Silver vanadates (SVOs) have been widely investigated as cathode materials for high-performance lithium-ion batteries (LIBs). However, similar to most vanadium-based materials, SVOs suffer from structural collapse/amorphization and vanadium dissolution from the electrode into the electrolyte during the Li insertion and extraction process, causing poor electrochemical performance in LIBs. We employ ultrathin Al2O3 coatings to modify β-AgVO3 (as a typical example of SVOs) by an atomic layer deposition (ALD) technique. The galvanostatic charge-discharge test reveals that ALD Al2O3 coatings with different thicknesses greatly affected the cycling performance. Especially, the β-AgVO3 electrode with ~10 nm Al2O3 coating (100 ALD cycles) exhibits a high specific capacity of 271 mAh g−1, and capacity retention is 31%, much higher than the uncoated one of 10% after 100 cycles. The Coulombic efficiency is improved from 89.8% for the pristine β-AgVO3 to 98.2% for Al2O3-coated one. Postcycling analysis by cyclic voltammetry (CV), cyclic voltammetry (EIS), and scanning electron microscopy (SEM) disclose that 10-nm Al2O3 coating greatly reduces cathode-electrolyte interphase (CEI) resistance and the charge transfer resistance in the β-AgVO3 electrode. Al2O3 coating by the ALD method is a promising technique to construct artificial CEI and stabilize the structure of SVOs, providing new insights for vanadium-based electrodes and their energy storage devices.

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Background: The surface condition of mechanical parts has an important impact on the performance of the machine. Surface microtexture technology based on bionics is an effective method to improve the comprehensive performance of the surface of machine parts. Processing microscopic pits, convex-hull, microgrooves, and scale texture on the surface of parts can reduce wear, increase friction, improve lubrication performance, enhance hydrophobic properties, decrease drag and reduce noise. Surface microtexture technology has been widely used in many types of machinery, embodying various properties in working situation. Objective: The objective of this study was to provide an overview of recent patents and related research on surface microtexture technology, and to provide a reference for further applications. Methods: This paper introduces the development of surface microtexture technology, reviews the representative patents on surface microtexture and their applications in industrial products, including cutting tools, bearings, gears, blades, etc. The advantages and disadvantages of various surface microtextures are analyzed. Results: Through the analysis and comparison of surface microtextures, the influence of surface microtexture on friction and wear, lubrication and sealing, reduction of drag and noise, and hydrophobicity is summarized. The main problems and future development of surface microtexture technology are discussed. Conclusion: Different shapes of microtexture have different functions. The geometrical parameters of microtexture have a great influence on the surface properties. Therefore, the surface performance can be improved by designing the shape of the microtexture and optimizing the geometric parameters. In the future, more patents for surface microtexture will be invented and applied.

Background: Friction and wear of parts in the machine seriously affect the service life and efficiency of the machine. The friction and wear characteristics of parts are important for the mechanical industry. The mechanism of friction and wear is complex and wear have far lacked a systematic theory. The friction and wear characteristics of materials or parts must be tested through test. Thus, the friction and wear tester plays an important supporting role in tribological research. The function and accuracy of the testers are critical to its accuracy and efficiency. Objective: This study summarizes the current development status of friction and wear testers and explains the development trend of friction and wear testers. Methods: This article reviews various representative patents related to friction and wear tester. The friction and wear tester is classified. The characteristics of various detection methods are analyzed, the problems existing in the current development are summarized and analyzed. Results: The advantages and disadvantages of the related patents of the existing friction and wear tester are analyzed. It is found that there are major problems such as low detection accuracy, low efficiency and incomplete functions. The development trend of friction and wear tester is expected. Conclusion: The optimization and progress of the friction and wear tester is conducive to improve the wear resistance of the material, the service life of the parts and the working accuracy. In the future, more friction and wear testers will be invented.

Objective: In order to improve the friction-increasing and wear-reducing performance of the unfolding wheel surface, the surface microstructure of the unfolding wheel used in the detection of 8 kinds of steel balls was optimized by parameter matching. Method: Firstly, based on Hertz's theory, the contact area between steel balls of different sizes and the unfolding wheel are analyzed. The wear depth model is established based on Archard adhesive wear model. Secondly, the appropriate microstructure parameters for friction and wear experiments were selected. The finite element analysis software is used to simulate the stress on the surface of the microstructure unfolding wheel and calculate the wear depth. According to the experimental results, the relationship between friction coefficient, wear depth and microstructure parameters is obtained by data fitting, and the objective function of optimization design is established. Finally, based on the genetic algorithm DNSGA-II and Python, the parameters are optimized, and the optimal solution is obtained by using the TOPSIS method. Results: The feasibility of the simulation method is verified by friction and wear experiments, and the correctness of the optimization method is verified. Conclusion: The research shows that the optimal parameters matching of microstructure for steel ball diameters of Ф16.6688mm~Ф22.2250mm: the shape is rhombus; the area of a single pit is close to the contact area, which is 0.0319mm2 ~ 0.0554mm2; the pit depth is 145μm~150μm, and the surface density of microstructure is (5.4~5.6) /mm2.