Ion‐Conducting, Electron‐Blocking Layer for High‐Performance Solid Electrolytes

Journal Article · Wed May 05 00:00:00 EDT 2021 · Small Structures

DOI:https://doi.org/10.1002/sstr.202100014· OSTI ID:1781943

Hitz, Emily M. ^[1]; Xie, Hua ^[1]; Lin, Yi ^[2]; Connell, John W. ^[3]; Rubloff, Gary W. ^[4]; Lin, Chuan-Fu ^[5]; Hu, Liangbing  ^[1]

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1. Department of Materials Science and Engineering University of Maryland, College Park Maryland 20742 USA
2. National Institute of Aerospace 100 Exploration Way Hampton Virginia 23666-6147 USA
3. Mail Stop 226 Advanced Materials and Processing Branch NASA Langley Research Center Hampton Virginia 23681-2199 USA
4. Department of Materials Science and Engineering University of Maryland, College Park Maryland 20742 USA, Institute for Systems Research University of Maryland College Park Maryland 20742 USA
5. Department of Mechanical Engineering The Catholic University of America Washington District of Columbia 20064 USA

Lithium metal batteries bring greater promise for energy density, often relying on solid‐state electrolytes to meet critical benchmarks. However, Li dendrite formation is a prevailing problem that limits the cycle life and Coulombic efficiency of solid‐state Li metal batteries. For the first time, a thin (<100 nm) layer of electronically insulating, ionically conducting lithium phosphorus oxynitride (LiPON) is applied using atomic layer deposition between a Li anode and garnet Li ₇ La ₃ Zr ₂ O ₁₂ (LLZO). The performance of a conformal LiPON layer as an electron barrier in symmetric Li‐LLZO cells is observed through potential step chronoamperometry, galvanostatic cycling, electron microscopy, and various spectroscopic techniques. The LiPON‐coated LLZO achieves 100 times lower electronic conductance than LLZO alone. Cycling carried out at 0.1 mA cm ⁻² for 100 cycles demonstrates that suppression of electron pathways into the bulk solid electrolyte improves the cycle life of a lithium metal cell. These findings suggest an electronic conductivity effect in solid‐state electrolytes. A strategy is demonstrated to design thin‐film (LiPON)‐modulated bulk solid‐state electrolytes (LLZO) capable of maintaining high ionic conductivity and electrochemical stability while reducing the effective electronic conductivity, which results in significantly decreased dendrite formation, improved cycle life, and greater interfacial integrity between the electrolyte and a Li anode.

• Sponsoring Organization: USDOE
• Grant/Contract Number: DESC0001160
• OSTI ID: 1781943
• Journal Information: Small Structures, Journal Name: Small Structures Vol. 2 Journal Issue: 8; ISSN 2688-4062
• Publisher: Wiley Blackwell (John Wiley & Sons)
• Country of Publication: Germany
• Language: English