Growth of cobalt-aluminum layered double hydroxide nanosheets on graphene oxide towards high performance supercapacitors: The important role of layer structure

Layered CoAl LDH (Cobalt-Aluminum layered double hydroxide) has been identified as a promising active electrode material for pseudocapacitors. However, some issues of CoAl LDH, such as poor conductivity and aggregation, limited its large-scale practical application. In addition, vague understanding of the role of the CoAl LDH's layer structure in pseudocapacitance process might mislead the research community on material modification. Herein, growth of CoAl LDH nanosheets with and without graphene oxide (GO) is prepared by hydrothermal method. To evaluate the role of layer structure in pseudocapacitance process, the CoOOH nanosheets with and without GO are also prepared by combining hydrothermal method with alkali etching treatment. As pseudocapacitance electrode material, the GO@CoAl LDH exhibits surpassing specific capacitance of 1725.71 F g(-1) at a current density of 1 A g(-1) and optimal 87.73% capacitance retention at 7 A g(-1) which are much higher than the other as-obtained materials. The study provides not only a better perspective to explore the importance of LDH layered structure during the electrochemical process, but also a direction to subsequent design of the novel Co-based or LDH-based electrode materials.