Self-sacrifice-template epitaxial growth of hierarchical MnO2@NiCo2O4 heterojunction electrode for high-performance asymmetric supercapacitor

Yuantao Li; Jiajun Zhu; Jiyang Xie; Yongyun Mao; Wanbiao Hu

doi:10.1016/j.jcis.2023.07.062

Self-sacrifice-template epitaxial growth of hierarchical MnO₂@NiCo₂O₄ heterojunction electrode for high-performance asymmetric supercapacitor

J Colloid Interface Sci. 2023 Nov 15;650(Pt B):1113-1124. doi: 10.1016/j.jcis.2023.07.062. Epub 2023 Jul 13.

Authors

Yuantao Li¹, Jiajun Zhu¹, Jiyang Xie², Yongyun Mao³, Wanbiao Hu⁴

Affiliations

¹ Key Laboratory of LCR Materials and Devices of Yunnan Province, National Center for International Research on Photoelectric and Energy Materials, School of Materials and Energy, Yunnan University, Kunming 650091, PR China.
² Key Laboratory of LCR Materials and Devices of Yunnan Province, National Center for International Research on Photoelectric and Energy Materials, School of Materials and Energy, Yunnan University, Kunming 650091, PR China; Electron Microscopy Center, Yunnan University, Kunming 650091, PR China.
³ Key Laboratory of LCR Materials and Devices of Yunnan Province, National Center for International Research on Photoelectric and Energy Materials, School of Materials and Energy, Yunnan University, Kunming 650091, PR China; Electron Microscopy Center, Yunnan University, Kunming 650091, PR China; Yunnan Key Laboratory of Carbon Neutrality and Green Low-carbon Technologies, Kunming 650091, PR China. Electronic address: maoyongyun123@126.com.
⁴ Key Laboratory of LCR Materials and Devices of Yunnan Province, National Center for International Research on Photoelectric and Energy Materials, School of Materials and Energy, Yunnan University, Kunming 650091, PR China; Electron Microscopy Center, Yunnan University, Kunming 650091, PR China. Electronic address: huwanbiao@ynu.edu.cn.

PMID: 37467640
DOI: 10.1016/j.jcis.2023.07.062

Abstract

Constructing three-dimensional (3D) hierarchical bimetallic pseudocapacitive materials with abundant opening channel and heterojunction structures is rather promising but still challenging for high-performance supercapacitors. Herein, a self-sacrifice-template epitaxial growth strategy was proposed for the first time to construct 3D hierarchical bimetallic pseudocapacitive material. By using this strategy, NiCo₂O₄ nanowires (NiCo₂O₄NW) arrayed randomly to form a porous shell via in-situ epitaxial growth fully enclosing a MnO₂ tube core, forming multiple transport channels and nano-heterojunctions between MnO₂ and NiCo₂O₄NW, which facilitates electron transfer, i.e. exhibiting high electronic conductivity than any single component. As a result of the self-sacrifice-template epitaxial growth method, special hollow tectorum-like 3D hierarchical structure with considerable inter-nanowire space and hollow interior space enables easy access of electrolyte to NiCo₂O₄NW surface and MnO₂ core, thereby resulting in highly exposed redox active sites of MnO₂ core and NiCo₂O₄NW shell for energy storage. Comprehensive evaluations confirmed MnO₂@NiCo₂O₄NW was a supercapacitor electrode candidate, delivering a superior energy density of 106.37 Wh kg^-1. Such performance can be ascribed to the synergistic coupling effect of 3D hierarchical tube and nano-heterojunction structures. The proposed self-sacrifice-template epitaxial growth strategy provides important guidance for designing high-performance energy storage materials.

Keywords: 3D hierarchical structure; Epitaxial growth strategy; Nano-heterojunction; Self-sacrifice-template method; Supercapacitor; Tube.