Coffee grounds-derived carbon as high performance anode materials for energy storage applications

In this study, we propose a facile process to synthesize nitrogen-doped carbon from agro-food used wastage of coffee grounds and fabricated as anode materials for Li/Na-ion batteries. The coffee grounds derived carbon (CGC) and nitrogen doped (N-CGC) porous carbon materials have been compared by experimental measurements as well as theoretical calculations. The nitrogen doping of 2.23–6.17% are successfully modified into the material. The experimental results indicate that N-CGC exhibits better reversible capacity and excellent rate capability than those of CGC anode due to different distribution functional groups of pyrrolic N and pyridinic N. We also use three different models to demonstrate the differences in carrier transport properties. The difference in electrochemical properties of CGC and N-CGC might be due to the appearance of extra states near the Dirac cone when examining the partial density of states (PDOS) of N-CGC by Density functional theory (DFT) calculations. This investigation is not only solving the problem of biomass waste disposal, also generates valuable functional carbon-based materials for energy storage applications.