A hybrid solid-state electrolyte endows a Li metal battery with excellent cycling life at 120 °C

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 11; no. 25; pp. 13446 - 13458
• Main Authors: Liu, Wen-Xue, Huang, Xue-Chun, Meng, Yan, Xiao, Dan, Guo, Yong
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 27.06.2023
• Subjects: Aluminum; Anions; Electrochemistry; Electrolytes; Flammability; High temperature; Ion currents; Ion migration; Ions; Lithium; Lithium batteries; Lithium-ion batteries; Metal-organic frameworks; Organic liquids; Polyolefins; Rechargeable batteries; Side reactions; Solid state; Solvents; Thermal stability
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d3ta01588b

Lithium-ion batteries (LIBs) equipped with conventional polyolefin separators and organic liquid electrolytes present severely limited high-temperature performances owing to their intrinsic drawbacks of poor thermal stability and high flammability, which can easily cause safety issues of combustion or even explosion. Here, a hybrid solid-state electrolyte (HSSE) is designed by introducing an aluminum-based metal-organic framework (MOF) material. The carefully selected Al-MOF not only exhibits a high-temperature stable microporous structure but also exposes open Al 3+ coordination sites after activation. The activated MOF can effectively coordinate anions and solvent molecules, which confines the migration of anions and free solvents but dramatically accelerates the Li + transportation (high transference numbers, t Li + = 0.84), simultaneously inhibiting the side reactions at the interface of electrode/electrolyte. As a result, the nonflammable HSSE shows excellent electrochemical stability (>5.5 V), good ionic conductivity (2.0 × 10 −4 S cm −1 ), and favorable mechanical stability in wide temperature regions. Compared to a LiFePO 4 |Li cell with a liquid electrolyte that quickly failed in several cycles at 120 °C, the cell with the HSSE keeps cycling for 200 cycles with a capacity retention of 90% and an average coulombic efficiency of 99%. This work sheds light on the practical application of LIBs under extreme high-temperature conditions. A hybrid solid-state electrolyte designed based on an activated Al-based metal-organic framework features high lithium-ion conductivity and excellent stability, which provides a practical method for the application of high-temperature batteries.