In situ self-assembly of SiO2 coating Co3O4/graphene aerogel and its enhanced electrochemical performance for supercapacitors

The SiO₂@Co₃O₄/GA composite with double-coating structure was successfully synthesized through an in situ self-assembly method. Microstructure measurements showed that the SiO₂ film coating the Co₃O₄ and then anchored on the plicated GA together to realize coating again. In this preparation process can form more stable Si–O–Co so its performance has a marked improvement. This structure not only can improve the capacitance of GA but also can effectively reduce the large volumetric expansion and aggregation of Co₃O₄. The electrochemical performance were charactered by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS). The SiO₂@Co₃O₄/GA exhibited a high capacitance of 620 F g⁻¹ at the current of 1 A g⁻¹ in 6 M KOH. After 1000 cycles, it displayed a good cycling ability of 94% capacitance retention. The excellent performance due to the interaction between SiO₂ and Co₃O₄ in the in situ self-assembly preparation process. The joint effort make it more stable and sustainable. Its superior performance suggest that SiO₂@Co₃O₄/GA has an tremendous potential in energy application.