Hard Carbon Derived from A New Type Resorcinol/2-Thenaldehyde Resin as High-Performance Anode Materials for Lithium-Ion Batteries

In order to further improve the electrochemical properties of the resorcinol-formaldehyde (RF) resin and its derived hard carbon, a new D (electron donor)-D-A (electron acceptor) type resorcinol / 2-thenaldehyde (RT) resin was prepared by the high-temperature hydrothermal method using resorcinol and 2-thenaldehyde as raw materials. As lithium-ion electrode materials, RT resin and its derived hard carbon (HCs700) had significantly higher specific capacities than RF resin and its derived hard carbon, respectively. Compared with RF resin, RT resin had an extra thiophene unit in the molecule. The introduction of thiophene unit (donor unit) enabled RT resin to have a narrower band gap (Eg: 1.85 eV vs. 2 eV), better redox performance, and ultimately higher specific capacity. And the introduction of the thiophene unit caused the doping of N in HCs700, which greatly improved the electrochemical properties of the carbon material and greatly increased the number of active sites for the lithium-ion reaction. After 300 cycles, the capacities of RT resin, HCs700, and HCs700@GPE (graphene) at the current density of 100 mA g -1 were 270.1, 596.6, and 462.8 mAh g −1 , respectively. The prepared HCs700 and HCs700@GPE electrode materials had good specific capacity and rate performance, which were well suited as anode materials for lithium-ion batteries.