Tailoring carboxyl tubular carbon nanofibers/MnO₂ composites for high-performance lithium-ion battery anodes

Three kinds of novel carboxyl modification tubular carbon nanofibers (CMTCFs) and MnO₂ composites materials (CMTCFs/MnO₂) are prepared by combining hyper-crosslinking, liquid phase oxidation and hydrothermal technology. The complex morphology and crystal phase of MnO₂ in CMTCFs/MnO₂ are effectively regulated by adjusting the hydrothermal reaction time. The δ-MnO₂ nanosheet-wrapped CMTCFs (CMTCFs@MNS) are used as anode and compared with the other two CMTCFs/MnO₂. Electrochemical analysis shows that CMTCFs@MNS electrode exhibits a large reversible capacity of 1497.1 mAh g⁻¹ after 300 cycles at 1000 mA g⁻¹ and a long cycling reversible capacity of 400.8 mAh g⁻¹ can be maintained after 1000 cycles at 10 000 mA g⁻¹. CMTCFs@MNS manifests an average reversible capacity of 256.32 mAh g⁻¹ at 10 000 mA g⁻¹ after twelve changes in current density. In addition, the structural superiority of CMTCFs@MNS electrode is clarified by characterizing the microscopic morphology and crystal phase of the electrode after electrochemical performance test.