The electrocatalytic activity of BaTiO3 nanoparticles towards polysulfides enables high-performance lithium-sulfur batteries

The slow redox dynamics and dissolution of polysulfides in lithium–sulfur (Li–S) batteries result in poor rate performance and rapid decay of battery capacity, thus limiting their practical application. Ferroelectric barium titanate (BT) nanoparticles have been reported to effectively improve the electrochemical performance of Li–S batteries due to the inherent self-polarization and high adsorption capacity of the BT nanoparticles towards polysulfides. Here in this paper, BT nanoparticles, behave as highly efficient electrocatalyst and demonstrate much higher redox dynamics towards the conversion reaction of polysulfides and Li2S than TiO2, as shown by both electrochemical measurements and density functional theory calculation. The coupling of the sulfur host of the hollow and graphitic carbon flakes (HGCF) and the BT nanoparticles (HGCF/S-BT) enable excellent electrochemical performance of Li–S batteries, delivering a 0.047% capacity decay per cycle in 1000 cycles at 1 C, 788 mAh g–1 at 2 C and a reversible capacity of 613 mAh g−1 after 300 cycles at a current density of 0.5 C at a S loading of 3.4 mg cm–2. HGCF/S-BT also shows great promise for practical application in flexible devices as demonstrated on the soft-packaged Li–S batteries.