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

Abstract

Low\npower density limits the prospects of lithium-ion batteries\nin practical applications. In order to improve the power density,\nit is very important to optimize the structural alignment of electrode\nmaterials. Here, we study the alignment of the graphite flakes by\nusing a magnetic field and investigate the impact of the preparation\nconditions on the degree of alignment. It is found that the higher\ndegree of alignment brings about the shorter Li⁺ transmission\npaths and facilitates Li⁺ diffusion in the path, which\nleads to the greater rate performance of lithium-ion batteries. The\nspecific capacity of vertically aligned electrodes with a loading\nof 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.\nIn addition, we obtain a quantitative relationship between the specific\ncapacity at 2C and the angle of alignment, i.e., the specific capacity\nincreases by 0.58 mAh g^–1 when the angle increases\nby 1°. This study not only can help us understand the mechanism\nof magnetic alignment technology but also provides a reliable experimental\nbasis for the application of magnetic alignment technology as a universal\napproach for constructing the structure of various electrode materials.