Utilization of Coal Fly-Ash derived Silicon (Si) as Capacity Enhancer of Li-Ion Batteries Anode Material

• Published in: E3S web of conferences 2024-01, Vol.481, p.1007
• Main Authors: Satria Yudha, Cornelius, Puspita Sari, Erica, Kurniawati Dewi, Dona, Paramitha, Tika, Griyasti Suci, Windhu
• Format: Article
• Language: English
• ISSN: 2267-1242; 2267-1242
• DOI: 10.1051/e3sconf/202448101007

The increasing demand for energy has caused a rise in coal usage, resulting in high fly ash generation. The high SiO 2 , Al 2 O 3 , and Fe 2 O 3 content in fly ashes (FAs) allow them to be processed in electrical energy storage technology, such as lithium-ion-based secondary batteries. The research aims to develop silicon from FAs for Li-ion battery applications. The fabrication of silicon materials employed in this study are (i) extraction of SiO 2 from FA, (ii) gelation of SiO 2 , (iii) magnesiothermic reduction of SiO 2 to Si under N 2 flow, (iv) purification of silicon, (v) the solid-state composite fabrication of Si/C. The as-prepared Si was characterized. XRD test showed the presence of silicon phase and minor impurities in Mg. SEM analysis of the Si showed that the material has a polymorph shape with a rough surface of micron-sized secondary particles. EDX test showed the presence of impurities in the form of O and Mg atoms; meanwhile, the EDX mapping confirmed the dominant distribution of Si in the sample. Galvanostatic charge-discharge analysis of a battery with 5%Si/C anode and LiNi 0.8 Co 0.1 Mn 0.1 O 2 or NCM811 cathode resulted in a specific charge and discharge capacity of 600 mAh/g and 473.6 mAh/g, respectively, which is greater than the graphite theoretical capacity of 372 mAh/g.