Structural Modification of Partially Ni-substituted MnHCF Cathode Material for Aqueous Zn-ion Batteries

The initial capacity fading and electrochemical profile modification of the nickel substituted manganese hexacyanoferrate cathode material in aqueous zinc-ion batteries was investigated. The outcome of the electrochemical tests suggested the structural transformation of the material; therefore, further characterization has been performed with the synchrotron-based x-ray absorption spectroscopy and powder x-ray diffraction. Indeed, the alteration of the structure was evident with both techniques. The dissolution of Mn and Ni was observed, alongside with the substitution of Mn with Zn. Furthermore, a new Zn-containing phase formation, and the modification of Mn species were demonstrated. Keywords: Aqueous batteries; Zn-ion batteries; X-ray absorption