HC Chemical Network News: Lithium-ion battery as a high energy density energy storage device is widely used in mobile phones, laptops and other portable electronic products. Lithium-ion batteries are the main source of power for the electric cars that attract attention today. This places more stringent requirements on the performance of lithium-ion batteries: higher energy density, longer service life, and wider operating temperature window. The current commercial lithium-ion battery anode material graphite, due to its low theoretical capacity (~370mAh/g) is difficult to meet these requirements. Therefore, scientific researchers in the corresponding fields in various countries around the world are looking for the next generation of lithium ion battery anode materials.
To address this issue, recently led by Professor Wang Donghai of The Pennsylvania State University in the United States, a new lithium-ion battery anode material was invented by a scientific research team led by Yu Zhaoxin and Song Jiangjiang: 'Red Phosphorus-Graphene' nanocomposite. material. The material was prepared by ball milling of red phosphorus and graphite. Red phosphorus is chemically stable, inexpensive and readily available, and environmentally friendly. Its theoretical capacity as a lithium-ion battery anode material can reach 2600mAh/g, 7 times that of commercial graphite electrodes. Graphene/graphene is introduced into the system due to its extremely high electronic conductivity to increase the electronic conductivity of the nanocomposite as a whole. In the high-speed ball milling process, micron-sized red phosphorus particles are broken to the nanoscale. Graphite is peeled off as a large specific surface area of graphene during the ball milling process. After a long period of mechanical force, graphene overlaps with each other to form a tightly coupled three-dimensional conductive network, and nano-sized red phosphorus particles are uniformly dispersed in the network. Infrared Spectroscopy (Infrared Spectroscopy) tests have shown that red phosphorus and graphene are combined in the form of a 'phosphor-oxygen-carbon (P-O-C)' chemical bond, which in turn provides a guarantee of superior battery performance. At room temperature, the discharge capacity of the nano-composite can reach 1400 mAh/g, which is four times that of current commercial lithium-ion battery cathode materials. After 300 cycles, the discharge capacity can still be maintained above 60%. The high temperature environment (60°C) is still a great challenge for current commercial lithium-ion batteries. With this material, the discharge capacity can be further increased to 1650 mAh/g at 60°C. After 200 cycles, the discharge capacity retention rate can be over 70%.
High-capacity, long-life, low-cost raw materials, and synthetic methods suitable for industrial production all contribute to the selection of new 'red phosphorus-graphene' nanocomposites as next-generation anode materials for lithium-ion batteries.
