Effect of in situ annealing on pulsed laser ablated mixed metal oxide (BixMyOz; M=Mn, Mo) thin film electrodes for flexible hybrid supercapacitor devices

Abstract

Recently, solid-state thin film hybrid supercapacitor devices (TFHSCs) have had greater attention due to their miniaturized device assembly, portability, and superior cycling stability. Herein, for the first time, we assembled BiMnxOy ǁ PVA-KOH ǁ Bi2MoO6 thin-film solid-state supercapacitor devices by pulsed laser deposition (PLD) technique. In the present work, Bi2MoO6 and BiMnxOy thin film electrodes are fabricated at in-situ annealed conditions and their structural, morphological, and electrochemical performances are examined distinctly. We assembled a thin-film based BiMnxOy ǁ PVA-KOH ǁ BiMnxOy symmetric supercapacitor device (SSD) and that device delivers a functioning voltage of 1.4 V. Also, the device exhibits an extremely specific areal capacitance of 41 mF cm−2 at 1 mA cm−2. Similarly, a thin film-based Bi2MoO6 ǁ PVA-KOH ǁ Bi2MoO6 SSD attained a maximum specific areal capacitance of 13.33 mF cm−2. Further, the assembled BiMnxOy ǁ PVA-KOH ǁ Bi2MoO6 TFHSC device delivers a voltage of 1.6 V and the TFHSC device exhibited a maximum specific areal capacitance of 52 mF cm−2 at a fixed current density of about 2 mA cm−2. The BiMnxOy ǁ PVA-KOH ǁ Bi2MoO6 TFHSC device shows outstanding stability performances such as 99 % of capacitance retention as well as 93 % of coulombic efficiency after 25,000 charge/discharge cycles. Additionally, the TFHSC device delivers a maximum areal energy density and power density of 18.5 μWh.cm−2, and 978.7 μW cm−2, respectively.