Unlocking the Potential of Oxygen-Deficient Copper-Doped Co3O4 Nanocrystals Confined in Carbon as an Advanced Electrode for Flexible Solid-State Supercapacitors

• Published in: ACS energy letters 2021-09, Vol.6 (9), p.3011-3019
• Main Authors: Liu, Shude, Kang, Ling, Hu, Jisong, Jung, Euigeol, Zhang, Jian, Jun, Seong Chan, Yamauchi, Yusuke
• Format: Article
• Language: eng ; jpn
• ISSN: 2380-8195; 2380-8195
• DOI: 10.1021/acsenergylett.1c01373

Battery-type materials for supercapacitors have attracted increasing research interest owing to their high energy density. However, their poor electrode kinetics severely limit the utilization of redox-active sites on the electrode surface, resulting in subpar electrochemical performance. Herein, we incorporate both Cu dopants and O vacancies into Co3O4 nanocrystals confined in a carbon matrix (Ov-Cu-Co3O4@C) which are assembled into nanowires. This heterostructured architecture with multifunctional nanogeometries provides a high intercomponent synergy, enabling high accessibility to active species. Moreover, the Cu dopants and O vacancies in Ov-Cu-Co3O4@C synergistically manipulate the electronic states and provide more accessible active sites, resulting in enhanced electrical conductivity and enriched redox chemistry. The Ov-Cu-Co3O4@C achieves a significantly improved specific capacity and rate performance, exceeding those of Co3O4@C. The asymmetric supercapacitors with Ov-Cu-Co3O4@C deliver a high energy density of 64.1 W h kg–1 at 800 W kg–1, exhibiting good flexibility without significant performance degradation under different bending states.