Selenium-doped cathode materials with polyaniline skeleton for lithium-organosulfur batteries

Sulfur-containing polymer (SCP) is considered as an outstanding cathode material for lithium-sulfur batteries. However, undesirable soluble polysulfides may shuttle in electrolyte, concluding long-chain Li2Sn (n > 4) and short-chain Li2Sn (n ≤ 4), as well as the sluggish conversion kinetics are yet to be solved to enhance the performance of lithium-sulfur batteries. Here Se-doped sulfurized polyaniline with adjusted sulfur-chain −Sx− (x ≤ 6) contribute to ensure the absence of long-chain polysulfides, and the skeleton with quinoid imine can endow strongly adsorption towards short-chain polysulfides by the reversible transition between deprotonated/protonated imine (-NH+= and -N=), which offer double insurance against suppressing “shuttle effect”. Furthermore, Se atoms are doped into sulfurized polysulfides to accelerate the redox conversion and take a frontier orbital theory-oriented view into catalytic mechanism. Se-doped sulfurized polyaniline as active materials for lithium-organosulfur batteries delivers good electrochemical performance, including high rate, reversible specific capacity (680 mA h g−1 at 0.1 A g−1), and lower capacity decay rate only of 0.15% with near 100% coulomb efficiency during long-term cycle. This work provides a valuable guiding ideology and promising solution for the chemistry-oriented structure design and practical application for lithium-organosulfur batteries.