Highly monodispersed Li2SO4 crystals towards Li2S-based lithium-sulfur battery cathodes

Li2S as a cathode of lithium sulfur batteries (LSB) and a precursor of advanced solid electrolytes have been widely investigated. However, suffered from the high cost and the low ionic/electronic conductivity, the controllable fabrication of Li2S crystals from the carbothermal conversion of Li2SO4 need to be improved urgently. Herein, polyacrylic acid (PAA) as a blocking agent is introduced to fabricate the monodispersed Li2SO4 (m-Li2SO4) crystals and the m-Li2S/carbon nanotube (CNT) cathode via subsequent carbothermal reaction. Our constructed Li2S/CNT||Li cells deliver a high initial discharge capacity of ∼900 mAh/g and a reversible specific capacity of 500 mAh/g at 2C. These results suggest the importance of regulating size and morphology of Li2SO4 crystals towards high-performance Li2S crystals.