A three-way electrolyte with ternary solvents for high-energy-density and long-cycling lithium-sulfur pouch cells

Lithium–sulfur(Li–S)batteries promise high-energy-density potential to exceed the commercialized lithiumion batteries but suffer from limited cycling lifespan due to the side reactions between lithium polysulfides(LiPSs)and Li metal anodes.Herein,a three-way electrolyte with ternary solvents is proposed to enable high-energy-density and long-cycling Li–S pouch cells.Concretely,ternary solvents composed of 1,2-dimethoxyethane,di-isopropyl sulfide,and 1,3,5-trioxane are employed to guarantee smooth cathode kinetics,inhibit the parasitic reactions,and construct a robust solid electrolyte interphase,respectively.The cycling lifespan of Li–S coin cells with 50μm Li anodes and 4.0 mg cm^(−2) sulfur cathodes is prolonged from88 to 222 cycles using the three-way electrolyte.Nano-heterogeneous solvation structure of LiPSs and organic-rich solid electrolyte interphase are identified to improve the cycling stability of Li metal anodes.Consequently,a 3.0 Ah-level Li–S pouch cell with the three-way electrolyte realizes a high energy density of 405 Wh kg^(−1) and undergoes 27 cycles.Thiswork affords a three-way electrolyte recipe for suppressing the side reactions of LiPSs and inspires rational electrolyte design for practical high-energy-density and long-cycling Li–S batteries.