@a4refillpad tried to get the ZigBee-based Xiaomi Outlet working as a repeater, and ultimately found that they just don’t work in conjunction with SmartThings:
My advice is not bother. Just ripped all mine out in disgust!!
50 dropped zigbee devices over 48 hours. Totally wrecks your mesh. I have close to 170 zigbee devices in the house, these outlets are a disaster if you have a lot of devices like me.
Some days later he came up with a CoRE piston workaround that got them working, but not reliably.
I haven’t hit the 32 device limit (yet), but I was planning on getting an Iris Smart Plug (that does both ZigBee and Z-Wave repeating). I just haven’t researched whether it will repeat with Xiaomi devices correctly.