Scalable spray-dried graphite/CNT/silicon composites with enhanced cycling stability for Li-ion battery anodes

This study presents a scalable and cost-effective spray-drying method for synthesizing graphite/silicon/carbon nanotube (G-Si-CNT) composites as high-performance anodes for lithium-ion batteries. By integrating graphite fines, nano-silicon (nSi), and a low loading (1 wt%) of single-walled CNTs, the resulting composites exhibit enhanced cycling stability and rate capability. The spray-drying process ensures uniform particle morphology and strong adhesion between components, effectively mitigating the mechanical degradation typically caused by silicon's volume expansion during cycling. Electrochemical tests reveal that the G-15% nSi-1%CNT composite achieves a capacity retention of 95.3% after 100 cycles with a discharge capacity of 630 mAh·g^-1 (3.15 mAh·cm^-2), outperforming CNT-free counterparts. While CNTs increase SEI-related losses due to higher surface area, their mechanical and conductive benefits outweigh this drawback. Impedance spectroscopy and post-mortem analyses confirm reduced charge-transfer resistance and improved structural integrity due to CNTs incorporation. The use of low-cost by-products from natural graphite spheroidization and low CNTs content offers significant economic advantages, positioning these composites as promising candidates for scalable, high-energy lithium-ion battery anodes.