▎ 摘　　要

Lithium sulfide as a promising cathode material not only have a high theoretical specific capacity, but also can be paired with Li-free anode material to avoid potential safety issues. However, how to prepare high electrochemical performance material is still challenge. Herein, we present a facile way to obtain high crystal quality Li2S nanomaterials with average particle size of about 55 nm and coated with Li3PS4 to form the nanoscaled coreshell Li2S@Li3PS4 composite. Then nano-Li2S@Li3PS4/graphene aerogel is prepared by a simple liquid infiltration-evaporation coating process and used directly as a composite cathode without metal substrate for lithium-sulfur batteries. Electrochemical tests demonstrate that the composite delivers a high discharge capacity of 934.4 mAh g(-1) in the initial cycle and retains 485.5 mAh g(-1) after 100 cycles at 0.1 C rate. In addition, the composite exhibits much lower potential barrier (similar to 2.40 V) and overpotential compared with previous reports, indicating that Li2S needs only a little energy to be activated. The excellent electrochemical performances could be attributed to the tiny particle size of Li2S and the superionic conducting Li3PS4 coating layer, which can shorten Li-ion and electron diffusion paths, improve the ionic conductivity, as well as retarding polysulfides dissolution into the electrolyte to some extent. (C) 2017 Elsevier B.V. All rights reserved.