Or are such tags only available without a battery?
There are no 13.56 MHz active tags. Tags that operate at 13.56 MHz use magnetic induction, making it difficult for them to communicate with readers more than a few meters away. There are battery-assisted 13.56 MHz tags, however. These use the battery to power a temperature or moisture sensor, and do not increase the read distance to the 300 feet (91 meters) or more that we tend to see from active tags operating at 433 MHz, 915 MHz or 2.45 GHz.
—Mark Roberti, Founder and Editor, RFID Journal
Can I Track Computers and Smartphones Via RFID? »