Anchoring polysulfide with artificial solid electrolyte interphase for dendrite-free and low N/P ratio Li-S batteries

Lithium sulfur batteries are regarded as a promising candidate for high-energy-density energy storage devices. However, the lithium metal anode in lithium-sulfur batteries encounters the problem of lithium dendrites and lithium metal consumption caused by polysulfide corrosion. Herein we design a dual-function PMMA/PPC/LiNO3 composite as an artificial solid electrolyte interphase (PMCN-SEI) to protect Li metal anode. This SEI offers multiple sites of CO for polysulfide anchoring to constrain corrosion of Li metal anode. The lithiated polymer group and Li3N in PMCN-SEI can homogenize lithium-ion deposition behavior to achieve a dendrite-free anode. As a result, the PMCN-SEI protected Li metal anode enables the Li || Li symmetric batteries to maintain over 300 cycles (1300 h) at a capacity of 5 mA h cm−2, corresponding to a cumulative capacity of 3.25 Ah cm−2. Moreover, Li-S batteries assembled with 20 µm of Li metal anode (N/P = 1.67) still deliver an initial capacity of 1166 mA h g−1 at 0.5C. Hence, introducing polycarbonate polymer/inorganic composite SEI on Li provides a new solution for achieving the high energy density of Li-S batteries.