Scientists from New York have created an advanced form of battery which is activated by spit and powered by bacteria.

The innovative creation is designed to be able to be used in extreme conditions where other batteries couldn’t function – and as they are disposable and made from paper, could be an eco-friendly alternative.

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A footballer spits
The devices can be activated by spit or dirty water (Tony Marshall/EMPICS Sport)

The biobatteries are the brain child of Professor Seokheun Choi from Binghampton University, who has worked on the project for five years.

Choi’s paper published in the journal Advanced Materials Technologies claims the battery can be “readily activated by one drop of saliva”.

So how does it work? Well Choi’s design consists of a single sheet of paper with 16 microbial fuel cells (MFC), made up of freeze-dried exoelectrogenic cells, and it’s these cells which react with the saliva.

This diagram shows the design of the MFCs (Binghampton University)

The oxygen-tight interface and engineered conductive paper reservoir allow the batteries to achieve maximised microbial election transfer efficiency.

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“On-demand micro-power generation is required especially for point-of-care diagnostic applications in developing countries,” said Choi.

“Typically, those applications require only several tens of microwatt-level power for several minutes, but commercial batteries or other energy harvesting technologies are too expensive and over-qualified. Also, they pose environmental pollution issues.”

AAA batteries
Will conventional batteries be old news? (PA)

Choi’s paper states that the batteries are a low-cost, disposable and eco-friendly alternative, with a long shelf life too – so what’s the catch?

Well, currently they only put out a small amount of energy, enough to power a light-emitting diode for about 20 minutes. However, considering that’s from power just generated from a drop of saliva, that’s actually pretty impressive.

Although the batteries create only a small amount of energy now, it’s hoped that future incarnations can have greater power and efficiency.

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