Fabrication of nanoporous metal core/oxide shell structure using equiatomic AlCoCrFeNi high entropy alloy (HEA) and its electrochemical property as supercapacitor electrode have been investigated in the present study. As-cast AlCoCrFeNi HEA consists of interconnected Al–Ni rich and Cr–Fe rich phases by spinodal phase separation. Nanoporous structure can be obtained by selectively dissolving the Al–Ni rich phase and retaining the remaining Cr–Fe rich phase by passivation in sulfuric acid solution at 313 K. In particular, the scale of nanoporous structure in the present study is predictable since it only depends on the scale of original spinodal-decomposed microstructure in as-cast state. When used as a binder free electrode for supercapacitor, Cr–Fe rich nanoporous structure exhibits high volumetric capacitance of 700 F cm−3 and excellent cycling stability of over 3000 cycle. As the microstructural scale in as-cast state becomes finer, the nanoporous structure exhibits better capacitance properties. The present result shows that Cr–Fe rich nanoporous metal core/oxide shell has a good potential for application as supercapacitor electrode.
Bibliographical noteFunding Information:
This research was supported by Basic Science Research Program through the National Research Foundation by the Ministry of Science, ICT and future Planning ( 2016R1A2B2013838 ). W.T. Kim acknowledges the support from Cheongju University through 2017 sabbatical leave program.
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Energy Engineering and Power Technology
- Physical and Theoretical Chemistry
- Electrical and Electronic Engineering