Lithium rich disordered rock salt materials are currently under investigation as a cathode for the next generation of lithium ion batteries. Advanced cathode material research is driven by the need for improved battery capacity and enhanced cyclic stability. The transition metal oxide of the cathode is the limiting factor behind the energy density and electrochemical behavior of the lithium ion battery. Mixed anion oxyfluorides, such as Li2Ni(III)O2F and LiNi(II)OF2, are promising future candidates for high energy density cathodes. In recent publications fluorine substituted metal oxides were shown to have high energy capacity and good capacity retention over long cycling, however the contribution of fluorine for such an improvement is not clear. Li2Ni(III)O2F and LiNi(II)OF2 had theoretical capacities of 216 mAh/g and 211 mAh/g , respectively, however experimental cycling reported higher capacities for both compounds. Upon initial charging from 1.5 V to 5.0 V, LiNi(II)OF2 had a capacity of 211 mAh/g and from 1.5 V to 5.2 V a capacity of 264 mAh/g. Upon initial charging of Li2Ni(III)O2F from 2.0 V to 4.8 V a capacity of 298 mAh/g was recorded. The aim of this project is to gain insight on how the covalent interactions between the ligands and the transition metal in nickel oxyfluorides improve electrochemical performance.

Chemical bonding in redox active oxyfluorides

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ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.