Exploring synergistic effects of polyaniline and carbon dots as capacitance enhancers on hybrid asymmetric brochantite/malachite//corn leaf-derived activated carbon supercapacitor

Asymmetric supercapacitors (ASCs) have emerged as promising, high-performance energy storage devices owing to their broad operating voltage range, which significantly improves their energy and power densities. This work thus developed a hybrid ASC consisting of the copper hydroxy compound, brochantite/malachite (BM), as a positive electrode, and the corn leaf-derived activated carbon (AC) as a negative electrode, utilizing dual-hybrid capacitive mechanisms. BM is a promising positive electrode material due to its favorable faradaic reaction, whereas the corn leaf-derived AC displayed a high surface area of 898.3 m 2 g −1 with micropores, enabling for a non-faradic storage mechanism at a negative electrode. The effects of different capacitance enhancers were further studied by investigating the capacitance efficiency of each electrode after adding corn leaf-derived carbon dot (CD) and polyaniline (PANI). According to Dunn's calculation, the results demonstrate that the addition of 10 %wt PANI to both the positive (BM-P10) and negative (AC-P10) electrodes produced the maximum capacitance and energy density due to the enhancement of pseudocapacitive behavior. At a current density of 1 A g −1 , the assembled BM-P10//AC-P10 ASC device at an operating voltage window of 1.5 V achieved a capacitance of 187 F g −1 , an energy density of 58.4 W h kg −1 , a power density of 1498.5 W kg −1 , and a capacitance retention of 73.3 % after 10,000 cycles. This work will lead to the development of sustainable and effective supercapacitor for energy storage applications and also provide an alternative way for utilizing biomass materials in the energy sector. • Asymmetric supercapacitor (ASC) consisted of copper-based and carbon electrodes. • Effects of polyaniline and carbon dots on both electrode performances were studied. • The addition of 10 %wt polyaniline displayed a better pseudocapacitive enhancement. • The ASC displayed a wider operating voltage window of 1.5 V. • The ASC exhibited 187 F g −1 and 58.4 W h kg −1 at 1 A g −1 .