Enhanced Air Stability and High Li-Ion Conductivity of Li 6.988 P 2.994 Nb 0.2 S 10.934 O 0.6 Glass-Ceramic Electrolyte for All-Solid-State Lithium-Sulfur Batteries

• Published in: ACS applied materials & interfaces Vol. 12; no. 19; pp. 21548 - 21558
• Main Authors: Ahmad, Niaz, Zhou, Lei, Faheem, Muhammad, Tufail, Muhammad Khurram, Yang, Le, Chen, Renjie, Zhou, Yaodan, Yang, Wen
• Format: Journal Article
• Language: English
• Published: United States 13.05.2020
• Subjects: superior Li+ conductivity; all-solid-state lithium-sulfur batteries; Li6.988P2.994Nb0.2S10.934O0.6 glass−ceramic electrolyte; low Interface impedance; high air-stability
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.0c00393

The development of novel sulfide solid-state electrolytes with high Li-ion conductivity, excellent air-stability, and a stable electrode-electrolyte interface is needed for the commercialization of all-solid-state cells. Currently, an ideal solid electrolyte, which can integrate the solid-state batteries, has not been developed. Herein, the Nb and O codoping strategy is excogitated to improve the chemical and electrochemical performance of sulfide electrolytes. The interactive effect of Nb and O in the novel Li P Nb S O glass-ceramic electrolyte results in a superior Li conductivity of 2.82 mS cm and remarkable air-stability and electrochemical stability against the Li metal compared to the Li P S counterpart at 25 °C. Solid-state P MAS-NMR revealed that doping of LiNbO (0 ≤ ≤ 1) not only enhances the degree of crystallization but also produces P OS units with bridging oxygen atoms in the Li P Nb S O glass-ceramic electrolyte and hence boosts the conductive deportment of glass-ceramics. Impressively, the developed electrolyte exhibits a stable full voltage window of up to 5 V versus Li/Li . Furthermore, electrochemical impedance spectroscopy analysis shows that the interface resistance of the Li S/Li P Nb S O /Li-In cell is lower than that of the cell with Li P S electrolyte. Besides, the battery of the Li P Nb S O electrolyte delivers initial discharge capacities of 472.7 and 530.9 mAh g after 50 cycles with 98.88% capacity retention from the second cycle. The Coulombic efficiency of the cell remains at ∼100% after 50 cycles. Thus, the proposed codoped strategy produced a sulfide electrolyte, which addressed the challenging issues of chemical/electrochemical stabilities and showed promising industrial prospects for next-generation all-solid-state batteries.