The utilization of geothermal silica as the silica source to synthesize silicone as lithium-ion battery anode component was comprehensively studied. Silicone conversion was performed using magnesiothermic reduction at a temperature of 650 °C for 7 h. The applied Mg:SiO2 mole ratio on magnesiothermic reduction were 1.6:1, 2:1, and 2.5:1. The purification treatments of silicone product were conducted using two stages of acid leaching using HCl and a mixture of HF and acetic acid. In lithium-ion battery anode preparation, the ratio of Si to graphite employed 100:0; 90:10; 50:50; 10:90; and 0:100. The best yield and the conversion of silicone were 26.46% for the yield and 85.60% for the conversion by using 2:1 of Mg:SiO2 ratio. In the purification treatments, silicone yield of 29.45% with silicone purity of 58.9% was achieved using HCl, and silicone yield of 25.97% with silicone purity of 98% was achieved by using mixed solution of HF and acetic acid. The best battery performance in term of specific capacity was found by applying Si:graphite ratio of 100:0 with the value of first cycle of 358.5 mAh/g in this research. These findings present the reliability and feasibility of the geothermal solid waste and acid leaching treatments to generate the high quality of silicone for lithium-ion battery anode component.
