An environmental benign approach to high performance anode for Li-ion battery: N-rich porous carbon from Cr(VI)-polluted water treatment

[Display omitted] •A N-rich carbon was consequently applied in water treatment and energy storage.•PEI modification was used to enhance the N content of carbon.•High N content contributed to adsorption for Cr(VI) and reduction to Cr(III).•PEI-NFPC/Cr (1 5 0) showed a high cycling capacity as an anode for Li-ion battery. This communication describes a novel and environmental benign method to prepare high performance anodes for Li-ion battery. The N-rich porous carbon after polyethylenimine (PEI) modification was first used for Cr(VI)-polluted water treatment to effectively adsorb Cr(VI) and reduce the adsorbed Cr(VI) to Cr(III). Then the Cr(III)-containing carbon was further used as an anode material for Li-ion battery, which exhibits high capacity up to 943.5 mAh/g after 100 cycles at 100 mA/g current rate and 1749.9 mAh g−1 in the first cycle. We demonstrated an efficient green strategy for materials utilization in both environmental and energy storage applications.