The EFL700A39 EnFilm solid-state lithium thin-film rechargeable battery from STMicroelectronics is just 220 micrometers thick and 25.7 mm square, making it ideal for powering ultra-low-profile mobile devices and personal technology such as smart cards, RFID tags, wearable technology and IoT devices. It has a nominal 3.9 V output with a capacity of 0.7 mAh. The battery is capable of supplying a peak output current of 10 mA and has an internal impedance of 100 ohms. The cell uses a LiCoO2 cathode, LiPON ceramic electrolyte and a lithium anode.

According to the data sheet the battery can be expected to still have a minimum of 80 % of its initial capacity after 4000 charge cycles which equates to a lifetime of over 10 years with a daily recharge. The EFL700A39 is RoHS compliant and UL certified, satisfying UN tests and criteria for battery transportation and complies with IEC 62133 safety specifications and the ISO7816/IEC10373 mechanical/flexibility smart card standards

STMicroelectronics are currently supplying engineering samples and small production quantities of the battery for applications including wireless sensor nodes, wearable technology, non-implantable medical monitors and back-up or storage for energy-harvesting devices. The unit price is $30.00 with a minimum order quantity of five units.