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Cobalt sulfide (CoS) is a promising battery-type material for electrochemical energy storage. However, the poor conductivity and slow charge transfer kinetics as well as the deficiency of electrochemically active sites seriously limit their applications. Herein, a class of the P-doping induced hexagonal CoS nanosheets with S defects (P-CoS

Carbon nanotube (CNT) film has attracted tremendous attention in functional material research for its unique structure and excellent properties. However, pristine CNT (PCNT) film is hydrophobic, and mechanical strength and conductivity are poor than reported individual CNT. These challenges impede its wide application. Highly efficient closed-loop recycling of both monomer and CNT film is a major challenge. Herein, hydrophilic CNT film with high mechanical strength and conductivity was prepared under the synergistic effects of in situ nitrogen doping and thiol-ene click reaction. The tensile strength, Young’s modulus, and electrical conductivity both in perpendicular and in longitudinal directions are 1,362, 1,658, 222, and 218% higher than those of PCNT film. Closed-loop recycling of CNT film and monomer with high recyclability (100 and 86.72%) has been achieved in a gentle acid environment. The CNT films are 100% recovered and reused to fabricate thiol-functionalized CNT film without deterioration of performance after three cycles, which provides a novel strategy for the preparation of high-performance CNT film and a pathway for high-efficiency closed-loop recycling of CNT film and monomer.

This work reports an electronic structure tuning strategy to synthesize Fe-Ni3Co2 LDH derived from metal-organic framework (MOF). The structure performs well in both supercapacitor and oxygen evolution reaction.

Hollow CuO/Co3O4 and Fe2O3 nanoframes derived from Co/Fe-based PBAs precursor according to the nanoscale Kirkendall effect have been fabricated. The asymmetric supercapacitor delivers a high electrochemical properties.

Herein, for the first time, a pre-intercalated non-metal ion (NH

High-performance energy storage and sensing devices have been undergoing rapid development to meet the demand for portable and wearable electronic products, which require flexibility, extensibility, small volume and lightweight. In this study, we construct a lightweight and flexible self-powered sensing system by integrating a highly stretchable strain sensor with a high-performance asymmetric supercapacitor based on ZnSe/CoSe2//ECNT (ECNT: electrochemically activated carbon nanotube film). The ZnSe/CoSe2 two-dimentional nanosheets on carbon nanotube (CNT) films are synthesized through a simple and efficient strategy derived from ZnCo-based metal-organic frameworks (MOFs). The density functional theory (DFT) simulations show the higher conductivity of the ZnSe/CoSe2/CNT electrode than the CoSe2/CNT electrode. Due to the synergistic properties of self-supported two-dimentional ZnSe/CoSe2 nanosheets with high specific surface area and the high pathway of one-dimention CNTs, the nanocomposite electrode provides efficient transmission and short paths for electron/ion diffusion. The asymmetric supercapacitor provides a stable output power supply to the sensors that can precisely respond to strain and pressure changes. The sensor can also be attached to a garment for measuring a variety of joint movements.

The rapid development of human–machine interfaces and artificial intelligence is dependent on flexible and wearable soft devices such as sensors and energy storage systems. One of the key factors for these devices is the design of a flexible electrode with high sensitivity, fast response time, and a wide working range. Here, we report the fabrication of strain sensors and all-solid-state flexible supercapacitors using Co@N-CNT/MXenes as an electrode material. The manufactured sensor shows a high tensile range (strain up to 200%) and high stability. The resistance change caused by the fingers touching the sensor can be used to transmit the Morse code information. Flexible supercapacitors serving as power supply demonstrate excellent cycling stability (85 000 cycles) and coulombic efficiency (99.7%) for their high surface area and pseudocapacitance. A self-powered integrated system composed of the strain sensor and flexible supercapacitor is fabricated and operates stably in a wide strain sensing test range. Moreover, the flexible solar-charging self-powered integrated system could be attached to the human body for stable human motion detection. This study clearly shows that appropriate selection of a single functional material to enable it to be used in multi-functional sensors and supercapacitors can simplify the process and reduce the cost of manufacturing wearable devices.

The lightweight carbon nanotube (CNT) has been attracting great attention in the field of flexible electronics, but it is still a challenge in increasing both high capacitance and high energy densi...

The rapid development of human-machine interfaces and artificial intelligence is dependent on flexible and wearable soft devices such as sensors and energy storage systems. One of the key factors for these devices is the design of a flexible electrode with high sensitivity, fast response time, and a wide working range. Here, we report the fabrication of strain sensors and all-solid-state flexible supercapacitors using Co@N-CNT/MXenes as an electrode material. The manufactured sensor shows a high tensile range (strain up to 200%) and high stability. The resistance change caused by the fingers touching the sensor can be used to transmit the Morse code information. Flexible supercapacitors serving as power supply demonstrate excellent cycling stability (85 000 cycles) and coulombic efficiency (99.7%) for their high surface area and pseudocapacitance. A self-powered integrated system composed of the strain sensor and flexible supercapacitor is fabricated and operates stably in a wide strain sensing test range. Moreover, the flexible solar-charging self-powered integrated system could be attached to the human body for stable human motion detection. This study clearly shows that appropriate selection of a single functional material to enable it to be used in multi-functional sensors and supercapacitors can simplify the process and reduce the cost of manufacturing wearable devices.

Carbon nanotube (CNT) buckypapers, or films, have the potential for wide applications because of their unique properties. Neat buckypapers or pristine CNT (PCNT) films have relatively large elongation but low strength and low modulus due to the weak interaction between CNTs. Chemical modifications of PCNT films can significantly strengthen the interaction between CNTs, resulting in high strength and high modulus but usually accompanied by low elongation. Here, we report the functionalization of pristine CNT films by thiol-ended hyperbranched polymers (THBP-n) via a thiol-ene click reaction that can introduce simultaneous improvements on the strength, modulus, and elongation to the PCNT film by 689, 812, and 32.4%, respectively. The high thiol content of THBP-n enables the formation of a network with a high degree of cross-linking between carbon nanotubes, which provides high-efficiency load transfer that increases the tensile strength and modulus of the resulting films and at the same time a compressible hyperbranched structure that allows for deformation and slip between CNTs and consequently improved elongation. The main factors affecting the mechanical performance of the functionalized CNT film are also investigated.

Rapid development of wearable electronics has created tremendous demand for miniature energy storage devices with many different architectures. Ideally, very large area high-performance electrode materials are continuously produced at high speed, which are later constructed into flexible supercapacitors of different shapes and sizes. Here we report the synthesis of very large area MnO2 nanosheets on a 10 µm thin carbon nanotube film using a facile hydrothermal reaction. The strong and flexible CNT-MnO2 nanosheet composite film demonstrates excellent faradaic pseudocapacitance when used as electrodes for flexible supercapacitors that can be reconfigured from planar supercapacitor to stretchable threadlike supercapacitors. A narrow strip of the CNT-MnO2 electrode can also be scrolled and twisted together with a negative electrode fabricated by synthesizing FeSe2 nanonuts on a carbon fibre to construct a novel coaxial yarn asymmetric supercapacitor. This architecture has shown a very high energy density up to 27.14 Wh kg−1 at a power density of 571.3 W kg−1 and a good capacity retention after 8000 galvanostatic charge-discharge cycles, together with excellent flexibility and long lifespan.

The manufacture of multifunctional and high-performance wearable supercapacitors (SCs) requires a new class of flexible electrodes with high conductivity, high mechanical stability, good water-proof ability and self-healable capability. Herein, we report a stretchable and self-healable SC based on a MoS2/PEDOT/CNT electrode. The specific capacitance of the SC could be retained up to 81.98% even after the 21st breaking/healing cycle. Furthermore, a sheet-type asymmetric supercapacitor (ASC) based on a MoS2/PEDOT/CNT positive electrode and SnS2/CNT negative electrode is constructed, and it exhibits high performance with an extended potential window of 1.7 V, areal capacitance of 103.76 mF cm-2 at 1.5 mA cm-2, and outstanding stability with no capacitance degradation under a wide range of bending conditions. The ASC is sealed by polyimide films, and it shows high electrochemical stability in hot water and under high speed centrifugation conditions, indicating good water-proof ability and wearability. The as-prepared ASC is also encapsulated in elastic films to provide 225% stretchability. The ASC devices packaged in all these ways exhibit high capacitance retention (>90%) under various bending and dynamic conditions.

Flexible threadlike supercapacitors have attracted extensive attention owing to recent breakthroughs in modern wearable electronics, taking advantage of their high flexibility, tiny volume, and good specific performance. Because CNTs possess very large specific surface area, low mass density, outstanding chemical stability and excellent electrical conductivity, they have been widely used as electrode materials for supercapacitors. This chapter discusses recent progress in charge storage mechanisms, active materials, electrolytes, designs of threadlike supercapacitors, CNT-based supercapacitor architecture (symmetric and asymmetric supercapacitors), and self-charging supercapacitors. The final section highlights future perspectives on research in this field.

High-performance fiber- and yarn-shaped supercapacitors based on commonly available fiber materials and production technologies are needed to meet the fast developing electronic textile market. In this investigation, natural cotton and stainless steel fibers (SSFs) are blended to form a conductive yarn for constructing novel high-performance two-ply yarn supercapacitors. The supercapacitors show very high areal capacitance, energy density, flexibility and electrochemical stability. The excellent performance is attributed to the high porosity, high conductivity and distributive metal fiber network formed in the blended yarn, coupled with the high electrochemical efficiency of the nanostructured polypyrrole (PPy) and poly(3,4-ethylenedioxythiophene)–poly(styrenesulfonate) (PEDOT:PSS) pseudocapacitance materials. The SSF-cotton blended yarn is economic to produce and retains the flexibility of a normal cotton yarn that is commonly used in apparel textiles. This greatly facilitates the integration of the two-ply yarn supercapacitor into electronic textiles.

In this work, hollow RuO2 nanotube arrays were successfully grown on carbon cloth by using a facile two-step method to fabricate a binder-free electrode. The well-aligned electrode displays excellent electrochemical performance. By using RuO2 hollow nanotube arrays as the positive electrode and Fe2O3 as the negative electrode, a flexible solid-state asymmetric supercapacitor (ASC) has been fabricated which exhibited excellent electrochemical performance, such as a high capacitance of 4.9 F cm−3, a high energy density of 1.5 mW h cm−3 and a high power density of 9.1 mW cm−3. In addition, the two-electrode SC shows high cycling stability with 97% capacitance retention after 5000 charge–discharge cycles. These excellent electrochemical performances are ascribed to the unique hollow structural design of electrodes, which can shorten the ion diffusion length, provide a fast ion transport channel, and offer a large electrode/electrolyte interface for the charge-transfer reaction. The structural design and the synthesis approach are general and can be extended to synthesizing a broad range of materials systems.

Conventional flexible supercapacitors can work under consecutive bending, folding and even twisting without performance degradation. Nevertheless, these devices can hardly be used under large tensile strain. Flexible stretchable and healable supercapacitors are highly desired due to their many potential applications in electric devices. However, it is challenging to fabricate supercapacitors that can withstand stretchability and self-healability. Herein, we report a stretchable and self-healable supercapacitor based on a carbon nanotube@graphene@PANI nanowire film. The supercapacitor possesses high energy density from 36.3 to 29.4 μW h cm-2 with the corresponding power density changing from 0.17 to 5 mW cm-2 at a current from 0.1 to 3 mA, and the highest capacitive performance can reach up to 261.5 mF cm-2. In terms of the bending test, the supercapacitor can operate under different static bending angles and dynamic bending conditions with different bending frequencies, and the capacitance was merely affected. Moreover, the supercapacitor can sustain a tensile strain up to 180% and 80.2% capacitance retention after the 10th healing cycle. This novel design integrating all stretchable and healable components provides a pathway toward the next generation of wearable energy devices in modern electronics.

Nanostructured CoSe2 chrysanthemum flower are synthesized via a simple hydrothermal route. The highly hierarchical and electrochemically active material is electrodeposited with PPy to produce high performance CoSe2@PPy core/shell structured electrodes. A flexible fiber asymmetric supercapacitor (FASC) assembled from a CoSe2@PPy core/shell positive electrode and an electrochemically activated carbon fiber (EACF) negative electrode exhibits high volumetric energy density, superior flexibility and long lifespan. The resulting FASC has been used to power a mini-scale flexible photodetector, demonstrating great potential for the development of high performance energy storage devices.

The development of high-energy cathode for rechargeable aqueous zinc-ion batteries (ZIBs) is highly attractive. However, the disproportionation effect of Mn2+ seriously affects the capacity retention of ZIBs during cycling. Defect engineering provides efficient methods to enhance conductivity and structural stability of active materials. Here, a novel in situ generated bulk oxygen deficient Mn3O4 nanoframes cathode for rechargeable aqueous ZIBs is reported, with high capacity and good electrochemical stability. The oxygen-deficient Mn3O4 spheres display an excellent gravimetric capacity of 325.4 mAh g−1 and a high energy density of 423 Wh kg−1 at a power density of 2257.2 W kg−1. Ex situ X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) characterization demonstrate the initial Mn3O4 is converted to ramsdellite MnO2 for insertion and extraction of H+ and Zn2+. Theoretical modeling reveal that numerous edge sites and oxygen vacancies act as preferential intercalation sites for the zinc ions, leading to a much greater capacity than that of defect-free Mn3O4. These results highlight the potentials of defect engineering as a strategy of improving the electrochemical performance of Mn3O4 in aqueous rechargeable batteries.

Light weight and flexible fiber-shaped supercapacitors (FSSCs) that are considered to be ideal energy storage devices for powering wearable electronics. A flexible, high energy density all-solid-state Pt/ n -CNT@PANI FSSCs was fabricated by using a simple method. The electrode was formed by twisting a number of CNT yarns ( n ) with one platinum filament as current collector, upon which PANI nanowires were deposited in-situ to form the final Pt/ n -CNT@PANI FSSCs. The electrode structure with n = 5 fabricated at a twist level of 1000 T/m showed the best electrochemical performance. The optimum flexible Pt/5-CNT@PANI FSSC exhibited a specific capacitance of 217.7 F/g at the current density of 0.2 A/g, indicating a 7-fold increase in specific capacitance than the initial Pt/1-CNT@PANI with one CNT yarn ( n = 1) of about 29.9 F/g. The Pt/5-CNT@PANI FSSC showed an energy density of 30.22 Wh/kg accompanied by a power density of 91.88 W/kg. The Pt/5-CNT@PANI exhibits remarkable electrocatalytic activity for hydrogen evolution reaction (HER) with a low onset overpotential of −188 mV and low Tafel slope of 84.99 mV/dec. The Pt/5-CNT@PANI yarns can be used as not only FSSC with excellent cycle stability and flexibility and but also an active and stable electrocatalyst for HER in alkaline electrolytes.

Fetal exposure to di-n-butyl phthalate (DBP) causes the adult disease such as lower testosterone production and infertility. However, the mechanism is still unknown. The objective of the present study is to determine how DBP affects the involution of fetal Leydig cells during the neonatal period and how this event causes the delayed development of the adult Leydig cells during puberty. The pregnant Sprague Dawley dams were randomly divided into 3 groups and were gavaged with 0 (corn oil, the vehicle control), 100 or 500mg/kg DBP from gestational day 12 (G12) to G21. The blood and testes were collected from male pups on postnatal day 4 (P4), P7, P14, P21, P28, and P56. Serum testosterone concentrations were assessed and the mRNA levels of Leydig cell- or gonadotroph cell-specific genes were measured. Prenatal exposure to DBP caused the aggregation of fetal Leydig cells, which slowly disappeared when compared to the control. This effect was associated with the reduction of testicular testosterone secretion and down-regulation of the mRNA levels of Leydig cell biomarkers including Scarb1, Star, Cyp11a1, Hsd3b1, Hsd11b1, and Hsd17b3 as well as the gonadotroph biomarkers including Lhb and Gnrhr. In conclusion, we demonstrated that the increased aggregation of fetal Leydig cells by DBP delayed fetal Leydig cell involution, thus leading to the disrupted development of the adult Leydig cells.

Electrochemical conversion reactions of metal oxides provide a new avenue to build high capacity anodes for sodium-ion batteries. However, the poor rate performance and cyclability of these conversion anodes remain a significant challenge for Na-ion battery applications because most of the conversion anodes suffer from sluggish kinetics and irreversible structural change during cycles. In this paper, we report an Fe2O3 single crystallites/reduced graphene oxide composite (Fe2O3/rGO), where the Fe2O3 single crystallites with a particle size of ∼300 nm were uniformly anchored on the rGO nanosheets, which provide a highly conductive framework to facilitate electron transport and a flexible matrix to buffer the volume change of the material during cycling. This Fe2O3/rGO composite anode shows a very high reversible capacity of 610 mAh g–1 at 50 mA g–1, a high Coulombic efficiency of 71% at the first cycle, and a strong cyclability with 82% capacity retention after 100 cycles, suggesting a potential feasibilit...

Linear flexible supercapacitors are of considerable interest for future wearable electronics and photodetectors. Inorganic metallic oxide-based electrochemical pseudocapacitors have a high energy density whereas supercapacitors based on carbon-nanotube (CNT) yarns show high flexibility and high power densities. Besides high power density and energy density, fabrication of linear supercapacitors with excellent flexibility is still a challenge. Here, we report a linear supercapacitor architecture obtained by integrating CNT yarn and a Cu filament with NiCo2O4 nanowires. NiCo2O4 nanowires grow in situ on the surface of CNT yarn intertwined with the Cu filament. Due to the high electrochemical performance of both NiCo2O4 nanowires and CNT yarn and the high charge-transport efficiency of the Cu filament as current collector, the supercapacitor demonstrates a specific areal capacitance as high as 277.3 mF cm2 and an energy density of 35.76 μWh cm−2 coupled with a power density 0.154 mW cm−2. The linear supercapacitor is very flexible and can be woven into a fabric without losing its capacity to store energy. Its capacitance remains at 89 % after 5000 charge/discharge cycles. The linear supercapacitor may be used as an ultraviolet photodetector with good stability in response to the UV light signal and also to power light-emitting diodes (LEDs).

Solid-state flexible energy storage devices play a crucial role in the development of wearable electronic textiles. In this study, we fabricated flexible asymmetric two-ply yarn supercapacitors from carbon nanotube yarns and surface-oxidized titanium filament. The crystalline structure of the TiO2 surface layer can be adjusted to amorphous, anatase and rutile states by altering the annealing temperature. The titanium filament with a rutile TiO2 surface layer produced at high annealing temperature showed far superior electrochemical performance over the filaments with amorphous and anatase TiO2 surface layers. The as-prepared asymmetric two-ply yarn supercapacitors in aqueous gel electrolyte can achieve a durable operating voltage up to 1.4 V, with a maximum energy density of 11.7 Wh kg−1 and a maximum power density of 2060 W kg−1. The asymmetric two-ply yarn supercapacitors exhibited excellent flexibility and cycling stability over 1200 cycles at straight, twisted and bent states.

Flexible threadlike supercapacitors with improved performance are needed for many wearable electronics applications. Here, we report a high performance flexible asymmetric all-solid-state threadlike supercapacitor with a NiCo2 Se4 positive electrode and a NiCo2 O4 @PPy (PPy: polypyrrole) negative electrode. The as-prepared electrodes display outstanding volume specific capacitance (14.2 F cm-3 ) and excellent cycling performance (94 % retention after 5000 cycles at 0.6 mA) owing to their nanosheet and nanosphere structures. The asymmetric all-solid-state threadlike supercapacitor expanded the stability voltage window from 0-1.0 V to 0-1.7 V and exhibits high volume energy density (5.18 mWh cm-3 ) and superior flexibility under different bending conditions. This study provides a scalable method for fabricating high performance flexible supercapacitors from easily available materials for use in wearable and portable electronics.

The manufacture of high-performance wearable supercapacitors (SCs) requires a new class of flexible electrodes with both high conductivity and high mechanical stability. Herein, we report a simple and efficient strategy to design novel CoSe2 two-dimensional nanosheets on carbon nanotube (CNT) films derived from Co-based Metal-Organic Frameworks (MOFs) via an in situ approach. The density functional theory (DFT) simulations show the higher conductivity of the CoSe2/CNT electrode than the Co3O4/CNT electrode. Due to the synergistic properties of self-supported two-dimensional CoSe2 nanosheets and the high pathway of one-dimensional (1D) CNTs, the nanocomposite electrode provides efficient transmission and short paths for electron/ion diffusion. A flexible asymmetric SC (ASC) assembled from the CoSe2 nanosheet positive electrode and FeSe2 nanorod negative electrode delivers high areal energy density of 0.25 mW h cm−2, superior mechanical stability and long lifespan. In addition, the flexible ASC device can power the CoSe2//CNT-based photodetector to generate fast and stable responses to light irradiation with different wavelengths, indicating the excellent practical application performance of flexible ASCs.

Two-ply yarn supercapacitors behave like conventional textile yarns to power next generation electronic textiles. To improve the capacitance of the yarn, we produced a metal filament reinforced carbon nanotube composite yarn which was further in situ polymerized with polyaniline nanowires for use as electrodes. The wearable two-ply yarn supercapacitor made from the composite electrodes possesses very high capacitance (91.67 mF cm−2) and energy density (12.68 μW h cm−2), and excellent long term cycling stability for charging-discharging and flexing deformation. The two-ply nanocomposite yarn supercapacitors have been connected in series and in parallel to power miniature electronic devices in smart textiles.

The large surface area of CoNiSe2/CoNiSe2/Ti 3D urchis electrodes have been synthesized with high durability for electrochemical reactions and excellent catalytic performance for HER in the alkaline solutions. The asymmetric supercapacitor based on CoNiSe2/CoNiSe2//CoNiO2/CoNiO2 displays a maximum specific capacitance of 11.6F cm−3 and a high energy density of 2.9 μWh cm−3 at 34 μW cm−3. The present work highlights the ternary selenide is an promising electrode material in the field of advanced energy storage and conversion.

Herein, an assembled asymmetric supercapacitor based on PANI@CNT-graphene//NiCo2O4@N-C exhibits high specific energy densities and excellent mechanical stability, with ~90% capacity retention after 5000 continuous cycles at the current of 1 mA. The structural design and the synthesis approach is general and can be extended to synthesize a broad range of materials.

Covalent organic frameworks (COFs) have emerged as promising electrode materials in flexible and wearable supercapacitors. However, achieving high electrical conductivity and high mechanical strength of flexible COF composite membranes is still a major challenge. Herein, we first prepared the COF complex by using hydroxyl-ended hyperbranched polymer (OHP) as a template via a simple solid-state mechanical mixing method, and the COF@OHP complex was then impregnated on a microporous carbon nanotube film (CNTF) to construct a composite membrane (CHCM) that can be prepared as CHCM electrodes for extensible and flexible supercapacitors. A large number of cavities, reactive end-groups and flexible polymer chains of the hyperbranched polymer are utilized to stabilize and disperse COFs and to enhance the COF-polymer’s interfacial interaction. CNTF is an attractive material for energy storage due to its excellent conductivity, slippability, flexibility, and high specific surface area. The CHCM electrode showed not only excellent electrochemical performance (high gravimetric capacitance of 249 F g−1 and charging-discharging stability of 80% after 10,000 cycles) in the relatively environmentally-friendly phosphoric acid (H3PO4) electrolyte, but also a high tensile strength of 180 MPa and an elongation of 10%. The gravimetric capacitance of the CHCM electrode reached 425 F g−1 in 2 M aq. H2SO4 electrolyte. This work will demonstrate a promising strategy for preparing wearable and flexible supercapacitors with high mechanical strength with potentially wide applications.

One-dimensional supercapacitors (SCs) are of great interest for future wearable electronics, but improvement in both high capacitance and high flexibility is still a challenge. Herein, we fabricate a high performance yarn asymmetric SC (ASC) using in situ prepared CuCo

In this work, hollow RuO2 nanotube arrays were successfully grown on carbon cloth by using a facile two-step method to fabricate a binder-free electrode. The well-aligned electrode displays excellent electrochemical performance. By using RuO2 hollow nanotube arrays as the positive electrode and Fe2O3 as the negative electrode, a flexible solid-state asymmetric supercapacitor (ASC) has been fabricated which exhibited excellent electrochemical performance, such as a high capacitance of 4.9 F cm-3, a high energy density of 1.5 mW h cm-3 and a high power density of 9.1 mW cm-3. In addition, the two-electrode SC shows high cycling stability with 97% capacitance retention after 5000 charge-discharge cycles. These excellent electrochemical performances are ascribed to the unique hollow structural design of electrodes, which can shorten the ion diffusion length, provide a fast ion transport channel, and offer a large electrode/electrolyte interface for the charge-transfer reaction. The structural design and the synthesis approach are general and can be extended to synthesizing a broad range of materials systems.

Materials engineering plays a key role in the field of electrochemical energy storage, and considerable efforts have been made in recent years to fulfil the future requirements of electrochemical energy storage using novel functional electrode materials. Among the transition metal oxides, ternary metal oxides possess multiple oxidation states that enable multiple redox reactions. They have been reported to exhibit a higher supercapacitive performance than single component metal oxides, and seem to be a group of the most promising and low cost materials for pseudo-capacitors. This paper presents a state-of-the-art review on the research progress of developing ternary oxide nanostructures for supercapacitors, with the focus on the synthesis of one-dimensional (1-D), two-dimensional (2-D) and three-dimensional (3-D) nanostructures and their potential applications in energy storage devices. The remaining challenges toward the rational design of ternary oxide nanostructured electrodes for next-generation supercapacitors are also proposed.

Methoxychlor is primarily used as an insecticide and it is widely present in the environment. The objective of the present study was to investigate the direct effects of methoxychlor and its metabolite hydroxychlor (HPTE) on rat neurosteroidogenic 3α-hydroxysteroid dehydrogenase (AKR1C14) and retinol dehydrogenase 2 (RDH2) activities. Rat AKR1C14 and RDH2 were cloned and expressed in COS-1 cells, and the effects of methoxychlor and HPTE on these enzymes were measured. HPTE was more potent to inhibit AKR1C14 and RDH2 activities than methoxychlor, with IC50 values of 2.602 ± 0.057 μM and 20.473 ± 0.049 μM, respectively, while those of methoxychlor were over 100 μM. HPTE competitively inhibited AKR1C14 and RDH2 when steroid substrates were used, while it showed a mode of mixed inhibition on these enzymes when NADPH/NAD+ were used. We elucidated the binding mode of methoxychlor and HPTE to the crystal structure of AKR1C14 by molecular docking and found that HPTE had higher affinity with the enzyme than methoxychlor. In conclusion, HPTE is more potent than methoxychlor to inhibit both AKR1C14 and RDH2.

Electrochemical conversion reactions of metal oxides provide a new avenue to build high capacity anodes for sodium-ion batteries. However, the poor rate performance and cyclability of these conversion anodes remain a significant challenge for Na-ion battery applications because most of the conversion anodes suffer from sluggish kinetics and irreversible structural change during cycles. In this paper, we report an Fe

Flexible threadlike supercapacitors with improved performance are needed for many wearable electronics applications. Here, we report a high performance flexible asymmetric all-solid-state threadlike supercapacitor with a NiCo

The unprecedented demand for portable, flexible and even wearable electronic devices have stimulated the development of green and powerful energy sources with excellent electrochemical performance. Lithium ion batteries (LIBs) have attractive attention due to their high-energy density, high-rate capacity and relatively low self-discharge. The integration of two-dimensional (2D) nanomaterials and their composites into LIBs offers opportunities to timely tackle the challenges of the ever-growing clean and sustainable energy demands. Therefore, it is crucial to design 2D nanomaterial electrodes for high performance flexible LIBs. This chapter covers the recent literature on flexible LIBs with 2D nanomaterials as the electrodes. The research demonstrates advancements in flexible electronics by incorporating various 2D nanomaterials into bendable batteries to achieve high electrochemical performance, excellent mechanical flexibility as well as electrical stability under stretching/bending conditions.

Fiber electronic devices show advantages for the direct use as wearable and embedded device units or integrated textile modules. We successfully developed a coaxial-type flexible fiber supercapacitor by using NiCo 2 O 4 nanosheets grown on Ni wire as the fiber electrodes. The volume capacitance of the fiber-shaped supercapacitor reached 10.3 F/cm 3 at a current of 0.08 mA and outstanding cycling stability. An energy density of 1.44 mWh cm −3 and a power density of up to 17 W cm −3 were also obtained for the fiber supercapacitor, which are almost 48-fold higher than the previous values. Furthermore, the coaxial-type fiber supercapacitor does not show any apparent degradation in the bending test, illustrating the promise for use as electrodes for portable and wearable energy storage.

Flexible lithium ion batteries (LIBs) have recently attracted increasing attention as they show unique promising advantages, such as flexibility, shape diversity, and light weight. Similar to conventional LIBs, flexible LIBs with long cycle life and high-rate performance are very important for applications of high performance flexible electronics. Herein, we report a three-dimensional (3D) web-like binderfree Li4Ti5O12 (LTO) anode assembled from numerous 1D nanowires exhibiting excellent cycling performance with high capacities of 153 and 115 mA·h·g−1 after 5,000 cycles at 2 C and 20 C, respectively, and excellent rate property with a capacity of 103 mA·h·g−1 even at a very high current rate of 80 C. Surprisingly, a flexible full battery assembled from the web-like LTO nanostructure and LiMn2O4 (LMO) nanorods exhibited a high capacity of 125 mA·h·g−1 at high current rate of 20 C, and showed excellent flexibility with little performance degradation even in seriously bent states.

Mesoporous Nb2O5 microspheres assembled by nanoparticles are successfully synthesized through a simple solvothermal process and subsequently annealing treatment, free of any template or catalyst. By controlling the reactant NbCl5 concentration, we could easily tune the diameter of the Nb2O5 spheres from 200 to 900 nm, which were also used to fabricate dye-sensitized solar cells. Studies found that dye-sensitized solar cells based on Nb2O5 with sizes of around 480 nm show a highest power conversion efficiency of 2.97% with a relatively high short current density (Jsc) of 6.8 mA cm−2 and an open circuit voltage (Voc) of 0.738 V, which benefits from its higher specific surface area for adsorbing more dye molecules, superior light scattering capacity for boosting the light-harvesting efficiency, and modest electron transport properties.