V2C MXene enriched with -O termination as high-efficiency electrocatalyst for lithium-oxygen battery. (June 2022)

• Record Type: Journal Article
• Authors: Xu, Haoyang; Zheng, Ruixin; Du, Dayue; Ren, Longfei; Li, Runjing; Wen, Xiaojuan; Zhao, Chuan; Shu, Chaozhu
• Is Part Of: Applied materials today. Volume 27(2022)
• Publication Date: 2022-06
• Subjects: Li-O2 batteries -- Electrocatalyst -- MXene -- Functional groups -- O terminal; Materials science -- Periodicals; Materials -- Research -- Periodicals; 620.1105
• DOI: 10.1016/j.apmt.2022.101464
• Languages: English
• ISSNs: 2352-9407

Abstract

Highlights: The O-terminal enriched V2 C MXene was fabricated. The surface terminal of V2 C MXene was optimized via a simple vacuum annealing strategy. The adsorption of intermediate on the V2 C MXene was modulated. The V2 CO2 electrode shows excellent electrocatalytic activity for ORR and OER. Abstract: Lithium-oxygen (Li-O2 ) battery is known as the most promising next generation energy storage device due to its ultrahigh theoretical energy density. Developing high-efficiency electrocatalyst is the key to reduce the overpotential and improve the energy efficiency of Li-O2 battery. In this work, catalytic activity of V2 C MXene with -O termination (V2 CO2 ) towards oxygen redox reactions in Li-O2 battery is studied. Density functional theory (DFT) calculations verify that the -O termination can effectively lower the reaction barrier, optimize the adsorption of reactants on V2 CO2, thus boosting the kinetics of oxygen electrode reactions. Specifically, at the current density of 100 mA g −1, V2 CO2 based Li-O2 battery delivers a high capacity of 8577.3 mAh g −1 and a long-term cycling stability of 302 cycles. These findings provide a way to regulate the surface functional groups of MXene to enhance its electrocatalytic activity towards oxygen redox reactions in Li-O2 batteries. Graphical abstract: We present a vacuum annealing strategy to synthesize the V2 C MXene with abundant -O terminal (V2 CO2 ) and the catalytic activity of V2 CO2 for the oxygen redox reactions in Li-O2 battery is studied. The existence of -O terminal can effectively reduce the reaction energy barrier and improve its constraint ability to surrounding electrons. Besides, the surface with modulated electronic structure by -O terminal shows a strong affinity with Li2 O2, which can effectively reduce the interface impedance. In addition, the unique two-dimensional layered structure of V2 CO2 is favorable for the mass transfer during reaction process. Thus Li-O2 battery with V2 CO2 electrode shows excellent electrochemical performance. Image, graphical abstract