X-ray imaging and micro-spectroscopy unravel the role of zincate and zinc oxide in the cycling of zinc anodes in mildly acidic aqueous electrolytes

DOI: 10.1016/j.jpowsour.2022.231063

Authors: Majid Kazemian (Diamond Light Source) , Francesca Rossi (University of Salento) , Andrea Casaroli (Politecnico di Milano) , Tommaso Caielli (Politecnico di Milano) , Burkhard Kaulich (Diamond Light Source) , Maya Kiskinova (Elettra – Sincrotrone Trieste) , Ivonne Sgura (University of Salento) , Benedetto Bozzini (Politecnico di Milano)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Power Sources , VOL 524

State: Published (Approved)
Published: March 2022
Diamond Proposal Number(s): 22398

Abstract: Sustainability, environmental and safety concerns raised by the increasing demand of batteries are driving research towards post-lithium technologies. Rechargeable Zn batteries are strong candidates, but still not practically viable, owing to the extensively studied, but poorly understood unstable behavior of Zn metal upon discharge-charge cycling. This limiting factor warrants more fundamental investigations and the present report provides the lacking molecular-level information on the Zn-based compounds forming at the electrode/electrolyte interface as a result of electrochemical cyclic in weakly acidic aqueous electrolyte. The results are obtained using ex situ X-ray absorption spectromicroscopy maps, modelled mathematically and complemented with cyclic voltammetry, symmetric-cell tests and electron microscopy. We have identified the role of the zincate precipitation resulting from local alkalinization during recharge, combined with additional zincate formation and decomposition to zinc oxide during discharge. The mathematical model allowed a transparent interpretation of morphochemical changes observed. The synergy of these processes leads to electrochemical localization effects, resulting in the formation of a complexly structured and low conductive ZnO-based template, that might play a role in driving shape changes.

Journal Keywords: Zn anode; Mildly acidic; Zincate; X-ray absorption spectroscopy; STXM; Hyperspectral mapping

Diamond Keywords: Batteriesl Zinc-ion

Subject Areas: Materials, Chemistry, Energy


Instruments: I08-Scanning X-ray Microscopy beamline (SXM)

Added On: 07/02/2022 09:56

Documents:
1-s2.0-S0378775322000878-main.pdf

Discipline Tags:

Energy Storage Energy Physical Chemistry Energy Materials Chemistry Materials Science

Technical Tags:

Spectroscopy X-ray Absorption Spectroscopy (XAS)