CoAl-layered double hydroxide nanosheets-coated spherical nickel hydroxide cathode materials with enhanced high-rate and cycling performance for alkaline nickel-based secondary batteries

A series of Co–Al layered double hydroxide nanosheets-coated spherical nickel hydroxide with improved high-rate and cycling performance are successfully synthesized through a hydrothermal method. Scanning electron microscopy images show that Co–Al layered double hydroxide is uniformly anchored on the surface of nickel hydroxide. As cathode material for nickel-based battery, the Ni(OH)2@Co–Al layered double hydroxide(10%) displays a highest high-rate properties and cycling performance. The discharge capacities of the as-obtained Ni(OH)2@Co–Al LDH(10%) reach up to 299.7, 276.6, 247.5 and 223.2 mA h g−1 at 0.2, 1.0, 5.0 and 10.0C, respectively. After 500 cycles at 1C/1C, the Ni(OH)2@Co–Al LDH (10 wt%) delivers a high capacity retention of 87.3%. These performance improvements are ascribed to the fact that Co–Al layered double hydroxide not only forms a stable high conductive layer of β-CoOOH and γ-CoOOH, but also provides many capacity through a reversible conversion between and γ-CoOOH and CoAl LDHs, eventually leading to the improvement of the reversible property, proton diffusion and conductivity of the Ni(OH)2 cathode. Consequently, the spherical Ni(OH)2@Co–Al layered double hydroxide(10%) is a promising cathodes material for advanced nickel-based secondary batteries.