A NiO–graphene hybrid film with 3D hierarchically porous structure has been rationally designed and constructed through a series of controlled fabrication processes. Multilayered porous graphene ...sheet network with the pore size of several micrometers is created via a so-called “on-water spreading” method, which is facile, economical, efficient and scalable. Then, the cross-like NiO nanoflakes film is uniformly grown onto the porous graphene sheet framework by a chemical bath deposition. The NiO–graphene hybrid film exhibits specific capacitance of 540 F g−1 at 2 A g−1 with 80% capacitance retention after 2000 cycles in 2 M KOH aqueous solution, which is much higher than that achieved from the bare NiO nanoflakes film (370 F g−1, with 66% capacitance retention). Moreover, chronoamperometry and electrochemical impedance spectroscopy measurements reveal that the NiO–graphene hybrid demonstrates enhanced reaction kinetics with about only 50% of respond time for NiO/NiOOH reaction and 79% of charge-transfer resistance compared with those of the bare NiO film. The proposed strategy could offer an effective way to fabricate graphene-based electrode materials for applications in various energy-storage devices.
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•Multilayered graphene network was fabricated via the on-water spreading method.•The NiO–graphene hybrid film exhibits hierarchically porous structure.•The hybrid film shows better pseudocapacitive performance than the bare NiO film.
Cube-like and plate-like LiLi0.2Mn0.54Ni0.13Co0.13O2 particles are obtained after treated in LiCl and KCl molten salts at 800 °C, respectively, comparing to the ball-like original particles calcined ...in air. The oxide treated in KCl molten salt with large specific area of 17.05 m2 g−1 delivers high discharge capacities of 254.1 mAh g−1 and 168.5 mAh g−1 at current densities of 200 mA g−1 and 2000 mA g−1, respectively. In addition, enhanced cycle stability with capacity retention of 94.9% after 80 cycles at charge–discharge current densities of 200 mA g−1 is obtained for the oxide treated in LiCl molten salt with sacrifice of a little capacity. Such electrochemical performance change is proved to be independent of Li+ diffusion coefficient. It appears that the treatment in molten salts can effectively reform the electrochemical performances of LiLi0.2Mn0.54Ni0.13Co0.13O2 cathode materials for various applications.
•Cube and plate-like particles are obtained after treated in LiCl and KCl molten salts.•Oxide treated in KCl molten salt has large specific area of 17.05 m2 g−1.•And discharge capacity of 168.5 mAh g−1 is obtained at 10 C.•Oxide treated in LiCl molten salt has enhanced capacity retention of 94.9%.
A porous Co3O4 nanoflake array film grown on nickel foam is prepared by a hydrothermal synthesis for pseudo-capacitor application. The pseudocapacitive behavior of the Co3O4 nanoflake array is ...investigated by cyclic voltammograms (CV), galvanostatic charge–discharge tests and electrochemical impedance spectroscopy (EIS) in 2 M KOH at different temperatures. The specific capacity is 210, 289 and 351 F g−1 at 2 A g−1 tested at −5 °C, 25 °C and 60 °C, respectively, corresponding to that of 184, 243 and 242 F g−1 at 20 A g−1. After 4000 cycles at 2 A g−1, the remaining specific capacity is 187, 342 and 124 F g−1 tested at −5 °C, 25 °C and 60 °C. It shows that with increasing the temperature from −5 °C to 60 °C, the specific capacity increases, while the cycling stability becomes worse. The operation temperature has a pronounced influence on the pseudocapacitive performance of Co3O4 nanoflake array.
•Porous Co3O4 nanoflake arrays film is studied as cathode for capacitor in 2 M KOH.•The porous Co3O4 nanoflake arrays film possesses large surface area (105 m2 g−1).•Temperature has a pronounced influence for the electrochemical performance.•Proposed the degradation mechanism of the Co3O4 nanoflake arrays film.
Atypical femur fracture (AFF) is an uncommon complication of long-term bisphosphonate use, but the risk declines substantially after treatment cessation. We report a case of a 70-year-old woman with ...osteopenia treated with alendronate for 9 years who presented with right mid-thigh pain and radiographic findings of focal lateral cortical thickening in the right mid-femur and lateral cortex irregularity in the proximal-mid left femur. Alendronate was discontinued, but she remained on estrogen for menopausal symptoms. Four years later, a horizontal linear translucent defect was seen in the right mid-femur area of cortical hypertrophy, consistent with an incomplete AFF. The patient underwent prophylactic intramedullary rodding of the right femur and estrogen was discontinued. Three years later (7 years after initial presentation), the cortical irregularities in the left femur were more prominent and three small horizontal linear translucent defects were now evident, consistent with early incomplete atypical fracture development. The patient also suffered a wrist fracture. She was treated with teriparatide for 1.5 years with resolution of the translucent defects in the left but not the right femur, although abnormal thickening of the lateral cortex persisted in both femurs. Our case demonstrates incomplete atypical femur fracture progression in a patient with long-term bisphosphonate exposure, even after treatment cessation. These findings highlight the importance of follow-up for patients who develop diaphyseal femur stress fractures and the potential for early healing with anabolic therapy. This case also demonstrates the challenge in managing older patients with incomplete AFF at risk for progression to complete AFF and osteoporotic fracture.
Traditional methods to synthesize layered double hydroxides (LDHs) with large interplanar spacing require the synthesis of precursor and subsequent ion exchange process. In this work, a one-step ...ionothermal strategy involving a "two-stage water injection" method is developed for the first time to synthesize cobalt iron layered double hydroxide (CoFe LDH) with 11.3 Aa interplanar spacing from an easily available ionic liquid analog, deep eutectic solvent (DES) system. The expansion of interplanar spacing is accompanied with the occurrence of tetrahedrally coordinated cobalt, and the insertion of molecules possibly being acetaldehyde, ethanol and biuret. In addition, more CO sub(3) super(2-) and fewer Cl super(-) and cyanate/isocyanate anions were intercalated. The nominal formula of a CoFe LDH sample with exclusively 11.3 Aa (003) interplanar spacing was determined to be Co sub(0.901)Fe sub(0.099)C sub(1.398)O sub(6.857)N sub(0.925 )H sub(3.375)Cl sub(0.018). As a representative demonstration for its improved electrochemical activity, supercapacitor application and OER catalytic activity of the LDHs with different interplanar spacings are displayed, which indicates that the increasing interplanar spacing is a powerful way to improve the electrochemical activity of LDH. The innovative methodology developed in this work should be widely applicable based on the mechanism we investigated, thus providing a fast, simple and cheap way towards LDH with large interplanar spacings.
A NiO–graphene hybrid is synthesized by a liquid phase deposition method. As an anode material for lithium ion batteries, the cyclic stability and rate capability of NiO is significantly improved ...after the incorporation of graphene sheets. The NiO–graphene hybrid electrode delivers a capacity of 646.1mAhg−1 after 35cycles at a current density of 100mAg−1, corresponding to 86.3% capacity retention. When the current density is increased to 400 and 800mAg−1, it still maintains a capacity of 509 and 368.5mAhg−1, respectively. The thermodynamic and kinetic properties of NiO electrodes with and without graphene are investigated by galvanostatic intermittent titration technique. The relationship between the rate and voltage hysteresis is also discussed. The polarization of both the electrodes in all cases obeys ohmic rule in the present rate range. The incorporation of graphene sheets can partly reduce the voltage polarization thereby the voltage hysteresis with increasing the current density. However, the extrapolation to zero current ends up in an approximate residual voltage for both the NiO electrodes.
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High-performance electrochromic films with large color contrast and fast switching speed are of great importance for developing advanced smart windows. In this work, ...crystalline/amorphous WO3 core/shell (c-WO3@a-WO3) nanowire arrays rationally are synthesized by combining hydrothermal and electrodeposition methods. The 1D c-WO3@a-WO3 core/shell hierarchical structures show a synergistic effect for the enhancement of optical modulation, especially in the infrared (IR) region. By optimizing the electrodeposition time of 400s, the core/shell array exhibits a significant optical modulation (70.3% at 750nm, 42.0% at 2000nm and 51.4% at 10μm), fast switching speed (3.5s and 4.8s), high coloration efficiency (43.2cm2C−1 at 750nm) and excellent cycling performance (68.5% after 3000 cycles). The crystalline/amorphous nanostructured film can provide an alternative way for developing high-performance electrochromic materials.
Polypyrrole-coated high Na content Na0.91MnO2 porous microcubes are prepared through high temperature calcination followed by a chemical ice water bath process. The higher sodium content of ...Na0.91MnO2 makes capacity increase up to 50 mAh g−1 compared with Na0.7MnO2.05. The thus wider interlayer space makes ion/electron insertion/extraction faster. Porous structure providing shorter ion/electron diffusion distance compared with hollow sphere structure. The conductive polymer modified sodium manganate oxide cathode for sodium ion full batteries exhibits ultrahigh initial capacity, cycling stability and rate capability.
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Highly conductive cathode material with enhanced Na+ diffusion kinetics is of great importance in the exploration of sodium ion batteries. In this work, Na0.91MnO2 porous microcube which is coated with highly conductive polypyrrole (PPy) is obtained. The high Na content in the layered sodium manganate oxide brings about wider interlayer distance resulting in high capacity and electrochemical kinetics. The higher sodium content of Na0.91MO2 makes capacity increase up to 50 mAh g−1 compared with Na0.7MnO2.05. Furthermore, the well-designed combination between porous structure and conductive PPy coating exhibits fast ion/electron transfer inside the electrode and high cycling stability. The PPy coated Na0.91MnO2 delivers a high initial capacity of 208 mAh g−1, encouraging capacity retention and rate capability. Based on the porous Na0.91MnO2@PPy cathode, the sodium ion full cells with puffed millet porous carbon anode show remarkably stable cycling and high-rate performances.
Three Ni-P-O compound catalysts with tunable architectures and compositions have been fabricated using a facile one-pot solvothermal method, which are named astrocyte-network Ni-P (Ni-P
an
), ...silkworm cocoon-like Ni-P (Ni-P
sc
), and microsphere Ni-P (Ni-P
m
), respectively. The final architecture of the Ni-P-O catalysts is strongly dependent on the Ni
2+
/H
2
PO
2
−
molar ratio in the reaction system, which leads to a delicate balance between kinetic and thermodynamic growth regimes. Three-dimensional ensemble of Ni-P
an
with a higher P content is composed of many amorphous Ni-P nanowires with a diameter of about 4 nm, which delivers a significantly larger BET surface area of 500.5 m
2
g
−1
. Moreover, nickel phosphides and nickel phosphates are formed in the three Ni-P-O samples. Ni-P
an
exhibits a higher peak current density of ∼1490 A g
−1
, better electrode accessibility, faster charge-transfer process, and long-term chronoamperometry stability (≥20 000 s) toward methanol oxidation in alkaline solution, which are superior to most state-of-art Ni-P catalysts and the Ni-P
sc
and Ni-P
m
in this case. The superior catalytic performance of the Ni-P
an
catalyst is attributed to its unique microstructure and compositions. According to X-ray photoelectron spectroscopy, a strong electronic interaction between nickel phosphides and nickel phosphates might also contribute to the improved catalytic activity of the Ni-P
an
catalyst.
A self-assembly three-dimensional astrocyte-network Ni-P-O compound catalyzes methanol electro-oxidation in alkaline environments with superior electrocatalytic activity and stability.
TiO2@WO3 core/shell nanorod arrays are prepared by the combination of hydrothermal and electrodeposition method. The array films show remarkable enhancement of the electrochromic properties. In ...particular, a significant optical modulation (57.2% at 750nm, 70.3% at 1800nm and 38.4% at 10μm), fast switching speed (2.4s and 1.6s), high coloration efficiency (67.5cm2C−1 at 750nm) and excellent cycling performance (65.1% after 10,000 cycles) are achieved for the core/shell nanorod arrays. The improved electrochromic properties are mainly attributed to the core/shell structure and the porous space among the nanorod array, which makes the ion diffusion become easier and it also gives larger surface area for charge-transfer reactions. The data present great promise for the TiO2@WO3 core/shell nanorod arrays as practical electrochromic materials.
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•TiO2@WO3 core/shell nanorod arrays are successfully prepared.•The arrays exhibit larger optical modulation, fast switching speed and high CE.•Excellent cycling performance are achieved for the core/shell nanorod arrays.
