Electrodeposition of Cobalt‐Copper Oxides Decorated with Conductive Polymer for Supercapacitor Electrodes with High Stability

Abstract

Here, we report about the synthesis of Cobalt‐Copper (CC) mixed oxides prepared by electrodeposition and thermal annealing, and coated with PEDOT:PSS (CCP) for supercapacitor electrodes. The electrodes’ morphology and electrochemical performance were investigated by combining XRD, XPS, SEM, cyclic voltammetry, and galvanostatic charge/discharge tests. The initial capacity of the CC electrode was 26 mAh/g at a scan rate of 5 mV/s with a coulombic efficiency of 92 %. The CC electrode featured a capacity retention of 81 % at a constant current density of 1 A/g after 5000 cycles. CCP electrodes slightly reduced the specific capacity but increased both coulombic efficiency and cyclic stability. CCP1 electrode featured a specific capacity of 21 mAh/g at 5 mV/s scan rate with better coulombic efficiency 95 % along with capacity retention of 92.3 % over 5000 cycles. Increasing the amount of PEDOT:PSS lowered the CC electrodes’ specific capacity, but significantly improved the capacity retention up to 100 %.

Electrodeposited Cobalt–Copper mixed oxides for supercapacitor electrodes and investigation of the Co/Cu ratio on the electrochemical performance

“…According to the table and comparison of intensity values, it is well understood that the spinel phase peaks are more evident within the CC4 sample, indicating that more spinel phase has been formed in this coating. These results are consistent with previous reports [32][33][34].…”

“…8 °, 59.3 °, and 65.2° indexed to the (220), (311), (400), (511), and (440) planes of the cubic phase of Co 3 O 4 which is in agreement with standard JCPDS data[31,32]. CuO sample shows well-defined peaks at different angles which are marked with a black symbol in Fig.1a.…”

“…Based on the integral of the CV cathodic current over time, the specific capacity of the electrodes was calculated, using Eq. ( 8) [32]: where m is the mass of the materials.…”

“…In order to calculate the specific capacity of the electrodes from the galvanostatic discharge curves, Eq. ( 9) was used [32]:…”

“…Among the various methods deployed for spinel synthesis [23][24][25][26][27][28][29][30], electrochemical deposition is considered a fast and direct preparation of the supercapacitor electrode method. Electrochemical deposition methods have been widely used due to easy composition control and high deposition rate as well as low cost compared to other multistep routs [30][31][32]. The formation and percentage of spinel phase in the coating structure depend on the synthesis method and the ratio of cobalt and copper elements during deposition.…”