Washington, Sep 24 : Ever thought about getting a birthday gift wrapped in a paper that sings "Happy Birthday" to you? Well, thanks to an amazing battery made out of paper, this could soon be a reality.

Made of cellulose, the stuff of paper, the new battery can have a variety of applications.

According to Albert Mihranyan and colleagues, scientists are trying to develop light, eco-friendly, inexpensive batteries consisting entirely of non-metal parts and the most promising materials include so-called conductive polymers or "plastic electronics."

One conductive polymer, polypyrrole (PPy), seemed promising, but was often regarded as too inefficient for commercial batteries.

However, the scientists realized that by coating PPy on a large surface area substrate, and carefully tailoring the thickness of the PPy coating, both the charging capacity and the charging
(discharging) rates can be drastically improved.

The secret behind the performance of this battery is the presence of the homogeneous, uninterrupted, nano-thin coating - about 1/50,000th the thickness of a human hair - of PPy on individual cellulose fibres, which in turn can be moulded into paper sheets of exceptionally high internal porosity.

It was special cellulose, extracted from a certain species of green algae, with 100 times the surface area of cellulose found in paper, which allowed the new device to hold and discharge electricity very efficiently.

The innovative design of the battery cell was surprisingly simple yet very elegant since both of the electrodes consist of identical pieces of the composite paper separated by an ordinary filter paper soaked with sodium chloride serving as the electrolyte.

The potential difference is solely due to differences between the oxidized and reduced forms of the functional PPy layer.

The scientists said that the battery recharged faster than conventional rechargeable batteries and was apparently well suited for applications involving flexible electronics, such as clothing and packaging.

Alternatively, low-cost very large energy storage devices having electrodes of several square yards in size could potentially be made in the future.

The study appears in an upcoming issue of ACS'''' Nano Letters. (ANI)