Facile Synthesis of Birnessite δ-MnO₂ and Carbon Nanotube Composites as Effective Catalysts for Li-CO₂ Batteries

Abstract

Li-CO₂ batteries are one type of promising energy storage and conversion devices to capture and utilize the greenhouse gas CO₂, mitigating global temperature rise and climate change. Catalysts that could effectively decompose the discharge product, Li₂CO₃, are essential for high-performance Li-CO₂ batteries. Benefiting from the interconnected porous structure, favorable oxygen vacancy, and the synergistic effects between the carbon nanotube (CNT) and layered birnessite δ-MnO₂, our Li-CO₂ cathodes with the as-prepared CNT@δ-MnO₂ catalyst can efficiently afford a large reaction surface area and abundant active sites, provide sufficient electron/Li⁺ transport pathways, and facilitate electrolyte infiltration and CO₂ diffusion, demonstrating low overpotential and superior cycling stability, which have been proven by both experimental characterization and theoretical computation. It is expected that this work can provide guidance for the design and synthesis of high-performance electrochemical catalysts for Li-CO₂ batteries.