The application status and development direction of graphite in lithium batteries
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Update time : 2021-11-19 14:14:34
Graphite: ideal anode material Natural graphite is made of carbonaceous material of organic origin under high temperature. It is steel gray and black gray with semi-metallic luster. The crystal structure belongs to the hexagonal crystal system. It has a hexagonal layered structure and has high temperature resistance, heat conduction and electrical conductivity. , Lubrication, plasticity and corrosion resistance.
Graphite is an earlier negative electrode material. Compared with other carbon materials, its conductivity and crystallinity are higher, and its good layered structure and charge-discharge voltage are also very suitable for the de-embedding movement of the positive electrode material, and the current technology is mature, The cost is low, and it is an ideal negative electrode material.
Modification: Optimize the performance of anode materials
Graphite negative electrodes generally use natural flake graphite, but there are several shortcomings:
(1) The flake graphite powder has a large specific surface area, which has a greater impact on the first charge and discharge efficiency of the negative electrode; (2) The layer structure of graphite determines that Li+ can only be embedded from the end surface of the material and gradually diffuse into the particles. Due to the anisotropy of flake graphite, the Li+ diffusion path is long and uneven, resulting in a low specific capacity; (3) The layer spacing of graphite is small, which increases the diffusion resistance of Li+, and the rate performance is poor. Li+ is easy to deposit and form lithium dendrites on the graphite surface during fast charging, which causes serious safety hazards.
In order to solve these problems, natural graphite can be modified by technologies such as particle spheroidization, surface oxidation, surface fluorination, surface coating with soft carbon, hard carbon materials, and other methods of surface modification and microstructure adjustment. From the comprehensive consideration of cost and performance, the current industrial graphite modification mainly uses carbon coating process. The commercial application of modified natural graphite has a specific capacity of 340-370 mA•h/g, a coulombic efficiency of 90%-93% in the first week, and a 100% DOD cycle life of more than 1,000 times, which can basically meet the needs of small consumer electronics products. Battery performance requirements.
Innovation: tap the potential of graphite applications
With the rapid development of new energy vehicles, 3C and other industries, people are successively aiming at the new technological direction of lithium-ion batteries, pursuing higher performance such as high energy density, high power density and longer life. This puts a higher level of graphite anode Require.
Graphite concentrate can be further processed to obtain graphite products, such as graphene, spheroidized graphite, expandable graphite, flexible graphite, fluorinated graphite, nuclear graphite, silicon-impregnated graphite and other high-end products. The development and utilization of these high-end products will raise the application of graphite in lithium batteries to a new level. For example, graphene has excellent conductivity and can alleviate the volume expansion of electrode materials, thereby greatly improving the performance of power batteries. Therefore, graphene is widely used in lithium-ion batteries' positive electrodes, negative electrodes, current collectors, separators, conductive additives, etc. , The future market prospects are particularly broad, and it is the focus of current research. Spherical graphite has the characteristics of good electrical conductivity, high crystallinity, low cost, high theoretical lithium insertion capacity, low charge and discharge potential and flatness. It is a replacement product for negative electrode materials used in the production of lithium-ion batteries at home and abroad.
Luoyang Trunnano Tech Co., Ltd (TRUNNANO) is a professional graphite powder supplier with over 12 years experience in chemical products research and development. We accept payment via Credit Card, T/T, West Union and Paypal. Trunnano will ship the goods to customers overseas through FedEx, DHL, by air, or by sea.
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