In Situ Generated Li₂S-C Nanocomposite for High-Capacity and Long-Life All-Solid-State Lithium Sulfur Batteries with...

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 Li₂S, and the large volume change during cycling. Herein, a Li₂S@C nanocomposite with Li₂S nanocrystals uniformly embedded in conductive carbon matrix, is in situ generated by the combustion of lithium metal with CS₂. Benefiting from its unique architecture, the Li₂S@C exhibits exceptional electrochemical performance as cathode for ASSLSBs, with both ultrahigh areal Li₂S loading (7 mg cm^-2) and 91% of Li₂S utilization (corresponding to a reversible capacity of 1067 mAh g^-1). Moreover, the Li₂S@C also possesses outstanding rate capability and cycling stability. High reversible capacity of 644 mAh g^-1 is delivered at 2 mA cm^-2 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.