Electrochemical Energy Storage Properties Research Articles

Boosting electrochemical energy storage properties of SrGd2O4 through Yb3+ and Tm3+ rare earth ion doping

Electrochemical supercapacitors represent advanced energy storage devices that excel in the swift storage and delivery of electrical energy, effectively bridging the gap between conventional capacitors and batteries. The present work, aimed to investigate charge storage properties of SrGd2O4 and rare earth ions Yb3+ and Tm3+ doped in SrGd2O4. Both materials were prepared via simple sol-gel synthesis and characterized by XRD, XPS, and FE-SEM with EDS. Characterization confirmed the presence of Tm3+ and Yb3+ in the SrGd2O4 matrix with a uniform distribution of elements. The charge storage behavior of pure SrGd2O4 and SrGd2O4:Yb4Tm1 in various electrolytes was thoroughly explored. Large electrochemical potential windows were shown by both electrode materials in aqueous 6M KOH (1.7 V), which is essential for supercapacitors to achieve high specific energy. Furthermore, SrGd2O4:Yb4Tm1 demonstrated a substantially more pronounced charge storage effect in 6M KOH electrolyte, with almost double times higher specific capacitance values compared with an un-doped SrGd2O4 sample. The main impact on the electrochemical window had matrix SrGd2O4, while the main impact on specific capacitance had rear earth dopants (Yb3+ and Tm3+). Improved charge storage characteristics of SrGd2O4:Yb4Tm1 were also evident through a notable reduction in overall resistance observed in electrochemical impedance spectroscopy experiments. Concerning the two-electrode GCD measurements, the SrGd2O4:Yb4Tm1 electrode in 6M KOH showed a specific capacitance of 143 F g−1, with the specific energy of 12.5 Wh kg−1 at 0.6 A g−1. These findings demonstrate the potential of rare earth ion doping in enhancing the energy storage properties of SrGd2O4, offering promising avenues for the development of high-performance supercapacitors.

Carbon and Nitrogen‐Co‐Doped Se/NiSe2/CoSe2 Nanocomposite as Superior Performance Electrode Material in Hybrid Supercapacitors

AbstractMetal selenides are essential electrode materials for promising electrochemical energy storage with comparable or improved electrochemical performance than metal oxides. Herein, Se/NiSe2/CoSe2 (S/NS/CS) is fabricated using a solvothermal approach with the assistance of polyethyleneimine, followed by annealing at different temperatures (300, 400, 500, and 600 °C) for one hour under an argon atmosphere. After annealing, all electrodes’ physical and electrochemical properties were examined, which determined that the best electrode is NiCo2O4/NiO (NCO/NO) formed at 500 °C. Additional hydrothermal method uses NCO/NO with SeO2 as a selenium source to prepare S/NS/CS nanocomposite, with a specific surface architecture that enables easy ion movement and robust conductivity, giving it exceptional electrochemical energy storage properties. It exhibited a remarkable capacitance of 468 F g−1 at a current density of 0.5 A g−1. For practical applications, the hybrid S/NS/CS//AC device was designed using S/NS/CS as a positive electrode and commercial activated carbon (AC) as a negative electrode. The asymmetric device demonstrated an excellent capacitance of 142 F g−1 (189 C g−1) and a superb specific energy of 44 Wh kg−1 at a specific power of 840 W kg−1 at a current density of 1 A g−1, providing 80 % capacity retention and 100 % coulombic efficiency after 5000 cycles.

Exfoliation of Ca3Co4O9 to Two-Dimensional Single-Crystalline Misfit Calcium Cobaltates for Energy Storage Applications.

Layered materials have become indispensable in the development of two-dimensional (2D) systems, offering extensive specific surface area and exceptional electrical, electrochemical, and optical properties critical for diverse applications in energy storage, catalysis, sensing, and optoelectronics. While mono- and biatomic layered materials have demonstrated remarkable characteristics in lower dimensions, the quest for complexity in materials has opened new avenues for tailoring properties to specific requirements. Within this context, misfit-layered compounds (MLCs) stand out as promising candidates. In this study, we present a successful synthesis of few-layered misfit CaCoO2-CoO2 2D nanosheets in bulk quantities from bulk calcium cobalt oxide (CCO-B or CCO). These newly synthesized 2D exfoliated misfit nanosheets demonstrate remarkable 7-fold electrochemical energy storage properties, surpassing their parent bulk CCO, as cathode materials in aqueous Zn-ion batteries. This work addresses the longstanding challenge of exfoliating bulk MLCs to nanostructured, lower dimensional MLCs, opening doors for utilization in advanced energy storage systems and beyond.

Construction of a nanostructured NiCo2S4/Ni/Ni9S8 composite for energy storage applications

It is necessary to investigate and develop nickel-cobalt sulfide electrodes with superior electrochemical behavior. This work produced the NiCo2S4/Ni/Ni9S8 nanostructure composite (NCS/N/NS) for energy storage in supercapacitors using a solvothermal technique with polyethyleneimine (PEI) as a carbon source, followed by an hour of annealing in an argon atmosphere, and a hydrothermal method with thiourea as a sulfur and nitrogen source. Outstanding electrochemical energy storage properties are provided by NCS/N/NS. The produced electrode material, NCS/N/NS, demonstrated an exceptional capacitance of 1620 F g−1 (696 C g−1) at 1 A g−1 when employed for SCs. An NCS/N/NS was used as the positively charged electrode and the opposite electrode of commercial AC to build an NCS/N/NS//activated carbon (AC) asymmetric device for practical usage. At 1 A g−1, the asymmetric device produced a specific power of 887 W kg−1 and a unique specific energy of 53 Wh kg−1. Moreover, it exhibits a 100% coulombic efficacy and a 95% capacity retention after 3000 cycles, respectively.

Improved ion adsorption capacities and diffusion dynamics in surface anchored MoS2⊥Mo4/3B2 and MoS2⊥Mo4/3B2O2 heterostructures as anodes for alkaline metal-ion batteries.

First-principles calculations were performed to analyze the atomic structures and electrochemical energy storage properties of novel MoS2⊥boridene heterostructures by anchoring MoS2 nanoflakes on Mo4/3B2 and Mo4/3B2O2 monolayers. Both thermodynamic and thermal stabilities of each heterostructure were thoroughly evaluated from the obtained binding energies and through first-principles molecular dynamics simulations at room temperature, confirming the high formability of the heterostructures. The electrochemical properties of MoS2⊥Mo4/3B2 and MoS2⊥Mo4/3B2O2 heterostructures were investigated for their potential use as anodes for alkaline metal ion batteries (Li+, Na+ and K+). It was revealed that Li+ and Na+ can form multiple stable full adsorption layers on both heterostructures, while K+ forms only a single full adsorption layer. The presence of a negative electron cloud (NEC) contributes to the stabilization of a multi-layer adsorption mechanism. For all investigated alkaline metal ions, the predicted ion diffusion dynamics are relatively sluggish for the adsorbates in the first full adsorption layer on MoS2⊥boridene heterostructures due the relatively large migration energies (>0.50 eV), compared to those of second or third full adsorption layers (<0.30 eV). MoS2⊥Mo4/3B2O2 exhibited higher onset and mean open circuit voltages as anodes for alkaline metal-ion batteries than MoS2⊥Mo4/3B2 hybrids because of enhanced interactions between the adsorbate and the Mo4/3B2O2 monolayer with the presence of O-terminations. Tailoring the size and horizontal spacing between two neighboring MoS2 nano-flakes in heterostructures led to high theoretical capacities for LIBs (531 mA h g-1), SIBs (300 mA h g-1) and PIBs (131 mA h g-1) in the current study.

Morphology and Crystallinity Effects of Nanochanneled Niobium Oxide Electrodes for Na-Ion Batteries.

Niobium pentoxide (Nb2O5) is a promising negative electrode for sodium ion batteries (SIBs). By engineering the morphology and crystallinity of nanochanneled niobium oxides (NCNOs), the kinetic behavior and charge storage mechanism of Nb2O5 electrodes were investigated. Amorphous and crystalline NCNO samples were made by modulating anodization conditions (20-40 V and 140-180 °C) to synthesize nanostructures of varying pore sizes and wall thicknesses with identical chemical composition. The electrochemical energy storage properties of the NCNOs were studied, with the amorphous samples showing better overall rate performance than the crystalline samples. The enhanced rate performance of the amorphous samples is attributed to the higher capacitive contributions and Na-ion diffusivity analyzed from cyclic voltammetry (CV) and the galvanostatic intermittent titration technique (GITT). It was found that the amorphous samples with smaller wall thicknesses facilitated improved kinetics. Among samples with similar pore size and wall thickness, the difference in their power performance stems from the crystallinity effect, which plays a more significant role in the resulting kinetics of the materials for Na-ion batteries.

High-performance CF/MXene/β-PbO2 materials as anodes for asymmetric supercapacitors

MXene has excellent capacitive properties as a two-dimensional material, but its cycling stability is poor. β-PbO2 is one of the common crystalline forms of lead dioxide, and it has excellent electrochemical properties and cyclic stability and has potential as a capacitor electrode material. However, the capacitive performance of β-PbO2 as a capacitor electrode material is not ideal. Therefore, CF/MXene/β-PbO2 (CMP) composites were prepared in this study by combining β-PbO2 with CF/MXene (CM) using a constant current electrodeposition method, and their electrochemical energy storage properties were investigated. The ordered structure of interwoven CF is used to fix MXene, which has metallic properties and large layer spacing, as the matrix material. This utilization enables faster ion transport and electron storage. The electrochemical advantages of β-PbO2 and CM can be unified by the synergistic effect of the composites, which results in a high specific capacity (399.42 F g−1) of the CMP electrode at 0.2 A g−1. In addition, the CM//CMP asymmetric supercapacitor constructed in 1 M Na2SO4 solution has a wide potential window of 2.0 V and a high specific capacitance of 193.8C g−1, and the capacity remains 54.3% of the initial value after 5000 cycles at a charge/discharge rate of 40 mA g−1. This work provides important research ideas and clues for the application of β-PbO2 composite electrode materials in supercapacitors.

Facile synthesis of high-entropy (Co0.2Cr0.2Fe0.2Mn0.2Ni0.2)3O4 nanopowders and their electrochemical properties as supercapacitor electrode

High-entropy oxide (HEO) nanopowders are expected to have unique electrochemical energy storage properties due to their unique structural characteristic and tailorable chemical composition. However, HEO nanopowders are difficult to be prepared because of severe grain coarsening and particle agglomeration in high temperature calcination. In this study, a polyacrylamide gel method was presented to prepare high-entropy (Co0.2Cr0.2Fe0.2Mn0.2Ni0.2)3O4 nanopowders. The mole ratio of acrylamide/metal cations (A/M) had a significant influence on the average particle size of HEO nanopowder, which was decreased with the increase of A/M mole ratio. Electrochemical tests demonstrated that as-prepared HEO nanopowders had a specific capacitance of 384 F/g at a current density of 1 A/g, which was remained 57 % as the current density was increased to 20 A/g. Furthermore, a relatively high capacitance retention of 60 % was obtained after 2000 charge-discharge cycles at 5 A/g. In addition, a HEO//activated carbon asymmetric supercapacitor was assembled, which achieved an energy density of 24 Wh/kg at a power density of 746 W/kg. This study presents a simple and cost-effective method to prepare HEO electrode material for supercapacitors.

Intercalation in 2H-TaSe[formula omitted] for modulation of electronic properties and electrochemical energy storage

Two-dimensional transition metal dichalcogenides (TMDs) exhibit an extensive variety of novel electronic properties, such as charge density wave quantum spin Hall phenomena, superconductivity, and Dirac and Weyl semi-metallic properties. The diverse properties of TMDs suggest that structural transformation can be employed to switch between different electronic properties. Intercalation and zero valence doping of molecules and atoms into the van der Waals gap of TMDs have emerged as effective approaches to modify the charge order states of the material. This eventually leads to phase transition or the formation of different phases, thus expanding the electronic, thermoelectric and optical applications of these materials. In this study, electronic and electrochemical energy storage properties of such an intercalated TMD, namely, 2H-TaSe2 via intercalation of lithium (Li), sodium (Na) and potassium (K) have been investigated. The intercalation of these ions into the dichalcogenide resulted in a modified band structure and novel structural effects, leading to the emergence of a 1 eV band gap. Possibility of electrochemical energy storage application is also explored in this study. Furthermore, the importance of multi orbital electron–electron correlations in intercalated TaSe2 is also investigated via dynamical-mean-field theory with local density approximation.

Synergistic Engineering of Architecture and Composition in Bimetallic Selenide@Carbon Hybrid Nanotubes for Enhanced Lithium‐ and Sodium‐Ion Batteries

AbstractDeveloping sustainable and affordable anode materials that are capable of delivering high performance in both lithium‐ion batteries (LIBs) and sodium‐ion batteries (SIBs) remains a significant challenge. Bimetallic selenide@carbon hybrids are considered as one of the most promising anode materials in LIBs and SIBs due to their high electronic conductivity, high specific capacity, and fast reaction kinetics. Herein, a series of bimetallic selenide@carbon hybrid nanotubes are successfully prepared as anodes of LIBs or SIBs based on the dual regulation of component and micro‐nanostructure. The selenization strategy plays a key important role in determining the composition, microstructure, and electrochemical energy storage properties of anode materials. As a consequence, the ZnSe/CoSe2@NPC NTs(I)‐600 exhibit a reversible capacity of 1328.3 mAh g−1 at 0.1 A g−1 and superior rate capability (269.1 mAh g−1 at 10 A g−1) towards Li+ storage. Meanwhile, ZnSe/CoSe2@NPC NTs(II)‐700 achieve 354.1 mAh g−1 at 0.1 A g−1 and ultralong cycling stability (97.6% of capacity retention after 40 000 cycles at 10 A g−1) used as anode materials in SIBs. This study provides a feasible strategy to fabricate selenide‐based composites as anode materials for high‐performance LIBs and SIBs via architecture engineering and composition tailoring.

In situ growth of oxometallate-based coordination polymer decorated Ti3C2Tx MXene with enhanced water-assisted proton channels for flexible all-solid-state supercapacitor

As promising electrode material contender for supercapacitors, MXene has high conductivity, abundant surface functional groups, and large surface area. However, the self-restacking of MXene leads to poor ion-accessible surface area and restricted ion transport routes. Water-assisted proton channels contained by Polyoxometallate-based coordination polymer (POMCP) can improve the efficiency of ion transport between MXene layers, which is conducive to enhancing the storage capacity and rate performance. Herein, [PW12O40]@[Cu6O(TZI)3(H2O)6]4·OH·31H2O (CuCP) decorated Ti3C2Tx (CuCP/MX) was synthesized by in-situ hydrothermal method. Attribute to the extended interlayer space and enhanced ion transport efficiency, CuCP/MX exhibits excellent electrochemical energy storage properties. It is worth revealing that when assembling into an all-solid-state supercapacitor device (SC), excellent specific capacitance (380 mF/cm2) and energy density (68.4 μWh/cm2 at 540 μW/cm2) were exhibited. CuCP/MX is a considerable electrode material for supercapacitors for flexible electronic devices.

Synthesis and characterization of azodianiline covalent organic frameworks intended for energy storage

Two covalent organic frameworks (COFs), a subgroup of porous organic polymers, based on diamine and trialdehyde monomers were synthesized to explore the effect of the building block structure on final electrochemical energy storage properties. One was synthesized from azodianiline (AZO) and tris (4-formyl phenyl) amine (TFPA) precursors and the other was prepared from AZO and 1,3,5-tris (p-formyl phenyl) benzene (TFPB). The former COF (TFPA-AZO-COF) and the latter one (TFPB-AZO-COF) were then evaluated by various characterization techniques. Specific surface area of 987 m2g−1 was found for TFPB-AZO-COF, while 425 m2g−1 was estimated for TFPA-AZO-COF. Specific capacity of 450 Fg−1, energy density of 24.6 W hkg−1, and power density of 8500 Wkg−1 were measured for TFPB-AZO-COF, while 160 Fg−1, 9.8 Whkg−1, and 8600 Wkg−1 were obtained for TFPA-AZO-COF. Stronger resonance in TFPB-AZO-COF accounted for better performance in terms of electrochemical energy storage.

Cu1.5Mn1.5O4 hollow sphere decorated Ti3C2Tx MXene for flexible all-solid-state supercapacitor and electromagnetic wave absorber

Flexible energy storage systems and electromagnetic pollution have become issues that need to be resolved in equipment research and development due to the widespread use of portable electronic devices and 5G networks. MXene is competent for supercapacitors and electromagnetic wave absorbers through sensible composite and microstructure design. Herein, Cu1.5Mn1.5O4 Hollow Nanosphere Decorated Ti3C2Tx MXene (CuMnHS@MX) was prepared by simple electrostatic self-assembly. Hybrid membranes can be quickly prepared by vacuum-assisted filtration. CuMnHS@MX exhibits excellent electromagnetic wave absorption performance and electrochemical energy storage properties. High specific capacitance (2089 mF/cm2 at 2.5 mA/cm2) and excellent cycle stability (99.89% after 8000 cycles) are achieved, which are attributed to the increased interlayer spacing and improved interlayer ion transport efficiency. When assembled into symmetrical flexible all-solid-state supercapacitor (SC), the device has a specific capacitance of 382.9 mF/cm2 and an energy density of 53.18 μWh/cm2 at a power density of 277.8 μW/cm2. Meanwhile, CuMnHS@MX has advantageous absorbing properties. When the thickness is 4 mm, the minimum reflection loss (RLmin) is −53.42 dB at 6.08 GHz. Adjustable absorbing property is achieved, and the absorbing energy efficiency can cover X and most C, Ku bands. These excellent EMA properties are derived from the 3D structure and rich dipole/interface polarization. CuMnHS@MX is a promising bifunctional material for electrochemical energy storage and electromagnetic wave absorption.

Combustion-Synthesized KNiPO4: A Non-toxic, Robust, Intercalating Battery-Type Pseudocapacitive Electrode for Hybrid Supercapacitors as a Large-Scale Energy Storage Solution

Polyanionic-type electrode material made of (PO4)n− polyhedral covalently bonded with Ni–O linkage is envisaged as a novel electrode material for intercalative battery-type hybrid supercapacitors. Highly porous, flake-type KNiPO4 showed robust electrochemical performances as a result of its open framework structure and active participation of the Ni2+/3+ redox couple that results in superior pseudocapacitive intercalating charge storage in the aqueous KOH electrolyte. The KNiPO4 electrode shows the specific charge storage equivalent to 168.5 mAh/g (capacitance of 935 F/g) at 1 A/g current rate in the potential window of 0.65 V in the aqueous 2 M KOH electrolyte. KNiPO4 electrodes exhibit excellent long-term cycle stability at 10 A/g for 5000 cycles with 87% of the initial capacity retention of the electrode and coulombic efficiency (η = td/tc) equivalent to 95.1% after 5000 cycles. Further, in full cell hybrid supercapacitor (HSC) mode in which porous KNiPO4 acted as the positive electrode and activated carbon (AC) functioned as the negative electrode, in the voltage window of 1.6 V, the highest energy density equivalent to 200 Wh/kg and power density equivalent to ∼819 W/kg were obtained at 1 A/g current rate. At a higher current rate (10 A/g), the hybrid supercapacitor attains a very high power density equivalent to 7981 W/kg with a retention of energy density close to 75 Wh/kg with superior cyclic stability. Coulombic efficiency of the full cell [asymmetric supercapacitor (ASC) mode] has lost only 3.4% with excellent capacity retention (92.3%) of its initial value after 2200 cycles. The robust performance and long cycle life of the electrode in full cells confirm the applicability of the material to power implantable biomedical devices. Further, high power performance coupled with superior cyclic stability coupled with strong electrochemical energy storage properties of the KNiPO4 electrode makes it suitable for bulk, grid-level charge storage applications.

Flexible laterally-configured electrochromic supercapacitor with feasible patterned display

A flexible laterally-configured electrochromic supercapacitor was designed and fabricated through a fully-solution process. The laterally-configured transparent conductive electrode PEDOT:PSS-AgNWs/PET was prepared by spraying technology and then the magenta electrochromic polymer (PProDOT) and gel electrolyte were cast sequentially onto the laterally-configured electrode. The as-prepared device exhibits alternative color changes between magenta and transparent within the potential range −0.9 V and 0.9 V, and the electrochromic behavior is retained even if bent, proving its excellent flexible display properties. As expected, a “ZJUT” patterned flexible display device works clearly when applying driving potentials to the two circuits simultaneously. In addition, the asymmetric device (PProDOT||PEDOT:PSS) integrates excellent electrochromic and electrochemical energy storage properties in terms of high optical contrast of 59.5 %, large coloration efficiency of 423.5 cm2·C−1, fast switching time (7.4 s and 3.9 s), reasonable areal capacitance of 2.15 mF/cm2 at a current density of 0.05 mA/cm2 and robust cyclic stability which can retain 85.65 % and 77.42 % of its initial optical contrast and capacitance even after 1000 cycles of mechanical deformation. Hence, this work demonstrates the flexible laterally-configured electrochromic supercapacitor has great potential in the portable and wearable display fields, such as smart watches and electronic paper.

Impact of Post-Synthesis heat treatment avoidance on cobalt carbonate hydroxide as a Battery-Type electrode material

In this study, the electrochemical energy storage properties of one-dimensional (1D) hierarchical nanowire array (NWA) of cobalt carbonate hydroxide hydrate (Co6(CO3)2(OH)8·H2O) (CCH) is explored. The 1D nanostructure is advantageous due to their better charge/ion transport properties. The material was synthesized via. simple, and facile hydrothermal approach. The highlighting feature of this work lies in its post-synthesis process, where the authors deliberately avoided the post-synthesis heat treatment process to utilize the hydrated (x‧H2O) part associated with the lattice water which eventually led CCH in a unique robust crystal structure. Here, the authors have explored multifaceted aspects of 1D CCH NWAs, including the nanowire synthesis, their growth mechanism, and pseudocapacitive charge storage properties. The authors propose a novel charge storage mechanism, insertion pseudocapacitance, which depends on the (de)intercalation of cations (e.g., Li+, Na+, K+, and H+), where tunnels play a significant role in charge storage properties. In this type of charge-storage mechanism, cationic diffusion occur from the interior of the crystalline framework along with the surface-confined phenomena. The electrochemical energy storage performance in terms of specific capacity (Csp) is found to be 243.55 mAhg−1 @ 5 mVs−1 scan rate and 161.465 mAhg−1 at 2500 mAg−1 current density. The material exhibited excellent capacity retention of ∼ 95 % and ∼ 86 % at significantly higher current densities of 20,000 mAg−1 and 100,000 mAg−1, respectively. This work tries to establish the structure-electrochemical property correlation of the CCH which has an exceptional crystal structure that is deduced ∼ 20 years after its first report. Therefore, the authors emphasize exploring the fundamental understanding of the CCH from the crystallographic point of view and its relevance to electrochemical energy storage. This work will help in exploring the next-generation metal carbonate hydroxide hydrate-based (MCH) materials.

Bifunctional Cu(II)-based 2D coordination polymer and its composite for high-performance photocatalysis and electrochemical energy storage.

Coordination polymers (CPs) have been widely proven as sacrificial electrode materials for energy storage applications because of their high porosity, specific surface area and tunable structural topology. In this work, a new 2D Cu(II)-based CP, formulated as [Cu2(btc)(μ-Cl)2(H2O)4]n (CP-1) (H3btc = benzene-1,3,5-tricarboxylic acid), fabrication of copper oxide nanoparticles (CuO NPs) and its composite (CuO@CP-1) were successfully synthesized using solvothermal, precipitation and mechanochemical grinding approaches. Single-crystal X-ray analysis authenticated a two-dimensional (2D) layered network of CP-1. Further, CP-1, CuO NPs and composite were characterized by diffraction (Powder-XRD), spectroscopic (FTIR), microscopic (SEM), and thermal (TGA) techniques. The porosity and surface behavior of CP-1 and the composite were demonstrated using BET analyzer. Topological simplification of CP-1 shows a 3-c connected hcb periodic net. The photocatalytic behavior of CP-1 was examined over methyl red (MR) dye in the presence of sunlight and showed a promising degradation efficiency of 96.80%. The electrochemical energy storage properties of CP-1, CuO NPs and composite were investigated using cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) analysis under aqueous 1 M H2SO4 electrolyte. The electrochemical results show better charge storage performance of CP-1 with a specific capacitance of 602.25 F g-1 at 1 A g-1 current density by maintaining a retention of up to 84.51% after 5000 cycles at 10 A g-1 current density. Comparative electrochemical studies reveal that CP-1 is a promising electrode material for energy storage.

A Novel High-Performance Anode Material with an Enlarged Potential Window for a Hybrid Energy Storage System

Cobalt-iron (CoFe) layered double hydroxides (LDHs) have received much interest for supercapacitors (SCs) because of their ion-insertable layer structure. However, there is still a need for more effort to increase their potential window and overall electrochemical energy storage capability as SC electrodes. In this work, we present a straightforward approach to synthesizing CoFe-LDHs on zinc oxide seeded carbon cloth (ZnO@CC) via a one-step hydrothermal reaction; the obtained electrode is denoted as CoFe-LDH@ZnO@CC. The electrochemical energy storage properties of CoFe-LDH@ZnO@CC are tested as an anode material using a three-electrode setup for SC applications in 1 M Na2SO4 electrolyte. It can operate in a wider potential window reaching up to 1.6 V, exceeding most previously reported anode materials. The CoFe-LDH@ZnO@CC displayed capacitive charge storage accounting for 76% of the total charge stored at 20 mV/s. The CoFe-LDH@ZnO@CC anode delivered a maximum capacitance of 299.8 F/g at 2 A/g, outstanding cycle stability, and retained 97.7% of the initial capacitance value for 5000 cycles at 16 A/g. This study introduces a new strategy for structurally designing electroactive materials for energy storage devices, which might be useful as an anode for SCs.

Photocatalytic degradation and electrochemical energy storage properties of CuO/SnO2 nanocomposites via the wet-chemical method

Integrating semiconducting functional materials is a way to enlarge the photoexcitation, energy range, and charge separation, greatly elongating the photocatalytic efficiency to enhance the chemical and physical properties of the materials. This work depicts and investigates the impact of cuprous oxide (CuO) and tin dioxide (SnO2)-based catalysts with various CuO concentrations on photocatalytic and supercapacitor applications. Moreover, three distinct composites were made with varied ratios of CuO (5, 10, and 15% wt. Are designated as AT-1, AT-2, and AT-3) with SnO2 to get an optimized performance. The photocatalytic properties indicate that the CuO/SnO2 nanocomposite outperformed its bulk equivalents in photocatalysis using Methyl blue (MB) dye in a photoreactor. The results were monitored using a UV–visible spectrometer. The AT-1 ratio nanocomposite displayed 96% photocatalytic degradation compared to pure SnO2 and CuO. CV analysis reveals a pseudocapacitive charge storage mechanism from 0.0 to 0.7 V in a potential window in an aqueous medium. The capacitive performance was also investigated for all electrodes, and we observed that a high capacitance of 260/155 F/g at 1/10 A/g was attained for the AT-1 electrode compared to others, specifying good rate performance.

Polyaniline decorated salt activated phenolic resin/PAN-based carbon nanofibers with remarkable cycle stability for energy storage applications

Polyaniline (PANI) decorated salt-activated phenolic resin (PR)/polyacrylonitrile (PAN)-based carbon nanofibers (PANI/CNFs) were fabricated by the consecutive solution electrospinning, salt activation and PANI electrodeposition methods for supercapacitor applications. The electrochemical energy storage properties of the PANI-decorated activated PANI/CNFs (activated PAN: CNF-A, activated PR/PAN28 (weight ratio of PR and PAN is 2:8): CNF28-A) were evaluated by assembling the electrodes into a symmetric supercapacitor (SSC) device. The specific capacitance of the device was ca. 336F g−1 at the current density of 1 A/g. The device possessed an energy density of 13.33 Wh kg−1 at a power density of 200 W kg−1 with a retention life of nearly 100 % after 5,000 cycles.