Hierarchical carbon aerogels via catalyst-free spinodal engineering: A pathway to sustainable high-performance supercapacitors

Despite considerable progress in porous carbons, there is still a need for methods that couple phase separation and carbonization to produce thick, binder free monoliths that combine continuous electron pathways with rapid ion access for high performance supercapacitor electrodes. Here, spinodal decomposition is employed to synthesize aerogels with tunable hierarchical pore structures by varying the ratios of resorcinol, formaldehyde, and water. After carbonization, the aerogels show enhanced mechanical strength, surface area, and electrical conductivity. The optimized sample exhibits a compressive modulus of approximately 1.67 GPa and an electrical conductivity of approximately 55 S m−1 and delivers a specific capacitance of 339.2 F g−1 at 0.5 A g−1 in 6 M KOH with approximately 98.4 percent retention over 40,000 cycles. A symmetric coin cell supercapacitor using 1 M tetraethylammonium tetrafluoroborate in acetonitrile achieves 22.9 Wh kg−1 at 1000 W kg−1 and approximately 98.38 percent stability after 100,000 cycles. These properties arise from a continuous coral like architecture that shortens ion diffusion paths and promotes rapid transport. In addition, a long short term memory model is used to model and forecast cycling stability, in agreement with the experimental trends. Overall, this catalyst free spinodal approach offers a practical pathway to high performance, hierarchically porous carbon aerogels for next generation supercapacitors and related energy storage systems.