The Sony NP-F970 is a rechargeable battery (6600mAh, 47Wh, 7.2V)
Lithium-ion technology with no memory effect
Highly efficient, compact and light-weight
Built-in microprocessor accurately communicates remaining battery time to the camera

See also:
Globalmediapro DC970 Battery 47WH with DC
Globalmediapro DC1170C Battery 65WH with DC