Comparing Ni vs. NiO as the Nickel Source in the All-Dry Laboratory and Industrial Scale Synthesis of LiNi0.925Mn0.02Co0.055O2

Either Ni or NiO was used as the nickel source in two separate samples (Ni-92 and NiO-92 respectively) to make LiNi0.925Mn0.02Co0.055O2 layered oxide single crystal material using the all-dry synthesis process. In-situ X-Ray Diffraction was conducted at the Canadian Light Source to probe phase evolutions during a temperature ramp up to 950°C. For the formation of such high nickel cathode materials within a small alumina capillary, using NiO is advantageous over pure Ni metallic powder. Both reaction pathways include the formation of a spinel intermediary phase before eventually reaching the layered phase. The onset of the layered phase happens relatively early for the NiO-92 sample, leading to the formation of a well-ordered structure at 635°C. However, the metallic Ni in the Ni-92 sample needs to first undergo oxidation to form a rock salt phase, which is then lithiated, becoming the spinel phase around 595°C and reaching the layered phase at a higher temperature than NiO-92. Work at NOVONIX shows that the all-dry synthesis method can be scaled up industrially to synthesize both Ni-92 and NiO-92 with equal or better electrochemical performance compared to optimized commercial high nickel material made from co-precipitated precursors.