Construction Of Porous Structures Research Articles

Facilely construction of multistage channel in PVDF-HFP for high ionic conductivity and prominent anti-lithium dendrites

Safety concerns such as lithium dendrite growth, leakage and volatilization regularly plague conventional liquid lithium metal batteries. However, solid polymer electrolytes can mitigate these issues due to their chemical and electrochemical stability. In this paper, we show that the construction of porous structures gives PVDF-HFP based polymers excellent solution retention, quick Li+ transport channels, and ultra-long Li-symmetric cycle stability. PVDF-HFP based electrolyte membrane with porous structure exhibits excellent electrolyte retention (129.5 %) and superior ionic conductivity (2.4 × 10-3 S cm−1 at 20 ℃). In addition, Lithium-symmetric half battery uses the DPH250 porous electrolyte film to stably last more than 2000 h during the lithium plating/stripping process. DI regulation of PVDF-HFP electrolyte membrane is beneficial to achieve uniform lithium deposition, and better solve the interface problems existing in solid state batteries. LiFePO4/DPH250-LiPF6/Li batteries exhibit stable cycling performance and reversible specific discharge capacity, suggesting a potential strategy for stabilizing lithium metal batteries.

Cu/Nb2O5 composite aerogel for CO2 hydrogenation to methanol: Construction of porous structure and abundant active interfaces

Catalytic conversion of CO2 offers a promising method to mitigate the green-house gas and recycle CO2 into value-added chemicals. Cu-based aerogels hold the potential as high-performance catalysts due to the three-dimensional morphology, high porosity, and self-supporting skeletons. Herein, we successfully applied Cu/Nb2O5 composite aerogel into CO2 hydrogenation, which achieved high production rate and selectivity towards methanol. Further mechanism study demonstrated that abundant interfaces between Cu and Nb2O5 were formed throughout the porous networks of Cu/Nb2O5 aerogel, acting as the active sites for the adsorption, activation, and selective conversion of CO2. Besides, the production of methanol was via the formate pathway over Cu/Nb2O5. This work opens up an appealing approach for the design of efficient catalysts with rich active sites for hydrogenation of CO2.

Fundamental Understanding and Facing Challenges in Structural Design of Porous Si‐Based Anodes for Lithium‐Ion Batteries

AbstractAs one of the most electrochemical energy storage devices, lithium‐ion batteries (LIBs) remain the workhorse of the energy market due to their unparalleled advantages. Remarkably, Si‐based materials play a pivotal role in LIBs anodes owing to ultrahigh theoretical capacity of Si and rich natural resources. However, bulk silicon materials are difficult to meet the current commercial demand because of their low conductivity, sluggish reaction kinetics, and huge volume expansion. The construction of porous structures has been acknowledged as an effective way to solve the above issues. Herein, the delicate design of porous Si‐based anode materials including synthetic strategies, the engineering of surface morphology and micro/nano‐structure, and the regulation of different compositions, as well as their applications in LIBs is systematically summarized. Particularly, the fine engineering of different pore parameters for Si‐based materials is on focus. Importantly, the relationship between thick electrodes and tortuosity/porosity, and the structural effect between pores and battery performance are also discussed in depth. Finally, the applications of porous Si‐based anodes in full‐cells and their commercial achievements are briefly described. This review is expected to provide a basic understanding and deep insight into developing porous Si‐based anodes for high‐energy lithium storage.

Preparation of hollow bidirectional porous 3D peony-flower structure ZnCO3/ZnO with gas sensitive properties at room temperature

ZnO is the most common gas sensitive material, but it can only respond at high temperature for its extremely high initial resistance, and its recovery time is often longer. The construction of porous structure can improve the gas adsorption capacity, and electrolyte doping can reduce the initial resistance and recovery time. In this study, the Zn5(OH)6(CO3)2 precursor was prepared and then calcined to prepare the 3D hollow peony flower-like ZnCO3/ZnO nanocomposites with vertical and parallel bidirectional pores. The bidirectional porous structure increased the specific surface areas to 350.280 m2·g−1. For 100 ppm NOx (NO2: NO=17:5) gas detection, the electrolyte (ZnCO3) doping decreased the recovery time to 15 s at room temperature (25 ℃), and its gas response reached to 159 at room temperature and 233 at 45 ℃. Due to electrolyte doping, the gas-sensitive property was sharply increased, and the recovery time was much shorter than the response time, both them were much very rare. The excellent and unique gas sensitivity could be attributed to the larger specific surface area, flower-like porous structure and the ionic lattice field interactions.

Efficient removal of formaldehyde by diatomite decorated with BiOCl/TiO2 under visible-light irradiation: Effects of key preparation parameters

The diatomite decorated with BiOCl/TiO2 (BiOCl/TiO2@diatomite) composites were prepared by supporting BiOCl/TiO2 heterogeneous junction on the surface of diatomite with precipitation-calcination method. This work systematically studied the effects of terminal pH, calcination temperature, and TiO2/BiOCl ratio. Furthermore, the relationship between structure and photocatalytic performance of the composite was investigated. The results demonstrated that composite with optimized performance (84.1% formaldehyde degradation rate of 1.0 g photocatalyst) can be obtained at terminal pH of 6, calcination temperature of 500 °C, and TiO2/BiOCl ratio of 55/45. It is indicated that the phase structure, grain size, and porous structure can be significantly affected by the above preparation parameters. In conclusion, the formaldehyde adsorption and degradation properties can be enhanced by the construction of porous structure and heterogeneous junction of composites. Overall, BiOCl/TiO2@diatomite composites exhibited excellent formaldehyde degradation performance under visible light due to the multi-layer structure and the combination of TiO2 and BiOCl on the surface of diatomite.

Design and Construction of Porous Structures in PVDF Membranes in Phase Separation Processes

In this article, the morphologies of membranes formed by three different systems, i.e. favorable diluent/unfavorable diluent/PVDF system, water-soluble solvent/ unfavorable diluent/PVDF system, and favorable diluent/unfavorable diluent/water-soluble polymer/PVDF system, were characterized, and the relationship between porous membrane morphology and the components of favorable diluent/unfavorable diluent and water-soluble solvent/unfavorable diluent in the system was investigated. The transformation from mesopores to bicontinuous porous structures, from finger-shaped pores to bicontinuous porous structures was realized, and meanwhile PVDF microporous membranes with microfiber-shaped porous structures were manufactured.