Charging lithium battery anode material expansion is difficult to overcome the new method of the United States and China R & D team

　　Author ：Iflowpower – Portable Power Station Supplier

According to foreign media reports, since silicon has a high energy density, it has become an extremely attractive lithium-ion battery anode material. However, in the charging period, the expansion shrinkage can reach 300% when the silicon in the cell is interacting with lithium. And over time, it will significantly reduce the performance, short circuit of the battery, and ultimately lead to battery scrap.

In order to improve the above disadvantages and generally maintain the energy density of the battery, the anode of a lithium-ion battery is currently employed using a silicon monoxide (SiOx, X≈1). The application of silicon-based oxide anode is highly high, and the cycle performance is also improved. However, the material still does not prevent volume changes, and weak conductivity is weak.

A large number of research work has been carried out to deal with the above technical problems. Today, the research team in my country and the United States has published research results and found two new improvement methods. The research results of the US team: Non-adhesive silica oxide / carbon complex Kentucky University (UNIVERSITYE) research team After mixing silicon-based oxide particles and kraftlignin, synthesizing a high performance non-bonded Silicon-based oxide / carbon complex (Binder-freesiox / c) for making electrodes of lithium ion batteries.

After heat treatment, the lignin forms a conductive body (ConductiveMatrix), which can accommodate a large number of silicon-based oxide particles to ensure electronicconductivity, connectivity, and adapt to the lithiation / deodentation reaction during the lithiation / Delithiation. Volume change. This material does not need to use conventional binders or conductors.

The performance of the electrode made of the composite material is extremely excellent. Compared with the relatively small silicon-based oxide electrode (160%) of the volume change rate, the mechanical electrochemical properties are excellent, the ferbonmatrix is ​​large, and can be adapted to volume changes. The results of our team research: Micro SiOx / C Cabens (Core-Shell) Composite my country's research team developed an efficient solution to prepare a micro SiOx / C core shell complex.

The study group mixed citricacid and a ball milling silicon-based oxide made it carbon, followed by a textured SiOx / C-core shell complex - SiOx micro core and citrate carbon CONFORMALCARBONSHELL. The carbon shell has greatly increased the electrical conductivity of silicon-based oxides, and the volume change in adaptation to the lithiuming / deod lithium reaction. The electrodes made by the SiOx / C complex are 1296.

3mAh / g, and COMBICEFFICIENCY is as high as 99.8%, and the capacity retention rate is 65.1% (843.

5mAh / g) after the charge and discharge is 200 times. According to the research team, the discharge efficiency of the complex is extremely excellent. The method can achieve mass production, cost-effective, can produce high-performance anode materials made from SiOx / C complex composites.