Hierarchical porous NiCo₂O₄ nanosheet arrays directly grown on carbon cloth with superior lithium storage performance

Abstract

Binary metal oxides have been explored as advanced candidates in lithium-ion battery (LIB) anodes due to their high specific capacity. Herein, the hierarchical structures of porous NiCo₂O₄ nanosheets directly grown on a conductive carbon cloth substrate (3D NCO-PSA/CC) were obtained by a facile in situ synthetic strategy. When applied as a binder-free LIB anode, it exhibited satisfactory performance with a high discharge capacity (a first discharge capacity of 2090.8 mA h g^-1 and a stable capacity of 1687.6 mA h g^-1 at 500 mA g^-1), superior rate capacity (discharge capacity of 375.5 mA h g^-1 at 6000 mA g^-1) and excellent reversibility (coulombic efficiency of approximately 100%). The outstanding performances should be attributed to the 3D porous structures, nanosheets and good conductivity of NCO-PSA/CC that could not only ensure the rapid transport of Li⁺ ions and electrons but also remit the huge volume change during lithiation/delithiation processes. Undoubtedly, the present facile and effective strategy can be extended to other binary metal-oxide materials for use as high-performance energy storage and conversion devices.