Characterization of high-temperature heat-treated bamboo-based white charcoals for lithium ion battery electrode

Abstract

Bamboo charcoal has high ecological and economic value, and is a sustainable and valuable resource for the development of advanced materials such as supercapacitors and batteries. The carbon content in bamboo-based white charcoal produced in traditional Korean kiln reaches 100% when the charcoals heat treated up to 2400℃. X-ray diffraction shows that graphite begins to form at 1500℃, becomes more pronounced at 1800℃, and crystallizes into a dense turbostratic structure at 2000℃. At 2400℃, discrete graphite peaks are confirmed in d002 and d100 planes, while carbon isotope peaks disappear. Raman spectroscopy shows that graphite crystals form at 1800℃, as indicated by a clear 2D band at 2680 cm⁻¹. At 2400℃, the height of the D band at 1350 cm⁻¹ is lower than that of the G band at 1580 cm⁻¹, indicating a high degree of graphitization. The isothermal nitrogen adsorption–desorption curves show that the monolayer value of the sample decreases up to 1300℃, accompanied by a low-pressure hysteresis phenomenon. When heat-treated at 1500℃ or higher, this phenomenon disappears and the monolayer value decreases significantly, indicating the disappearance of micropores and occurrence of graphitization. After 10 min. of heat treatment at 2400℃, the specific surface area of the graphitized charcoal becomes 8.45 m²/g, similar to that of artificial graphite, which shows promising results of 217 mAh/g at a current density of 0.02 A/g for using in Lithium ion battery electrode.