Sodium Ion Capacitor Using Pseudocapacitive Layered Ferric Vanadate Nanosheets Cathode

Qiulong Wei; Yalong Jiang; Xiaoshi Qian; Liang Zhang; Qidong Li; Shuangshuang Tan; Kangning Zhao; Wei Yang; Qinyou An; Jinghua Guo; Liqiang Mai

doi:10.1016/j.isci.2018.07.020

Sodium Ion Capacitor Using Pseudocapacitive Layered Ferric Vanadate Nanosheets Cathode

iScience. 2018 Aug 31:6:212-221. doi: 10.1016/j.isci.2018.07.020. Epub 2018 Jul 26.

Authors

Qiulong Wei¹, Yalong Jiang², Xiaoshi Qian³, Liang Zhang⁴, Qidong Li², Shuangshuang Tan², Kangning Zhao², Wei Yang², Qinyou An⁵, Jinghua Guo⁴, Liqiang Mai⁶

Affiliations

¹ State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China; Department of Materials Science and Engineering, University of California Los Angeles, Los Angeles, CA 90095, USA.
² State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China.
³ Department of Materials Science and Engineering, University of California Los Angeles, Los Angeles, CA 90095, USA.
⁴ Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
⁵ State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China. Electronic address: anqinyou86@whut.edu.cn.
⁶ State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China. Electronic address: mlq518@whut.edu.cn.

Abstract

Sodium ion capacitors (SICs) are designed to deliver both high energy and power densities at low cost. Electric double-layer capacitive cathodes are typically used in these devices, but they lead to very limited capacity. Herein, we apply a pseudocapacitive layered ferric vanadate (Fe-V-O) as cathode to construct non-aqueous SICs with both high energy and power densities. The Fe-V-O nanosheets cathode displays remarkable rate capability and cycling stability. The pseudocapacitive sodium storage mechanism of Fe-V-O, with over 83% of total capacity from capacitive contribution, is confirmed by kinetics analysis and ex situ characterizations. The capacitive-adsorption mechanism of hard carbon (HC) anode is demonstrated, and it delivers excellent rate capability. Based on as-synthesized materials, the assembled HC//Fe-V-O SIC delivers a maximum energy density of 194 Wh kg^-1 and power density of 3,942 W kg^-1. Our work highlights the advantages of pseudocapacitive cathodes for achieving both high energy and power densities in sodium storage devices.

Keywords: Electrochemical Energy Storage; Energy Materials; Nanoelectrochemistry.