An easy way of synthesizing low-cost carbon nanomaterials without the need for a high-temperature processing approach is critical for energy storage applications because the demand has increased for affordable, long-term, and environmentally friendly synthesized carbon-based materials. Herein, we have synthesized multilayered graphitic carbon nanoonions (CNOs) using the oil-wick flame pyrolysis approach, employing biowaste (chicken fat) oil as a cost-effective precursor. The prepared CNOs can provide enhanced ion movement, and less resistance for electron transport by interconnecting CNO particles with one another. Furthermore, hetero atoms (S, N)-doped CNOs (h-CNOs) were synthesized to optimize the hydrophilic and conductive properties of carbon materials, which eventually exalt the capacitive charge transfer kinetics. The h-CNOs demonstrated a superior, highest specific capacitance of 261 F/g, while the un-doped CNOs showed a capacitance of 180.6 F/g at a current density of 1 A/g. In addition to the capacitance, the h-CNOs also demonstrated a rate capability of 69% and good cycling stability of 97.5% under high current densities. The asymmetric supercapacitor was fabricated using the h-CNOs as the negative and MCS (MnCo2S4) as the positive electrode. The device showed high energy and power performance of 32.8 Wh/kg and 7350 W/kg, respectively, with capacitance retention of 97% over 5000 cycles. Considering the facile strategic way to produce novel carbonaceous material derived from biowaste oil (chicken fat oil), this could be considered a potential advantage for commercial energy storage devices and may open the door to producing inexpensive, industrially revolutionizing energy storage devices.
