In situ Mössbauer analysis of bacterial iron-oxide nano-particles for lithium-ion battery

Nanometric amorphous iron-based oxides of bacterial origin show a great potential as an Fe³⁺/Fe⁰ conversion anode material for lithium-ion batteries. By means of in situ Mössbauer spectroscopy, chemical states of Fe ions were examined under the discharge-charge process of the bacterial iron-oxide electrode in a lithium-ion half-cell. As for the first discharge process, the successive reduction of Fe³⁺ → Fe²⁺ → Fe⁰ occurred in the electrode as a function of the cell voltage. While on the charge process, Fe⁰ in the electrode was oxidized directly to Fe³⁺ without going through Fe²⁺.