Bendable all-solid-state asymmetric supercapacitors based on MnO₂ and Fe₂O₃ thin films

Abstract

The growing interest in portable and consumable electronics demands efficient and low-cost energy storage devices with excellent flexibility and of light weight. We demonstrate flexible high-performance all-solid-state thin-film asymmetric supercapacitors (ASSTF-ASCs) using α-MnO₂ and α-Fe₂O₃ thin films as positive and negative electrodes, respectively. The as-fabricated ASSTF-ASC devices have excellent electrochemical performance with extended potential window of 2.0 V and excellent cycling stability for 2500 cycles. Impressively, an MnO₂//Fe₂O₃ asymmetric cell demonstrates high specific capacitance of 145 F g¯¹ with a high energy density of 41 Wh kg¯¹ while maintaining a power density of 2.1 kW kg¯¹. A parallel combination of two MnO₂//Fe₂O₃ asymmetric cells is able to illuminate a panel of 31 light emitting diodes (LEDs). These findings may offer new opportunities for the use of asymmetric configurations in energy storage devices for various portable electronic systems.