Fe3O4@uio66 core-shell composite for detection of electrolyte leakage from lithium-ion batteries.

Fe3O4is an environmentally friendly gas sensing material with high response, but the cross-response to various analytes and poor thermal stability limit its practical applications. In this work, we prepared Fe3O4@uio66 core-shell composite via a facile method. The selective response to volatile organic compounds, especially to electrolyte vapors of lithium-ion batteries, as well as long-term stability of Fe3O4@uio66 has been dramatically enhanced compared to pure Fe3O4, due to the preconcentrator feature and thermal stability of the uio66 thin shell. Real-time detection of electrolyte leakage for an actual punctured lithium-ion battery was further demonstrated. The Fe3O4@uio66 sensor, after aging for 3 months, was able to detect the electrolyte leakage in 30 s, while the voltage of the punctured battery was maintained at the same level as that of a pristine battery over 6 h. This practical test results verified ability of the Fe3O4@uio66 sensor with long-term aging stability for hours of early safety warning of lithium-ion batteries.

Radio frequency pasteurization and heating uniformity of canned pineapple.

This research investigated heating uniformity and pasteurization of canned pineapple using radio frequency (RF) energy. Experiments were conducted in a 6 kW, 27.12 MHz pilot-scale RF system. Results showed that the temperature difference was more than 16°C, and the standard deviation was 4.38°C at the end of heating when using RF heating alone. Water bath-assisted RF (WRF) heating effectively improved the heating uniformity, the temperature difference was less than 7°C and the standard deviation was 2.52°C at the end of heating in the condition of electrode gap (210 mm), chord length of the fruit block (26 mm), and the initial temperature of sugar solution (80°C). When the total number of colonies reached 4-log reduction, water bath (WB) heating alone needed 660 s, and WRF heating needed 180 s. Vitamin C, hardness, and color of fruit blocks were well preserved using WRF heating compared with WB alone. PRACTICAL APPLICATION: This study shows that the pasteurization of canned food by radio frequency heating can achieve better food quality than the traditional pasteurization methods. Therefore, this research can promote the application of radio frequency heating technology in canned food pasteurization.

MOF-Derived Porous Hollow Co3O4@ZnO Cages for High-Performance MEMS Trimethylamine Sensors.

Trimethylamine (TMA) sensors based on metal oxide semiconductors (MOS) have drawn great attention for real-time seafood quality evaluation. However, poor selectivity and baseline drift limit the practical applications of MOS TMA sensors. Engineering core@shell heterojunction structures with accumulation and depletion layers formed at the interface is regarded as an appealing way for enhanced gas sensing performances. Herein, we design porous hollow Co3O4@ZnO cages via a facile ZIF-67@ZIF-8-derived approach for TMA sensors. These sensors demonstrate great TMA resistive sensing performance (linear response at moderate TMA concentrations (<33 ppm)), and a high sensitivity of ∼41 is observed when exposed to 33 ppm TMA, with a response/recovery time of only 3/2 s. This superior performance benefits from the Co3O4@ZnO porous hollow structure with maximum heterojunctions and high surface area. Furthermore, great capacitive TMA sensing with linear sensitivity over the full testing concentration range (0.33-66 ppm) and better baseline stability were investigated. A possible capacitive sensing mechanism of TMA polarization was proposed. For practical usage, a portable sensing prototype based on the Co3O4@ZnO sensor was fabricated, and its satisfactory sensing behavior further confirms the potential for real-time TMA detection.

The ß-modification of trizinc borate phosphate, Zn(3)(BO(3))(PO(4)).

Crystals of ß-Zn(3)(BO(3))(PO(4)) have been grown by the Kyropoulos method. The asymmetric unit contains three Zn sites, three B-atom sites (all with symmetry 3), two P sites (both with m symmetry) and nine O-atom sites (four with m symmetry). The fundamental building units of the title structure are isolated BO(3) triangles and PO(4) tetra-hedra, which are bridged by ZnO(4) tetra-hedra or ZnO(5) trigonal bipyramids through common O atoms, leading to a three-dimensional framework structure. Some significant structural differences between the ß-polymorph and the α-polymorph are discussed.

Enhanced performance of nano-Bi2WO6-graphene as pseudocapacitor electrodes by charge transfer channel.

The nano-Bi2WO6/reduced graphene oxide composite obtained by a simple hydrothermal reaction demonstrates a larger specific capacitance of 922 F/g at a charge and discharge currents of 3 A/g with longer cycle life. The As comparison, pristine Bi2WO6 nanoparticles have poor specific capacitance of 574 F/g at a charge and discharge currents of 2 A/g with weak cycle life. Though analyzing the Cyclic voltammetry curves, it is found that there are two oxidation reaction occurring in the materials: oxidation of Bi (III) to Bi (IV) and Bi (III) to Bi (V). The oxidation of Bi (III) to Bi (IV) is reversible while Bi (III) to Bi (V) will cause nonreversible destroy on structure. In this nano-Bi2WO6/reduced graphene oxide composite, graphene with well conductivity will enhance the electrically conducting as charge transfer channel, so that electrons will be transfer much faster in oxidation and most Bi (III) is oxidized to be Bi (IV) which ensure larger specific capacitance and long cycle life. This nano-Bi2WO6/reduced graphene oxide composite has application prospect in high-performance pseudo-capacitors.