In Situ XRD Studies During Synthesis of Single-Crystal LiNiO2, LiNi0.975Mg0.025O2, and LiNi0.95Al0.05O2 Cathode Materials

High-nickel, cobalt-free, single-crystal positive electrode materials could provide the ultimate intersection of high-specific capacity, low cost, and long-lifetime in lithium-ion batteries. In this work, the synthesis of LiNiO2, LiNi0.975Mg0.025O2, and LiNi0.95Al0.05O2 is studied by dynamic XRD during heating, in order to guide improvements in synthesis procedures. A comparison of Li2CO3 and LiOH center dot H2O lithium sources shows that either can be used to prepare these materials, but Li2CO3 requires a higher temperature. Mg doping is shown to be beneficial in lowering the temperature required to get fully lithiated, crystalline material. Additional experiments show that synthesis with a 480 degrees C preheat step, or synthesis directly from individual metal hydroxides (without a precursor), could be used as potentially viable alternative synthesis methods. (C) 2020 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited.