Freestanding NiFe Oxyfluoride Holey Film with Ultrahigh Volumetric Capacitance for Flexible Asymmetric Supercapacitors

Kun Liang; Kyle Marcus; Zhenzhong Yang; Le Zhou; Hao Pan; Yuanli Bai; Yingge Du; Mark H Engelhard; Yang Yang

doi:10.1002/smll.201702295

Freestanding NiFe Oxyfluoride Holey Film with Ultrahigh Volumetric Capacitance for Flexible Asymmetric Supercapacitors

Small. 2018 Jan;14(3). doi: 10.1002/smll.201702295. Epub 2017 Nov 14.

Authors

Kun Liang¹, Kyle Marcus¹, Zhenzhong Yang², Le Zhou³, Hao Pan⁴, Yuanli Bai⁴, Yingge Du², Mark H Engelhard⁵, Yang Yang^{1

3}

Affiliations

¹ NanoScience Technology Center, University of Central Florida, Orlando, FL, 32826, USA.
² Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
³ Department of Materials Science and Engineering, University of Central Florida, Orlando, FL, 32826, USA.
⁴ Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, FL, 32816, USA.
⁵ Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.

PMID: 29134753
DOI: 10.1002/smll.201702295

Abstract

In this work, a freestanding NiFe oxyfluoride (NiFeOF) holey film is prepared by electrochemical deposition and anodic treatments. With the combination of good electrical conductivity and holey structure, the NiFeOF holey film offers superior electrochemical performance with maximum specific capacitance of 670 F cm^-3 (134 mF cm^-2 ), due to the following reasons: (i) The residual metal alloy framework can be used as the current collector to improve electrode conductivity. Moreover, the as-prepared freestanding NiFeOF holey film can be used as a supercapacitor electrode without reliance on binders and other additives. The residual metal alloy framework and binder-free electrode effectively reduce electrode resistance, thus improving electron transport. (ii) The highly interconnected holey structure and hierarchical pore distribution provide a high specific surface area to improve electron transport, enhancing rapid ion transport, and mitigating diffusion limitations throughout the holey film. (iii) The excellent mechanical characteristics facilitate flexibility and cyclability related performance. Additionally, the NiFeOF holey film presents exceptional electrochemical performance, showing that it is a promising alternative for small/microsize electronic devices.

Keywords: holey films; oxyfluoride; porous structures; supercapacitors; volumetric capacitance.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.
Research Support, Non-U.S. Gov't