Several different aspects to this, so I just want to clear up a couple…
You gotten very good advice about using the Fibaro Z wave sensor with a temperature probe, and the various selection issues involved with that.
Choosing zigbee devices for use with SmartThings
I did want to mention first that the zigbee standard allows for multiple different profiles, including manufacturer proprietary. The different profiles cannot work with each other, They don’t even use the same addressing standard.
SmartThings uses the “zigbee home automation” profile (ZHA 1.2). Devices that use that exact profile can probably be made to work with SmartThings, although they may require a custom device type handler.
Devices using other zigbee profiles may not work with SmartThings at all, or may be able to be paired but then keep disconnecting from the network.
So just being “zigbee” isn’t enough.
Shopping at Alibaba
Next, the product descriptions on Alibaba are often incorrect, commonly because they copied the English from a different similar looking product without understanding all the differences. A lot of things are marked as “Wi-Fi” which are actually zigbee or Z wave, some things are marked “US Z wave” when in fact they are on the Asian frequency and would not work with the SmartThings hub. And some are marked “zigbee” when they’re actually accessories without any radio at all. I can’t be sure on this one, but that’s what it looks like – – that this is just the probe sensor, not the networked piece.
Many times if you ask if a device is certified for the “zigbee home automation profile” as long as it is a zigbee device intended for automation, they will tell you that it is. Because they don’t understand the difference.
Anyway, if you are going to buy from AliBaba it’s a good idea to write and ask them for a copy of their certification before purchasing.
The DS18B20
In this particular case, you can find the same probe from very reliable sources, including Amazon, so you might want to just consider sourcing there. 
Again, this particular piece doesn’t have a radio – – that’s what you’re going to use the Fibaro sensor for.