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.

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