The rapid development of integrated electronics and the boom in miniaturized and portable devices have increased the demand for miniaturized and on-chip energy storage units. Currently thin-film batteries or microsized batteries are commercially available for miniaturized devices. However, they still suffer from several limitations, such as short lifetime, low power density, and complex architecture, which limit their integration. Supercapacitors can surmount all these limitations. Particularly for micro-supercapacitors with planar architectures, due to their unique design of the in-plane electrode finger arrays, they possess the merits of easy fabrication and integration into on-chip miniaturized electronics. Here, the focus is on the different strategies to design electrode finger arrays and the material engineering of in-plane micro-supercapacitors. It is expected that the advances in micro-supercapacitors with in-plane architectures will offer new opportunities for the miniaturization and integration of energy-storage units for portable devices and on-chip electronics.

The binary skutterudite CoSb3 is a narrow bandgap semiconductor thermoelectric (TE) material with a relatively flat band structure and excellent electrical performance. However, thermal conductivity is very high because of the covalent bond between Co and Sb, resulting in a very low ZT value. Therefore, researchers have been trying to reduce its thermal conductivity by the different optimization methods. In addition, the synergistic optimization of the electrical and thermal transport parameters is also a key to improve the ZT value of CoSb3 material because the electrical and thermal transport parameters of TE materials are closely related to each other by the band structure and scattering mechanism. This review summarizes the main research progress in recent years to reduce the thermal conductivity of CoSb3-based materials at atomic-molecular scale and nano-mesoscopic scale. We also provide a simple summary of achievements made in recent studies on the non-equilibrium preparation technologies of CoSb3-based materials and synergistic optimization of the electrical and thermal transport parameters. In addition, the research progress of CoSb3-based TE devices in recent years is also briefly discussed.

Flexible devices play an important role in various fields such as electronics, industry, healthcare, military, space exploration, and so on. Traditional materials used for flexible devices include silicon, inorganic oxides,...

How to prevent the agglomeration of nanoparticles in nanocomposites remains a key challenge. Using nanometer suspension as a doping agent provides an effective approach to solve this challenge. A new technique that consists of chemical coprecipitation, ball milling and sedimentation separation metheds was developed for preparing hard magnetic M-type BaFe12O19 nanometer suspension. The single-phase BaFe12O19 nanoparticles dispersed uniformly in alcohol have been prepared by this new technique. Magnetic nanocomposite thermoelectric materials with a homogeneous dispersion of BaFe12O19 nanoparticles were prepared through a combination process of an ultrasonic mixing of BaFe12O19 nanometer suspension and In-filled CoSb3 thermoelectric matrix material and spark plasma sintering. The microstructure analysis of magnetic nanocomposite thermoelectric materials confirmed that using the nanometer suspension as a doping agent is an effective way to solve the agglomeration phenomenon of nanoparticles in nanocomposites. In addition, the decline of thermoelectric performance in the high-temperature intrinsic excitation region of In-filled CoSb3 can be effectively suppressed by the magnetic phase transition of BaFe12O19 nanoparticles dried by nanometer suspension from ferromagnetism to paramagnetism. It is also confirmed that using the BaFe12O19 nanometer suspension as a thermoelectric performance enhancer is an effective way to solve the challenging problem of performance deterioration of thermoelectric materials at high temperature.

Indoor formaldehyde from substandard furniture and decorative materials seriously endangers human health. How to remove effectively indoor formaldehyde with low concentration at room temperature is a challenging problem. Using a MnO2/AlOOH composite by the MnO2 modification as a catalyst provides an effective approach to solve this challenge. Here, a new type of MnO2/AlOOH composite catalyst with high ability to remove indoor low-concentration formaldehyde was prepared by redox reaction at room temperature. A MnO2/AlOOH composite with a homogeneous dispersion of MnO2 has high specific surface area and a large amount of surface hydroxyl (−OH) which plays a major role in the adsorption of formaldehyde. A partially crystalline structure was observed in the composite, which contains multivalent Mn ions and a large number of vacancy defects. The surface −OH of composite shows strong oxidation activity through the charge exchange of multivalent Mn ions and vacancy defects. The composite has a higher ability to remove indoor low-concentration formaldehyde compared to the birnessite MnO2 at room temperature. This study proposes a new idea for the improvement of catalytic performance in the structure and composition of the catalyst.

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How to realize the synergistic optimization of electrical–thermal–mechanical properties of thermoelectric materials is a key challenge. Using the Bi0.5Sb1.5Te3 nanoparticle as a mixed agent provides an effective way to address this challenge. Here, Bi0.5Sb1.5Te3/In0.25Co4Sb12 nanocomposites with different contents of Bi0.5Sb1.5Te3 nanoparticles were successfully prepared by ultrasonic dispersion combined with spark plasma sintering. Phase and microstructure characterization presented that Te nanoparticles were precipitated from Bi0.5Sb1.5Te3 during the SPS sintering process. Transport measurement results showed that the electrical conductivity was increased due to the increased carrier concentration induced by the charge transfer between Te nanoparticles and the matrix. The Seebeck coefficient was also increased due to the selected electron scattering and increased scattering factor. The lattice thermal conductivity was dramatically suppressed because of the enhanced phonon scattering induced by the Bi0.5Sb1.5Te3 nanoparticles and in situ-precipitated Te nanoparticles and increased dislocations. As a result, a higher average ZT value of 1 was obtained in the range of 300–700 K by the decoupling of the electrical and thermal transport properties for the nanocomposite with 0.1 wt % of Bi0.5Sb1.5Te3 nanometer suspension. Furthermore, the flexural strength, fracture toughness, and hardness of the nanocomposites were also improved significantly. This work demonstrates that using the Bi0.5Sb1.5Te3 nanoparticle as a mixed agent can realize the synergistic optimization of electrical–thermal–mechanical properties of the In-filled CoSb3 thermoelectric material.