Lithium-ion batteries have revolutionized mobile electronic technology and are being put into use in new energy equipment, but further improvements in life and electricity will require new technologies. One option is a lithium metal battery, which lasts longer and charges faster, but this technology has problems. Lithium deposits called dendrites tend to grow on the anode, potentially causing a short circuit, which can lead to battery failure, fire or explosion.
Now, researchers from the Institute of Chemistry of the Chinese Academy of Sciences, the University of the Chinese Academy of Sciences, and the China High-Pressure Science and Technology Research Center have designed a thin film separator based on carbon allotropes. Known as graphdiyne, it is used as a filter for lithium ions and prevents dendrite growth [Shang et al., Material. 10 (2018) 191-199].
Lithium metal batteries are similar in concept to lithium ion batteries, but rely on lithium metal anodes. During discharge, the lithium metal anode provides electrons to the cathode through an external circuit. However, during charging, lithium metal is deposited on the anode. It is during this process that undesirable dendrites can form.
This is where the separator membrane enters. Membrane separators made of ultra-thin (10 nm) graphidiyne (a two-dimensional hexagonal monolayer of carbon atoms bridged by butadiyne chains) have some remarkable properties. Graphene diacetylene not only has elasticity and firmness at the same time, its chemical structure also forms a uniform porous network, so that each hole allows only one lithium ion to pass through. This regulates the movement of ions through the membrane, making the diffusion of ions highly uniform. It is important that this characteristic of the battery effectively suppresses the growth of lithium dendrites.
Li Yuliang, from the Institute of Chemistry of the Chinese Academy of Sciences, who led the study, explained: "Inhibiting lithium dendrites can stabilize the solid electrolyte interface, thereby improving the life of the device and the Coulomb efficiency." It can avoid dendritic short circuits, thereby improving battery safety .
The researchers believe that graphitic diacetylene films can overcome some of the tough problems currently faced by lithium and other alkaline metal batteries.
"Graphite diacetylene is an ideal material with a super-conjugated structure, inherent band gap, natural macropore structure and semiconductor properties, which shows great prospects for solving major scientific problems in this field," Li said.
Two-dimensional materials are also simple under ordinary laboratory conditions and easy to produce.
"Although more efforts are needed to improve the quality of large-scale graphite diacetylene membranes, we believe that graphite diacetylene may bring some major breakthroughs in the safety of lithium batteries," the researchers told reporters.
Reflective warning`s reflection part of the vest is the use of lattice micro-rhombus type refraction and high refractive index of glass beads back to the principle of reflection, through the post-processing of advanced processing technology made. It can reflect the distant light back to the light. Both in the day or night have a good retroreflective optical performance. Especially at night, it can play the same high visibility as the day. The use of this high-energy reflective material made of safety clothing, whether the wearer is in the distance, or in the light or scattered light interference, it can be relatively easy to be found by the night driver.
Reflective warning vests are made of high-visibility reflective material It can make the traffic police work smoothly in the night or special weather in order to reduce the rate of the casualties. it plays a special role in security especially in traffic engineering.When the motor vehicle fails, the driver needs to wear a reflective warning vest, and away from the faulty vehicle to prevent the occurrence of secondary accidents. This kind of reflective warning vest is mainly applicable to police, road officials, traffic commanders, road maintenance personnel, motorists, motorcycles and bicycles drivers, dark light workers and so on in one word, the local worker who needs to use light warning. Widely used in traffic engineering, shipbuilding industry, steel industry, machinery industry, oil industry, ambulance, parking lot, airport, traffic police and outdoor work or construction, plays an important role in good security warning .
When Car Reflective Vest use the aluminum lattice reflective material, not only in a small angle (from the reflective warning vest wearer far away), reflective brightness is high, even at a large angle (from the reflective warning vest wearer closer ), it still has a good reflective brightness, so that the locomotive driver earlier identified roadside vehicle side of the staff, as soon as possible to respond to effectively prevent the occurrence of secondary accidents.
According to reflective vest`s wearing [far distance discovers, near distance recognise" s character. It balances the big and small angle of optical performance. It has a large reflection angle.
Knitting Reflective Garments Series,Knitting Reflective Garments,High Visibility Reflective Knitting Vest,Reflective High Visibility Polo Shirt
Daoming Optics & Chemical Co., Ltd , https://www.reflectives.nl