An electrochemical route to exfoliate vein graphite into graphene with black tea

Abstract

The study is focused on exfoliating vein graphite into graphene using an unsophisticated and low-cost process through a non-oxidative production route. High-quality graphene production with low-cost methods that give high yields and suitable for large-scale production, using vein graphite is a challenge to address, though there are many methods for graphene production. Vein graphite directly received from the mining site was electrochemically exfoliated to small particles which were further exfoliated by ultrasonic vibration. In addition, commonly used highly toxic, expensive solvents were substituted by inexpensive and nontoxic aqueous black tea solution, in the exfoliation by ultrasonic vibration process. Four different tea types were used to compare the quality and quantity of yields. Ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction and Raman spectroscopy were utilized for the characterization, and the study uncovers a low-cost, nontoxic, promising and nonoxidative route to exfoliate vein graphite into either single or double-layer graphene. The study uncovers that the four different tea types tested can be used to successfully exfoliate graphite. The suitability of the exfoliated graphene for applications was checked by utilizing them to prepare electrochemical double layer supercapacitors (EDLC). Electrochemical properties of fabricated EDLC were investigated by cyclic voltammetry (CV) and Galvanostatic charge-discharge curves (GCD). Graphene based EDLC exhibited energy density of 0.385 W h kg−1 and a power density of 17.3 W kg−1 for the 0.01 V s−1 scan rate.