Boffins reckon they have discovered why lithium batteries in laptops and mobile phones may overheat, fizzle and occasionally catch fire.
Researchers at Cambridge University laid the blame on lithium dendrites which can form on carbon anodes when batteries are charged quickly.
The dendrites - essentially metal fibres - could grow long enough to cause a short circuit, they concluded.
The researchers used Nuclear Magnetic Resonance (NMR) spectroscopy, to observe how the dendrites develop and reckon their findings could help avoid explosive problems with lithium batteries in the future.
Professor Clare Grey, of Cambridge University's chemistry department said: "These dead lithium fibres have been a significant impediment to the commercialisation of new generations of higher capacity batteries.
"Fire safety must be solved before we can get to the next generation of lithium-ion batteries and before we can safely use these batteries in a wider range of transport applications," she added.
"Now that we can monitor dendrite formation inside batteries, we can identify when they are formed and under what conditions. Our new method should allow researchers to identify which conditions lead to dendrite formation and to rapidly screen potential fixes to prevent the problem."