Exquisite microstructure design of quaternary nickel cobalt manganese iron layered double hydroxides for high performance hybrid supercapacitors

Although layered double hydroxide (LDH) materials have delivered numerous merits, such as low cost, ease of synthesis, environmental friendliness and high theoretical specific capacity, the shortcomings of unsatisfactory rate capability and poor cycle stability seriously limit their practical applications. Controllable preparation of electrode materials possessing exquisite microstructure is considered as one of the most effective strategies to improve the electrochemical performance. In this paper, a new quaternary nickel cobalt manganese iron layered double hydroxide (NiCoMnFe-LDH) material with a delicate microstructure design of combining dense nano-sheets grown on NiCoMnFe-LDH thin film and outspread nanospheres assembled by tiny nanosheets is electro-deposited on carbon cloth by introducing moderate amount of ion elements and regulating the growth time. Ternary NiCoMn-LDH material is also prepared under the same condition for comparison, which shows a distinct morphology feature of thick nanosheets stacking. NiCoMnFe-LDH electrode delivers more outstanding electro-chemical properties than NiCoMn-LDH electrode from the aspects of specific capacity, rate capability, electrical conductivity and cyclic stability. Moreover, the as-assembled NiCoMnFe-LDH//AC aqueous hybrid super-capacitor device possesses a high specific energy and a satisfactory lifespan. The ease of fabrication and brilliant energy storage characteristics enable this newly-constructed aqueous hybrid supercapacitor a powerful candidate for practical applications.