In improvements of the capacity, safety, and cyclability of LIBs. 1− 5 Many efforts were undertaken during the last decades, resulting Of metallic Ni is suppressed and contributes to a capacity lossĬompared with the early discharge/charge cycles.īatteries (LIBs) deliver electricity in portable electronicĭevices. XAS results indicate that Fe can be reversibly reoxidized to Fe 3+ during charge whereas Mn does not reach the oxidation state Metal particles embedded in a LiOH/Li 2O matrix. A further increase of the LiĬontent leads to a successive conversion of the cations to nanosized Of this sample clearly shows the signal of Li in a diamagnetic environment,Įxcluding Li–O–TM bonds. Thus, the majority of cations is located on octahedral sites.įurthermore, an improvement of the PDF model is achieved taking intoĪccount small amounts of LiOH. That the principal structure can be sufficiently well modeled assumingĬoexisting NiO, a mixed monoxide, and a small amount of residual spinel PDF analysis of the pattern after an uptake of 2 Li/fu evidences Indicates movement of these cations from tetrahedral sites to octahedral Of the pre-edge features in X-ray absorption near-edge spectroscopy Increasing amounts of Li, Mn 3+, and Fe 3+ are simultaneously reduced. Operando X-ray absorption spectroscopy (XAS)Įxperiments indicate that ≈0.8 Li/fu is consumed without detectableĬhanges of the electronic structure. Of the sample against Li delivers a high reversible capacity of ≈840 ![]() Spectroscopy maps, giving no hints for a phase separation. Such advanced characterization is essential because a homogeneousĭistribution of the elements is observed in energy-dispersive X-ray To inaccurate assumption of the stoichiometry and oxidation states. Such a finding can easilyīe overlooked by using only inhouse X-ray powder diffraction, leading Phase, which is clearly demonstrated by analysis of the pair distributionįunction (PDF) and synchrotron X-ray data. Nanosized oxide NiFeMnO 4 consists of a mixture of NiO and
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