High-Voltage and Wide-Temperature Lithium Metal Batteries Enabled by Ultrathin MOF-Derived Solid Polymer Electrolytes with Modulated Ion Transport

Abstract

Solid polymer electrolytes (SPEs) of superior ionic conductivity, long-term cycling stability, and good interface compatibility are regarded as promising candidates to enable the practical applications of solid lithium metal batteries (SLMBs). Here, a mixed-matrix SPE (MMSE) with incorporated metal–organic frameworks (MOFs) and ionic liquid is prepared. The dissociation of Li salt in MMSE can be promoted effectively due to the introduction of MOF via the Fourier-transform infrared spectroscopy (FT-IR) analysis, density functional theory calculation, and molecular dynamics simulation. The as-formed MMSE exhibits an ultralow thickness of 20 μm with a satisfactory ionic conductivity and lithium-ion transference number (1.1 mS cm–1 at 30 °C, 0.72). The optimized SLMBs with high-voltage LiMn0.75Fe0.25PO4 (LMFP) exhibit an excellent cyclability at 4.2 V under room temperature. Moreover, Li/MMSE/LiFePO4 cells have desirable cycle performance from −20 to 100 °C, and their capacity remains 143.3 mA h g–1 after being cycled 300 times at 10 C at 100 °C. The Li/LiFePO4 pouch cells also show excellent safety under extreme conditions. The Li symmetric cells can work steadily even at a supreme current density of 4 mA cm–2 at 100 °C. From the above analysis, these MMSEs present new opportunities for the development of SLMBs with good electrochemical properties.

Bifunctional MOF Doped PEO Composite Electrolyte for Long-Life Cycle Solid Lithium Ion Battery

“…With the formation of amide bonds from acid groups and amino groups, the movement of UiO-66-COOH and UiO-66-NH 2 restricted each other via amide bonds to construct MOF long-chains in the SPEs, which provide the fast ion transmission channel and the polymer as the main ion transmission channel. Compared with single MOF (UiO-66-COOH or UiO-66-NH 2 ), which has been confirmed for the rapid transportation of individual lithium ions due to their porous structure, ,, the MOF-2 had not only a similar porous structure to single MOF but also additional ion transmission channels between different MOF long chains, where PEO was a solid “solvent” for lithium ions transmission.…”

Multiscale Structural Gel Polymer Electrolytes with Fast Li+ Transport for Long‐Life Li Metal Batteries

“…These results verify that nanosized SiO 2 promotes the dissociation of LiPF 6 and release amounts of free Li + ions, contributing to the improvement of ionic conductivity, which is similar to the previous reports. [ 40,41 ] The Fourier transform infrared (FTIR) spectrum is taken to verify SiO 2 containing the surface ‐OH groups. The signals in the range of 3000–3750 cm −1 are generally attributed to the surface ‐OH groups, [ 42 ] which could immobilize anions to accelerate the dissociation of LiPF 6 (Figure S10, Supporting Information).…”

Toward Sustainable Solid Polymer Electrolytes for Lithium-Ion Batteries

“…There are many options when it comes to passive fillers, including ceramics, carbon-based materials, or metal–organic frameworks, each one with distinct effects in the SPE properties. Zeolites are appearing as a promising option because of their ability to stabilize the SPE structure, improving the cyclability of the battery …”

“…40 Further, ether-based electrolytes in situ polymerized by a ring-opening reaction in the presence of aluminum fluoride (AlF 3 ) show promising characteristics to overcome the limited oxidative stability and poor interfacial charge transport of current SPEs. 41 There are many options when it comes to passive fillers, including ceramics, 45 carbon-based materials, 46 or metal− organic frameworks, 47 each one with distinct effects in the SPE properties. Zeolites are appearing as a promising option because of their ability to stabilize the SPE structure, improving the cyclability of the battery.…”