Carbon coated lithium sulfide particles for lithium battery cathodes

In this paper, we investigated the properties of carbon coated lithium sulfide particles prepared following either a dry coating process or a wet coating process, using, respectively, sucrose or polyacrylonitrile (PAN) as carbon source. X-ray diffraction analysis revealed that the crystalline structure of the pristine Li2S was basically preserved upon both coating processes. The dry coating process (Li2S-Csucrose) resulted in Li2S particles covered only partially by smaller carbon particles, whereas the wet coating method (Li2S-CPAN) gave Li2S particles, homogenously decorated with thin carbon flakes. As a result, the cycling performance of Li2S-C based electrodes was significantly improved, particularly for Li2S-CPAN, for which a coulombic efficiency of more than 99.5% was obtained.

► Encapsulated lithium sulfide as cathode material for lithium sulfur batteries. ► Prevention of polysulfide dissolution by carbon encapsulation of lithium sulfide particles. ► High coulombic efficiencies (>99.5%) and stable cycling performance.