Pitch-derived carbon as a superior conductive scaffold for enhanced silicon-carbon composite anodes

Abstract Silicon-carbon composites are increasingly recognized for their potential to enhance the energy density of lithium-ion batteries, presenting significant implications for commercial energy storage solutions. This study focuses on the pivotal role of the carbon source in these composites, specifically the influence of coal tar pitch (CTP) with different softening points on their electrochemical performance. The investigation compares CTP-derived pyrolytic carbon from pitches with softening points of 80 °C (CTP80) and 250 °C (CTP250), resulting in CTP80@Si and CTP250@Si composites. The CTP250@Si composites, post carbonization, exhibit more advanced graphitization and superior electrochemical properties, including a specific capacity of 1413.4 mAh·g−1, an initial coulombic efficiency of 78.67%, and a capacity retention of 76.70% after 100 cycles. These composites also demonstrate improved structural stability with minimal electrode degradation, outperforming the CTP80@Si counterparts. The findings highlight the significance of the pitch’s softening point in shaping the electrochemical attributes of silicon-carbon composites, positioning CTP250 as a promising carbon source for next-generation anode materials. Future work will aim to optimize the synthesis process and further improve the composite’s properties to meet the expanding demands of the lithium-ion battery industry.