In Situ Generated Li2S-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 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.

Poly(ethylene oxide)-Li10SnP2S12 Composite Polymer Electrolyte Enables High-Performance All-Solid-State Lithium Sulfur Battery.

Composite polymer electrolyte membranes are fabricated by the incorporation of Li10SnP2S12 into the poly(ethylene oxide) (PEO) matrix using a solution-casting method. The incorporation of Li10SnP2S12 plays a positive role on Li-ionic conductivity, mechanical property, and interfacial stability of the composite electrolyte and thus significantly enhances the electrochemical performance of the solid-state Li-S battery. The optimal PEO-1%Li10SnP2S12 electrolyte presents a maximum ionic conductivity of 1.69 × 10-4 S cm-1 at 50 °C and the highest mechanical strength. The possible mechanism for the enhanced electrochemical performance and mechanical property is analyzed. The uniform distribution of Li10SnP2S12 in the PEO matrix inhibits crystallization and weakens the interactions among the PEO chains. The PEO-1%Li10SnP2S12 electrolyte exhibits lower interfacial resistance and higher interfacial stability with the lithium anode than the pure PEO/LiTFSI electrolyte. The Li-S cell comprising the PEO-1%Li10SnP2S12 electrolyte exhibits outstanding electrochemical performance with a high discharge capacity (ca. 1000 mA h g-1), high Coulombic efficiency, and good cycling stability at 60 °C. Most importantly, the PEO-1%Li10SnP2S12-based cell possesses attractive performance with a high specific capacity (ca. 800 mA h g-1) and good cycling stability even at 50 °C, whereas the PEO/LiTFSI-based cell cannot be successfully discharged because of the low ionic conductivity and high interfacial resistance of the PEO/LiTFSI electrolyte.