Preparation of 3D spherical Ni/Al LDHs with significantly enhanced electrochemical performance as a superior cathode material for Ni/MH batteries

Nickel-based hydroxides with excellent electrochemical performance have been considered as cathode materials for Ni/MH batteries. In this paper, a Ni/Al layered double hydroxides (Ni/Al LDHs) material with three-dimensional (3D) spherical structure is synthesized by a facile stable dual complexation eprecipitation method. SEM images show that the obtained Ni/Al LDHs possess 3D spherical structure composed of nanosheets. XRD and CV tests indicate that doping of Al increases the distance between Ni - Al layers, greatly improving the specific capacity of the obtained materials. The electrochemical tests show that the specific capacity of the obtained material with 18% Al is up to 383.4 mAh g(-1) at a current density of 1 A g(-1). In addition, when the current density is further increased to 10 and 20 A g(-1), the specific capacity of this material still maintains 345.0 mAh g(-1) and 307.9mAh g(-1), respectively, which implies that this cathode material can provide remarkable power densities. Moreover, the material composed of Ni/Al LDHs keeps 97.6% initial capacity after 5000 cycles at a current density of 10 A g(-1), showing an excellent cycling stability and durability. (c) 2018 Elsevier Ltd. All rights reserved.