The improvement on capacity retention of silicon/graphite composites with TiN additive as anode materials for Li-ion battery

Silicon (Si) exhibits promising prospects due to its largest capacity among all known anode materials of lithium ion batteries. Carbon-coated silicon/graphite composites with titanium nitride (TiN) additives were synthesized from pyrolyzing phenolic resin. Pyrolyzed carbon acts as a mechanical and electrochemical buffer that enhances cycling performance and the morphology of composites. In addition, inactive TiN serves as a buffer matrix that efficiently prevents Si from cracking during the charging/discharging process and enhances the electrochemical properties of composites. Optimal composition of the composite, 45 wt.% phenolic resin, 25 wt.% graphite, 10 wt.% silicon and 20 wt.% TiN, exhibits a charging capacity about 650 mAh/g in the first cycling test and 443 mAh/g after seven cycling tests and maintains a higher coulombic efficiency.