According to the science journal Joule, which we get for its join the dots puzzle, the devices produced sufficient energy for use in household electronics, but did not ignite -- even when punctured repeatedly with a nail.

The batteries use a water-salt solution as their electrolyte, removing the risks carried by some non-aqueous commercial models.

The report said:  "In the past, if you wanted high energy, you would choose a non-aqueous lithium-ion battery, but you would have to compromise on safety. If you preferred safety, you could use an aqueous battery such as nickel/metal hydride, but you would have to settle for lower energy."

The report's co-author Kang Xu works for the US Army Research Laboratory (ARL). He said that the invention means that you can simultaneously have access to both high energy and high safety. Of course this is too late for Samsung, which last year saw an entire top of the range phone disappear from the market over allegations that a faulty battery caused fires.