Diamond-like-carbon (DLC)/N-gradient CN_x nano-multilayer films with different thicknesses of nitrogen-content gradient CN_x layers were prepared on silicon substrate via direct-current magnetron sputtering, in which the nitrogen-content gradient appears in an inverted "U" shape. The microstructure, surface morphology, mechanical and tribological properties in vacuum and air were characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, scratch testing and ball-on-disk wear tests. The results show that the surface of the multilayer films is smooth and all of them are amorphous. The hardness, elastic modulus, and adhesion of the multilayer films gradually decrease, and the surface roughness and wear rate increase with the increase of N-content gradient CN_x layer thickness. The wear resistance of the multilayer films is better in vacuum rather than in air. The multilayer film with a CN_x layer thickness of less than 30 nm exhibits a hardness in the range of 21.9-23.1 GPa, an interface adhesion in the range of 54.2-54.3 N, a friction coefficient of approximately 0.19 in air and 0.18 in vacuum, and a wear rate in the range of (0.98-1.16)×10^-16 m³/(N·m) in air and (0.83-0.88)×10^-16 m³/(N·m) in vacuum.

Fe₃O₄/CS carbon aerogel electrode material with a high specific capacitance was prepared via in-situ growth with chitosan (CS) and FeCl₃·6H₂O as raw materials. The crystal structure and structural defects of the samples were analyzed by X-ray diffraction and Raman spectroscopy, and the composition and morphology were characterized by X-ray photoelectron spectroscopy and scanning electron microscopy, and their electrochemical properties were tested in a three-electrode system. The results show that Fe₃O₄ can be loaded on the CS carbon aerogel with their effective bonding. The amino groups on the chitosan molecules achieve self-doping of N atoms during the carbonization process, and the N content of the composite is as high as 7.21% (mole fraction). In addition, the composite carbon aerogel exhibits a high specific capacitance of 315.5 F/g at a current density of 0.5 A/g when introducing 0.4 g FeCl₃·6H₂O into 1.0 g CS. The specific capacitance of the composite carbon aerogel is approximately 3 times greater than that of original chitosan carbon aerogel.

The boron-doped mesoporous carbon (BMCs) and boron-doped graphene-based mesoporous carbon (BMC/GO) were synthesized by a solvent evaporation-induced self-assembly method with block copolymer F127 as a soft template, boric acid as a boron source, phenolic resin prepolymer carbon sources and graphene-oxide (GO) as modifiers. The structures of the materials were characterized by transmission electronic microscopy, X-ray diffrication, nitrogen adsorption-desorption, and X-ray photoelectric microscopy. The electrochemical properties of samples were tested by electrochemical workstation. The structural characterization shows that the as-prepared composite material BMC/GO-40 (the mass of GO suspension is 40%) exhibits a great specific surface areas (i.e., 462.5 m²/g), and the average pore size is approximately 5 nm. The boron element mainly exists in the framework of mesoporous carbon in two forms, i.e., BC₃ bonding and BCO₂/BC₂O bonding. Based on the results by electrochemical tests, the maximum specific capacitance can be obtained via the addition of an appropriate amount of boron doping and the adjustment of the composite amount of graphene oxide. The capacity of BMC/GO-40 sample is 167 F/g at a current density of 0.5 A/g.

The relationship between the Weibull modulus of bending strength and its thickness of single cell before and after reduction was investigated by a coaxial ring force method. The Weibull modulus of NiO-YSZ anode supported cell is 4.56, 4.78 and 6.16 for the thickness of 1.1 mm, 0.9 mm and 0.7 mm, respectively. The Weibull modulus increases gradually with the decrease of sample thickness due to the reduced internal defect number of anode. The Weibull modulus of Ni-YSZ anode supported cell increases to 8.66, 12.49 and 9.37, respectively, since a plastic Ni phase inhibits the crack propagation. The single cell with a thickness of 0.9 mm shows a greater performance with the corresponding bending strength of 122.9 MPa. The crack sources of the sample mainly come from the internal defects of the anode and the agglomeration of Ni particles. Based on the experimental results, the influence of single cell thickness on its mechanical properties can be demonstrated at different crack source types and fracture modes.

The La_0.5Sr_0.5CoO₃(LSCO) oxide bottom electrodes were epitaxially grown on (001) SrTiO₃(STO) substrates via off-axis magnetron sputtering at different deposition temperatures. Based on the results of X ray diffraction (XRD), atomic force microscopy (AFM) and four probe square resistance test, the optimal deposition temperature for (00l) epitaxial LSCO films is 550℃. In addition, the Pt/Na_0.5Bi_0.5TiO₃(NBT)/LSCO/STO ferroelectric capacitor was fabricated on LSCO/STO heterostructure via laser pulse deposition. The results indicate that NBT films are (00l) epitaxial. The leakage current density of Pt/NBT/LSCO heterostructure increases with increasing temperature from room temperature to 70℃. The conduction mechanism is ohmic conduction at low voltage and space charge limited current at a high voltage. At 5 V driving voltage, the Pt/NBT/LSCO capacitor exhibits saturated hysteresis loops and retention characteristics both at room temperature and 70℃ without fatigue after 10¹⁰ inversion.

Conventional energy storage devices often need to be replaced or wired for charging due to their limited capacity, which is difficult to meet the working demands of wearable electronic devices in some special occasions. Using the "piezoelectric effect" of piezoelectric materials to construct a piezoelectric self-chargeable energy storage device based on the conversion of force to electricity is an effective solution to the problem s above. Recent development on the piezoelectric and self-chargeable energy storage devices was reviewed. In addition, the design principle, characteristics, construction base and applications were also introduced.

The core-shell composites (FeCo@TiO₂, FeCo@TiO₂@Fe₃O₄) were fabricated via hydrolysis reactions with flattened FeCo as the core and TiO₂ and Fe₃O₄ as the shell. The morphology and phase composition of the core-shell composites (i.e., FeCo@TiO₂, FeCo@TiO₂@Fe₃O₄) were characterized by scanning electron microscopy and X-ray diffraction. The results show that the core-shell composite is flattened with diameters of 20-50 μm and thicknesses of 3-5 μm. The main components of the coating layer are TiO₂ and Fe₃O₄, which are uniformly distributed on the flattened FeCo core. The complex permittivity and permeability of the samples were measured in a frequency range of 2~18 GHz, and the reflection loss of the samples was calculated based on the transmission line theory. It is indicated that the effective absorption bandwidth of the FeCo@TiO₂@Fe₃O₄ samples at room temperature is 3 GHz (RL<-10 dB) with the thickness of 2.5mm, and the minimum reflection loss of the sample is -35.4 dB. The effective absorption bandwidth is 2GHz, and the minimum RL value is -29.2 dB after annealing at 500℃. The thermogravimetric analysis indicates that the weight gain of FeCo@TiO₂@Fe₃O₄ is 20% less than that of FeCo at 800℃.

Fe@(ZnO/C) composite was prepared with resorcinol, zinc acetate dihydrate and ferrous sulfate heptahydrate by a wet chemical method and a subsequent high-temperature heat treatment. The results show that Fe@(ZnO/C) ternary composite with a ball-chain Fe powder has a better impedance matching and a higher attenuation coefficient, showing a superior electromagnetic wave absorption performance. The optimum reflection loss () is -56.01 dB at 10.91 GHz with a thickness of 2.73 mm and the effective absorption bandwidth () is up to 5 GHz (i.e., 8.54-13.54 GHz).

The transition metals (i.e., Co, Mn) supported rod-like CeO₂ nanomaterials with different proportions were prepared by an one-step hydrothermal method. The influence of transition metals (Co, Mn) content on the crystal lattice constant, element content of different valence states of the catalyst, specific surface area and CO catalytic oxidation performance were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, X-ray photoelectron microscopy, specific surface area analysis, H₂-temperature programmed reduction and CO-temperature programmed desorption, respectively. In addition, compared to pure CeO₂, CeO₂ nanorods supported Co or Mn show a greater catalytic activity for CO at a low temperature. The temperature range of Co-CeO₂ with catalytic oxidation CO of 50% (T_50%) is 97-133℃, and that of Mn-CeO₂ is 107-195℃. Co-CeO₂ and Mn-CeO₂ with 40% (in mole fraction) of Co or Mn show the optimum catalytic performance, and the T_50% of 40% Co-CeO₂ is 97℃ and 40% Mn-CeO₂ is 107℃, respectively. The introduction of transition metal (Co, Mn) enhances the synergistic effect on the catalyst surface and produced more active oxygen, thus effectively enhancing the catalytic oxidation performance of the nanomaterials.

Fumed silica and polydimethylsiloxane were mixed with water to prepare a suspension with a certain viscosity. The three-dimensional aggregates of fumed silica nanoparticles in the spraying process were used to form a micro-/nano-grade rough structure for super-hydrophobic coating, and a low surface energy material of polydimethylsiloxane was stored in the three-dimensional pores of gas-phase chain silica nanoparticles, and self-healing superhydrophobic coatings were prepared via simple spraying on the surface of different substrates. After the surface of the coating is destroyed by oxygen plasma, the coating can be restored to its super-hydrophobic performance by only placing at room temperature or treating at 100℃ for 30 min. The number of self-healing exceeds 20 times. Also, the coating has good high-temperature resistance, acid and alkali resistance, friction resistance and erosion resistance performance.