Powering up with a breath of fresh air

Researchers at the Institute of Physical Chemistry of the Polish Academy of Sciences in Warsaw have combined an enzyme, carbon nanotubes and silicate to make a composite cathode material. The cathode sits in a biofuel cell or zinc-oxygen biobattery and uses nothing more than air as its oxygen source. At present, many laboratories work on glucose-oxygen biofuel cells that generate a voltage of 0.6-0.7 V whereas a zinc-oxygen biobattery with the cathode can produce 1.75 V for many hours. Such a system could one day be used to power cardiac pacemakers or hearing aids or even active contact lenses and other medical aids.