Sulfonate-rich polymer intercalated LDH artificial SEI film to enable high-stability Li-S batteries

Abstract

Constructing a functional solid electrolyte interface (SEI) is of great significance to promote the practical application of lithium-sulfur batteries (LSBs). In this work, we design and synthesize a sulfonate-rich polymer intercalated LDH (LDH@PSS) and obtain organic-inorganic hybrid artificial SEI film on the surface of Li by spin-coating. The PSS intercalated LDH has a large layer spacing, which effectively improves the transfer kinetics of lithium ion. More importantly, the PSS polymer chain with rich sulfonic groups have strong electronegativity and can electrostatically repel polysulfide anions, which effectively suppress the self-discharge behavior caused by the “shuttle effect”. The symmetrical battery using LDH@PSS-Li shows a cycle life of up to 3100 h at 1 mA cm−2current density. In-situ optical tests also further confirm that the modified materials have excellent dendrite inhibition ability. The shuttle current and self-discharge tests show that LDH@PSS-Li can effectively prevent the parasitic reaction between polysulfide and lithium. After 200 cycles at 0.2 C, the battery maintains a reversible capacity of 1032.6 mAh cm−2, with a reduced capacity decay rate from 0.321 % of unprotected Li anode to 0.086 % per cycle. Consequently, LDH@PSS composite material as artificial SEI film has great application potential for the anodic protection of LSBs.