Fiber-shaped Asymmetric Supercapacitors Research Articles

High-energy and wearable fiber-shaped asymmetric supercapacitors based on the combination of fluorinated polyimide and Co3O4 on carbon fibers

This study reports a fiber-shaped asymmetric supercapacitor (f-ASC) made from carbonized fluorinated polyimide deposited onto carbon fiber (c-fPI@CF) as a negative electrode coupled with cobalt oxide-embedded c-fPI@CF (Co3O4@c-fPI@CF) as a positive electrode. The thermal decomposition of fPI evolves gases, mostly stemming from the fluorine-containing moiety (–CF3) of fPI. This process leads to the formation of a distinct microporous structure characterized by small graphitic regions and a high specific surface area of 1071 m2 g−1. Asymmetric configuration enlarges the operating voltage of the f-ASC, contributing to the increase in energy density. The resulting f-ASC shows a capacitance of 56 F cm−3 at 0.5 A cm−3, exceeding other fiber supercapacitors and good cycle stability even under mechanical deformation, demonstrating its feasibility as a wearable power source. It also delivers a significant energy density of 10.0 mWh cm−3 and a power density of 1.16 W cm−3. According to first-principles calculations, the graphitic structure of c-fPI increases the conductivity of Co3O4@c-fPI and stabilizes the exposed metal spots of the Co3O4. Therefore, this f-ASC exhibits great potential for future wearable energy storage systems.

Core-shell heterostructured Ni(OH)2@activation Zn-Co-Ni layered double hydroxides electrode for flexible all-solid-state coaxial fiber-shaped asymmetric supercapacitors

The increasing requirements for wearable and portable electronics are driving the interests of high performance fiber supercapacitor. Layered double hydroxide (LDH) is broadly used in electrode materials, owing to the adjustability of components and the unique lamellar structure. However, limited active sites and poor electrical conductivity hinder its applications. Herein, the core–shell heterostructured Ni(OH)2@activation Zn-Co-Ni layered double hydroxides (Ni(OH)2@A-ZnCoNi-LDH) electrode was fabricated by loading pseudocapacitance material on the A-ZnCoNi-LDH to improve the electrochemical performance. Significantly, benefits from the synergistic effect of the multi-metal ions and the core–shell heterostructure, the electrodes demonstrated a capacitance of 2405 mF·cm−2 at 1 mA·cm−2. Furthermore, Ni(OH)2@A-ZnCoNi-LDH was used as the core electrode and carbon nanotube (CNT) film coated with Fe2O3@reduced graphene oxide (rGO) was wrapped around the core electrode to assemble coaxial fiber asymmetric supercapacitor, which illustrated an ultrahigh energy density of 177.7 µWh·cm−2 at 0.75 mW·cm−2. In particular, after consecutive charging and discharging 7000 cycles, the capacitance retention of the device was 95 %, indicating the excellent cycling stability. Furthermore, the device with high flexibility can be woven into textiles in different shapes. The fabricated device has an excellent development prospect as an energy source in wearable electronic devices.

Surface sulfidation of NiCo-layered double-hydroxide nanosheets for flexible all-solid-state fiber-shaped asymmetric supercapacitors

Surface sulfidation of NiCo-layered double-hydroxide nanosheets for flexible all-solid-state fiber-shaped asymmetric supercapacitors

Fibrous asymmetric supercapacitor based on wet spun MXene/PAN Fiber-derived multichannel porous MXene/CF negatrode and NiCo2S4 electrodeposited MXene/CF positrode

Fiber-shaped supercapacitors (FSSCs) are emerging potential power sources for next-generation flexible and wearable miniaturized electronic devices. However, the practical application of FSSCs is hindered by their low energy density due to limited design and constraints in fiber-shaped electrodes production. Herein, a rational design of wet spun MXene (Ti3C2Tx)/PAN fibers derived multichannel porous MXene/Carbon Fiber (W-MX/CF) is reported as a negative electrode (negatrode), and ultrathin NiCo2S4 electrodeposited W-MX/CF (NiCo2S4@W-MX/CF) as a positive electrode (positrode) for the fabrication of an asymmetric FSSC. It demonstrates high areal capacitance from both the negatrode (CA = 2160 mF cm−2) and positrode (CA = 1421 mF cm−2) fabricated from 80 wt% MXene loaded CF (W-MX/CF-4) with optimized multichannel porous features and faradaic NiCo2S4 nanosheets arrays grown on W-MX/CF-4. Solid-state fiber-shaped asymmetric supercapacitor was assembled using NiCo2S4-13@W-MX-4 and W-MX/CF-4 as positrode and negatrode, respectively, with PVA/KOH as solid electrolyte. The device exhibits a remarkable energy density of 40.70 mWh cm−3 at a power density of 301.51 mW cm−3, demonstrating an efficient FSSC. The present work shows a novel way to enhance the performance of FSSCs by exploiting synergistic effects between MXene and carbon fiber derived from PAN, prepared by a facile wet-spinning method employing a solvent/non-solvent exchange process.

Vanadium metal‐organic framework‐derived multifunctional fibers for asymmetric supercapacitor, piezoresistive sensor, and electrochemical water splitting

AbstractFiber‐shaped integrated devices are highly desirable for wearable and portable smart electronics, owing to their merits of lightweight, high flexibility, and wearability. However, how to effectively employ multifunctional fibers in one integrated device that can simultaneously achieve energy storage and utilization is a major challenge. Herein, a set of multifunctional fibers all derived from vanadium metal‐organic framework nanowires grown on carbon nanotube fiber (V‐MOF NWs@CNT fiber) is demonstrated, which can be used for various energy storage and utilization applications. First, a fiber‐shaped asymmetric supercapacitor (FASC) is fabricated based on the CoNi‐layered double hydroxide nanosheets@vanadium oxide NWs@CNT fiber (CoNi‐LDH NSs@V2O5 NWs@CNT fiber) as the positive electrode and vanadium nitride (VN) NWs@CNT fiber as the negative electrode. Benefiting from the outstanding compatibility of the functional materials, the FASC with a maximum working voltage of 1.7 V delivers a high‐stack volumetric energy density of 11.27 mW·h/cm3. Then, a fiber‐shaped integrated device is assembled by twisting a fiber‐shaped piezoresistive sensor (FPS; VN NWs@CNT fiber also served as the highly sensitive material) and a FASC together, where the high‐performance FASC can provide a stable and continuous output power for the FPS. Finally, the S‐VOx NWs@CNT fiber (sulfur‐doped vanadium oxide) electrode shows promising electrocatalytic performance for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), which is further constructed into a self‐driven water‐splitting unit with the integration of the FASCs. The present work demonstrates that the V‐MOF NWs@CNT‐derived fibers have great potential for constructing wearable multifunctional integrated devices.

All-pseudocapacitive coordination towards flexible asymmetric fiber-shaped supercapacitors with ultrahigh energy and power density

An asymmetric fiber-shaped supercapacitor with excellent flexibility, ultra-high energy and power density is developed, demonstrating great practical importance.

Multilayer Core-Sheath Wires with Cus Nanosheet Arrays and Pedot Sheaths for High-Performance Fiber-Shaped Asymmetric Supercapacitors

Multilayer Core-Sheath Wires with Cus Nanosheet Arrays and Pedot Sheaths for High-Performance Fiber-Shaped Asymmetric Supercapacitors

Interfacial Control of NiCoP@NiCoP Core-Shell Nanoflake Arrays as Advanced Cathodes for Ultrahigh-Energy-Density Fiber-Shaped Asymmetric Supercapacitors.

Efficient improvement of the energy density and overall electrochemical performance of fiber-shaped asymmetric supercapacitors (FASCs) for practical applications in portable and wearable electronics requires highly electrochemically active materials and a rational design. Herein, two-step phosphorization (TSP) processes are performed to directly grow 3D well-aligned NiCoP@NiCoP (NCP@NCP TSP) nanoflake arrays (NFAs) on carbon nanotube fibers (CNTFs). Profiting from the metallic characteristics and excellent electrochemical performance of NiCoP and the hierarchical design of the core-shell heterostructure, the NCP@NCP TSP NFAs/CNTF hybrid electrode exhibits significantly improved electrochemical performance. The as-fabricated NCP@NCP TSP NFAs/CNTF electrode possesses an ultrahigh areal capacitance of 10035mFcm-2 at a current density of 1mAcm-2 , with excellent rate capability and cycling stability. Furthermore, an FASC device with a maximum operating voltage of 1.6V is assembled by adopting NCP@NCP TSP NFAs/CNTF as a positive electrode, hierarchical TiN@VN core-shell heterostructure nanowire arrays (NWAs)/CNTF as negative electrode, and KOH-PVA as a gel electrolyte. The FASC device exhibits a high areal capacitance of 430.4mFcm-2 and an ultrahigh energy density of 51.02mWhcm-3 . Thus, the rationally designed NiCoP@NiCoP electrode is a promising candidate for incorporation into next-generation wearable and portable energy-storage devices.

A top-down cutting method for construction of high-performance fiber-shaped quasi-solid-state asymmetric supercapacitors

Fiber-shaped asymmetric supercapacitors (FSASCs) have great potential as a future wearable energy storage system because of good weavability, a wide operating voltage window, and high energy density. Conventional bottom-up construction methods for fiber supercapacitors are time-consuming or highly costly. This work proposes a novel facile top-down cutting method to construct FSASCs. FSASCs with desired sizes can be rapidly constructed and easily scaled up by cutting a thin-film supercapacitor into fiber-shaped devices. Serial and parallel FSASCs free of external wire connection were assembled by cutting stacked film supercapacitors and multiplying the cutting width, respectively. Besides, the as-prepared FSASCs exhibit superior comprehensive electrochemical performance, including a high volumetric capacitance of 14.7 F/cm3, a high energy density of 93.5 μWh/cm2, and excellent flexibility. The cutting method with advantages of high simplicity, low cost, and high efficiency may be a general construction method for fiber-shaped energy storage devices.

3D printing coaxial fiber electrodes towards boosting ultralong cycle life of fibrous supercapacitors

Fiber-shaped asymmetric supercapacitors (FASCs) with high electrochemical performance have become an important component of modern wearable fiber-shaped electronic devices. However, terrible cycling stability restricts their further development in energy storage fields. The most common strategy is to coat the carbon layer on the surface of the electrode materials, whereas the carbon layer is prone to peel off during bending process, which decrease the cyclic stability of the electrodes or devices. To overcome this challenge, the coaxial fiber electrodes have been achieved via 3D printing direct ink writing (DIW) technology and the FASC device has the excellent electrochemical cycle performance owing to the compact architectures of the positive and negative electrode. Benefited from the suitable charge match of two electrodes and the uniformity of carbon layer coated on the surface of electrodes, the as-fabricated FASC device embraces high areal capacitance of 318.82 mF cm-2, superior areal energy density of 143.15 μWh cm-2, and excellent long-term cycling performance with capacitance retention of 98.63% after 12,000 cycles.

Direct coherent multi-ink printing of fabric supercapacitors.

Coaxial fiber-shaped supercapacitors with short charge carrier diffusion paths are highly desirable as high-performance energy storage devices for wearable electronics. However, the traditional approaches based on the multistep fabrication processes for constructing the fiber-shaped energy device still encounter persistent restrictions in fabrication procedure, scalability, and mechanical durability. To overcome this critical challenge, an all-in-one coaxial fiber-shaped asymmetric supercapacitor (FASC) device is realized by a direct coherent multi-ink writing three-dimensional printing technology via designing the internal structure of the coaxial needles and regulating the rheological property and the feed rates of the multi-ink. Benefitting from the compact coaxial structure, the FASC device delivers a superior areal energy/power density at a high mass loading, and outstanding mechanical stability. As a conceptual exhibition for system integration, the FASC device is integrated with mechanical units and pressure sensor to realize high-performance self-powered mechanical devices and monitoring systems, respectively.

Rationally designed hierarchical C/TiO2/Ti multilayer core-sheath wires for high-performance energy storage devices.

Fiber-shaped supercapacitors (FSCs) are promising power sources for wearable electronic devices due to their small size, excellent flexibility and deformability. The performance of FSCs has been severely affected by the framework of the fibrous electrodes and the interface between the electrode materials and current collector. Herein, we propose an ingenious strategy that combines anodizing etching and CVD methods to transform the less-active titanium wires into unique hierarchical carbon/TiO2 nanotube/Ti (CTNT) core-sheath wires, which have high conductivity, good mechanical strength and porous structure on the surface. CTNT wires can be used not only as a high-performance electrode, but also as an ideal substrate for depositing active materials. We have demonstrated the deposition of MnO2 and MoS2 on the surface of CTNT to prepare MnO2@CTNT and MoS2@CTNT core-sheath composite wires through electrochemical deposition and hydrothermal reaction, respectively. The specific areal capacitance of a single wire (MoS2@CTNT) can reach up to 557.83 mF cm-2 in a three-electrode system. Two such wires were further used as electrodes for making an all-solid-state asymmetric fiber-shaped supercapacitor (AFSC). The prepared AFSC has a wide voltage window of 2.7 V, a large areal capacitance of 121.42 mF cm-2 and an excellent energy density of 74.37 μW h cm-2. It also shows good rate performance and stability, and even after 10 000 cycles of charging and discharging, a capacitance retention rate of 76.5% can be achieved.

A novel fiber-shaped asymmetric supercapacitor prepared by twisting carbon fiber/carbon nanotube/MnO2 and carbon fiber/carbon nanotube/polypyrrole electrodes+

In the study, a novel fiber-shaped asymmetric supercapacitor with high specific capacitance has been successfully constructed by twisting two self-made composite electrodes. Prior to manufacturing these electrodes, carbon nanotube is first deposited on carbon fiber by electrophoretic deposition to obtain carbon fiber/carbon nanotube composites. Subsequently, the positive and negative composite electrodes are prepared by the electrochemical deposition of manganese dioxide and electrochemical polymerization of polypyrrole, respectively. As a result, the novel fiber-shaped asymmetric supercapacitor performs a wide potential window of 1.7 V and a high energy density of 22.8 μWh cm−1 at the current density of 0.5 A g−1. Meanwhile, it still maintains great capacitance retention of 91.6% and 86.1% from 500 bending repetitions and 5000 cycles, respectively, which is due to the excellent flexibility and long cycle life. It is significant that the promising performance of the novel fiber-shaped asymmetric supercapacitor is of greatly potential for portable and wearable electronics in the future.

PANI//MoO3 Fiber-shaped Asymmetric Supercapacitors with Roll-type Configuration

An asymmetric fiber-shaped supercapacitor (FSC) with roll-type configuration, displaying high power and energy density characteristics, has been fabricated for energy storage in wearable devices. The positive and negative electrodes of the asymmetric FSC consist of polyaniline (PANI) and MoO3, respectively, and are deposited on a carbon fiber (CF) substrate using a chemical bath deposition method. A polyvinyl alcohol/H2SO4 gel is used as electrolyte, which also maintains the CF electrodes in fiber form. The asymmetric PANI//MoO3 roll-type FSC exhibits a wider potential range than its symmetric PANI//PANI counterpart, resulting in higher energy and power densities. The asymmetric PANI//MoO3 roll-type FSC shows an energy density of 67.51 µWh/cm3 with a power density of 59.71 mW/cm3 at a current of 10 mA, which is more than twice the energy density of symmetric PANI//PANI roll-type FSC (30.42 µWh/cm3 and 25.12 mW/cm3).

Flexible coaxial fiber-shaped asymmetric supercapacitors based on manganese, nickel co-substituted cobalt carbonate hydroxides

A wearable coaxial fiber-shaped asymmetric supercapacitor based on well-aligned Mn, Ni co-substituted Co carbonate hydroxide nanoneedle arrays on carbon fibers is successfully fabricated, and it exhibits excellent electrochemical performances.

A simple route to fiber-shaped heterojunctioned nanocomposites for knittable high-performance supercapacitors

Fiber-shaped asymmetric supercapacitors composed of heterojunctioned NiCo2S4@MgS nanocomposites were demonstrated and can be conveniently knitted into fabrics for wearable electronics.

Surface-functionalized Fe2O3 nanowire arrays with enhanced pseudocapacitive performance as novel anode materials for high-energy-density fiber-shaped asymmetric supercapacitors

Fiber-shaped asymmetric supercapacitors (FASCs) have potential applications in next-generation wearable and portable electronics due to their high power density, remarkable flexibility, fast charge-discharge capability, long cycle life and light weight. However, low specific capacitance and energy density hinder their practical applications. To obtain anode materials with high conductivity and high specific capacity, we first synthesize Fe2O3 nanowire arrays (NWAs) on carbon nanotube fibers as negative electrodes and then obtain FeS2 and FeP NWAs negative electrodes by sulfuration and phosphorization, respectively. The transformation processes effectively enhance the desirable properties of the electrode materials, improving the areal capacitance from 292 mF cm−2 to 833 mF cm−2 (sulfuration) and 1135 mF cm−2 (phosphorization) at a current density of 1 mA cm−2, demonstrating a significant improvement compared to Fe2O3 NWAs and, importantly, that phosphorization produces better results than sulfuration. Furthermore, the fabricated FASC exhibits outstanding mechanical flexibility and weavability and thus has great potential in for practical application in novel wearable and portable supercapacitors, which are expected to be the next generation of flexible energy-storage devices.

CoNi2S4 Nanoplate Arrays Derived from Hydroxide Precursors for Flexible Fiber-Shaped Supercapacitors.

A high-quality porous CoNi2S4 nanoplates array was in situ synthesized on carbon fibers (CFs) by a hydrothermal method via a CoNi-layered double hydroxide (LDH) precursor transformation process. The CoNi2S4@CFs electrode exhibits largely enhanced supercapacitor performance with a specific capacitance of 1724 F/g at 1 A/g, in comparison with that of the CoNi-LDH (1302 F/g) precursor. Furthermore, the CoNi2S4@CF electrode shows an extremely high rate capability with capacity retention of 79% under a charge density of 60 A/g, whereas the retention rate of CoNi-LDH@CFs is only ∼34%. The abundant pore structure, improved electrical conductivity, and lower internal resistances of CoNi2S4@CFs (1.0 Ω) compared to those of CoNi-LDH@CFs (9.5 Ω) are responsible for the enhancement of energy storage performance. By using the CoNi2S4 nanoplate array as the positive electrode, an all-solid-state asymmetric fiber-shaped supercapacitor was further obtained, which exhibits outstanding flexible, foldable, and wearable capability. In view of the component tunability for LDH materials, the hydroxide precursor transformation method with merits of mild conditions and easy operation can be extended to the synthesis of a variety of metal sulfides for broad applications in electronic devices.

Tungsten oxynitride nanowires as negative electrode for fiber-shaped supercapacitor

Holey tungsten oxynitride nanowires are vertically aligned on carbon nanotube fibers and applied as negative electrode of high performance supercapacitor. Due to the rich nitrogen doping and holey structure, this negative electrode displays an excellent electrical conductivity, a high volumetric capacitance of 265 F cm−3 at 0.08 A cm−3 and a good capacitance retention of 94.15% after 20000 cycles at 1.0 A cm−3. When it is applied in an asymmetric flexible fiber-shaped supercapacitor matched with a manganese-based positive electrode, the device achieves a remarkable volumetric capacitance of 52 F cm−3 at 0.5 A cm−3 and an extraordinary volumetric energy density of 23.4 mW h cm−3 at 0.45 W cm−3 with a maximum working voltage of 1.8 V. Therefore, this simple fabrication of stable negative materials opens a new pathway for application of high energy density asymmetric fiber-shaped supercapacitor in new generation flexible energy storage devices.

Facile construction of 3D porous carbon nanotubes/polypyrrole and reduced graphene oxide on carbon nanotube fiber for high-performance asymmetric supercapacitors

Flexible fiber-based supercapacitors applied in portable energy storage devices and wearable electronics have recently aroused widespread research interests. However, challenges still exist in the pursuit of facile fabrication technique for simultaneously realizing high capacitive performance and excellent mechanical stability. Here, two novel types of core-sheathed hybrid electrodes with carbon nanotube fiber (CNF) as the core and three-dimensional (3D) porous carbon nanotubes/polypyrrole (CNTs/PPy) or reduced graphene oxide (rGO) as the sheath were hierarchically constructed through one-pot electrochemical deposition. An all-solid-state asymmetric fiber-shaped supercapacitor was assembled by wrapping the gel electrolyte coated negative CNF/rGO electrode along the positive CNF/CNTs/PPy electrode. Thanks to the combination of abundant 3D pore structure and synergistic effect of different components in the fiber electrodes, the resulted supercapacitors exhibited a broadened potential window of 1.6 V, a high areal specific capacitance of 58.82 mF cm−2 and a high areal energy density of 20.91 μW h cm−2. It should be noted that 98.6% of the initial capacitance of the supercapacitor device can still be maintained after experiencing 200 reciprocating bending cycles, demonstrating outstanding mechanical stability. Moreover, the supercapacitor exhibited excellent cyclic performance, which was testified by 90% capacity retention after 10000 times of galvanostatic charge-discharge process.