Evaluation of manganese chromium metal organic framework and cobalt nickel iron layered double hydroxide composite synthesised by electrodeposition for supercapacitor applications

Abstract

Chronopotentiometry electrodeposition was used to synthesize manganese chromite metal organic framework (MnCr-MOF- τ) on nickel foam (NF) where τ represents, the duration of the electrodeposition time in minutes. The same procedure was used to deposit cobalt nickel iron layered double hydroxide (CoNiFe-LDH) on MnCr-MOF-20 min to form the MOF-20 min @ CoNiFe-LDH. The synergetic effect of the highly porous MOF with a metal centre and branches with enhanced conductivity increases the performance of the composite. The high reversible redox kinetics of the LDH endowed the composite electrode with high electrochemical performance. The electrode yielded a specific capacity of 296 ± 5 mAh g−1 at a specific current of 0.5 A g−1 in a 3-electrode set-up with a high-capacity retention of 70.4 % after 5, 000 galvanostatic charge discharge (GCD) cycles in 2 M KOH electrolyte. The composite was incorporated into a supercapacitor device with activated carbon from Amarula husk (AMH) as the negative electrode. The fabricated MOF-20 min @ CoNiFe-LDH//AMH device produced a high electrochemical performance in a 2-electrode set-up with a specific energy of 76.6 ± 0.5 Wh kg−1 at a specific power of 724.9 ± 0.5 W kg−1. The device also showed great stability with a capacity retention of 81.2 ± 0.5 % after 10, 000 GCD cycles at 10 A g−1.