Yolk Double-Shell Cathode for Encapsulating Polysulfides and Initialing Redox Kinetics toward High-Performance Lithium–Sulfur Batteries

Lithium–sulfur batteries (LSBs) sustain a series of serious challenges, such as unreasonable cathode configuration, unsatisfactory mass transfer kinetics, disgusting lithium polysulfide (LiPSs) shuttle escape, and so on, which have obstructed the further exploration of the commercialization process. In this study, a “yolk double-shell” structure of cathode materials Fe₃O₄@FeP@C accommodates the active sulfur and guides the unobstructed transformation of the intermediates, of which state-of-art-shaped yolk double-shell architecture prevents LiPSs from escaping into the electrolyte, meanwhile, the doped-N substances enhance the chemisorption and transformation of LiPSs, promoting the mass transfer-reaction kinetics. Based on the above advantages, excellent electrochemical performances have been obtained, and S/yolk–shells-2 cathode exhibits an excellent initial specific capacity of 1250.38 mAh g^–1 at 0.5 C, maintaining a capacity of 368.39 mAh g^–1 at 2.0 C for 1000 stable cycles, and the discharging specific capacities keep 549.25 and 454.99 mAh g^–1 after 250 cycles at 4.0 and 5.0 C, respectively. Surprisingly, the S/yolk–shells-2 cathode displays an initial high specific capacity of 1014.79 mAh g^–1 at an ultrahigh sulfur loading of 6.23 mg cm^–2. The study elaborately designed and fabricated yolk double-shell materials as a cathode host for encapsulating LiPSs and accelerating mass transfer reactions toward high-performance LSBs.