Interwoven N and P dual-doped hollow carbon fibers/graphitic carbon nitride: An ultrahigh capacity and rate anode for Li and Na ion batteries

Flexible and thin energy storage devices have attracted enormous attentions. An easy and large-scale method has been employed to fabricate flexible and interwoven N, P dual-doped carbon fibers/graphitic carbon nitride (huCP/g-C3N4) using filter paper as a precursor. The huCP/g-C3N4 composite as self-supporting anode for lithium ion batteries exhibits high reversible capacities of 1030 mAh g(-1) after 1000 cycles at 1 A g(-1) and 360 mAh g(-1) after 4000 cycles at 10 A g-1 along with excellent rate performance (133 mAh g(-1) at 30 A g-1). For sodium ion batteries, huCP/g-C3N4 as anode delivers high reversible capacities of 345 mAh g(-1) after 380 cycles at 0.1 A g(-1) and 110 mAh g-1 after 4000 cycles at 1 A g(-1). This excellent electrochemical performance can be attributed to the high contents of doped N and P in huCP/g-C3N4 and graphitic carbon nitride network, which not only create more defects and active sites but also expand the layer planes and provide interconnected conductive network. (C) 2017 Elsevier Ltd. All rights reserved.