A wet granulation method to prepare graphite particles with a high tap density for high volumetric energy density lithium-ion storage

Graphite is the most widely used anode material for lithium ion batteries (LIBs). Increasing the sphericity and tap density of the graphite particles is important for improving their volumetric energy density. We report a simple approach to prepare high tap-density graphite granules by high-shear wet granulation. Graphitic onion-like carbon (GOC) and artificial graphite (AG) were densified into granules by wet-granulation to obtain WG-GOC and WG-AG, respectively. Results indicate that, compared with the original graphite before granulation, the tap densities of WG-GOC and WG-AG increased by 34% and 44%, respectively. The respective volumetric energy densities of WG-GOC and WG-AG increased by 35% and 55% at a current density of 50 mA g⁻¹. The rate performance of WG-GOC was also significantly improved. The volumetric capacity of WG-GOC at a current density of 2 000 mA g⁻¹ was 169.1% of the original GOC. The significant improvement of electrochemical performance is ascribed to the increased tap density of the graphite granules.