Nano-Ag laminated ternary layered double hydroxides for hybrid supercapacitors

Abstract

Ternary layered double hydroxide (LDH)-based active materials can serve as potential electrode materials in the development of high-performance supercapacitors (SCs) due to their good structural features and high electrochemical activity. Herein, we report the rational design of conductive nano-silver (Ag) particles integrated hierarchical nickel-cobalt-molybdenum LDH (Ag@NCM LDH) using simple methods by excluding the non-conductive binders. The ternary NCM LDH material prepared with an equal volume ratio of water and ethanol displayed a hybrid morphology of micro flowers in situ grown on the nanosheet layer (i.e., MFs@NSs). The ternary NCM LDH MFs@NSs electrode demonstrated superior electrochemical properties to other NCM electrodes (prepared with different solvent volume ratios) and binary metal hydroxides as well. Thanks to the ternary metal hydroxides, nano-Ag particles, and MFs@NSs architecture, the prepared Ag@NCM LDH electrode achieved a high areal capacity of 890 μAh cm−2 at 5 mA cm−2. Moreover, the Ag@NCM LDH electrode showed good cycling stability with 88.8% retention after 15,000 cycles (measured at 30 mA cm−2). A hybrid SC (HSC) construction of Ag@NCM LDH and activated carbon electrodes revealed a high areal capacitance of 1752.2 mF cm−2 (at 5 mA cm−2) as well as superior energy and power densities of 0.569 mWh cm−2 and 3.82 mW cm−2, respectively. Especially, an HSC demonstrated long-life stability with 108.5% retention after 15,000 cycles (measured at 40 mA cm−2). Besides, HSC was tested to store the solar energy via a solar cell panel and subsequently powered different electronic components with its stored energy.