Oxygen Vacancies on Layered Niobic Acid That Weaken the Catalytic Conversion of Polysulfides in Lithium–Sulfur Batteries

Oxygen vacancies are usually considered to be beneficial in catalytic conversion of polysulfides in lithium–sulfur batteries. Now it is demonstrated that the conversion of polysulfides was hindered by oxygen vacancies on ultrathin niobic acid. The inferior performance induced by the oxygen vacancy was mainly attributed to the decreased electric conductivity as well as the weakened adsorption of polysulfides on the catalyst surface. This work shows that the care should be taken when designing a new catalyst for the lithium–sulfur battery using a defect‐engineering strategy. In lithium–sulfur batteries, oxygen vacancies are usually considered beneficial in the catalytic conversion of polysulfides. The conversion of polysulfides is now shown to be hindered by oxygen vacancies on ultrathin niobic acid. The inferior performance induced by the oxygen vacancy was attributed to the decreased electric conductivity and the weakened adsorption of polysulfides on the catalyst surface.