Enhancement of Capacitive Behavior of Porous Carbon Derived from the Mixed Oil-Based Carbon Precursor

Abstract To address increasingly pressing energy and environmental challenges, developing green, high-performance energy storage systems is paramount. Supercapacitors (SCs) garner significant attention due to their high-power density and long cycle life. However, their performance largely depends on advanced electrode materials that combine a high specific surface area with excellent electrical conductivity. Porous carbon (PC) is obtained via the chemical activation process for the mixed carbon precursor of petroleum coke and waste tire oil. Besides, the in-situ S and N incorporation into the carbon skeleton of PC is also realized during the activation process due to the enrichment of S and N elements in the carbon precursor. The systematic structural characterization reveals that PC possesses a specific surface area of up to 2272 m2 g−1, a hierarchical pore structure, and good hydrophilicity. As an electrode for SCs, the PC electrode exhibits a high specific capacitance of 320 F g−1 at 1 A g−1 in the aqueous electrolyte. Even at an extremely high current density of 100 A g−1, it still retains 88.12% of its initial capacity, demonstrating excellent rate capability. In addition, the PC electrode also affords superior capacitive behavior in terms of capacitance and rate capability in the organic electrolyte, embodying its extraordinary compatibility with different electrolyte systems. Moreover, the PC electrode still delivers satisfactory gravimetric and areal capacitances even at high mass loading of 10 mg cm−2. The Li-ion capacitor fabricated with PC presents extraordinary electrode performance with respect to rate capability, durability, and Ragone performance. This research not only offers novel approaches for the high-value utilization of petroleum coke and waste tire oil but also provides theoretical guidance and practical pathways for designing and preparing high-performance carbon-based electrode materials for SCs.