Multifunctional cation-vacancy-rich ZnCo2O4 polysulfide-blocking layer for ultrahigh-loading Li-S battery

The major hurdle in Li-S battery commercialization is the severe shuttle effect and sluggish reaction kinetics of polysulfide conversion during charge-discharge cycling. Herein, to overcome these barriers, we designed and synthesized Zn defective Zn/Co oxide (ZDZCO) nanosheets, a cation-vacancy-rich bimetallic oxide for the construction of a multifunctional polysulfide-blocking layer. Both theoretical and experimental studies have comprehensively demonstrated that the ZDZCO shows robust binding capability towards polysulfides and a high catalytic ability for fast polysulfide conversion. Through a facile coating process, the multifunctional ZDZCO polysulfide-blocking layer is incorporated on a commercial polypropylene separator, forming a composite separator. The resultant separator facilitates an ultrahigh sulfur loading of 21.06 mg cm-2 and an areal capacity as high as 24.25 mAh cm-2. This study illuminates a promising and practical strategy to construct high-performance Li-S batteries with high sulfur loading. A multifunctional cation-vacancy-rich ZnCo2O4 modified separator has been developed to create a strong affinity to polysulfides and rapid catalytic conversion between the polysulfides for the achievement of ultrahigh areal loading and high-performance Li-S batteries. [Display omitted] •Cation-vacancy-rich bimetallic oxide constructs a novel multifunctional polysulfide-blocking layer.•Cation vacancies boost catalytic performance of the multifunctional polysulfide-blocking layer.•The Li-S battery achieves an ultrahigh loading of 21.06 mg cm-2 and prolonged lifespan of 60 cycles.