Scalable Freeze-Tape-Casting Fabrication and Pore Structure Analysis of 3D LLZO Solid-State Electrolytes

Journal Article · Fri Dec 20 00:00:00 EST 2019 · ACS Applied Materials and Interfaces

DOI:https://doi.org/10.1021/acsami.9b11780· OSTI ID:1601218

Shen, Hao  ^[1]; Yi, Eongyu  ^[2]; Heywood, Stephen ^[3]; Parkinson, Dilworth Y.  ^[4]; Chen, Guoying  ^[2]; Tamura, Nobumichi ^[4]; Sofie, Stephen ^[3]; Chen, Kai ^[5]; Doeff, Marca M.  ^[2]

---

1. Xi'an Jiaotong Univ., Xi'an, Shaanxi (China). State Key Lab. for Mechanical Behavior of Materials, Center for Advancing Materials Performance from the Nanoscale (CAMPNano); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
3. Montana State Univ., Bozeman, MT (United States)
4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS)
5. Xi'an Jiaotong Univ., Xi'an, Shaanxi (China). State Key Lab. for Mechanical Behavior of Materials, Center for Advancing Materials Performance from the Nanoscale (CAMPNano)

Nonflammable solid-state electrolytes can potentially address the reliability and energy density limitations of lithium-ion batteries. Garnet-structured oxides such as Li₇La₃Zr₂O₁₂ (LLZO) are some of the most promising candidates for solid-state devices. Here, three-dimensional (3D) solid-state LLZO frameworks with low tortuosity pore channels are proposed as scaffolds, into which active materials and other components can be infiltrated to make composite electrodes for solid-state batteries. To make the scaffolds, we employed aqueous freeze tape casting (FTC), a scalable and environmentally friendly method to produce porous LLZO structures. Using synchrotron radiation hard X-ray microcomputed tomography, we confirmed that LLZO films with porosities of up to 75% were successfully fabricated from slurries with a relatively wide concentration range. The acicular pore size and shape at different depths of scaffolds were quantified by fitting the pore shapes with ellipses, determining the long and short axes and their ratios, and investigating the equivalent diameter distribution. The results show that relatively homogeneous pore sizes and shapes were sustained over a long range along the thickness of the scaffold. Additionally, these pores had low tortuosity and the wall thickness distributions were found to be highly homogeneous. These are desirable characteristics for 3D solid electrolytes for composite electrodes, in terms of both the ease of active material infiltration and also minimization of Li diffusion distances in electrodes. The advantages of the FTC scaffolds are demonstrated by the improved conductivity of LLZO scaffolds infiltrated with poly(ethylene oxide)/lithium bis(trifluoromethanesulfonyl)imide (PEO/LITFSI) compared to those of PEO/LiTFSI films alone or composites containing LLZO particles.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V); National Natural Science Foundation of China (NSFC); National Key Research and Development Program of China; China Scholarships Council
• Grant/Contract Number: AC02-05CH11231; 51671154; 91860109; 2016YFB0700404
• OSTI ID: 1601218
• Journal Information: ACS Applied Materials and Interfaces, Vol. 12, Issue 3; ISSN 1944-8244
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
solid-state electrolyte
freeze tape casting
hard X-ray micro computed tomography
structure analysis
LLZO