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Flexible and low-cost poly(ethylene oxide) (PEO)-based electrolytes are promising for all-solid-state Li-metal batteries because of their compatibility with a metallic lithium anode. However, the low room-temperature Li-ion conductivity of PEO solid electrolytes and severe lithium-dendrite growth limit their application in high-energy Li-metal batteries. Here we prepared a PEO/perovskite Li 3/8 Sr 7/16 Ta 3/4 Zr 1/4 O 3 composite electrolyte with a Li-ion conductivity of 5.4 × 10 −5 and 3.5 × 10 −4 S cm −1 at 25 and 45 °C, respectively; the strong interaction between the F − of TFSI − (bis-trifluoromethanesulfonimide) and the surface Ta 5+ of the perovskite improves the Li-ion transport at the PEO/perovskite interface. A symmetric Li/composite electrolyte/Li cell shows an excellent cyclability at a high current density up to 0.6 mA cm −2 . A solid electrolyte interphase layer formed in situ between the metallic lithium anode and the composite electrolyte suppresses lithium-dendrite formation and growth. All-solid-state Li|LiFePO 4 and high-voltage Li|LiNi 0.8 Mn 0.1 Co 0.1 O 2 batteries with the composite electrolyte have an impressive performance with high Coulombic efficiencies, small overpotentials, and good cycling stability.
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Molecular layer deposition of polyhydroquinone thin films for Li‐ion battery applications
Abstract Many next‐generation materials for Li‐ion batteries are limited by material instabilities. To stabilize these materials, ultrathin, protective coatings are needed that conduct both lithium ions and electrons. Here, we demonstrate a hybrid chemistry combining molecular layer deposition (MLD) of trimethylaluminum (TMA) and p‐hydroquinone (HQ) with oxidative molecular layer deposition (oMLD) of molybdenum pentachloride (MoCl5) and HQ to enable vapor‐phase molecular layer growth of poly(p‐hydroquinone) (PHQ)—a mixed electron and lithium ion conducting polymer. We employ quartz crystal microbalance (QCM) studies to understand the chemical mechanism and demonstrate controlled linear growth with a 0.5 nm/cycle growth rate. Spectroscopic characterization indicates that this hybrid MLD/oMLD chemistry polymerizes surface HQ monomers from the TMA‐HQ chemistry to produce PHQ. The polymerization to PHQ improves air stability over MLD TMA‐HQ films without crosslinking. Electrochemical measurements on hybrid MLD/oMLD films indicate electronic conductivity of ~10−9 S/cm and a Li‐ion conductivity of ~10−4 S/cm. While these coatings show promise for Li‐ion battery applications, this work focuses on establishing the coating chemistry and future studies are needed to examine the stability, structure, and cycling performance of these coatings in full Li‐ion cells.
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- Award ID(s):
- 2219060
- PAR ID:
- 10543432
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- AIChE Journal
- Volume:
- 70
- Issue:
- 12
- ISSN:
- 0001-1541
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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