Effect of iron on delithiation in LixCo_1−yFe_yO₂. Part 2:in-situ XANES and EXAFS upon electrochemical cycling

Effect of iron on delithiation in LixCo1−yFeyO2. Part 1: in-situ electrochemical and X-ray diffraction study

“…This behaviour could be due to a partial migration of Fe in the structure in the heavy delithiated range (end of charge), altering the interslab distance and hence the cell parameter evolution on subsequent discharge. However, it is not a redox effect: new EXAFS results, (see Part 2 of this series 33 ), show a concurrent variation of Co-O and Fe-O distances for LCF1 on charge and discharge.…”

Exploring the influence of iron substitution in lithium rich layered oxides Li2Ru1−xFexO3: triggering the anionic redox reaction

“…53,54 Whereas LRFO exhibits two redox reactions with varying degree of reversibility, the rst being the (Ru 4+ /Ru 5+ at 3.75 V vs. Li) transition and second being the (Fe 3+ /Fe 4+ at 4 V vs. Li) redox couple. 55,56 In the case of LRO and LRTO, as the cell is charged to 3.75 V vs. Li a redox peak corresponding to the oxidation of Ru can be Oxygen gas is irreversibly removed from the surface. 57 Or following the argument by Sathiya et al 23,24 the peak can indicate a reversible anionic redox reaction occurring at oxygen centres.…”

Metal Oxide Nanoparticles

“…[304] The electrochemical processes that occur during the charge-discharge cycles have been the focus of significant interest, in particular the use of in situ experiments carried out on prototype lithium batteries. [305][306][307][308] For example, X-ray absorption spectroscopy (XAS) has been used to investigate the insertion/extraction of lithium in NiCo 2 O 4 spinel oxide. [309] Reversible capacities of approximately 884 mA h g À1 versus Li [310] have been observed when NiCo 2 O 4 spinel oxide has been used as the active electrode material in lithium cells.…”