Electrochemical behavior of negative electrode from Co(OH)2 and graphene for lithium batteries

A negative material for lithium-ion batteries was prepared from graphene and cobalt hydroxide with different ratios by hydrothermal reaction. The crystal structure and crystalline phases of pure Co-hydroxide and 4Co-hydroxide:1 graphene were identified by X-ray diffraction (XRD). The functional groups and structure analysis of Co(OH)(2) with graphene were characterized by Fourier transmission infrared (FTIR) spectra and X-ray photoemission spectroscopy (XPS). The surface morphology was studied with field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The cycle life of the cells was carried out with potential windows between 0.01 and 3 V vs. Li/Li+ using a current density of 0.1 C. Furthermore, electrochemical impedance spectra (EIS) measurements were applied. The obtained diffusion coefficient (1.62 x 10(-17) m(2) s(-1)) for the Li/4Co(OH)(2)-1G cell explains the higher mobility of Li+ ion diffusion than that of the other cells. The specific discharge capacity of 4Co(OH)(2)-1G cell delivered about 690 Ah kg(-1) up to more than 100 cycles. Also, this cell has a higher specific discharge capacity rather than the other cells.

Automated summary

A negative material for lithium-ion batteries was prepared by hydrothermal reaction using graphene and cobalt hydroxide with different ratios. The material's crystal structure, functional groups, and morphology were analyzed through various techniques. The obtained 4Co(OH)2-1G cell showed a high specific discharge capacity and improved lithium ion diffusion mobility.