Fabrication of FeOx-Decorated on Ethanol Pretreated Ti Grids for Asymmetric Supercapacitors

FeOx grown on titanium grids were synthesized by a hydrothermal approach and their electrochemical properties were investigated. Among all FeOx materials, FeOOH-decorated Ti grid with ethanol dried (Ti@FeOOH-1) exhibits a higher specific capacitance (159.7 F g^-1 at a current density of 0.5 A g^-1) than that of Fe₂O₃-decorated Ti grid with ethanol dried (Ti@Fe₂O₃-1) (51.9 F g^-1 at a current density of 0.5 A g^-1). However, the capacitance retention of Ti@Fe₂O₃-1 after 1000 cycles is about 83.3% of the initial capacitance while Ti@FeOOH-1 only keeps cycling performance with 67.7% retention. Considering the importance of high specific capacitance for supercapacitor, we chose Ti@FeOOH-1 as the electrode material in our experiment. An asymmetric supercapacitor was successfully fabricated using Ti@MnO₂ as the positive electrode and Ti@FeOOH-1 as the negative electrode. The tests show that the asymmetric supercapacitor has high specific capacitance (77 F g^-1 at a current density of 1 A g^-1) and excellent cycling ability (97.5% retention after 1000 cycles). The synthesis of FeOx grown on titanium grids brings new probability to design a potential negative electrode material for supercapacitors.