Sulfide solid-state electrolytes have garnered considerable attention owing to their notable ionic conductivity and mechanical properties. However, achieving an electrolyte characterized by both high ionic conductivity and a stable interface between the electrode and electrolyte remains challenging, impeding its widespread application. In this work, we present a novel sulfide solid-state electrolyte, Li3.04P0.96Zn0.04S3.92F0.08, prepared through a solid-phase reaction, and explore its usage in all-solid-state lithium sulfur batteries (ASSLSBs). The findings reveal that the Zn, F co-doped solid-state electrolyte exhibits an ionic conductivity of 1.23 × 10–3 S cm–1 and a low activation energy (Ea) of 9.8 kJ mol–1 at room temperature, illustrating the aliovalent co-doping’s facilitation of Li-ion migration. Furthermore, benefiting from the formation of a LiF-rich interfacial layer between the electrolyte and the Li metal anode, the Li/Li3.04P0.96Zn0.04S3.92F0.08/Li symmetrical cell exhibits critical current densities (CCDs) of up to 1 mA cm–2 and maintains excellent cycling stability. Finally, the assembled ASSLSBs exhibit an initial discharge capacity of 1295.7 mAh g–1 at a rate of 0.05 C and at room temperature. The cell maintains a capacity retention of 70.5% for more than 600 cycles at a high rate of 2 C, representing a substantial improvement compared to the cell with Li3PS4. This work provides a new idea for the design of solid-state electrolytes and ASSLSBs.
Jun Pan,Huili Peng,Yehao Yan,Yuzhou Bai,Jian Yang,Nana Wang,Shixue Dou,Fuqiang Huang
Polymer solid-state batteries (SSBs) possess the advantages of good interfacial contact, but their application faces low ionic conductivity. Here, three-dimensional (3D) porous composite polymer electrolytes with propylene carbonate plasticizer (3D-PPLLP-CPEs) fabricated effectively, displaying high ionic conductivity even at room temperature. Electrochemical in-situ polymerization of 3D-PPLLP-CPEs occurs during the first discharge process, avoiding safety issues caused by the liquid plasticizer without sacrificing the ionic conductivity of the electrolyte. Besides, the controllable in-situ generated LiF-enriched interface can avoid the Li dendrite growth. To further promote the practical value of SSBs, micro-sized Si@Li 3 PO 4 @C with high initial Coulombic efficiency was adopted to replace lithium foil. The LiNi 1/3 Co 1/3 Mn 1/3 O 2 (NCM111)//Micro Si@Li 3 PO 4 @C full cell has achieved capacity of 129.1 mAh g −1 at a current density of 0.2 C, with capacity retention of 98.5% after 100 cycles, which is the best performance based on the Si anode in SSBs. Even at the high current density of 2.0 A g −1 , the capacity remains 92.5 mAh g −1 . This design of CPEs and electrodes has paved a new way to construct practical SSBs.