Enhanced cycling stability performance for supercapacitor application of NiCoAl-LDH nanofoam on modified graphite substrate
By Polat, Seda; Atun, Gülten
Published in Journal of Industrial and Engineering Chemistry
2021
Abstract
The high capacitive, cost-effective, non-toxic nickel–cobalt layered double hydroxide nanofoam pseudocapacitive electrode materials doped with aluminium (NiCoAl-LDH) have been hydrothermally synthesized on the electrochemically modified graphite (G) substrate with zinc and copper (Zn/G and Cu/Zn/G). The Al3+ diffusion in the LDH during the hydrothermal synthesis resulted in an ultrathin nanofoam morphological structure well adapted to the entire surface of Zn/G and Cu/Zn/G. The high areal capacitance of the best efficient NiCoAl-LDH/Cu/Zn/G electrode of 2.17Fcm−2 at 5mAcm−2 decreases to 1.83mFcm−2 at 75mAcm−2 showing an excellent rate capability of 84%. An asymmetric supercapacitor (ASC) designed with graphite as negative electrode exhibits an energy density of 29.3Whkg−1 at a power density of 575Wkg−1. It still remains at 5.6Whkg−1 at a higher power density of 3477Wkg−1 at a discharge time of 5.8s indicating ultra-fast energy storage ability of the G//NiCoAl-LDH/Cu/Zn/G device. Its cyclic tests were also made by constructing a coin-cell-type device for industrial applications. The capacitance of the coin-cell operating within 1.6V was protected around 100% even after over 10,000 charge–discharge cycles at the current densities up to 1.8mAcm−2.