Superior lithium storage in nitrogen-doped carbon nanofibers with open-channels

- Nitrogen-doped carbon nanofibers are prepared by an electrospinning process with 2-step carbonization.
- The addition of waste poly(vinyl butyral) induces the open channels on the surface of nanofibers.
- The urea plays a role in the increases of the nitrogen contents of nanofibers.
- The carbon nanofibers exhibit high reversible capacity and long-term cycling stability.

Increasing porosity and nitrogen doping are the most effective strategies for enhancing lithium storage in carbon-based anodes for lithium-ion batteries (LIBs). In this study, we prepare nitrogen-doped carbon nanofibers with open channels (N-CNFO) using a simple electrospinning method with subsequent two-step carbonization using polyacrylonitrile, waste poly(vinyl butyral) (W-PVB), and urea. The W-PVB induce open channels including pores of various sizes, and the urea increase the nitrogen content of the carbon fibers. N-CNFO exhibit excellent electrochemical properties as an anode material for LIBs, including high reversible capacity (734 mA h g−1 at 0.2 C), superior rate capability (388 and 358 mA h g−1 at 3 C and 5 C, respectively), and excellent cycling performance (330 mA h g−1 at 1 C after 500 cycles). These properties are imparted to the material owing to the high electrical conductivity of the web structure, the increased number of active sites derived from the open channel structure, and the high nitrogen content, specifically that of N-5 species. This facile synthesis using a waste resource may offer a new direction for the design of superior carbon-based anode materials for high-energy LIBs.

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