Boosting the charge storage of layered double hydroxides derived from carbon nanotube-tailored metal organic frameworks

Abstract

Metal-organic frameworks derived nanoarchitectures attract considerable interests especially in electrochemical energy storage. However, controllably tuning crystal size with synchronously improving conductivity of metal-organic frameworks derived nanostructure is still the challenge for further capacity enhancement. Herein, we first conceive a strategy for the controllable synthesis of carboxylated carbon nanotubes connected hollow layered double hydroxides via sequential ion exchange of carboxylated carbon nanotubes-tailored metal-organic framework nanoarchitectures. By introducing the carboxylated carbon nanotubes, the derived hollow nanohybrids appear much smaller size and higher specific surface area, which is crucial to electrochemical reactions between electrolyte ions and electrodes. Owing to its well-designed structure and improved conductivity, the as-synthesized nanohybrids exhibit a significantly boosted specific capacity (855C g−1 at 1 A g−1) and unprecedented rate capability (91% capacity retention at 15 A g−1). When compared with the literature data by the “Ragone plots”, the hybrid supercapacitor assembled by as-synthesized nanaohybrids and active carbon demonstrates the extraordinary performance with a high energy density of 49.9 Wh kg−1 at a power density of 895 W kg−1. This novel strategy can stimulate the controllable synthesis of diverse metal-organic frameworks derived nanoarchitectures for energy storage, molecular adsorption, catalysis, drug delivery and separation towards sustainability.