The synthesis of Co3O4/C composite with aloe juice as the carbon aerogel substrate for asymmetric supercapacitors

Transition metal oxide (TMO)-based 3D hollow nanocomposites with a high loading capacity, large specific surface area, and good dispersity have gained considerable attention for energy-related applications. The controllable fabrication of TMO-based hollow nanostructures with adequate mass transfer channels through a simple and eco-friendly method is highly desirable. Herein, 3D net-like Co3O4/C composites were solvothermally fabricated and calcined using aloe juice as a novel carbon substrate. The as-prepared material showed a specific capacitance of 1345.2 F g−1 at 1 A g−1 and excellent charge–discharge stability with capacitance retention of 92.7% after 10000 cycles. Moreover, an asymmetric supercapacitor composed of an ALC-700 positive electrode and an active-carbon negative electrode exhibited a high energy density of 68.17 Wh⋅kg−1 at 549 W kg−1 and excellent cycling performance. We report the first use of carbonized aloe juice as a carbon matrix to obtain a 3D hierarchical porous structure for energy devices. The proposed method of aerogel can be generalized to utilize the juices of other fruits, sugarcane, and various plants.