Catalytic Solid-State Sulfur Conversion Confined in Micropores toward Superhigh Coulombic Efficiency Lithium-Sulfur Batteries

Achieving the solid-solid conversion of sulfur is a fundamental solution to eliminating the shuttling of soluble polysulfides and improving the cycling stability of lithium-sulfur batteries. However, the sluggish solid reaction kinetics seriously challenge the battery performance. In this work, a micropore-confined catalysis strategy to achieve the smooth solid-solid conversion of sulfur is proposed. It is realized by storing sulfur in a microporous carbon host with narrow pore size and uniformly distributed single-atom Co catalytic sites. The microporous structure avoids the contact of electrolyte solvents with the inner sulfur, preventing the formation and dissolution of polysulfides and efficiently suppressing sulfur loss during cycling. The introduced single-atom Co catalytic sites promote the charge transfer to accelerate the solid-solid conversion of sulfur. When coupled with a liquid carbonate electrolyte, the battery exhibits a remarkably high Coulombic efficiency (CE) of approximate to 99.88% and a minimal capacity decay rate of approximate to 0.016% per cycle for 1000 cycles at 0.5 C. Even when coupled with the solid-state electrolyte, the battery still delivers a significantly high capacity of 1100 mAh g-1 and a remarkably high CE of approximate to 99.83% over 200 cycles. This work reveals a promising solution for developing practical stable LiS batteries. A micropore-confined catalysis strategy is proposed to realize a smooth solid-solid sulfur conversion. This leads to high Coulombic efficiency and long-term stability for the LiS batteries both with the liquid carbonate and solid-state electrolytes, revealing a promising solution for their practical applications. image