A novel Cu-MOF@Si/C prepared by the pulse discharge and hydrothermal method as an anode material for lithium-ion battery

Metal-organic framework (MOF) composite materials have attracted significant interest owing to their customizable shape and porosity. However, the widespread use of MOFs in lithium-ion batteries is limited because of its low ionic conductivity and charging capacity. In this study, Si nanospheres are synthesized using the pulse-discharge method. Subsequently, a composite of Cu-MOF-coated Si nanospheres (Cu-MOF@Si) is developed via a solvothermal process using MOF-199 as the precursor. This is followed by the synthesis of a novel Cu-MOF@Si/C composite via thermal decomposition. Cu-MOF@Si/C composites have been employed as anode materials in lithium-ion batteries. After undergoing 300 charge and discharge cycles at a rate of 100 mA g−1, the composite exhibited a capacity of 725.4 mAh g−1 and an initial Coulombic efficiency of 96.86 %. In addition, the battery showed an excellent rate performance and maintained a high discharge capacity even at current densities of 0.2, 0.5, 1.0, and 2.0 C. These findings suggest that the conductive network formed during the annealing of the Cu-MOF@Si/C composite is vital for enhancing the ionic conductivity and mitigating the expansion of Si nanoparticles during battery cycling.