Honeycomb-like carbon materials derived from coffee extract via a salty thermal treatment for high-performance Li-I2 batteries

Sustainable, conductive, and porous carbon materials are ideal for energy storage materials. In this study, honeycomb-like carbon materials (HCM) are synthesized via a salty thermal treatment of abundant and sustainable coffee extract. Systematic materials characterization indicates that the as-prepared HCM consists of heteroatoms (N and O, etc.) doped ultra-thin carbon framework, possesses remarkable specific surface area, and excellent electrical conductivity. Such properties bestow HCM outstanding materials to be the blocking layer for Li-I-2 battery, significantly eliminating the dissolution of I-2 in the cathode region and stopping the I-2 from shutting to anode compartment. Furthermore, our electrochemical investigation suggests that HCM could incur surface pseudo-capacitive iodine-ions charge storage and contribute additional energy storage capacity. As a result, the resultant Li-I-2 battery achieves a robust and highly reversible capacity of 224.5mAh.g(-1) at the rate of 10C. Even under a high rate of 50C, the remarkable capacity of the as-prepared Li-I-2 battery can still be maintained at 120.2mAh.g(-1) after 4000 cycles.