Zeolitic imidazolate framework-L-assisted synthesis of inorganic and organic anion-intercalated hetero-trimetallic layered double hydroxide sheets as advanced electrode materials for aqueous asymmetric super-capacitor battery

Fine-tuning the interlayer space and composition of the layered double hydroxide (LDH) is a promising strategy to obtain high-performance battery-type electrode materials for super-capacitor battery. In this work, a series of two-dimensional (2D) porous hetero-trimetallic Zinc-Nickel-Cobalt LDHs sheets intercalated with nitrate anion and different Zn/Ni ratios (Zn_xNi_1-xCo-LDH-NO₃^–, x = 0, 0.25, 0.5, 0.75, and 1.0) are firstly synthesized through a Zeolitic imidazolate framework-L (ZIF-L)-assisted co-precipitation reaction and ion etching procedure. Among which, the Zn_0.25Ni_0.75Co-LDH-NO₃^– electrode, with a Zn/Ni ratio of 1:3, provides a high specific capacity (275 mAh g⁻¹ at 1 A g⁻¹). To further tune the interlayer space, Zn_0.25Ni_0.75Co-LDH-BA^–/AA^– (BA^– = benzoate anion and AA^– = acetate anion) sheets intercalated with BA^– or AA^– are synthesized by an anion-exchange method. A super-capacitor battery device (Zn_0.25Ni_0.75Co-LDH-BA^–//activated carbon) using Zn_0.25Ni_0.75Co-LDH-BA^– as the positive electrode can achieve a high energy density (51.8 Wh kg⁻¹ at 789 W kg⁻¹) and superb durability (94.6% over 10,000 cycles). This work can shed light on regulating the interlayer space of LDHs for advanced electrochemical energy storage applications.