M. Mahallati, M. Khosravi,
Volume 39, Issue 2 (8-2020)
In this research, using phenolic resin as the precursor of carbon and various amounts of ethylene glycol as a pore former, porous samples of hard carbon were synthesized. Samples were characterized by x-ray diffraction (XRD) and N2 adsorption-desorption methods. Broad diffraction peaks represent the amorphous structure of samples. Moreover, the gas adsorption-desorption curves showed that the adsorption isotherms of samples were of type IV and all samples had meso-micro porous structure. Charge-discharge tests were performed on samples to obtain their capacities. The sample with higher capacity, broader XRD pattern and appropriate porosity, was selected for silicon incorporation. Silicon nanoparticles were obtained by mechanical milling of its micro particles. According to XRD patterns, silicon nanoparticles had a crystalline structure. Field emission scanning electron microscopy (FESEM) images approved uniform distribution of nanoparticles. XRD patterns of nanocomposites evidenced the existence of hard carbon and silicon. The electrochemical test results showed that the capacity, coulombic efficiency and cycle life of nanocomposites were improved by increasing the amount of silicon.
