Novel application of CoAl-layered double hydroxide/reduced graphene oxide nanocomposite as a highly efficient cathode additive for nickel-based secondary batteries

A series of Co–Al layered double hydroxide (Co–Al LDHs)@reduced graphene oxide (rGO) nanocomposite are successfully synthesized through a hydrothermal method and applied as novel cathode additives for nickel-based secondary batteries for the first time. The obtained Co–Al LDHs@rGO nanocomposite is composed of many thin nanosheets, displaying laminated structure. The effects of various Co–Al LDHs@rGO on the properties of nickel cathodes were compared and its action mechanism was further investigated. Interestingly, the Ni(OH)2 electrode added with Co–Al LDHs@rGO(10%) delivers best high-rate performances and more stable cycling stability as comparison with the pure Ni(OH)2 and Ni(OH)2+CoO electrodes. Owing to its soft and flexible structure, Co–Al LDHs@rGO(10%) is conducive to modify the electronic conductivity, proton diffusion and electrochemical reversibility of the electrode by forming a more effective and stable conductive network. Especially, Co–Al LDHs@rGO(10%) with high electrochemical activity can contribute much higher discharge capacity than the commercial CoO. Owing to its high efficiency and low cobalt content, Co–Al LDHs@rGO(10%) can be applied as an effective, cheap, and promising cathode additive for nickel-based rechargeable batteries.