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

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 (O-v-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 O-v-Cu-Co3O4@C synergistically manipulate the electronic states and provide more accessible active sites, resulting in enhanced electrical conductivity and enriched redox chemistry. The O-v-Cu-Co3O4@C achieves a significantly improved specific capacity and rate performance, exceeding those of Co3O4@C. The asymmetric supercapacitors with O-v-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.

Automated summary

Incorporating Cu dopants and O vacancies into Co3O4 nanocrystals confined in a carbon matrix, termed as O-v-Cu-Co3O4@C, helps improve the specific capacity and rate performance of the material. The heterostructured architecture with multifunctional nanogeometries enables high intercomponent synergy, leading to enhanced electrical conductivity and enriched redox chemistry, ultimately resulting in a significantly improved energy density of 64.1 W h kg(-1) at 800 W kg(-1) for asymmetric supercapacitors.