Enhanced electrochemical performances based on ZnSnO microcubes functionalized in-doped carbon nanofibers as free-standing anode materials.

The binary composite, ZnSnO microcubes (ZSO MC) homogeneously parceled in an N-doped carbon nanofiber membrane (ZSO@CNFM), was synthesized a mild hydrothermal, electrospinning and carbonization process as a flexible lithium-ion battery (LIB) anode material. The unique carbon-coating layer architecture of ZSO@CNFM not only plays a crucial role in alleviating the volume change of ZSO MC during lithium ion insertion/extraction processes, but also constructs a three-dimensional (3D) transport network with the help of interconnected carbon nanofibers (CNFs) to ensure the structural integrity of the material and promote the electrochemical reaction kinetics. Due to its good flexibility characteristics, the as-prepared ZSO@CNFM can be directly adopted as an anode material for LIBs without the use of copper foil, conductive carbon black and any binder. Electrochemical surveying results manifest that the optimal ZSO@CNFM electrode displays excellent cycling stability (582.6 mA h g after 100 lithiation/delithiation cycles at 100 mA g), high coulombic efficiency (CE, 99.6% at 100th cycles), and superior rate performance (349.5 mA h g at 2 A g). The good electrochemical properties can be ascribed to the synergistic effect of the high theoretical specific capacity of ZSO MC, favourable stability of the carbon substrate, the open structure of ZSO@CNFM and the 3D continuous highly conductive framework for rapid electron/ion transfer.