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A series of porous La0.6Sr0.4Co1–xFexO3–δ (x = 0–1) nanofibers with diameters of 54–71 nm are synthesized by electrospinning using appropriate polymers and different processing parameters. When tested as a catalyst for oxygen evolution reaction (OER), an La0.6Sr0.4Co0.6Fe0.4O3–δ (LSCF6464) nanofiber catalyst (with a specific surface area of 24.2 m2 g−1) exhibits a potential (vs Ag/AgCl) of 647 mV at 10 mA cm−2disk, which is much smaller than that of a powder-type commercial LSCF (786 mV) and also smaller than that of the state-of-the-art IrO2 catalysts (660 mV). The LSCF6464 nanofiber catalyst further delivers an outstanding durability, with almost no observable change in potential at a current density of 10 mA cm−2disk for more than 3 h. In contrast, the performance of an IrO2 catalyst degrades continuously under the same testing conditions. The findings suggest that the LSCF nanofiber is a promising OER electrocatalyst for metal–air batteries and water electrolysis.

Flexible V-O-C composite nanofibers were fabricated from solution precursors via electrospinning and were investigated as free-standing and additive-free film electrodes for supercapacitors. Specifically, composite nanofibers (V0, V5, V10 and V20) with different vanadyl acetylacetonate (VO(acac)2) contents of 0, 5, 10 and 20 wt% with respect to polyacrylonitrile (PAN) were prepared. The composite nanofibers were comparatively studied using XRD, Raman spectroscopy, XPS, N2 adsorption-desorption, FE-SEM, TEM and S-TEM. The vanadium element was found to be well-dispersed in the carbon nanofibers, free from the formation of an aggregated crystalline phase, even in the case of V20. A specific surface area of 587.9 m(2) g(-1) was reached for V10 after calcination, which is approximately twice that of the vanadium-free carbon nanofibers (V0, 300.9 m(2) g(-1)). To perform as an electrode for supercapacitors in an aqueous electrolyte, the V10 film delivered a specific capacitance of 463 F g(-1) at 1 A g(-1). V10 was also able to retain a specific capacitance of 380 F g(-1), even at a current density of 10 A g(-1). Additionally, very stable cycling stability was achieved, maintaining an outstanding specific capacitance of 400 F g(-1) at 5 A g(-1) after charge-discharge cycling 5000 times. Thus, V-O-C composite nanofibers are highly attractive electrode materials for flexible, high-power, thin film energy storage devices and applications.

Although a wide variety of three-dimensional porous electrode architectures have been created for supercapacitors to markedly enhance the charge and mass transfer associated with cycling, their low volumetric energy densities limit applications in many energy storage systems. In this work, we report a unique electrode architecture consisting of Ni3S2 nanosheet-onto-Ni3S2-nanorods grown on nickel foam and prepared using a simple one-step hydrothermal method. When tested as an electrode for a supercapacitor (using a three-electrode configuration), this material exhibited excellent rate capability and cycling stability at high cycling rates. The obtainable capacitance decreased by

In operando resonance Raman spectroscopy suggests quantitative correlation between phonon band properties and the amount of charge storage of high-energy density NiO2H x battery/pseudocapacitive material. Comparing the spectroscopic evolution using different electrolytes reveals the contributions of breaking/formation of O-H bonds and insertion/extraction of cations to electrochemical charge storage of NiO2H x .

To develop high-power and fast energy storage devices, electrode materials with superior ionic and electronic transport properties should be developed. Herein, a novel composite electrode with TiO2 nanotubes connected onto a conductive carbon nanofiber network is designed and realized through a general route. The carbon matrix is first synthesized using an electrospinning technique and heat-treatment, and the embedded rutile TiO2 nanoparticles are formed in situ as the starting materials for the hydrothermal reaction. After hydrothermal treatment, a three-dimensional (3D) porous architecture is developed. The mechanistic analysis demonstrates that the raw embedded rutile TiO2 nanoparticles react with NaOH solution and go out around the carbon nanofiber matrix to form a well-connected 3D porous nanotube/nanofiber architecture. By using the as-prepared films as electrodes for lithium-ion batteries (LIBs) without the application of any additional conductive agent or binder, high initial capacity and excellent rate performance (214 mA h g−1 at 5 C rate, 180 mA h g−1 at 10 C rate, 138 mA h g−1 at 20 C rate and 112 mA h g−1 at 30 C rate) are achieved. Moreover, the electrode shows stable cycling performance, especially at a high rate of 30 C, without undergoing decay after 1000 cycles.

As a lithium-intercalation material, high crystallinity is important for Li4Ti5O12 to achieve good capacity and cycling stability, while a large surface area and a short lithium diffusion distance are critical to increase rate capacity. In this study, well-crystallized Li4Ti5O12 nanoplates with outstanding electrochemical performance were facially prepared through a two-step hydrothermal preparation with benzyl alcohol–NH3·H2O (BN) as the solvent and a subsequent intermediate-temperature calcination at 500 °C for 2 h in air. To support the superiority of benzyl alcohol–NH3·H2O (BN) for hydrothermal synthesis, ethanol–NH3·H2O (EN) was also comparatively studied as solvent. In addition, different hydrothermal reaction times were tried to locate the optimal reaction time. The nature of as-prepared Li4Ti5O12–BN (LTO–BN) and Li4Ti5O12–EN (LTO–EN) was characterized by XRD, N2 adsorption/desorption tests, SEM, TEM and TGA-DSC. Compared with EN, the BN hydrothermal solvent facilitated the formation of nanosheet-Li4Ti5O12 with wall thicknesses of 8–15 nm and better crystallization. After a 6 h hydrothermal reaction at 180 °C and subsequent calcination, well-crystallized Li4Ti5O12–BN nanoplates were produced, which demonstrate a superior discharge capacity of 160 mA h g−1, even at 40 C, maintaining a capacity of 88.8% compared with that at 1 C. The nanoplates also exhibited excellent cycling stability, retaining a discharge capacity of 153 mA h g−1 after 1000 charge–discharge cycles at 10 C.

We demonstrate a facile and effective way for the fabrication of a flexible, homogeneous and neat α-MoO3 thin-film electrode for lithium-ion batteries with high performance without using any binder and conductive additives. Single-crystalline α-MoO3 nanobelts with uniform width of around 200 nm and length at the micrometer level are first synthesized by a simple water-based hydrothermal route. The as-obtained α-MoO3 slurry is then directly deposited onto a copper foil current collector by the doctor blade method. The formation of the α-MoO3 film and its good adhesion to the current collector is realized via van der Waals attraction forces through a drying process. The structure and morphology of the α-MoO3 nanobelt particles and thin-film electrode are systematically characterized by XRD, Raman spectra, TEM, SEM and XPS techniques, and the electrochemical properties are investigated by CV and constant current discharge–charge test techniques. The α-MoO3 film electrode exhibits a reversible specific capacity of ∼1000 mA h g−1 at 50 mA g−1 and a stable capacity retention of 387–443 mA h g−1 at 2000 mA g−1, indicating its high Li storage capacity, superior rate performance and good cycling stability. The electrode material, as well as the fabrication technique, is highly promising for practical use in high energy and power density lithium-ion batteries.

An amenable method for improving rate performance of Li4Ti4.85Al0.15O12 electrode by post-synthesis treatment in formaldehyde aqueous solution at room temperature is introduced. The as-prepared samples are characterized by XRD, BET, SEM, HR-TEM, XPS and electronic conductivity measurement. The treatment causes no noticeable change on the phase structure and has only little effect on the specific surface area and particulate morphologies. It also only slightly decreases the lithium ion diffusion coefficient. However, it substantially increases the electronic conductivity due to the creation of Ti3+ in the oxide lattice. The post-synthesis treatment for a period of 4 h effectively increases the capacity at 10 C rate for Li4Ti4.85Al0.15O12 from 125 mA h g−1 for the untreated sample to 160 mA h g−1, and the electrode performance is also fairly stable. This method is highly attractive for synthesis of high-performance Li4Ti5O12 electrodes owing to its simplicity, energy saving and efficiency. As a general method, post-synthesis treatment using formaldehyde may be applicable to other electrodes.

Film electrodes composed of 1D TiO2 or TiO2/Ag composite hollow fibers were fabricated by a coaxial electrospinning technique, and were applied as the anode of lithium-ion batteries free of any binder or conductive additive. SEM and TEM characterization demonstrated that uniform hollow fibers with an average outer diameter of around 1.5 μm and wall thickness of around 200 nm were successfully obtained. Ag nanoparticles were dispersed in the TiO2/Ag composite hollow fibers homogeneously. SEM, TEM and BET surface area characterizations demonstrated that the TiO2 and TiO2/Ag hollow fibers have a mesoporous wall structure. Galvanostatic charge and discharge tests demonstrated that the TiO2 film electrode had poor capacity and rate capability by using conventional copper foil as the current collector. The incorporation of silver with the formation of the TiO2/Ag composite electrode was marginal in improving the electrode performance. Modifying the copper foil with silver paste increased the surface roughness obviously, which significantly increased the electrode performance of the TiO2 film electrode with the second discharge capacity reaching 130 mAh g−1 at 1 C rate. The electrode morphology was successfully preserved after 50 electrochemical cycles. Electrospinning is highly promising as a powerful technique for the fabrication of binder and conductive additive-free TiO2 film electrodes for lithium-ion batteries, while increasing the surface roughness of the current collector is critical to achieve high performance.