Electrochemical performance enhancement of symmetric supercapacitors with nanocomposite activated peanut shell carbon@silver nanowire/nanoparticle electrodes

Silver nanowires (AgNWs)/nanoparticles (AgNPs) (referred to as AgNWPs) were synthesized using a polyol method. Activated peanut shell carbon (APC) was obtained by KOH activation of peanut shell carbons (PCs). Nanocomposites of PCs, APCs, and carbon black acetylene (AB) with AgNWPs (referred to as PCs@AgNWPs, APCs@AgNWPs, and AB@AgNWPs, respectively) were prepared for use as electrodes of electrical double layer capacitors (EDLCs). X-ray diffraction (XRD) results revealed a cubic crystalline phase of AgNWPs, while amorphous and graphitic phases were found in PCs and APCs, as verified by Raman spectroscopy. Environmental scanning electron microscopy (E-SEM) and transmission electron microscopy (TEM) displayed AgNPs adhering to the surfaces of AgNWs. The Surface area of APCs was five times higher than that of PCs, as determined by BET (Brunauer-Emmett-Teller) and BJH (Barrett-Joyner-Halenda) techniques. The Electrochemical testing of all electrodes was performed. Interestingly, all nanocomposite electrodes exhibited improved electrochemical performance. The highest specific capacitance (Cs) of 387.71 F g−1 at 0.5 A g−1 and 105.26% capacity retention at 20 A g−1 for 10,000 charge/discharge test cycles was achieved for an APC@AgNWPs electrode. An assembled symmetric supercapacitor (SSC) APC@AgNWPs//APC@AgNWPs device illustrated good performance with Cs of 89.38 F g−1 at 1 A g−1 and capacity retention of 78.49%.