Design and growth of SrO/CNTs composite electrode for high-performance asymmetric supercapacitor

Although transition metal oxides (TMOs) were extensively investigated as electrodes materials in supercapacitor devices, their higher pricing and availability constraints prevent for wide spread uses. In contrast, alkaline earth metal oxides like SrO are typically unnoticed for energy storage applications, despite their cost-effectiveness, natural abundance, chemical stability, and naturally promising properties. In order to fill this gap, we present the preparation of pure SrO and its composites with carbon nanotubes (SrO/CNT-25 and SrO/CNT-50) by hydrothermal method, and studied the effect of incorporating CNTs into a SrO framework to improve the capacity of energy storage systems (ESSs). The structural, morphological, and compositional studies of prepared were investigate using XRD, SEM, and XPS analysis respectively. The electrochemical activity is assessed using a three-electrode setup, demonstrating that the SrO/CNT-25 composite possesses a superior specific capacitance of 226.55 F/g and a prolonged maximum discharge time compared to SrO and SrO/CNT-50. The SrO/CNT-25 demonstrated good capacitive contributions (32.2 %) and diffusive contribution (65.8 %) at a scan rate of 125 mV/s. Moreover, Asymmetric supercapacitor (ASSC) was fabricated by active materials (SrO/CNT-25) and activated carbon which employ as the positive and negative electrode accordingly. The ASSC device shows a specific capacity of 385 C/g, with energy density of 45.41 Wh/kg, power density of 7500 W/kg, capacity retention of 95.98 % and coulombic efficiency of 99.18 % after 3000 charging and discharging cycles. The present results represented the novelty of applying the SrO/CNTs-25//AC device for sustainable ESSs. The synergistic impact between SrO and CNTs enhances interfacial transfer of charge and electrochemical presentation that offering a sustainable and economical alternative to traditional TMO-based ESSs.