Currently the batteries used in smartphones and computers are mostly made of toxic materials such as lithium that can be difficult to dispose of and have limited global supplies.
Now, researchers at MIT have come up with an alternative system for generating electricity, which harnesses heat and uses no metals or toxic materials.
The new approach is based on MIT’s discovery announced around 6 years back.
According to that discovery, a wire made from tiny cylinders of carbon known as carbon nanotubes can produce an electrical current when it is progressively heated from one end to the other, for example by coating it with a combustible material and then lighting one end to let it burn like a fuse.
That discovery represented a previously unknown phenomenon, but experiments at the time produced only tiny amount of current in a simple laboratory setup. Now, the MIT team has increased the efficiency of the process more than a thousandfold .
In their latest version, the device is more than 1 percent efficient in converting heat energy to electrical energy,
While the initial experiments had used potentially explosive materials to generate the pulse of heat that drives the reaction, the new work uses sucrose, otherwise known as ordinary table sugar.
Already, the device is powerful enough to show that it can power simple electronic devices such as an LED light. And unlike batteries that can gradually lose power if they are stored for long periods, the new system should have a virtually indefinite shelf life.
That could make it suitable for uses such as a deep-space probe that remains dormant for many years as it travels to a distant planet and then needs a quick burst of power to send back data when it reaches its destination.
In addition, the new system is very scalable for use in the increasingly tiny wearable devices that are emerging. Batteries and fuel cells have limitations that make it difficult to shrink them to tiny sizes
