In our work, ultra-thin Ni/Co hydroxides (Ni1Co2) with a sheet-like structure are successfully grown on the surface of conductive nickel foam via a one-pot hydrothermal reaction, avoiding the need for binders and conducting agents. In the reaction, NO₃ ⁻ ions from reactants release OH⁻ ions partially with Co²⁺ ions turning into Co³⁺ ions and then OH⁻ ions can react with Ni²⁺, Co²⁺ or Co³⁺ in a mixed solvent of water and ethanol, without the necessary addition of an extra alkali source. When used for supercapacitors, the resulting free-standing Ni1Co2 composites exhibit an impressive specific capacitance of 2654.9 F g⁻¹ at a current density of 1 A g⁻¹ and a favorable cycling stability with 77% retention even at a high current density of 10 A g⁻¹ after 1500 cycles. In order to do research into the electrochemical properties of Ni1Co2 composites, a simple asymmetric supercapacitor (ASC) is constructed, using the Ni1Co2 nanosheets as the positive electrode and activated carbon (AC) as the negative electrode. This ASC with an extended voltage window of 0–1.6 V presents an outstanding energy density of 42.4 W h kg⁻¹ (at a power density of 823.2 W kg⁻¹) and still retains 24.8 W h kg⁻¹ (at 10 170.8 W kg⁻¹). Meanwhile, the excellent cycling stability of this ASC device has been revealed via a great specific capacitance retention of 94% after 3000 cycles (at a current density of 5 A g⁻¹). So the Ni1Co2-based composites could be one of the potential materials for high-performance energy storage.

Although solid Au is usually most stable as a face-centered cubic (fcc) structure, pure hexagonal close-packed (hcp) Au has been successfully fabricated recently. However, the phase stability and mechanical property of this new material are unclear, which may restrict its further applications. Here we present the evidence that hcp → fcc phase transformation can proceed easily in Au by first-principles calculations. The extremely low generalized-stacking-fault (GSF) energy in the basal slip system implies a great tendency to form basal stacking faults, which opens the door to phase transformation from hcp to fcc. Moreover, the Au lattice extends slightly within the superficial layers due to the self-assembly of alkanethiolate species on hcp Au (0001) surface, which may also contribute to the hcp → fcc phase transformation. Compared with hcp Mg, the GSF energies for non-basal slip systems and the twin-boundary (TB) energies for "Equation missing"<!-- image only, no MathML or LaTex --> and "Equation missing"<!-- image only, no MathML or LaTex --> twins are larger in hcp Au, which indicates the more difficulty in generating non-basal stacking faults and twins. The findings provide new insights for understanding the nature of the hcp → fcc phase transformation and guide the experiments of fabricating and developing materials with new structures.

In recent years, electrospun nanomaterials have been regarded as efficient electrocatalysts for energy storage and conversion due to their large surface area, unique chemical structure, easily tunable composition, and excellent electron and mass transportation properties. In this review, we will discuss the recent progress regarding the electrochemical catalytic reactions based on advanced electrospun nanomaterials, including the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), carbon dioxide reduction reaction (CO₂RR), nitrogen reduction reaction (NRR), and small molecule oxidation reaction. After a brief description of the electrospinning technique and electrospun nanomaterials, we will focus on the relationship among the morphology, composition, and architecture of the electrospun nanomaterial-based electrocatalysts and their electrocatalytic performance. In addition, the remaining challenges and perspectives for further advances have been addressed. With the fast development of the electrocatalytic energy conversion devices, the research on the advanced electrospun nanomaterials in this field is anticipated to be significantly attractive and exciting in the near future.

ZnO–NiO–Co ₃ O ₄ hybrid nanoflakes are fabricated via a simple hydrothermal method followed by a subsequent annealing process.