Research progress of lithium rich manganese based cathode materials
Recently, the relevant research team of Ningbo Institute of materials, Chinese Academy of Sciences said that it has made some progress in the research field of lithium rich manganese based cathode materials. The specific discharge capacity of lithium rich manganese based cathode materials is as high as 300mAh / g, which is about twice the specific discharge capacity of current commercial cathode materials such as lithium iron phosphate and ternary materials. Some people in the industry believe that lithium rich manganese based cathode materials are ideal for the new generation of high energy density power lithium battery cathode materials. Lithium rich manganese based materials have the advantages of low cost, high capacity, non-toxic and safe, and can meet the application requirements of lithium batteries in small electronic products, electric vehicles and other fields.
Although lithium rich manganese based cathode materials have high discharge specific capacity? However, in order to apply it to power lithium batteries, we must also solve the disadvantages of low coulomb efficiency, poor cycle life and low rate performance of lithium rich manganese based batteries. Recently, the research team has improved the first charge discharge efficiency and rate performance of lithium rich manganese based cathode materials by improving the activity of lattice oxygen, which provides a new idea for the modification research of the materials. At present, the research team is promoting the pilot development of lithium rich manganese based cathode materials.
Cotton can also be used as material?
Yes, natural cotton can also be used as battery raw material. The advanced carbon materials research department of China Academy of metal science recently said that the hollow carbon fiber foam with high conductivity was prepared by natural carbonization as precursor and high temperature carbonization. Finally, the three-dimensional hollow carbon fiber foam sulfur positive electrode with sulfur density of up to 21.2 mg /cm2 was obtained.
It is understood that lithium sulfur battery is regarded as one of the most promising next-generation high-energy electrochemical energy storage systems. However, in the process of charge and discharge, lithium sulfur battery based on multi electron reaction will produce "shuttle effect", resulting in irreversible capacity loss, which seriously restricts the practical process of lithium sulfur battery. The lithium sulfur battery using three-dimensional hollow carbon fiber foam sulfur as the positive electrode can effectively inhibit the shuttle effect, thus ensuring the good cycle stability of the lithium sulfur battery. The composite electrode can achieve 70% capacity retention rate after 150 cycles.
This study not only shows the method of preparing high conductivity carbon materials with natural materials as raw materials, but also puts forward a new idea of inhibiting the "shuttle effect" of lithium sulfur battery, which opens up a new way for the development of lithium sulfur battery with high performance and high surface capacity.
Find a breakthrough in replacing "lithium" with "magnesium" electrolyte
According to foreign media reports, Toyota Motor Company is studying to replace the lithium electrolyte used in lithium-ion batteries with magnesium electrolyte. Toyota believes that magnesium has two advantages over lithium: first, magnesium allows intensive energy storage; In addition, lithium is an unstable metal element, which is easy to cause fire, and magnesium is relatively safer. Researchers at Toyota North America Research Institute said they had found a way to make magnesium electrolyte by using the materials used in hydrogen storage. Toyota says it may take 20 years to put the technology into large-scale use.
New additives improve battery capacity
Like Toyota, Nissan is also looking for ways to improve the performance of electric vehicle batteries. Nissan's technical means is to add an additive called "amorphous silicon oxide" into the battery to improve the capacity of lithium-ion batteries. This chemical can make the battery retain more lithium ions, so as to improve the overall performance of the battery. This technology opens the door to using new chemical elements to make electric vehicle batteries with longer endurance.
Graphene material with high hopes
Graphene, as a new nano material with the thinnest, strongest strength and strongest conductivity, is called "black gold", and scientists even say it will "completely change the 21st century". If graphene material can be successfully applied in lithium-ion battery, it can greatly improve the charging and discharging speed of lithium-ion battery, achieve a great breakthrough in battery technology, and promote the leap forward development of new energy industry.
Recently, the first graphene based lithium ion battery product was released in Beijing. This graphene based lithium-ion battery named "alkene king" has excellent performance and can work at - 30 ℃ - 80 ℃. The battery cycle life is about 3500 times and the charging efficiency is 24 times that of ordinary charging products.
This is not the first graphene battery successfully developed. Chaowei group, Haibao special power supply Co., Ltd. and other enterprises have respectively promoted relevant R & D, applied graphene to lead-acid batteries, and greatly improved the battery capacity.
Ubiquitous Nanotechnology
Nanotechnology is also widely used in the research and development of new battery materials.
Stanford Professor Cui Yi is committed to combining nanotechnology with batteries, and has developed a series of battery nanotechnology, including the research on silicon nanowires replacing graphite cathode, New York shell nanostructure cathode, metal lithium cathode, sulfur cathode and so on.
Japanese researchers also announced that they have developed a spongy carbon material with a large number of nano pores by a simple method. The surface area of this carbon material is much larger than that of graphite of the same weight. If it is used to make the electrode of battery, the battery capacity can become larger.
