The development of new electrode materials with high specific capacity for excellent supercapacitive storage and energy conversion is highly desirable. The combination of metal and metal oxide with carbon is an effective strategy to achieve active bimetallic nanocatalysts. Herein, we developed a facile method to synthesize CoxMn1-xO@GC and Co/MnO@GC nanocomposites by an in situ conversion of Co-Mn PBAs. The as-prepared carbon hybrids, especially the resulting Co/MnO@GC carbonized under 700 °C (Co/MnO@GC-700), preserve the nanocubic morphology of Co-Mn PBAs and show excellent supercapacitance and OER performance. Specifically, an outstanding specific capacitance of 2275 F g-1 can be obtained with Co/MnO@GC-700 as the electrode material at a current density of 4 A g-1. When used as OER catalysts, Co/MnO@GC-700 shows a low overpotential of only 358 mV at 10 mA cm-2 in 1 M KOH. Moreover, a fabricated asymmetric supercapacitor device (ASC device), in combination with active carbon, shows a high cell voltage of 1.7 V and a considerably high specific capacitance of 246 F g-1 at 2 A g-1. Our nanoarchitecture design derived from PBAs provides a new opportunity for future applications in high-performance energy storage and transformation systems.
The enhancement of the anomalous Hall effect has been realized by capping one monolayer Cu on Ni thin films. This approach with artificial interface engineering is proved to be an effective way to improve spin to charge transformation and may have potential application in spintronics.
The anomalous Hall effect (AHE) in epitaxial Fe films on GaAs(111) has been investigated as a function of film thickness and temperature. The intrinsic contribution from the Berry curvature is singled out from the extrinsic ones and determined to be 821 −1 cm −1 , which agrees to the theoretical prediction of 842 −1 cm −1 and is considerably smaller than 1100 −1 cm −1 for Fe(001). This result provides a direct experimental evidence for the anisotropy of the intrinsic AHE in single crystal Fe, reflecting its electronic band structure.
Mg-substituted α- and β-phase nickel hydroxides with high specific capacitance and good stability have been synthesized via sacrificial metal-based replacement reaction. 2D α- and β-phase nickel-magnesium hydroxide (NiMg-OH) have been synthesized by sacrificing magnesium (Mg) powder with nickel salt aqueous solutions. Interestingly, the phase of the obtained NiMg-OH can be controlled by adjusting the nickel precursor. As well, the Mg powder is used not only as Mg source but also alkali source to form NiMg-OH. The α-phase nickel-magnesium hydroxide sample (α-NiMg-OH) exhibits lager surface area of 290.88 m2 g–1. The electrochemical performances show that the α-NiMg-OH presented a superior specific capacitance of 2602 F g–1 (1 A g–1) and β-phase nickel-magnesium hydroxide sample (β-NiMg-OH) exhibits better stability with 87% retention after 1000 cycles at 10 A g–1. The hybrid supercapacitor composed of α-NiMg-OH and activated carbon (AC) display high storage performance and cycle stability, it presents 89.7 F g–1 (1 A g–1) and of 0–1.6 V potential window and it maintains capacitance retention of 84.6% subsequent to 4000 cycles.
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