Iodine and Nitrogen-Codoped Carbon Microspheres for Ultrahigh Volumetric Capacity of Li-Ion Batteries

Because of its high density, a carbon microsphere is a good candidate for ultrahigh volumetric capacity electrode materials. We find that the synergistic effects of nitrogen and iodine element can tremendously improve the carbon electrode capacity. Here, we present a high volumetric capacity anode consisting of iodine and nitrogen codoping carbon microspheres synthesized by a low-temperature solvothermal route. A reversible capacity of 1418 mAh cm–3, which is much larger than that of commercial graphitic carbon anode, is achieved at a current density of 0.05 mA cm–2 by using these carbon microspheres as anode material. After 100 charge–discharge cycles at 0.1 mA cm–2 and 500 charge–discharge cycles at 1 mA cm–2, carbon microspheres retained volumetric capacities of 1335 and 1090 mAh cm–3, respectively