Smartphones with batteries that recharge inside five minutes could be on sale next year according to a company that’s been working on the technology for several years. But ongoing mysteries about how exactly it works means there’s still scepticism.

We covered the claims by StoreDot back in 2014, noting that it had explained that:

The technology is based around “Nanodots” which the company describes as spherical “bio-organic peptide molecules” that are only two nanometers in diameter. A peptide is a chain of amino acids that is shorter than a protein, though peptides can self-assemble to form proteins.

At that time the company demoed a bulky external charger that appeared to fully recharge a Samsung S4 in 26 seconds. It said the next steps were to build the technology into batteries, then refine it so the batteries had similar capacities to existing models. It had projected late 2016 for getting finished batteries delivered to manufacturers.

Now the company says the product, renamed FlashBattery, is at the pilot production stage with two battery manufacturers. In turn it believes mass production will start in the first quarter of next year.

Even if that timetable proves correct, there’s still the challenge of either getting manufacturers to use the batteries in new phones, or producing them as an unofficial third-party product for phones that have removable batteries (which could possibly bring warranty issues).

StoreDot also claims it’s produced an electric car battery that can be recharged in five minutes while still having enough capacity for an average 300 mile range. That’s still very much at the proof of concept stage and the main difference appears to be that it uses a custom chemical compound with a high combustion point, meaning overheating from a super-fast charge isn’t a problem. That’s a claim that’s going to need some rigorous testing, particularly if traditional gas stations are going to be persuaded to house charging points.