Volume 11 Issue 3 ( September 2024)

Demand for lithium-ion batteries (LIB) in wireless electronics, power tools, electric vehicles, and reliable energy storage systems is increasing. To meet lithium-ion battery (LIB) requirements, silicon or Si has been considered a state-of-the-art anode material owing to its significantly different specific capacity compared to the other anode. In this study, we attempted to synthesize crystalline Si (cSi) from coal combustion fly ash. The Si was prepared by caustic extraction, acidic precipitation, and magnesiothermic reduction of the as-obtained silica. Carboxylic acids, i.e. citric acid, acetic acid, and lactic acid, were used as the gelling agents. The SiO₂ and Si were characterized thoroughly to ensure the end-product quality. Based on our findings, the as- obtained SiO₂ samples are in an amorphous phase, while the as-obtained Si micro-powder has a highly crystalline structure. Based on the SEM-EDX analysis, the Si samples have high purity. In a full-cell LIB application, the pure Si anode coupled with LiNi_0.6Co_0.2Mn_0.2O₂ (NCM) cathode delivered poor electrochemical performance; however, when graphite was mechanically introduced Si, the performance was significantly improved. The Li-ion storage mechanism of Si/Graphite was investigated. The coal fly ash-derived Si powder can be utilized and modified to obtain Li-ion batteries with excellent electrochemical performance.

Keywords: Anode, Battery, Fly-ash, Material, Silicon, Waste