Oxygen Vacancy-Rich RuO₂–Co₃O₄ Nanohybrids as Improved Electrocatalysts for Li–O₂ Batteries

Abstract

Lithium oxygen (Li−O 2 ) batteries have shown great potential as new energy-storage devices due to the high theoretical energy density. However, there are still substantial problems to be solved before practical application, including large overpotential, low energy efficiency, and poor cycle life. Herein, we have successfully synthesized a RuO 2 −Co 3 O 4 nanohybrid with a rich oxygen vacancy and large specific surface area. The Li−O 2 batteries based on the RuO 2 −Co 3 O 4 nanohybrid shown obviously reduced overpotential and improved circulatory property, which can cycle stably for more than 100 cycles at a current density of 200 mA g −1 . Experimental results and density function theory calculation prove that the introduction of RuO 2 can increase oxygen vacancy concentration of Co 3 O 4 and accelerate the charge transfer. Meanwhile, the hollow and porous structure leads to a large specific surface area about 104.5 m 2 g −1 , exposing more active sites. Due to the synergistic effect, the catalyst of the RuO 2 −Co 3 O 4 nanohybrid can significantly reduce the adsorption energy of the LiO 2 intermediate, thereby reducing the overpotential effectively.

Cobalt Single Atom Incorporated in Ruthenium Oxide Sphere: A Robust Bifunctional Electrocatalyst for HER and OER

“…Likewise, the oxygen XPS profile (Figure 3c) was further de-convoluted into three peaks at 529.9, 531.2, and 532.4 eV, which can be assigned to metal-oxygen (MÀ O) bonds, oxygen vacancies, and adsorbed OH groups, respectively. [10] The XPS results above suggest the modification in the electronic environment of Co-SAC/RuO 2 active sites, owing to the strong interaction of Co single atoms and RuO 2 . Moreover, for Co-SAC/RuO 2 , the Ru 3d and 3p peaks show a slight shift to lower energy (Figures S8, S9) as compared with those for pristine RuO 2 , because of the electronic transfer from Co to Ru, which suppresses the overoxidation of RuO 2 ; Co single atoms in RuO 2 play an important role in regulating and promoting the electrocatalytic activity and stability in HER and OER.…”

3D Co3O4‐RuO2 Hollow Spheres with Abundant Interfaces as Advanced Trifunctional Electrocatalyst for Water‐Splitting and Flexible Zn–Air Battery

“…[54][55][56] The XPS measurements of the reference samples are also studied, and a similar phenomenon is obtained (Figure S3, Supporting Information). [53,57] OER is a key half-reaction for water-splitting and the rechargeable Zn-air battery. Hence, this study looked into the electrocatalytic performances of as-prepared samples and references.…”

Interface engineering of hierarchical NiCoP/NiCoSx heterostructure arrays for efficient alkaline hydrogen evolution at large current density

“…Additionally, the characteristic peaks framed by the dashed rectangle can be assigned to the A1g mode of Co 3 O 4 caused by slight surface oxidation of the catalyst. 37,38…”

“…Additionally, the characteristic peaks framed by the dashed rectangle can be assigned to the A1g mode of Co 3 O 4 caused by slight surface oxidation of the catalyst. 37,38 X-ray photoelectron spectroscopy (XPS) was utilized to investigate the chemical valence states of NiCoP/NiCoS x /NF. The XPS survey spectra (Fig.…”