Nitrogen-doped porous carbon materials based on ginkgo shells for the lithium-ion batteries

In this study, by introducing melamine into the layered structure of ginkgo shells, both the internal structure was altered and nitrogen atoms were introduced, thereby achieving a dual effect of nitrogen doping and structural modification. The study demonstrated that the combined use of melamine and ZnCl 2 successfully enhanced the electrochemical performance of the material. The optimized material GKN-1.5 has a relatively low specific surface area (332.23 m 2  g −1 ), but its proportion of mesopores and average pore size (5.77 nm) are both higher than those of GK (954.13 m 2  g −1 , 4.46 nm). Additionally, the nitrogen content of GKN-1.5 is 13.73 %, while that of GK is 3.46 %, indicating that nitrogen atoms have been successfully introduced into the resulting material. When assembled into a lithium-ion battery, GKN-1.5 exhibited a charging capacity of 594.75 mAh g −1 and a discharging capacity of 1030.35 mAh g −1 during the first charge-discharge cycle, with an initial coulombic efficiency of 57.72 %, compared to GK (348.38 mAh g −1 , 929.24 mAh g −1 , 37.47 %). Additionally, in cycling performance tests, GKN-1.5 maintained a reversible capacity of 678.05 mAh g −1 after 200 cycles at a current density of 100 mA g −1 . In contrast, GK exhibited a reversible capacity of 370.83 mAh g −1 at the same current density. This study proposes a method for modifying the natural structure of biomass while introducing heteroatoms.