Nanocrystalline copper-chromium-layered double hydroxide with tunable interlayer anions for electrochemical capacitor application

Abstract

Nanocrystalline copper-chromium-layered double hydroxide (CuCr-LDH) is prepared by facile chemical co-precipitation method. In order to investigate effects of interlayer anions on electrochemical properties of CuCr-LDH, the carbonate (CO32−) and nitrate (NO3-) anions are intercalated in to the layered CuCr-LDH. The obtained samples are characterized by powder X-ray diffraction (P-XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDS)-elemental mapping analysis to study crystal structural, chemical bonding, surface textural as well as compositional properties. The layer-by-layer stacking of CuCr(OH)2 nanosheets that intercalated with CO32− and NO3− anions is evidenced by powder X-ray diffraction. The layered arrangement of CuCr(OH)2 nanosheets and homogeneous distribution of constituent elements over CuCr-LDH crystals are also evidenced by FESEM micrographs and EDS mapping analysis. The NO3− intercalated CuCr-LDH electrochemical capacitor electrode demonstrated a maximum specific capacitance of 843 Fg−1 with capacity retention up to 85 % after 1500 CV cycles, superior to CO32− intercalated CuCr-LDH with a specific capacitance of 522 Fg−1 and capacity retention up to 72 %. The NO3- intercalated CuCr-LDH demonstrated improved electrochemical capacitive activity as compared to CO32− intercalated CuCr-LDH.