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 Wkg(-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. (C) 2019 Elsevier Ltd. All rights reserved.