Hierarchical porous carbon nanosheets and their favorable high-rate performance in lithium ion batteries

Novel hierarchical porous carbon nanosheets (HPCS) with quantities of micropores and mesopores were prepared on a large-scale by using thermoplastic phenolic formaldehyde resin as the carbon source and copper nitrate as the template precursor. The HPCS, possessing a thickness of about 40 nm and the width of several microns, exhibited a high specific capacity and favorable high-rate performance when used as an anode material for lithium ion batteries (LIBs). The reversible capacities were 748 mA h g−1 at a current density of 20 mA g−1 and 460 mA h g−1 even at 1 A g−1, which were much higher than those of traditional porous carbon materials. It also showed superior cyclical stability for only 0.3% capacity loss per cycle under high rate charge-discharge process, suggesting that HPCS should be a promising candidate for anode materials in high-rate LIBs. The roles of various-sized pores in HPCS in Li storage were discussed briefly.