Single-ion conducting electrolytes present a unique alternative to traditional binary salt conductors used in lithium-ion batteries. It has been shown theoretically that single-ion electrolytes can eliminate the salt concentration gradient and polarization loss in the cell that develop in a binary salt system, resulting in substantial improvements in materials utilization for high power and energy densities. Here, we describe synthesis and characterization of a class of single-ion electrolytes based on aromatic poly(arylene ether)s with pendant lithium perfluoroethyl sulfonates. The microporous polymer film saturated with organic carbonates exhibits a nearly unity Li + transference number, very high conductivities (e.g., > 10 −3 S m −1 at room temperature) over a wide range of temperatures, great electrochemical stability, and outstanding mechanical properties. Excellent cyclability with almost identical charge and discharge capacities has been demonstrated at ambient temperature in the batteries assembled from the prepared single-ion conductors.

Ionic liquid-based solid electrolytes with outstanding room-temperature ionic conductivity and excellent electrochemical stability are developed for all-solid-state Li metal batteries.

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In this study, the ionic conductivity of 77.5Li 2 S•22.5P 2 S 5 and 77.5Li 2 S•(22.5-x)P 2 S 5 •xP 2 O 5 glassy solid-state electrolytes (SSEs) and the relationship of conductivity and lithium deposition behavior in a symmetric lithium metal cell in terms of P 2 O 5 concentration have been investigated. The mechanical milling method has been used to prepare the glassy electrolytes. By adding only a small amount (0.25 mol %) of P 2 O 5 , both the ionic conductivity and the longest cycling performance improve with no signs of short circuiting up to 54 cycles. All symmetric lithium metal cells using 77.5Li 2 S•(22.5-x)P 2 S 5 •xP 2 O 5 (mol %) electrolytes with P 2 O 5 addition of x < 9 display longer cycling performance compared to cells with pure Li 2 S•P 2 S 5 SSEs (x = 0), indicating the suppression of dendrite growth with the addition of P 2 O 5 . The reduced dendritic lithium growth is attributed to higher ionic conductivity and better compaction of the electrolyte pellets with P 2 O 5 addition. The better compaction is confirmed by examination of the pellet density of each SSE composition. The trends established by this study will help inform the optimal performance of 77.5Li 2 S•(22.5-x)P 2 S 5 •xP 2 O 5 glassy solid-state electrolytes (SSEs) in solid-state battery applications.

Exploring solid-state electrolytes as alternatives for flammable liquid carbonate electrolyte is considered as one of the key routes toward next-generation lithium polymer batteries assembled with a high-capacity electrode. In this work, we synthesized an organic−inorganic hybrid solid electrolyte with ionic liquid moieties tethered onto dumbbell-shaped octasilsesquioxanes through oligo(ethylene glycol) spacers. The hybrid electrolyte is featured by its high room-temperature ionic conductivity (1.2 × 10 −4 S/cm at 20 °C with LiTFSI salt), excellent electrochemical stability (4.6 V vs Li + /Li), and great thermal stability. Excellent capability of the hybrid electrolyte to mediate electrochemical deposition and dissolution of lithium has been demonstrated in the symmetrical lithium cells. No short circuit has been observed after more than 500 h in the polarization tests. Decent charge/discharge performance has been obtained in the prepared electrolyte based all-solid-state lithium battery cells at ambient temperature.