"Pod" composites extend the life of lithium-ion batteries

Lithium-ion batteries are the most widely used batteries in daily life, but they have shortcomings in short life due to various reasons. The problem of electrode degradation is most troublesome for scientists. This is because during the continuous discharge and charging process, the lithium ions in the battery will repeatedly react with the metal electrode, and the long-term accumulation will lead to the gradual degradation of the electrode, which will eventually have an irreversible effect on the battery performance. According to the American Physicist Network, scientists at the Chemical Engineering Institute of the A-STAR Institute in Singapore have developed a new technology that can reduce electrode degradation, which can extend the life and capacity retention of lithium-ion batteries.

The technique uses a composite of pea pod structures consisting of cobalt oxide (cobalt trioxide) nanoparticles (similar to peas in pea pods) and nano carbon fibers (similar to shells covered in peas). The cobalt oxide nanoparticles act as an active material to store lithium ions, and the surrounding hollow carbon fibers can protect the cobalt oxide particles from breaking. In addition, these carbon fibers also play the role of conducting electrons from nanoparticles.

Cobalt oxide is considered to be a highly promising anode material due to its stronger ion adsorption and retention capabilities compared to conventional anode materials such as tin. In addition, cobalt oxide can be readily converted to lithium cobalt oxide, a cathode material that has entered commercial applications.

To make this pod structure material, the researchers first heated the crude cobalt carbonate to which the polymeric glucose was attached at a temperature of 700 ° C in a confined space filled with inert gas, and then placed it in the air at 250 ° C. The temperature is heated. Electron scanning microscopy shows that the composite material of this structure is very neat in structure, and its length is a few micrometers, and the diameter is generally about 50 nanometers.

The electrode made of the pea pod structure composite material can significantly improve the battery capacity and the storage capacity of the lithium ion battery. It is found that the battery made by the battery has a capacity of 91% after 50 charge and discharge cycles.

The researchers said that in addition to the application prospects in the field of lithium-ion batteries, this pod composite is an achievement in itself, because this technology is the first to realize the magnetic nanoparticles embedded in hollow carbon fibers. This "nanoparticle capsule" technology can be extended to many fields, such as genetic engineering, catalysis, gas detection, capacitors and magnetic materials manufacturing.

Editor-in-chief

Lithium-ion batteries are much better than nickel-hydrogen batteries in many properties such as energy density, but the lifespan is a short-sighted one. After less than 1000 charge and discharge, the lithium-ion battery usually does not stand up. Therefore, Singapore researchers have developed this "pea pod", which is both a icing on the cake and a charcoal in the snow. By the way, many people were told when they bought their mobile phones that their lithium-ion batteries had to be “charged for more than 12 hours in the first three times” and “every time they used electricity”, which was purely embarrassing. In fact, overcharging or over-discharging can not only make it prolong life, but it can cause fatal injuries.