Porous Graphitic Carbon Nanosheets as a High-Rate Anode Material for Lithium-Ion Batteries

Two-dimensional (2D) porous graphitic carbon nanosheets (PGC nanosheets) as a high-rate anode material for lithium storage were synthesized by an easy, low-cost, green, and scalable strategy that involves the preparation of the PGC nanosheets with Fe and Fe3O4 nanoparticles embedded (indicated with (Fe&Fe3O4)@PGC nanosheets) using glucose as the carbon precursor, iron nitrate as the metal precursor, and a surface of sodium chloride as the template followed by the subsequent elimination of the Fe and Fe3O4 nanoparticles from the (Fe&Fe3O4)@PGC nanosheets by acid dissolution. The unique 2D integrative features and porous graphitic characteristic of the carbon nanosheets with high porosity, high electronic conductivity, and outstanding mechanical flexibility and stability are very favorable for the fast and steady transfer of electrons and ions. As a consequence, a very high reversible capacity of up to 722 mAh/g at a current density of 100 mA/g after 100 cycles, a high rate capability (535, 380, 200, and 115 mAh/g at 1, 10, 20, and 30 C, respectively, 1 C = 372 mA/g), and a superior cycling performance at an ultrahigh rate (112 mAh/g at 30 C after 570 charge–discharge cycles) are achieved by using these nanosheets as a lithium-ion-battery anode material.