Dual-functional vinylpyrrolidone electrolyte additive as anode surface leveler and cathode catalyst for lithium Metal-Oxygen batteries

To overcome the limitations of lithium-ion batteries, Li metal–O2 breathing batteries (LMOBs) have been extensively investigated because of the exceptional energy density provided by the O2 cathode and Li metal anode. However, the dendrite growth and consequent surface degradation on the Li metal anode are significant issues prohibiting the safe and long-term cell operation. In this study, vinylpyrrolidone (VP) was homogeneously introduced into the electrolyte of LMOBs to flatten the Li metal anode and eliminate the dendrite growth and to activate a cathodic reaction with reduced overpotential. A smooth surface morphology and high-quality solid-electrolyte interface layer were achieved on the Li metal anode owing to dipolar VP molecules. We also verified the catalytic effect of VP molecules on the O2 cathode reaction. Finding a homogeneous and dual-function electrolyte additive to stabilize the Li metal anode and activate the Li-O2 cathode reaction is a new strategy to develop tailored LMOBs.