Mitigating oxygen loss to improve the cycling performance of high capacity cation-disordered cathode materials

• DOI: 10.1038/s41467-017-01115-0
• Publication Date: 2017-10-11T14:05:32Z
• Authors: Jinhyuk Lee; Joseph K. Papp; Raphaële J. Clément; Shawn Sallis; Deok-Hwang Kwon; Tan Shi; Wanli Yang; Bryan D. McCloskey; Gerbrand Ceder
• Keywords: Science; Q; 500; Materials Engineering; 540; Physical Chemistry; 7. Clean energy; 01 natural sciences; Article; 0104 chemical sciences; Engineering; Affordable and Clean Energy; Chemical Sciences

AbstractRecent progress in the understanding of percolation theory points to cation-disordered lithium-excess transition metal oxides as high-capacity lithium-ion cathode materials. Nevertheless, the oxygen redox processes required for these materials to deliver high capacity can trigger oxygen loss, which leads to the formation of resistive surface layers on the cathode particles. We demonstrate here that, somewhat surprisingly, fluorine can be incorporated into the bulk of disordered lithium nickel titanium molybdenum oxides using a standard solid-state method to increase the nickel content, and that this compositional modification is very effective in reducing oxygen loss, improving energy density, average voltage, and rate performance. We argue that the valence reduction on the anion site, offered by fluorine incorporation, opens up significant opportunities for the design of high-capacity cation-disordered cathode materials.