Yes, paper can be made from algae (“pond scum”); and now it is possible to store electrical charges in such paper – that is, make a battery of it. Here’s some of the report in the Economist:

Albert Mihranyan of Uppsala University in Sweden and his colleagues have built a battery that is, in essence, made of paper. It is lightweight and slim, and although still unsuitable for everyday use, could be employed to trace products supplied to shops or baggage passing through airports.

The device developed by Dr Mihranyan and his colleagues, which they describe in NanoLetters, is based on cellulose—the material from which paper is made. This is not any old cellulose, though. It is extracted not from trees or cotton, as the cellulose used in paper is, but from algae. Dr Mihranyan used algal cellulose because its fibres are wispier. That gives it a greater surface area and thus allows it to store more electric charge.

Cellulose does not, however, conduct electricity, so Dr Mihranyan needed to coat it with a substance that does. He chose a polymer called a polypyrrole which, soaked into the algal cellulose, produced a combination that conducted electricity well. He then fashioned the anode and cathode of his battery from the stuff. For the electrolyte, he used filter paper soaked in brine.

The battery thus consisted of this brine-soaked filter paper sandwiched between two cellulose electrodes that were, in turn, held between two glass slides. Platinum strips attached to the electrodes provided electrical contacts to the outside world. The electrical energy itself was stored and released by chemical changes in the polypyrrole. This molecule can exist in two forms, known technically as “oxidised” and “reduced”, and a current will flow between the two when they are part of a circuit. The result was a one-volt battery that could be charged in seconds—and charged and discharged 100 times without serious loss of performance.

[Source: The Economist]