Boosted crystalline/amorphous Fe2O3-δ core/shell heterostructure for flexible solid-state pseudocapacitors in large scale. (March 2018)

• Record Type: Journal Article
• Authors: Sun, Shuo; Zhai, Teng; Liang, Chaolun; Savilov, Serguei V.; Xia, Hui
• Is Part Of: Nano energy. Volume 45(2018)
• Page Start: 390
• Page End: 397
• Publication Date: 2018-03
• Subjects: Pseudocapacitors -- Hematite -- Amorphous layer -- Oxygen defects -- Interface -- Large-scale; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2018.01.015
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Poor electronic conductivity and sluggish ion diffusion are the two main obstacles that limit the pseudocapacitive performance of Fe2 O3 . In this work, oxygen-deficient Fe2 O3-δ nanorod arrays with a unique crystalline core/amorphous shell heterostructure are prepared via a facile and controllable method. The tunable amorphous layer facilitates the Li + diffusion while introduced oxygen defects in Fe2 O3 can be effectively tuned to improve electronic conductivity. More importantly, the resultant crystalline/amorphous interface greatly increases charge storage sites for improved specific capacitance. Consequently, the crystalline core/amorphous shell Fe2 O3-δ integrated on graphene delivers a large capacitance of 701 F g −1 (701 mF cm −2 ) at 1 A g −1, which is almost double the capacitance of the conventional Fe2 O3-δ nanorods without amorphous surface layer on graphene. Besides large capacitance, the electrode also exhibits greatly improved rate capability and cycle performance. To construct asymmetric supercapacitor, similar strategy is implemented to prepare Co3 O4-δ nanosheet arrays with superior pseudocapacitive performance compared to its pristine counterpart. Importantly, flexible and large-scale (10 × 10 cm 2 ) asymmetric supercapacitors are fabricated with promising device performance, demonstrating the smart electrode design is promising for practical application. Graphical abstract: A unique crystalline core/amorphous shell heterostructure is developed for the Fe2 O3-δ nanorods (ASV-FO). The tunable amorphous layer and oxygen vacancies endow the electrode with fast ion and electron transport, respectively. Importantly, the induced crystalline/amorphous interface can provide extra sites for Li + storage. The ASV-FO electrode exhibits greatly enhanced pseudocapacitive performance and is successfully applied in flexible and solid-state pseudocapacitors in large scale.fx1 Highlights: A unique Fe2 O3-δ crystalline core/amorphous shell heterostructure is developed. Amorphous layer and oxygen defect are tuned simultaneously via a facile method. The resultant crystalline/amorphous interface provides extra sites for Li + storage. A high-performance solid-state pseudocapacitor is assembled in large-scale (10 × 10 cm 2 ).