Design of CoP-CoO heterostructure to enhance the polysulfide redoxconversion for lithium-sulfur batteries

The design of effective cathode materials is the significant to the development of lithium-sulfur batteries.Herein, a spindle-shaped CoP-CoO heterostructures sulfur cathode substrate composed of countlessfine nee-dle-like structures is prepared through a facile two-step process by controlling the sulfurization degree. Theas-prepared heterostructures combine the advantages of high adsorbability (by CoO) and conductivity (byCoP), and realizes the smooth capture-diffusion-transformation of polysulfides at the interface. CoO has a highadsorption capacity for polysulfides, while CoP promotes the redox kinetics towards polysulfides conversion.The rapid transfer of polysulfide from CoO surface to CoP surface helps to accelerate the nucleation of polysul-fide and improve the capture efficiency. Therefore, the battery with CoP-CoO@S cathode reaches a high initialcapacity of 1456.7 mAh g-1at 0.2 C, and the capacity retains 832 mAh g-1after 100 cycles. Even the specificcapacity of 500 mAh g-1can achieved at 1C after 300 cycles. Our study offers the potential perpective for therational design of lithium-sulfur batteries cathode materials, which can realize immobilization and conversionof polysulfides at the same time, and further promote the actual application of Li-S batteries.

Automated summary

In this study, a novel lithium-sulfur battery cathode substrate material, CoP-CoO heterostructures, was successfully designed. The prepared heterostructures can achieve the capture, diffusion, and transformation of polysulfides, leading to high initial capacity and cycling stability.