Magnetic Field Regulating the Graphite Electrode for Excellent Lithium-Ion Batteries Performance

Low power density limits the prospects of lithium-ion batteries in practical applications. In order to improve the power density, it is very important to optimize the structural alignment of electrode materials. Here, we study the alignment of the graphite flakes by using a magnetic field and investigate the impact of the preparation conditions on the degree of alignment. It is found that the higher degree of alignment brings about the shorter Li+ transmission paths and facilitates Li+ diffusion in the path, which leads to the greater rate performance of lithium-ion batteries. The specific capacity of vertically aligned electrodes with a loading of 8.9 mg cm(-2) can reach 59.1 mAh g(-1) at 2C, which is 4.5 times higher than that of reference electrode. In addition, we obtain a quantitative relationship between the specific capacity at 2C and the angle of alignment, i.e., the specific capacity increases by 0.58 mAh g(-1) when the angle increases by 1 degrees. This study not only can help us understand the mechanism of magnetic alignment technology but also provides a reliable experimental basis for the application of magnetic alignment technology as a universal approach for constructing the structure of various electrode materials.