CoCx‑induced interfacial octahedral Co2+ sites of NiCo-LDH electrode with improved faradic reactivity toward high-performance supercapacitor

Baoyi Yin; Liang Hao; Xiaogan Li; Qiguo Yang

doi:10.1016/j.jcis.2023.07.170

CoC_x‑induced interfacial octahedral Co²⁺ sites of NiCo-LDH electrode with improved faradic reactivity toward high-performance supercapacitor

J Colloid Interface Sci. 2023 Dec:651:602-611. doi: 10.1016/j.jcis.2023.07.170. Epub 2023 Jul 27.

Authors

Baoyi Yin¹, Liang Hao², Xiaogan Li¹, Qiguo Yang³

Affiliations

¹ School of Microelectronics, Dalian University of Technology, Dalian 116024, China.
² Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering, School of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China. Electronic address: haoliang@usst.edu.cn.
³ Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering, School of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China.

PMID: 37562302
DOI: 10.1016/j.jcis.2023.07.170

Abstract

Battery-like electrode materials are characterized by large theoretical capacitance but suffer from poor surface reactivity and insufficient electroactive sites thus limiting their practical charge storage capacity. To overcome this challenge, an effective strategy for vacancy modulation on battery-like electrode materials is necessary. Herein, we report for the first time an elaborately designed three-dimensional (3D) hierarchical heterostructure consisting of CoC_x@NiCo-LDH on conductive nickel foam as a freestanding supercapacitor electrode. Benefiting from the weakening of the coordination of CoO bonds, the CoC_x structure induces in-situ reconstruction of the NiCo-LDH lattice, resulting in the formation of abundant oxygen vacancies (interfacial octahedral Co²⁺ sites) that lower the OH^- adsorption energy as determined by the density functional theory (DFT) calculation. The resulting CoC_x@NiCo-LDH/NF electrode exhibits an ultrahigh rate capability (2330 mF cm^-2 at 0.3 mA cm^-2, with capacitance retention of 51.5 % at 30 mA cm^-2) and remarkable cycling performance (capacitance retention of 81.6 % after 10,000 cycles). Additionally, the assembled asymmetric devices deliver an extremely high energy density of 246 μWh cm^-2 at the power density of 798 μW cm^-2, with 87.8 % capacitance retention after 10,000 cycles at 8 mA cm^-2. Overall, this study presents a simple yet effective strategy to construct high-performance battery-like electrodes for potential applications in energy storage, transportation, and communication.

Keywords: Battery-like electrode; Supercapacitor; Ultrahigh rate capability; Vacancy modulation.