Polyaniline-derived carbon nanotubes as anode materials for potassium-ion batteries: Insight into the effect of N-doping.

• The N-doped carbon nanotubes (N-CLNTs) were prepared through the carbonization of PANI nanotubes. • The N-CLNTs possesses 3D interconnected networks with unique 1D tubular structure. • The N-CLNTs-700 exhibits excellent cycling stability. • The excellent performance of N-CLNTs-700 attribute to multiple synergistic effects. Potassium-ion batteries (PIBs), as an inexpensive alternative to lithium-ion batteries (LIBs), have attracted significant attention for large-scale energy storage owing to their high capacity and low cost. The polyaniline (PANI) is a promising carbon source for high-performance PIBs anodes because of its diversity of morphologies and high N content. However, the PANI-derived carbon is rarely utilized as PIBs anode. Herein, the cross-linked porous N-doped carbon nanotubes (N-CLNTs) were prepared through the carbonization of PANI nanotubes. By adjusting the carbonization temperature, the N-CLNTs with different N content were designed to systematically elaborate on the effect of the N-doping on the electrochemical properties for PIB anodes. Owing to the synergistic effect of the high N-5/N-6 content and unique 1D tubular structure, the N-CLNTs-700 delivers a reversible capacity of 261 mAh g−1 at 0.05 A g−1 after 150 cycles and can still remain 168 mAh g−1 at 2 A g−1 over 3000 cycles. These results shed light on the design of carbon materials to efficiently enhance the electrochemical performance of PIBs. [ABSTRACT FROM AUTHOR]