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• 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]

Nanometerization of tin-based materials is beneficial to alleviate the volume effect, and thus improving the cycle stability of tin-based materials. Meanwhile, the smaller size can enhance the reversibility of the conversion reaction, which is crucial for increasing the capacity of tin-based materials. Therefore, reducing the size of tin-based materials may bring the advantages of cycle stability and specific capacity. In this work, we tried to disperse tin ions with organic skeleton to maximize the dispersion of active materials. Tin-based anode material based on polyethyleneimine‑sodium xanthogenate is synthesized by in-situ method at room temperature, and the thiocarboxyl group of polyethyleneimine‑sodium xanthogenate greatly increases the dispersion of metal ions. Carbon nanotubes (CNTs) are further introduced to improve the conductibility of tin-based materials owing to the existence of non-conductive organic groups. The anode material exhibits a long cycle life which delivers a specific capacity of 560 mAh g−1 after 1000 cycles. By analyzing the differential charge capacity (dQ/dV) curves, we find that the conversion reaction of tin-based materials is highly reversible. Polymers skeleton is introduced into tin-based materials as the anode material for lithium ion battery and the conversion reaction of tin-based material exhibits an excellent reversibility. Unlabelled Image • Polymers skeleton is introduced into tin-based materials as the anode material for lithium ion battery. • Electrode material is synthesized at room temperature without a crystallization process. • Conversion reaction of tin-based material exhibits an excellent reversibility. • The composite electrode material exhibits a long cycle life up to 1000 cycles. [ABSTRACT FROM AUTHOR]