Atomically dispersed Co-N4C2 catalytic sites for wide-temperature Na-Se batteries. (January 2023)

• Record Type: Journal Article
• Authors: Dong, Wen-Da; Li, Yan; Li, Chao-Fan; Hu, Zhi-Yi; Hsu, Liang-Ching; Chen, Li-Hua; Li, Yu; Lei, Aiwen; Su, Bao-Lian
• Is Part Of: Nano energy. Volume 105(2023)
• Publication Date: 2023-01
• Subjects: Over-coordinate SA catalyst -- Cathode electrolyte interphase -- Sodium ethylene mono-carbonate -- Solid-phase Na-Se electrochemistry -- Na-Se batteries; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2022.108005
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Sodium-selenium (Na-Se) batteries have been widely regarded as promising large-scale energy storage systems owing to the high volumetric energy density of 2530 W h L −1 and natural abundance of the element sodium. However, critical drawbacks including sluggish redox kinetics, severe volume variation and shuttle effect seriously deteriorate the electrochemical performance. Herein, we propose a precompetitive coordination strategy for over-coordinated single-atom catalyst, and subsequently synthesize the six-coordinated Co electrocatalyst supported carbon nanofibers (Co-N4 C2 ) for solid-state conversion in wide-temperature Na-Se batteries. The Co-N4 C2 catalyst can not only boost the redox kinetics of solid-phase Na2 Se2 /Na2 Se, but also accelerate the electroreduction of ethylene carbonate to construct robust cathode electrolyte interphase, thereby inhibiting the irreversible phase transformation of active Se species. Furthermore, for the first time, the components of the cathode electrolyte interphase as sodium ethylene mono-carbonate are identified. Consequently, the as-synthesized free-standing Se@Co-N4 C2 cathode with high Se-loading realizes high capacity, cycling stability and rate capability at both room temperature (20.0/40.0 ℃) and low temperature (− 11.7 ℃). Graphical Abstract: Six-coordinated Co-N4 C2 sites bidirectionally regulate the solid-phase conversion kinetics and accelerate the formation of robust CEI via EC-electroreduction. Sodium ethylene mono-carbonate is identified as component of cathode electrolyte interphase. ga1 Highlights: Precompetitive coordination strategy is proposed to fabricate over-coordinated SA electrocatalyst. Co-N4 C2 sites bidirectionally catalyze the solid-phase conversion between Se and Na2 Se without shuttling behavior. The sodium ethylene mono-carbonate (SEMC) is identified as a component of cathode electrolyte interphase (CEI). The capacity decay mechanism in carbonate electrolytes is attributed to the irreversible phase transformation of Se species. The Se@Co-N4 C2 cathode with high Se-loading of 67 % realizes high capacity, cycling stability and rate capability.