Nitrogen-enriched graphene-like carbon architecture with tunable porosity derived from coffee ground as high performance anodes for lithium ion batteries

Nitrogen-enriched graphene-like carbon nanosheets were prepared using coffee ground as the carbon and nitrogen resource, calcium carbonate and iron nitrate and their derivatives as the structural templates and the graphitization catalysts. The wrinkled nanosheets are randomly intertangled and cross-linked, constructing a three-dimensional (3D) porous architecture. With various amount of the templates and catalysts, the obtained porous carbon materials exhibit moderate specific surface areas of 450-540 m(3) g(-1) with tunable pore sizes of 8.2-11.6 nm. As lithium ion battery anodes, the as-prepared carbon materials demonstrate significantly enhanced energy storage capability including improved specific capacity and rate capability due to the unique comprehensive structure feature that consists of both amorphous carbon and graphite components, enriched nitrogen species in carbon framework, and the optimized pore size. Additionally, the carbon materials exhibit superior cycling stability because of their stable structure, for example, a high reversible capacity of up to 760 mAh g(-1) can be achieved at 100 mA g(-1) after 100 discharge/charge cycles. This research indicates that the asprepared porous carbon material could be a promising anode candidate for next-generation high performance lithium-ion battery with high energy density and high power density.