Supercapacitive performances of mesoporous tremella-like CoFe2O4/C electrode material

Abstract

Ferrous gluconate has been widely used in the treatment of iron deficiency anemia due to good therapeutic effect, high utilization and low toxicity. However, the improper management of waste expired ferrous gluconate may also result in the flow of excessive Fe²⁺ into the environment, which may do harm to the organisms in the world. For this purpose, expired waste ferrous gluconate was firstly recycled in form of CoFe₂O₄/C by a fluid method and a post-calcination at the different temperatures of 400°C and 500°C, and the effect of the calcination temperature on the morphology, micro-structure and super-capacitive performances was also studied. The results showed that the obtained dark brown CoFe₂O₄/C powders exhibited the loose mesoporous tremella-like morphology and satisfactory electrochemical super-capacitive performances, in which CFO-400 delivered higher electrochemical performances than CFO-500 due to lower crystalline, higher electrical conductivity and higher surface area. For example, the specific capacitance of CFO-400 electrode was as high as about 503 F/g at 0.5 A/g in the three-electrode system, and it remained 106 F/g after 5000 cycles at 5.0 A/g with 86 % capacity retention in the symmetrical two-electrode capacitor, showing the satisfactory long cycle stability. No doubt, these results provided a new successful recovery strategy for the circular economy of expired ferrous gluconate.