A modified microbial fuel cell with a halogen salt or salt water oxidizer. The fuel cell is a batch cell, but flow-through cell embodiments are also envisioned. The cathode and anode are separated by a cation exchange membrane or saline bridge. The anode contains microorganisms in media or various water bed sediments. The cathode contains water and a halogenated salt oxidizer. The fuel cells operated continuously for over 3 months, providing approximately 10 times more power than those in the current literature for batch cells.