"Typically, FeF3∙3H2O and CoF3 were ball milled at a molar ratio of 9:1 for 30 min to reduce the particle size and get a homogeneous reactant mixture. Then, 170 mg of such mixture was dispersed in 1-propanol (75 ml) and stirred vigorously at room temperature for half an hour. The resulting suspension was transferred into a Teflon-lined 100 ml stainless-steel autoclave reactor, and subsequently sealed and heated at 210 °C for 24 h in an oven. For comparison, FeOF was also synthesized by the same procedure using pure FeF3∙3H2O as the starting material dispersed in butyl-alcohol. FeF3 was prepared by ball milling the as-purchased FeF3 for 6 h. The pre-lithiation of Fe0.9Co0.1OF is synthesized by ball milling Fe0.9Co0.1OF and LiH at a molar ratio of 1:2 for 10 h."
This is standard ceramic slurry processing, they mix the powders with some liquid and then heat the two ceramics together to do a solid state reaction. I am somewhat impressed that the reaction went suitably at 210C, but that's not particularly hot. I'd think that the raw material costs would dominate here.
EDIT: Ball milling is when you spin a jar on rollers with the ceramic powder and big teflon beads that crush it gradually over a long period of time. It can be done dry or wet, but it's not a fancy procedure.