Effect of AlF3 Surface Coating on High Energy Lmr-NMC Material

In this study, we explore the effect of AlF₃ surface coating on Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ to mitigate the voltage fade issue. The precursor of this high energy material was synthesized using carbonate co-precipitation method by a 20L continuous stirred tank reactor (CSTR). Then, the synthesized precursor was mixed with Li-source and calcined at 900°C to generate cathode material. This product was used as the base material for AlF₃ surface coatings.

A customized wet coating system was used for surface modification of the pristine material with 0.5, 1.0, 1.5 and 2.0 wt.% AlF₃. The morphology, surface area, particle size and its distribution of the pristine and coated materials were characterized by scanning electron microscopy (SEM), BET and particle size analysis. The composition and the structure of the materials were characterized by inductively coupled plasma mass spectroscopy (ICP-MS) and X-ray diffraction (XRD).

The coated and pristine cathode powders were electrochemically tested using Voltage Fade protocol of Argonne National Laboratory. We demonstrate that AlF₃ coating shows improved capacity retention compared to its pristine material. As a key factor, uniform surface coating provides improved capacity retention and rate capability of Li_1.2Mn_0.54Ni_0.13Co_0.13O₂.