Hello, I study about cathode (NCM) structure for Li-ion battery, and now I'm currently trying to refine my LiNiO2 data with REFLEX module (Powder refinement) in Materials Studio, but I'm not sure that I'm doing it properly.

First, it is important to know Li/Ni mixing (cation mixing) value, but every time I try to refine atoms occupancy, results are like this;

I think if there is mixing, then Li and Ni occupancy should be lower than 1, because they are both moved to the other site. But Li occupancy is still 1. Is there anything wrong during the refinement steps, or how can I understand that?

Second, I'm confused about Rwp and Rwp (w/o bck), Rp parameters. If I do refinement after powder processing (includes subtract background, smoothing), then the Rwp and Rwp (w/o bck) parameters are about 6~8 %, but Rp values are quite large, which is about 17~18 %.

However, If I do refinement without any processing, then the Rwp and Rp parameters are about 1~2 %, which are very low, but Rwp (w/o bck) vaules show 9 %.

I'm very confused with those results, so I need some advices about these.

Thanks a lot!