Abstract
Provided are hard carbon beads, their preparation method, and an energy storage device comprising the same. Microwave heating is used to synthesize cross-linked phenolic formaldehyde for reducing energy-consuming and controlling the crosslinking density of cured phenolic formaldehyde. The problems caused by high temperature heating and hydrothermal process for curing resin can be solved by the instant disclosure, which can increase the economic value of electrode and energy storage device comprising the hard carbon beads.