Scientists have now unravelled a tool of medical diagnostics to improve a battery's performance and its safe internal workings, a study reveals.

Mobile phones, cameras, iPods require robust, dependable batteries to function optimally. When the batteries fail, it is impossible to not look inside without destroying it.

But now researchers at Cambridge, Stony Brook and New York Universities have tweaked magnetic resonance imaging (MRI), a tool of medical diagnostics, to do just that.

"MRI is exciting because we are able to identify where the chemical species inside the battery are located without having to take the battery apart, a procedure which to some degree defeats the purpose," added Clare Grey, professor at Cambrige and Stony Brook universities.

Grey collaborated with Alexej Jerschow, professor of chemistry at New York University who heads a multi-disciplinary MRI research lab, the journal Nature Materials reported.

Their technique also created the possibility of improving battery performance and safety by diagnosing its internal workings, said a university statement.

In the case of the popular lithium-ion batteries, for example, the team was able to directly visualize the build-up of lithium metal deposits on the electrodes after charging the battery.

Such deposits can also detach from the surface, eventually leading to overheating, battery failure, and -- in some cases -- to fire or explosion.

MRI has been extremely successful in visualizing disorders and assessing the body's response to therapy. However, MRI is not typically used in the presence of a lot of metal, a primary component in many batteries.

This is because conducting surfaces effectively block the radio frequency fields, that are used in MRI to see beneath surfaces or inside the human body.

The researchers, however, have turned this limitation to advantage. Because radio frequency fields do not penetrate metals, one can actually perform very sensitive measurements on the surfaces of the conductors.