TiO₂ as second phase in Na₃Zr₂Si₂PO₁₂ to suppress dendrite growth in sodium metal solid-state batteries

Gao, Z., Yang, J., Li, G. , Ferber, T., Feng, J., Li, Y., Fu, H., Jaegermann, W., Monroe, C. W. and Huang, Y. (2022) TiO₂ as second phase in Na₃Zr₂Si₂PO₁₂ to suppress dendrite growth in sodium metal solid-state batteries. Advanced Energy Materials, 12(9), 2103607. (doi: 10.1002/aenm.202103607)

Abstract

Solid-state sodium–metal batteries will not achieve reasonable power density without electrolytes that solve the dendrite (filamentation) problem. Metal-filament formation during plating at ceramic/metal interfaces can cause electrical failure by internal short-circuit or mechanical failure by electrolyte fracture. Herein, an Na3Zr2Si2PO12 (NZSP) sodium-ion-conducting NASICON electrolyte in which TiO2 is incorporated as an additive is presented, leading to a two-phase composite NZSP(TiO2) with improved density, Young's modulus, hardness, grain structure, and bulk permittivity. These features of NZSP(TiO2) suppress dendrite growth along grain boundaries, microcracks, and micropores. As well as demonstrating ultralow ceramic/Na kinetic resistance with electrochemical measurements, X-ray photoelectron spectroscopy is performed to probe interfacial reaction mechanisms. The TiO2 phase forms within grain boundaries and along NZSP surfaces. This modifies the two-phase material's microstructure and improves its electrochemical performance, while also increasing the critical current density for dendrite formation. Design guidelines are discussed to mitigate microscopic defects and dendrites in two-phase ceramic electrolytes.

• Item Type: Articles
• Additional Information: Z.G. and J.Y. contributed equally to this work. This work was supported by the National Natural Science Foundation of China (Nos. 51632001 and U1764256). C.W.M. and G.L. were supported by the EPSRC Faraday Institution SOLBAT project, subaward FIRG007 under grant EP/P003532/1.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Li, Dr Guanchen
• Authors: Gao, Z., Yang, J., Li, G., Ferber, T., Feng, J., Li, Y., Fu, H., Jaegermann, W., Monroe, C. W., and Huang, Y.
• College/School: College of Science and Engineering > School of Engineering > Systems Power and Energy
• Journal Name: Advanced Energy Materials
• Publisher: Wiley
• ISSN: 1614-6832
• ISSN (Online): 1614-6840
• Published Online: 24 January 2022
• Copyright Holders: Copyright © 2022 Wiley-VCH GmbH
• First Published: First published in Advanced Energy Materials 12(9):2103607
• Publisher Policy: Reproduced in accordance with the publisher copyright policy