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Abstract Current sulfide solid‐state electrolyte (SE) membranes utilized in all‐solid‐state lithium batteries (ASLBs) have a high thickness (0.5–1.0 mm) and low ion conductance (<25 mS), which limit the cell‐level energy and power densities. Based on ethyl cellulose's unique amphipathic molecular structure, superior thermal stability, and excellent binding capability, this work fabricates a freestanding SE membrane with an ultralow thickness of 47 µm. With ethyl cellulose as an effective disperser and a binder, the Li6PS5Cl is uniformly dispersed in toluene and possesses superior film formability. In addition, an ultralow areal resistance of 4.32 Ω cm−2and a remarkable ion conductance of 291 mS (one order higher than the state‐of‐the‐art sulfide SE membrane) are achieved. The ASLBs assembled with this SE membrane deliver cell‐level high gravimetric and volumetric energy densities of 175 Wh kg−1and 675 Wh L−1, individually.
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Adverse Effects of Trace Non-polar Binder on Ion Transport in Free-standing Sulfide Solid Electrolyte Separators
Sulfide solid-state electrolyte (SE) possesses high room-temperature ionic conductivity. However, fabrication of the free-standing, sheet-type thin sulfide SE film electrolyte to enable all-solid-state batteries to deliver high energy and power density remains challenging. Herein we show that argyrodite sulfide (Li6PS5Cl) SE can be slurry cast to form free-standing films with low (≤5 wt%) loadings of poly(isobutylene) (PIB) binder. Two factors contribute to a lower areal specific resistance (ASR) of the thin film SEs benchmarked to the pristine powder pellet SSE counterparts: i) 1–2 orders reduced thickness and ii) reasonably comparable ionic conductivity at room temperature after the isostatic pressing process. Nevertheless, an increasing polymer binder loading inevitably introduced voids in the thin film SEs, compromising anode/electrolyte interfacial ion transport. Our findings highlight that electrolyte/electrode interfacial stability, as well as the selection of slurry components, including sulfide SE, binder, and solvent, play essential roles in thin film sulfide electrolyte development.
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- Award ID(s):
- 1751450
- PAR ID:
- 10493578
- Publisher / Repository:
- IOP Science
- Date Published:
- Journal Name:
- Journal of The Electrochemical Society
- Volume:
- 170
- Issue:
- 8
- ISSN:
- 0013-4651
- Page Range / eLocation ID:
- 080513
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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