The Coke-powered Nokia and the sugar battery problem

What it was

In January 2010, Daizi Zheng, a Chinese designer based in London, showed a phone concept for Nokia that swapped the lithium-ion battery for a bio battery. You would pour a sugary drink, Coca-Cola for example, into the handset, and enzymes would break down the carbohydrates to make electricity.

The claims around the project were generous. Reports at the time said one fill could last three to four times longer than a lithium-ion charge, that the cell would leave behind water and carbon dioxide, and that the whole phone could be biodegradable. Core77 described it as a client project for Nokia, and Engadget treated it as a vision rather than a working device. Nokia never said it planned to build it.

A phone you refill at the vending machine makes a good story. It is still waiting for a good chemistry.

Where the idea went

The chemistry was not invented for the phone. In August 2007, Sony announced a bio battery that used enzymes to break down glucose. Each of its 39-millimeter cubic cells reached 50 milliwatts, a record for the type at the time, and four of them in series ran a memory Walkman.

Sony kept working on it. In December 2011, at the Eco-Products exhibition in Tokyo, it showed a version that turned shredded paper into sugar and then into electricity, enough to spin a small fan. The company said the technology was still a long way from commercial use because its power output was too low. It could run a digital music player, but it was not strong enough to replace ordinary batteries.

In January 2014, a Virginia Tech team led by Y.H. Percival Zhang reported a sugar battery with much higher energy density and suggested it could be running phones and tablets within three years. That window passed without a product. Sugar batteries are still research, and their low output voltage remains a basic obstacle.

What it means now

The concept was right about one thing: a battery is part of a phone’s environmental cost, not only a line on its spec sheet. It was less convincing about the fuel. A drink that has to be grown, bottled and shipped is an odd way to save energy, a point readers raised at the time.

What you can buy instead is more modest. Power banks now come in housings made from recycled material, and folding solar panels can top up a phone from daylight. None of it fits in a can, but all of it exists.