Spatiotemporal Resolution of Phase Formation in Thick Porous Sodium Vanadium Oxide (NaV3O8) Electrodes via Operando Energy Dispersive X-ray Diffraction

Gurpreet Singh; Christopher R Tang; Andrew Nicoll; Jonah Torres; Lisa M Housel; Lei Wang; Kenneth J Takeuchi; Esther S Takeuchi; Amy C Marschilok

doi:10.1021/acs.jpcc.2c08255

Spatiotemporal Resolution of Phase Formation in Thick Porous Sodium Vanadium Oxide (NaV₃O₈) Electrodes via Operando Energy Dispersive X-ray Diffraction

J Phys Chem C Nanomater Interfaces. 2023 Feb 8;127(8):3940-3951. doi: 10.1021/acs.jpcc.2c08255. eCollection 2023 Mar 2.

Authors

Gurpreet Singh^{1

2}, Christopher R Tang^{1

3}, Andrew Nicoll^{1

2}, Jonah Torres^{1

4

5}, Lisa M Housel^{1

6}, Lei Wang^{1

6}, Kenneth J Takeuchi^{1

2

3

6}, Esther S Takeuchi^{1

2

3

6}, Amy C Marschilok^{1

2

3

6}

Affiliations

¹ Institute for Energy Sustainability and Equity, Stony Brook University, Stony Brook, New York 11794, United States.
² Department of Chemistry, Stony Brook University, Stony Brook, New York 11794, United States.
³ Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York 11794, United States.
⁴ Center for Inclusive Education, Stony Brook University, Stony Brook, New York 11794, United States.
⁵ Suffolk County Community College, Selden, New York 11784, United States.
⁶ Interdisciplinary Science Department, Brookhaven National Laboratory, Upton, New York 11973, United States.

Abstract

Herein, zinc vanadium oxide (ZVO) and zinc hydroxy-sulfate (ZHS) formation as discharge products in sodium vanadium oxide (NVO) cathode materials of two distinct morphologies, NVO(300) and NVO(500), is studied with ex situ and operando X-ray diffraction methods. ZHS formation upon discharge is shown to be favored at higher current densities and reversible upon charge, while ZVO formation is found to be favored at lower current densities but persists throughout cycling. Operando synchrotron-based energy dispersive X-ray diffraction (EDXRD) reveals reversible expansion of the NVO lattice due to Zn²⁺ during discharge, spontaneous ZVO formation following cell assembly, and ZHS formation concomitant with H⁺ insertion at potentials less than ∼0.8 V vs Zn/Zn²⁺. With spatially resolved EDXRD, ZVO formation is show to occur near the separator region first, eventually moving to the current collector region as discharge depth increases. ZHS formation, however, is found to originate from the current collector side of the positive electrode and then propagate through the porous electrode network. This study highlights the special benefits of the EDXRD method to gain mechanistic insight into structural evolution within the electrode and at its interface.