Lithium-sulfur batteries have attracted extensive attention owing to their environmental friendliness, abundant reserves, high specific discharge capacity, and energy density. The shuttling effect and sluggish redox reactions confine the practical application of Li-S batteries. Exploring the new catalyst activation principle plays a key role in restraining polysulfide shuttling and improving conversion kinetics. In this respect, vacancy defects have been demonstrated to enhance the polysulfide adsorption and catalytic ability. However, inducing active defects has been mostly created by anion vacancies. In this work, an advanced polysulfide immobilizer and catalytic accelerator is developed by proposing FeOOH nanosheets with rich Fe vacancies (FeVs). The work provides a new strategy for the rational design and facile fabrication of cation vacancies to improve the performance of Li-S batteries.