A novel PPESK fibrous membrane separator based on electrospinning technique for lithium-ion battery
In order to improve the low porosity, poor thermal stability and insufficient electrolyte wettability of commercial polyolefin separator, the novel PPESK fibrous membrane separator has been fabricated via electrospinning for the use of lithium-ion batteries. By the use of high-speed collection drum, the tensile strength of the electrospinning oriented PPESK fiber membranes increase significantly and reaches 18.9 MPa. Hot oven testing shows that oriented PPESK fiber membranes are thermally size stable at a high temperature of 220 °C. The oriented PPESK fiber membrane exhibits high level of porosity (83%) and excellent electrolyte uptake (720%). Moreover, the ionic conductivity increases to 1.85 mS cm -1 compared with the 0.41mS cm -1 of commercial Celgard 2400 separator. In addition, the lithium-ion battery assembled with electrospinning oriented PPESK fiber membrane shows high capacity retention, stable cycle performance and excellent rate capability. Therefore, the electrospinning oriented PPESK fiber membrane is likely to be a promising candidate of high-power lithium-ion battery owing to its comprehensive outstanding characteristics.
Membranes
This review evaluates the characteristics and advantages of employing polymer electrolytes in lithium/sulfur (Li/S) batteries. The main highlights of this study constitute detailed information on the advanced developments for solid polymer electrolytes and gel polymer electrolytes, used in the lithium/sulfur battery. This includes an in-depth analysis conducted on the preparation and electrochemical characteristics of the Li/S batteries based on these polymer electrolytes.
A New Vacuum Pressure Infiltration CFRP Method and Preparation Experimental Study of Composite
In order to prepare a carbon-fiber-reinforced polymer composite (CFRP) with ideal microstructure and properties, a new vacuum pressure infiltration CFRP method is proposed based on an analysis of existing CFRP preparation process methods. Research on composite material preparation systems was carried out by using this new method principle. The system mainly includes a fiber pre-forming module, a vacuum heating infiltration module, a hot-press curing molding module, and a data acquisition control module. Under the conditions of natural curing at 0 MPa + 6 h + 25 °C, vacuum heating curing at –0.05 MPa + 30 min + 80 °C, and hot-press curing at 0.7 MPa + 5 min + 50 °C, a two-dimensional (2D) CFRP with excellent microstructure and properties was successfully prepared. Observing the microstructure of the prepared composite material, it can be found that the inside of the composite material was sufficiently and uniformly infiltrated, and common preparation defects such as holes and delamination were effectively controlled. Through the performance test, the bending strength of the material reached 790 MPa.