 active sites onto the surface of activated carbon through a sol-gel/hydrothermal two-step synthesis strategy. The morphology and specific surface area of the composite material were analyzed through scanning electron microscopy, specific surface area measurements, and contact angle tests. The results indicated that the sol-gel/hydrothermal two-step synthesis strategy played a crucial role in the homogeneous combination and performance enhancement of the composite material. Under constant voltage mode, when the working voltage was 1.2 V, the desalination capacity of this composite material in a NaCl solution with an initial conductivity of 3000 μS·cm-1 reached 23.8 mg·g-1 (26% higher than materials prepared by conventional sol-gel methods). After 150 cycles, the capacity retention rate was 78%, and the retention capacity was significant (87%). Overall, the results demonstrate the potential of the sol-gel/hydrothermal two-step synthesis strategy in preparing high-performance CDI electrode materials. The modified electrode prepared using this method offers enhanced desalination capacity and durability, making it a promising candidate for seawater desalination and other water treatment applications.

Cobalt molybdate nanoflowers decorated bio-waste derived porous activated carbon nanocomposite: A high performance electrode material for supercapacitors

In this work, we report a supercapacitor electrode material based on nano-flower like cobalt molybdate decorated on porous activated carbon derived from waste onion peels (β-CoMoO4-POAC). The obtained POAC exhibits highly porous structure and after the hydrothermal treatment with salts of cobalt and molybdenum, we observed a uniform distribution of β-cobalt molybdate (β-CoMoO4) as nano-flowers on the surface of POAC. The chemical composition, morphology and porosity of the materials were thoroughly analyzed using field emission scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, infrared spectroscopy and Brunauer–Emmet–Teller surface area measurement. Due to its flower like and highly porous morphology, β-CoMoO4@POAC exhibits a high specific capacitance of 1110.72 F/g at a current density of 1 mA/cm2 with superior cyclic retention of 96.03% after 2000 cycles. The best electrochemical performance exhibited by β-CoMoO4@POAC is mainly due to its high surface area and porous nature of the material which assists in active transport of ions. This study reveals the exceptional electrochemical properties of β-CoMoO4@POAC which could be considered as a potential material for advanced energy storage devices.