Structural design of Ni-silicate/CNT hybrid films as anode materials for highly reversible lithium and sodium storage

Low-cost transition metal silicates are regarded as promising high-performance anode materials for cation storage due to their high capacitance. However, the intrinsically low conductivity of transition metal silicates should be properly addressed to fully utilize their high cation storage properties, which remains a challenge. Herein, we report a three-dimensional (3D) hybrid film featured with nickel silicate nanosheets combined with carbon nanotubes (Ni-silicate/CNTs) prepared by a one-step hydrothermal strategy. In the highly flexible film, bunches of ultrathin Ni-silicate nanosheets are uniformly anchored on the CNTs, which form a 3D interconnected network with open porosity. This Ni-silicate/CNT material shows excellent first cycle coulombic efficiency, good rate performance, and outstanding cycle performance (85.3% capacity retention after 1000 cycles at 3 A g⁻¹) when used as binder-free electrodes for LIBs. In addition, it can also deliver a high electrochemistry performance in SIBs, and the average reversible specific capacity is 643.7 mAh g⁻¹ at 0.05 A g⁻¹. Our results suggest the great potential of such Ni-silicate/CNT hybrid films as flexible LIB/SIB electrodes for practical applications.