Charge Storage Capability Research Articles

Electrostatic Interfacial Cross-Linking and Structurally Oriented Fiber Constructed by Surface-Modified 2D MXene for High-Performance Flexible Pseudocapacitive Storage.

Fiber supercapacitors are promising power supplies suitable for wearable electronics, but the internally insufficient cross-linking and random structure of fiber electrodes restrict their performance. This study describes how interfacial cross-linking and oriented structure can fabricate an MXene fiber with high flexibility and electrochemical performance. The continuous and highly oriented macroscopic fibers were constructed by 2D MXene sheets via a liquid-crystalline wet-spinning assembly. The oxyanion-enriched terminations of surface-modified MXene in situ could reinforce the interfacial cross-linking by electrostatic interactions while mediating the sheet-to-sheet lamellar structure within the fiber. The resultant MXene fiber exhibits high electrical conductivity (3545 S cm-1) and mechanical strength (205.5 MPa) and high pseudocapacitance charge storage capability up to 1570.5 F cm-3. Notably, the assembled fiber supercapacitor delivers an energy density of 77.6 mWh cm-3 at 401.9 mW cm-3, exceptional flexibility and stability exhibiting ∼99.5% capacitance retention under mechanical deformation, and can be integrated into commercial textiles to power microelectronic devices. This work provides insight into the fabrication of an advanced MXene fiber and the development of high-performance flexible fiber supercapacitors.

A Review on the Recent Development on Polymer Nanocomposite for Energy Storage Application

ABSTRACT: Since the demand for effective and sustainable energy solutions has been on the rise, the field of energy storage has made tremendous strides. Due to their special mix of features, polymer nanocomposites—materials made of polymers and nano-scale fillers have become intriguing materials for energy storage applications. The most current advancements in polymer nanocomposites for energy storage applications are presented in detail in this review study. The work starts with an overview of the fundamental ideas and difficulties surrounding energy storage, then it explores the synthesis and characterization methods employed to create polymer nanocomposites. The many types of nano-fillers used in polymer nanocomposites are then described, including conductive polymers, metal oxides, and carbon-based nano-materials. The main factors influencing how well polymer nanocomposites store energy, such as charge storage capability, conductivity, and cycle stability, are carefully explored. The paper also explores how polymer nanocomposites are used in flexible energy storage systems, lithium-ion batteries, and supercapacitors, among other types of energy storage technology. The impact of interface engineering, morphology, and nanofiller loading on the general effectiveness of polymer nanocomposites is underlined. Additionally, scalability, cost-effectiveness, and environmental impact of polymer nanocomposites for energy storage applications are reviewed, along with their problems and potential for the future. A thorough grasp of the most recent developments in polymer nanocomposites for energy storage applications is the goal of this study, which will make it easier to design and create the next generation of energy storage devices with improved performance and sustainability.

Multifunctional indium selenide devices based on van der Waals contacts: High-quality Schottky diodes and optoelectronic memories

Van der Waals semiconductors, with ultrathin body thickness and dangling-bond-free surfaces, have been employed to fabricate a vast range of electronic and optoelectronic devices such as transistors, photodiodes and memories. The integration of these different functional elements into one single device, usually referred to as multifunctional device, has received great research attention in the recent years. In this work, we realized a multifunctional device, based on the van der Waals semiconductor Indium Selenide (InSe), which can work both as a high-quality Schottky diode with current rectification and photovoltaic characteristics and as a memory. By exploiting the all-dry deterministic transfer fabrication method, we deposited the 2D InSe channel onto pre-deposited graphite and platinum electrodes, whose theoretical work functions differ of ∼1.0–1.4 eV. Thanks to a controllable InSe air passivation treatment, these devices, which start in a non-rectifying state with negligible electrodes-InSe barriers, gradually evolve into Schottky diodes, presenting a final sizeable Schottky barrier height of 556 ± 50 meV at the Pt-InSe interface, thus resulting in a gradual tuning of the device photoresponsivity and photovoltaic parameters (such as the open circuit voltage Voc). The multifunctional capabilities of these devices were demonstrated by using them as optoelectronic memories, which can achieve on-off ratios between the logical ‘1’ and ‘0’ up to 100 and retention times of thousands of seconds. This multifunctional behavior can be ascribed to the traps present in the system, which on one side influences the metal-semiconductor barriers and on the other introduces charge storage capabilities at the base of the memory operation. Our results demonstrate that trap state modulation can be an important tuning knob for thin InSe in the field of electronics and optoelectronics.

Synergistic effects of multifunctional nanostructured WO3-WS2 decorated on polypyrrole (WO3-WS2/PPy) for the removal of toxic heavy metals from wastewaters and high supercapacitor performance

Nowadays, developing a simple, economic, and scalable approach for environmental remediation and producing energy storage devices remains challenging. Herein, we report a novel WO3–WS2 decorated polypyrrole (WO3–WS2/PPy) nanocomposite for the removal of heavy metals, i.e., Cd(II) and Ni(II) and high-performance supercapacitor electrodes.The WO3–WS2/PPy showed significant improvement in the removal of Cd(II) (95.33%) and Ni(II) (89.95%), while WO3–WS2 and PPy revealed removal efficiency of 87.02 and 77.01% for Cd(II) and 82.97 and 74.66% for Ni(II), respectively. For the competitive adsorption experiment, Cu2+/Zn2+ causes a significant influence, while Na+/K+/Mg2+/Ca2+ exerted less effect on the adsorption of the aforementioned metal ions. The WO3–WS2/PPy exhibited higher selectivity toward Cd2+ than Ni2+. Along with, the WO3–WS2 decorated PPy based electrode showed a high specific surface area and support conductive networks, which synergistically improved charge storage capability. The WO3-WS2/PPy-based electrodes exhibit superior electrochemical performance with excellent rate capability, offering the high specific capacitance value of 624 F/g at 3 A/g current density and retaining capacitance stability of 81% after 5000 cycles in 1 M Na2SO4 electrolyte solution. The outcomes of this research infer that WO3-WS2/PPy is a promising candidate for wastewater treatment and high-performance energy storage applications.

Polymer‐Derived High‐Temperature Nonoxide Materials: A Review

This review is focused on an attractive class of polymer‐derived high‐temperature ceramics, namely, polymer‐derived nonoxide materials. With a brief introduction of high‐temperature nonoxides, the origin of using polycarbosilane (PCS) polymer melt spinning to synthesize silicon carbide (SiC) fibers is traced back. For SiC formation, the four stages for the conversion from polymer precursors to microcrystalline ceramics are examined first: crosslinking, polymer decomposition, ceramic formation, and crystallization. Also, the important parameters related to PCS pyrolysis are explained, and polymer‐derived SiC microstructures and compositions are evaluated. Solid‐solution carbides and transition metal carbides are further reviewed. For boride materials, the discussion is focused on transition metal borides and boride composites. Similar to PCS conversion to SiC, nitride materials mostly start with polycarbosilazane (PSZ) precursors and form into the final materials through pyrolysis. With different carbide and nitride precursors mixed and pyrolyzed together, high‐temperature nonoxide composites are formed. Such molecular‐level intermixing and versatile capability of forming different shapes enable many exciting properties. Among these are mechanical and thermal properties, along with electrical conductivity, electromagnetic shielding, and charge storage capability. An overview of applications of polymer‐derived nonoxides is provided, followed by a summary and outlook.

Highly photosensitive CsPbBr[formula omitted] NCs-graphene phototransistor with memory function

A high-performance Violet-light phototransistor with memory function was fabricated using CsPbBr3 nanocrystals as light absorption material, graphene as fast charge transfer channel, and graphene oxide as charge storage medium. The device demonstrated a responsivity of 2 × 103 A/W and a detectivity of 2.3 × 1012 Jones under illumination of a 405 nm laser. Moreover, the phototransistor showed an excellent photoswitching stability and a high response speed with the rise/decay times of 93/31 ms, respectively. The photoresponse mechanism was discussed using a charge injection model in an energy band diagram of CsPbBr 3 NCs and graphene interface. In addition, the device exhibited charge storage capabilities with a memory window of about 0.4 V attributed to graphene oxide as trapping layer. This work provides a viable route to fabricate phototransistors with storage capabilities.

Heterostructures of MXenes and transition metal oxides for supercapacitors: an overview.

MXenes are a large family of two dimensional (2D) materials with high conductivity, redox activity and compositional diversity that have become front-runners in the materials world for a diverse range of energy storage applications. High-performing supercapacitors require electrode materials with high charge storage capabilities, excellent electrical conductivity for fast electron transfer, and the ability of fast charging/discharging with good cyclability. While MXenes show many of these properties, their energy storage capability is limited by a narrow electrochemically stable potential window due to irreversible oxidation under anodic potentials. Although transition metal oxides (TMOs) are often high-capacity materials with high redox activity, their cyclability and poor rate performance are persistent challenges because of their dissolution in aqueous electrolytes and mediocre conductivity. Forming heterostructures of MXenes with TMOs and using hybrid electrodes is a feasible approach to simultaneously increase the charge storage capacity of MXenes and improve the cyclability and rate performance of oxides. MXenes could also act as conductive substrates for the growth of oxides, which could perform as spacers to stop the aggregation of MXene sheets during charging/discharging and help in improving the supercapacitor performance. Moreover, TMOs could increase the interfacial contact between MXene sheets and help in providing short-diffusion ion channels. Hence, MXene/TMO heterostructures are promising for energy storage. This review summarizes the most recent developments in MXene/oxide heterostructures for supercapacitors and highlights the roles of individual components.

Cobalt sulfide nanosheets decorated on polypyrrole nanowires for improved charge storage in supercapacitors

Nanostructured cobalt sulfide-based electrode materials for supercapacitors (SCs) still suffer from easy aggregation, sluggish reaction kinetics, and poor structural stability. To resolve these issues, we adopt a two-step electrochemical deposition method to fabricate CoS nanosheets decorated on polypyrrole (PPy) nanowires that grow directly on Ni foam. The PPy nanowires serve as supports for growing CoS nanosheets, which not only make the CoS nanosheets well dispersed but also reduce their size and thickness. In addition, the intensive interaction between CoS and PPy endows the nanoarchitecture with high mechanical strength. Therefore, the constructed [email protected] nanocomposites feature abundant electroactive sites, high charge transport and transfer efficiencies, a short ion diffusion distance, and good structural stability. As a result, the optimized [email protected] nanocomposites as SC electrodes demonstrate specific capacities of 860C g−1 at 1 A g−1 and 595C g−1 at 20 A g−1, as well as a 92% initial capacity retention after 5000 cycles at 10 A g−1. Furthermore, a fabricated asymmetric supercapacitor (ASC) device with [email protected] nanocomposites as the positive electrode realizes a specific energy of 51.1 Wh kg−1 at 800 W kg−1, suggesting a promising potential for their practical application in SCs. This work may provide a feasible strategy for fabricating other metal sulfide/conducting polymer nanocomposites with enhanced charge storage capabilities as SC electrodes.

Blending of a 3D cloud-like morphology with a 1D structure in a VO2/MXene nanocomposite to enhance the charge storage capability

VO2/MXene nanocomposite growth and its energy storage capability as supercapacitor electrode.

Nanoflower copper sulphide intercalated reduced graphene oxide integrated polypyrrole nano matrix as robust symmetric supercapacitor electrode material

Insertion of carbonaceous materials into polymeric matrix is a well-practiced approach for improving mechanical and electrochemical profile. Further, metal sulphides featured with high electrical conductivity and variable oxidation states have emerged as potential candidates for fabricating supercapacitor electrodes. In this work, polymer-derived PPy-rGO-CuS was prepared in the laboratory via in-situ chemical oxidative polymerization technique. The presence of CuS improved redox activity and charge storage capability of the polymer-derived composites. The electrochemical performance of the material, coated over C-paper was evaluated through two electrode symmetric system. The PPy-rGO-CuS composite with 10 % rGO and 5 % CuS (by mass of PPy) illustrated optimum specific capacitance 237.7 F g−1 at 1 A g−1. PGC5 also elucidated high cyclic behavior with constant capacitance retention up to 2000 galvanostatic charge-discharge (GCD) cycles. This enabled to scale up synergistic action among the chemical constituents involved therein. Nonetheless, energy density of PGC5 was recorded 21.1 Wh kg−1 at 1 A g−1. These features markedly affirmed the successful candidature of PGC5 as a high-performance polymer-derived composite electrode material for supercapacitor application.

One step synthesis of NiCo-LDH/CoNi2S4/rGO composite on Ni foam for asymmetric supercapacitor

The growth of NiCo-LDH/CoNi2S4/rGO composite on Ni foam was achieved with a simple one-step hydrothermal method. The obtained binder-free electrode (NiCo-LDH/CoNi2S4/rGO/Ni foam) was characterized with X-ray diffraction (XRD), field emission microscopy (FE-SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV) and galvanostastic charge/discharge (GCD). NiCo-LDH/CoNi2S4/rGO/Ni foam demonstrates a unique morphology with nanoparticles and nanowires mingled together, which endows the electrode large surface area as verified by the Brunauer–Emmett–Teller gas sorptometry measurement (BET). NiCo-LDH/CoNi2S4/rGO/Ni foam possesses excellent charge storage capabilities such as high areal capacitance, long cycling life and good rate performance. The asymmetric supercapacitor (ASC) with NiCo-LDH/CoNi2S4/rGO/Ni foam and activated carbon (AC) as positive and negative electrodes was assembled, characterized and successfully applied in practical applications, further confirming the great prospect of NiCo-LDH/CoNi2S4/rGO/Ni foam in energy storage.

Regulating crystal surface of Cu2O distributed in graphene film to explore supercapacitive performance in liquid or gel electrolyte

The morphologies of transition metal oxides have a decisive impact on the performance of their applications. In this work, two kinds of Cu2O nanocrystals with preferentially exposed {100} and {111} facets corresponding to Cu2O nano-cube (Cu2O NC) and Cu2O nano-octahedron (Cu2O NO) were designed. Then the different crystallographic Cu2O nanocrystals were self-assembled to be flexible self-supporting Cu2O and reduced graphene oxide films. By the comparison of the kinetic study of Cu2O nanocrystal with two different exposure facets, the nanocrystal with preferentially exposed {111} behaves a larger proportion of surface-confined charging process, indicating faster ion adsorption and transferability. The specific capacity of an electrode with different exposed facets behaves as an obvious shape-dependence in the aqueous two-electrode system. In contrast with the hydrogel electrolyte system, the shape-dependence disappeared due to the sufficient ions adsorb in the slow ion diffusion electrolyte. Based on the intrinsic crystallographic plane of the cuprite Cu2O, the charge-storage mechanism was elucidated. The so-called “crystallography-dependence” is relevant to the dangling bonds from the exposed {111} facets, which can act as active sites for electrochemical energy storage. Furthermore, the composite of Cu2O NO/rGO shows a high capacity of 737.4 F g−1. The Cu2O NO/rGO film with exposure {111} facets demonstrated preferential adsorption of electrostatic charges on the planes and showed better charge-storage capability. In other words, there is a crystallography-dependent adsorption ability during energy storage.

Ternary nanocomposite of GQDs-polyFc/Fe3O4/PANI: Design, synthesis, and applied for electrochemical energy storage

Redox-active and conductive polymers and transition metal oxides are appearing group of faradaic battery-type electrode materials that exhibit improved electrochemical properties in supercapacitors. Herein, we report a new class of ferrocenyl-based nanocomposite electrodes for the development of high-performance supercapacitors using a simple physical mixing method of redox active ferrocenyl modified GQDs with conductive polymer including PANI and Fe3O4. Having the popular redox-active organometallic compound like (Fc), PANI, and Fe3O4 as integrated constituent components, the obtained electrode materials exhibit remarkably charge storage and delivery capabilities. The structural properties of the electrode materials investigate by appropriate analyses. The highest capacity, energy density, and power density are to be 295 mAh g−1, 62.1 Wh kg−1 and 4140 W kg−1 for the nanocomposite, respectively. These results which can be attributed to the synergistic behavior of the different types of electrode materials in the hybrid nanocomposites, leading to the improved electrochemical performance. In addition, the cycling performance is tested with 5000 long cycles. The retention of charge storage (91.45%) after 5000 cycles at a current density of 1 A g−1 shows the great potential of GQDs-PolyFc/Fe3O4/PANI nanocomposites as electrode materials for future energy storage technologies. Finally, we conclude with some suggestions for future work.

Strategic N/P self-doped biomass-derived hierarchical porous carbon for regulating the supercapacitive performances

Biomass-derived porous carbons have received an extensive importance as effective electrode materials owing to their abundance and low cost. The unique porous architectures and large specific surface areas of biomass are beneficial for manipulating the charge storage performance of assembled supercapacitor devices. Here, we demonstrate nitrogen and phosphorus self-doped hierarchical porous carbon (N/P-HPC) derived from yeast (Y) and phytic acid (PA) precursors via freeze-drying-assisted esterification reaction and pyrolysis treatment. The supercapacitive performance and charge storage capability of N/P-HPC were regulated by optimizing the Y/PA composition and controlling the carbonization temperature. Accordingly, the resultant N/P-HPC-Y:PA(2:1)-800 (fabricated with an optimized Y:PA ratio of 2:1 and carbonized at 800 °C) reveals a high specific surface area of 978 m2 g−1 and a large pore volume of 0.592 cm3 g−1. As an electrode material, N/P-HPC-Y:PA(2:1)-800 delivers a high specific capacitance of 432 F g−1 at a current density of 1 A g−1 and can sufficiently retain about 250 F g−1 at 20 A g−1 under a three-electrode cell configuration in 1.0 M H2SO4 electrolyte. Moreover, the as assembled symmetric supercapacitor device operated with the N/P-HPC-Y:PA(2:1)-800 as both positive and negative electrode material exhibits an energy density of 13.6 Wh kg−1 at a power density of 500 W kg−1. Even at a larger current density of 20 A g−1, the device maintains an energy density of 10.4 Wh kg−1 and a maximum power density of 10 kW kg−1. The constructed device displays a large capacitance retention of 93.3% after 10 000 charge/discharge times at a higher current density of 10 A g−1, manifesting the enhanced cycling stability.

Transparent, photosensitive and highly efficient pseudocapacitive binder-free Mo-modified NiO thin film electrode for bifunctional optoelectronic and energy storage applications

We report a novel highly sensitive and pseudocapacitive transparent nickel oxide (NiO) thin film based electrode material fabricated on a conductive glass substrate using a facile binderless electrodeposition process. Effect of the incorporation of Mo-dopant ion on some surface structural and electrochemical properties of the electrode was examined for high performance optoelectronic and charge storage potentials. The material showed some uniqueness in some microstructural features and enhanced degree of crystallinity, suitable for charge extraction and transport with Mo doping. The deposited NiO film demonstrated red shift in band structure by exhibiting optical band gap narrowing from 3.88 to 3.61 eV with increasing Mo content. The degree of disorder as revealed from Urbach response of NiO film was found varying with Mo-content. The material also exhibited enhanced Ni2+ electronic transition states with increasing Mo content which quenched at a critical dopant concentration of 2.4 %. The fabricated NiO thin film electrode showed increased supercapacitive specific capacitance and areal capacity up to a peak value of 1412 Fg−1 and 101 mAh m−2 for 3 % Mo dopant content at 5 mVs−1 scan rate and 0.5 mA cm−2, respectively, but returned diminished at higher dopant content. Excellent cycling stability at ∼ 85 % after 5000 cycles, was also exhibited. Impedance spectroscopic features of Mo-doped NiO electrode indicated fast electrolytic ion transfer response with high rate charge storage capability. The study presents successful fabrication of Mo-modified NiO nanostructured electrode film and demonstrated the influence of Mo impurity on tailoring the properties of NiO host film as suitable electrode in high performance photocatalytic and supercapacitor devices.

In-situ construction of binder-free MnO2/MnSe heterostructure membrane for high-performance energy storage in pseudocapacitors

Manganese (Mn)-based oxides are considered suitable positive electrode materials for supercapacitors (SCs). However, their cycle stability and specific capacitance are significantly hindered by key restrictions such as structural instability and low conductivity. Herein, we demonstrated a novel nanorod (NR)-shaped heterostructured manganese dioxide/manganese selenide membrane (MnO2/MnSe) on carbon cloth (CC) (denoted as MnO2/MnSe-NR@CC) with a high aspect ratio by a straightforward and facile hydrothermal process. Experiments have demonstrated that doping selenium atoms to oxygen sites reduce electronegativity, increasing the intrinsic electronic conductivity of MnO2, decreasing electrostatic interactions with electrolyte ions, and thus boosting the reaction kinetics. Further, the selenium doping results in an amorphous surface with extensive oxygen defects, which contributed to the emergence of additional charge storage sites with pseudocapacitive characteristics. As expected, novel heterostructured MnO2/MnSe-NR@CC as an electrode for SC exhibits a high capacitance of 740.63 F/g at a current density of 1.5 A/g, with excellent cycling performance (93% capacitance retention after 5000 cycles). The MnO2/MnSe-NR@CC exhibited outstanding charge storage capability, dominating capacitive charge storage (84.6% capacitive at 6 mV/s). To examine the practical applications of MnO2/MnSe-NR@CC-ASC as a positive electrode, MnO2/MnSe-NR@CC//AC device was fabricated. The MnO2/MnSe-NR@CC//AC-ASC device performed exceptionally well, with a maximum capacitance of 166.66 F/g at 2 A/g, with a capacitance retention of 94%, after 500 GCD cycles. Additionally, it delivers an energy density of 75.06 Wh/kg at a power density of 1805.1 W/kg and maintains 55.044 Wh/kg at a maximum power density of 18,159 W/kg. This research sheds fresh information on the anionic doping method and has the potential to be applied to the synthesis of positive electrode materials for energy storage applications.

Covalency competition induced selective bond breakage and surface reconstruction in manganese cobaltite towards enhanced electrochemical charge storage

Manganese cobaltite (MnCo2O4) is a promising electrode material because of its attractive redox chemistry and excellent charge storage capability. Our previous work demonstrated that the octahedrally-coordinated Mn are prone to react with the hydroxyl ions in alkaline electrolyte upon electrochemical cycling and separates on the surface of spinel to reconstruct into δ-MnO2 nanosheets irreversibly, thus results in a change of the reaction mechanism with K+ ion intercalation. However, the low capacity has greatly limited its practical application. Herein, we found that the tetrahedrally-coordinated Co2+ ions were leached when MnCo2O4 was equilibrated in 1 mol L−1 HCl solution, leading to the formation of layered CoOOH on MnCo2O4 surface which is originated from the covalency competition induced selective breakage of the CoT–O bond in CoT–O–CoO and subsequent rearrangement of free CoO6 octahedra. The as-formed CoOOH is stable upon cycling in alkaline electrolyte, exhibits conversion reaction mechanism with facile proton diffusion and is free of massive structural evolution, thus enables utilization of the bulk electrode material and realizes enhanced specific capacity as well as facilitated charge transfer and ion diffusion. In general, our work not only offers a feasible approach to deliberate modification of MnCo2O4's surface structure, but also provides an in-depth understanding of its charge storage mechanism, which enables rational design of the spinel oxides with promising charge storage properties.

Importance of Nuclear Quantum Effects on Aqueous Electrolyte Transport under Confinement in Ti3C2 MXenes.

Protons display a high chemical activity and strongly affect the charge storage capability in confined interlayer spaces of two-dimensional (2D) materials. As such, an accurate representation of proton dynamics under confinement is important for understanding and predicting charge storage dynamics in these materials. While often ignored in atomistic-scale simulations, nuclear quantum effects (NQEs), e.g., tunneling, can be significant under confinement even at room temperature. Using the thermostatted ring polymer molecular dynamics implementation of path integral molecular dynamics (PIMD) in conjunction with the ReaxFF force field, density functional tight binding (DFTB), and NequIP neural network potential simulations, we investigate the role of NQEs on proton and water transport in bulk water and aqueous electrolytes under confinement in Ti3C2 MXenes. Although overall NQEs are relatively small, especially in bulk, we find that they can alter both quantitative values and qualitative trends on both proton transport and water self-diffusion under confinement relative to classical MD predictions. Therefore, our results suggest the need for NQEs to be considered to simulate aqueous systems under confinement for both qualitative and quantitative accuracy.

Kinetics-favorable heterojunctional CNTs@CuCo-LDH/BPQD electrode with boosted charge storage capability for supercapacitor

Component modulation and structure construction are the fundamental strategies in designing electrode materials for supercapacitors. Layered double hydroxide (LDH) is considered the promising electrode material, while with the drawback of low electron transmission efficiency and pulverization hinder. Herein, a novel kinetics-favorable heterojunctional self-supporting film electrode, composed of carbon nanotubes (CNTs), CuCo-LDH, and black phosphorus quantum dots (BPQD), is successfully prepared and directly utilized as electrodes in the supercapacitor. Highly conductive CNTs evenly and heavily entangled with CuCo-LDH hollow structures, resulting in robust mechanical property, enhanced electrical conductivity, and accelerated charge transfer during a redox reaction. Together with the surface decorated high-carrier-mobility BPQD, constructing heterojunction and acting as an electron donor to provide numerous active sites and facilitate energy storage behavior, a promoted pseudocapacitive performance was obtained and furtherly demonstrated by the density functional theory simulations based on the adsorption energies of OH–. The as-fabricated CNTs@CuCo-LDH/BPQD electrode presents a maximum capacitance of 1061.6 F g−1. The as-assembled hybrid supercapacitor device represents energy density up to 62.1 Wh kg−1 and remarkable cycling performance with 79.1% capacity retention after 10,000 cyclic tests. The prototype supercapacitor of this work shed light on the engineering of LDH-based materials for practical energy storage devices.

Intrinsically Conducting Polymer Binders for Battery Electrodes

Binder materials are needed to keep particles of active masses in electrodes for batteries and supercapacitors together and to ensure their adherence to the current collector. Mostly synthetic polymeric materials are used. Because they are electrochemically inert, they do not add to the storage capacity of the electrode. Intrinsically conducting polymers ICPs such as polyaniline, polythiophene or polypyrrole can provide these functions also. They show electronic conduction because of mobile charge carriers generated in them by oxidation or reduction. In addition to providing the binder-function, they improve electronic conductance of the electrode mass because of their inherent conductivity and can also contribute to the charge storage capability of the electrode in the range of potential of the redox activity of ICPs in the used electrolyte solution. In most reports on the application of ICPs as component of conductive binders, their incorporation results in enhanced specific capacity and notable improvement of C-rate capability of electrodes. In addition, ICP binders provide partial or complete wrapping of grains of active electrode materials, which effectively inhibits the interaction with the electrolyte, suppressing side reactions and degradation of functional properties.