Enhancing activated carbon supercapacitor electrodes using sputtered Cu-doped BiFeO3 thin films
Nantawat Tanapongpisit, Suchunya Wongprasod, Peerawat Laohana, Somchai Sonsupap, Jessada Khajonrit, Supansa Musikajaroen, Unchista Wongpratat, Benjaporn Yotburut, Santi Maensiri, W. Meevasana, Wittawat Saenrang
Abstract
This work describes the fabrication of a composite supercapacitor electrode made of Cu-doped BiFeO $$_3$$ (Cu-BFO) films on an activated carbon (AC) electrode using radio-frequency (RF) magnetron sputtering. To prevent exfoliation of Cu-BFO and AC upon immersion in an electrolyte, the nickel foam sandwiching electrode technique was introduced. The Cu-BFO films significantly enhanced electrochemical properties, increasing specific capacitance by up to 151% compared to that of an AC electrode. This was attributed to Faradaic reactions and specific surface area in the Cu-BFO/AC electrode. The highest specific capacitance achieved was 169 F $$\hbox {g}^{-1}$$ at 0.5 A $$\hbox {g}^{-1}$$ , and cycling stability retention was 93.12% after 500 cycles. However, the remaining percentage of the specific capacitance decreased differently with increasing thickness, which is also discussed. Furthermore, an asymmetric supercapacitor using Cu-BFO/AC and AC electrodes demonstrated a high energy density of 4.71 Wh $$\hbox {kg}^{-1}$$ , power density of 2.66 kW $$\hbox {kg}^{-1}$$ , and over 90% retention after 1000 cycles, highlighting its durability. The uniform RF magnetron sputtering deposition is vital for mass production. Combined with impressive retention in asymmetric supercapacitors, this scalability suggests a promising pathway for large-scale manufacturing. Consequently, this work could pave the way for the large-scale production of supercapacitors.