Effect of Lamellar Graphite on Electrochemical Properties of Silicon Anodes for Lithium Ion Batteries

Silicon particles are easy to agglomerate in the process of fabricating carbon coatings through pyrolysis of carbon precursor at high temperature. In this article, lamellar graphite coatings cover surface of silicon electrodes without the process of pyrolysis. Morphology for lamellar graphite and graphite coatings has been characterized. Effect of graphite coatings on electrochemical properties for silicon electrodes has been studied. Results show that lamellar graphite consists of flakes with high degree of crystalline and low density for defects. Graphite coatings with thickness of 8 and 16 μm have covered surface of silicon electrodes with silicon loading density above 1 mg cm −2 . Silicon particles in graphite‐coated electrodes possess higher electrochemical reactivity than those in silicon–graphite mixture electrodes. Graphite coating with thickness of 16 μm enhances initial coulombic efficiency from 60.3% to 74.2%. After 100 cycles, silicon electrodes with 16 μm graphite coating provide capacity of 581 mAh g −1 and possess better cycling stability than those with 8 μm graphite coating.