MnO2 nanoflakes anchored on carbon nanotubes as self-standing anode for sodium ion batteries

In this study, carbon nanotubes (CNTs) are grown in situ on the surface of carbon cloth (CC) using a pyrolysis method. Subsequently, a redox reaction between CNTs and KMnO4 allow for the successful loading of manganese dioxide (MnO2) nanoflakes onto the CNTs, resulting in the MnO2/CNTs/CC composite. This composite serves as a self-supporting anode material without the need for additional conductive agents or binders. The incorporation of CNTs plays a crucial role in enhancing the overall electrical conductivity of the electrode material. Furthermore, the MnO2 nanoflakes exhibit a substantial specific surface area, resulting in increases contact between the electrode and the electrolyte. A notable feature of this composite is the strong interaction between the CNTs and MnO2 nanoflakes. This interaction not only effectively mitigates the detachment of MnO2 nanoflakes during cycling but also facilitates efficient electron transport. The MnO2/CNTs/CC composite, when employ as anode material for sodium ion batteries, demonstrate commendable cycling stability, delivering a capacity of 317 mA h g−1 after 120 cycles at a current density of 0.1 A g−1. Moreover, it exhibit favorable rate performance, achieving a capacity of 161 mA h g−1 at a current density of 2 A g−1.