US invented new carbon fiber lithium-air battery energy density greatly improved

According to reports of the American Physicist Organization Network, American scientists have developed a new type of carbon fiber lithium-air battery whose energy density is now four times more widely used in mobile phones and rechargeable lithium-ion batteries in automobiles. The study was published in the latest issue. Energy and Environmental Science magazine.

Last year, a scientific team led by Yang Shaohong, a professor at the Massachusetts Institute of Technology (MIT) Department of Mechanical Engineering and Materials Science and Engineering, improved the energy density of lithium-air batteries by using rare metal crystals. In theory, lithium-air batteries have a higher energy density than lithium-ion batteries because they replace bulky solid-state electrodes with a porous carbon electrode that can store energy by trapping oxygen from the air passing over it. Oxygen and lithium ions combine to form lithium oxide.

The latest research has taken a step forward and the carbon fiber electrodes produced have more pores than other carbon electrodes. Therefore, when the battery is discharged, there are more pores to store solid lithium oxide.

Robert Mitchell, a co-author of the paper and a graduate student in MIT's Department of Materials Science and Engineering, said: “We used chemical vapor deposition to plant vertically aligned arrays of carbon nanofibers. These blanket-like arrays are high in conductivity and low in density. The energy storage 'bracket'."

Another researcher, Bert Galant, a graduate student at MIT's Mechanical Engineering Department, explained that during the discharge process, particles will appear on carbon fibers, and carbon will increase the weight of the battery, thus minimizing the amount of carbon. It is very important to leave enough space for ****. **** is the active chemical substance formed during the discharge of lithium-air batteries. Yang Shaohong said: “Our new blanket-like material has more than 90% of the pore space, and its energy density is four times that of a lithium-ion battery of the same weight. Last year we have demonstrated that carbon particles can be used as lithium. Air batteries make effective electrodes, but then the carbon structure had only 70% of the pore space.”

Scientists pointed out that because the arrangement of carbon-carbon electrode carbon particles is very orderly, and the carbon particles in other electrodes are very confusing, it is easier to observe the behavior of this electrode in the charging state by using a scanning electron microscope. Helping them to improve the performance of the battery also helps explain why the existing system will experience a decrease in performance after multiple charge and discharge cycles. However, the commercialization of this carbon fiber lithium air battery needs further study.