Porous MOF derived TiO2/ZnO/C@CNTs composites for enhancing lithium storage performance

Metal-organic frameworks (MOFs) materials and their derivatives have been widely used in the area of clean energy. When appropriate MOFs are selected for pyrolysis under suitable conditions, MO/C composites containing metal oxides (MO) and carbon layer can be obtained, and the skeletal structure of MOFs can also be maintained. In this contribution, porous double MOFs composites wrapped by carbon nanotubes (MIL-125/ZIF-8@CNTs) has been synthesized. After pyrolysis, the MIL-125 is transformed into TiO2/C, the ZIF-8 is converted into ZnO/C, multi-walled carbon nanotubes were wrapping on the surface of TiO2/ZnO/C, and finally formation of porous TiO2/ZnO/C@CNTs composites. Multi-walls CNTs could improve the electrical conductivity of the composites and increase the structural stability of the architectures, alleviating the volume expansion of materials during the charging/discharging process. The synthesized porous TiO2/ZnO/C@CNTs exhibits high specific capacity (the capacity is 816.8 mAhg−1 at the current density of 100 mAg−1 after 100 cycles) and excellent rate performance. Even at the high current density of 2 A g−1 after 300 cycles, the capacity still could reach up to 800 mA h g−1.