An approach to substitute costly-commercial capattery electrodes by activated carbon@Co with advanced retention: Detailed device study supported by DFT investigation

Modern technological development requires researchers to develop cost-effective materials for energy storage/ conversion device. The activated carbon, its composite with oxyhydroxide opens new areas for making low-cost commercial sustainable devices synthesized by hydrothermal method. Here, we have broadly compared the different types (Al, Co, Ni) of oxyhydroxide carbon composite for energy storage with detailed theoretical investigations. The detailed DFT simulation is done to see the electronic properties by evaluating the total density of the state and the orbital contribution of the density of the state along with the band structure. The band structure and orbital contribution of DOS show the metallic nature of the CoOOH and the quantum capacitance (QC) obtained for pure CoOOH is 3000 mu F. The crucial finding of the research is broad comparative electro-chemical performance, with surface area variation for all electrode materials AlOOH@activated carbon, CoOOH@activated carbon, and NiOOH@activated carbon, respectively. The specific capacitance value for otimized CoOOH@activated carbon, from cyclic voltammetry, is 230 F g(-1) at 10 mV/s. The bulk and charge transfer resistance calculated for CoOOH@activated carbon (Co@AC) is, respectively 0.82 Omega and 1.18 Omega. The energy, and power density values for CoOOH@AC are 37.34 W h kg(-1) and 4200 W kg(-1) at a current density of 2 A g(-1). The capacitance retention and Columbic efficiency for Co@AC are 72, and 96 % for Co@AC till the last 20,000 segments of GCD. Overall, out of all electrode, the devices with Co@AC electrode shows very promising performance. The fabricated device can glow 26 LED panels for 5 min.