In Situ Generated LiS-C Nanocomposite for High-Capacity and Long-Life All-Solid-State Lithium Sulfur Batteries with Ultrahigh Areal Mass Loading.

All-solid-state lithium-sulfur batteries (ASSLSBs) have attracted great attention due to their inherent ability to eliminate the two critical issues (polysulfide shuttle effect and safety) of traditional liquid electrolyte based Li-S batteries. However, it remains a huge challenge for ASSLSBs to achieve high areal active mass loading and high active material utilization simultaneously due to the insulating nature of sulfur and LiS, and the large volume change during cycling. Herein, a LiS@C nanocomposite with LiS nanocrystals uniformly embedded in conductive carbon matrix, is in situ generated by the combustion of lithium metal with CS. Benefiting from its unique architecture, the LiS@C exhibits exceptional electrochemical performance as cathode for ASSLSBs, with both ultrahigh areal LiS loading (7 mg cm) and 91% of LiS utilization (corresponding to a reversible capacity of 1067 mAh g). Moreover, the LiS@C also possesses outstanding rate capability and cycling stability. High reversible capacity of 644 mAh g is delivered at 2 mA cm even after 700 cycles. This work demonstrates that ASSLSBs with superior electrochemical performance can be realized via rational design of the cathode structure, which provides a promising prospect to the development of ASSLSBs with practical energy density surpassing that of lithium ion batteries.