Flexible Mn3O4/MXene Films with 2D-2D Architectures as Stable and Ultrafast Anodes for Li-Ion Batteries

Mn3O4 is regarded as a promising anode material for lithium-ion batteries (LIBs) based on its ultrahigh theoretical capacity (937 mAh g-1) and low cost but suffers from poor electronic conductivity and large volume variation during the lithiation/delithiation process, which result in dramatic capacity fading and inferior rate capability. Ti3C2Tx MXene, a novel two-dimensional transition metal carbide with metallic conductivity, excellent mechanical properties, and hydrophilic surface, could be an ideal candidate to improve the lithium storage performance of Mn3O4. Here, a unique flexible, 2D-2D Mn3O4/MXene film is fabricated by assembling 2D Mn3O4 with Ti3C2Tx nanosheets through a simple vacuum filtration approach. In this unique 2D-2D nanostructure, MXene nanosheets buffer the volume change of Mn3O4 during the charge/discharge process. Moreover, the introduction of MXene enables the fabricated 2D-2D nanostructure with excellent flexibility and can be directly used as an electrode for LIBs, which is beneficial for enhancing the energy density of the assembled batteries. As a result, the flexible film of Mn3O4-MXene-8-2 shows excellent lithium storage performances in terms of specific capacity (931 mAh g-1 at 0.05 A g-1), rate capability (624 mAh g-1 at 1 A g-1), and cycling stability, demonstrating its great potential for the application in LIBs.