Methods of preparing hard carbon material and energy storage device and method of enhancing plateau capacity

Abstract

Provided is a method of preparing a hard carbon material having closed pores. By employing Novolak oligomers, the cross-linking density of the phenolic-formaldehyde resins can be controlled within a range from 0.5 to 0.999 through a recondensation reaction. Based on the cross-linking density, an appropriate carbonization temperature is set for the thermal treatment, generating multiple closed pores in the hard carbon material and controlling the closed pore volume within a range from 0.1 cm3/g to 0.4 cm3/g. As a result, a hard carbon material with a desired closed pore structure and an enhanced closed pore volume can be obtained, thereby enhancing both the plateau capacity and the overall capacity when applied to the lithium-ion batteries.

Dependencies are inferred from the claim text.