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Date of Award

2017

Document Type

Campus Access Master's Thesis

Degree Name

Master of Science in Materials Science and Engineering (MS)

Administrative Home Department

Department of Materials Science and Engineering

Advisor 1

Yun Hang Hu

Committee Member 1

Joshua M. Pearce

Committee Member 2

Shiyue Fang

Abstract

Transition metal oxides have attracted much attention for electrode materials of supercapacitors due to their outstanding capacitive behavior. One of them is NiMoO4 with the high electrochemical activity of Ni. Constricted by its intrinsically poor electrical conductivity and limited electroactive sites of aggregated NiMoO4, the capacitive performance of NiMoO4 are far below expectation. Directly growth of NiMoO4 on nickel foam to fabricate binder-free electrodes is proposed to solve the issues. In this thesis, we successfully constructed interconnected NiMoO4 nanosheets on the Ni foam by a designed reaction between H2MoO4 aqueous solution and Ni foam. The effects of H2MoO4 concentration and reaction time were systematically investigated. The best electrochemical performance of NiMoO4 electrodes can be obtained with 0.005 M H2MoO4 for 80 hours. The maximum areal capacitance can reach 0.724 F/cm2 followed with outstanding rate capability (70.1% capacitance retention when current density increase from 1 mA/cm2 to 10 mA/cm2). The excellent areal capacitance and rate capability may be attributed to its interconnected NiMoO4 nanosheets and good adhesion between electroactive materials and current collector.

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