Defect-Rich Hierarchical Porous Mn-Doped CoP Hollow Microspheres Accelerate Polysulfide Conversion

Lithium-sulfur batteries (LSBs) with high theoretical specific capacities have been regarded as the development direction of next generation energy storage. However, the shuttle effect of lithium polysulfides (LiPSs) and the retardation of conversion kinetics have hindered their industrial application. Herein, Mn selectively doped CoP hollow microspheres are designed and synthesized to trap LiPSs and enhance Li-S reaction kinetics. Mn is successfully doped into (100) surfaces of Co3O4 via simple hydrothermal reaction, whereas it is only excessively accumulated on (111) surfaces. The unique selective doping of Mn not only provides an accurate and controllable synthesis path, but also makes synthesized target products rich in phosphorus defects after thermal shock. The adsorption, electrochemical, and in situ XRD and Raman tests prove its enhancement in adsorption capacity for LiPSs and inhibition of shuttle effect. Meanwhile, density functional theory calculations confirm that the reduced reaction energy barriers accelerate the reduction kinetics of sulfur redox conversion. Therefore, the optimal electrode displays an outstanding cycling stability with a capacity fading rate of just 0.0207% per cycle over 1000 cycles at 1 C. This work provides a novel design to promote the practical use of LSBs by introducing lattice defects, enlightening further developments of LSBs.