X-ray techniques describe modifications in the cathode material of aqueous Zn-ion batteries
|Zinc-ion batteries in aqueous battery systems (AZIBs) are attracting an increasing interest in the field of energy storage research and in the rechargeable battery market, due to the advantages of its components: zinc presents low cost, nontoxicity and interesting electrochemical properties, while the aqueous media gives the opportunity to avoid highly toxic, flammable and expensive organic solvents.
CERIC PhD candidate Dr Mariam Maisuradze, Prof. Marco Giorgetti (University of Bologna) and colleagues followed the electrochemical behaviour of a partially (10%) nickel-substituted manganese hexacyanoferrate used as cathode material in a AZIB system, monitoring the structural modification of the material using synchrotron-based x-ray techniques. In particular, scientists exploited x-ray absorption spectroscopy (XAS) available and the powder x-ray diffraction (PXRD), both available at the CERIC Italian Partner Facility at Elettra Sincrotrone Trieste. Combining the two techniques – XAS helps to outline the electrochemical activity of metals used in cathodes and their local structure, while operando PXRD allows to describe the crystallinity, symmetry, unit cell parameters and phase modification of the used material during the operational conditions, and their changes during the aging process – researchers could show the profound alteration that the system structure undergoes: the dissolution of both manganese and nickel has been observed, alongside with the substitution of manganese with zinc. Furthermore, scientists demonstrated a new zinc-containing phase formation, and the modification of manganese species.
These results may help shed light on the degradation processes occurring at the cathode in a AZIB system, enabling the development of longer-lasting next-generation batteries.
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