Even though smartphones get more powerful as each new iteration is released, one thing that never seems to improve - and sometimes actually gets worse - is their battery life. There are some ways to remedy this problem, such as battery cases like the one Apple recently revealed, but the best answer would be a longer-lasting battery. Now, Sony may have a solution to smartphones that need charging almost every day, as the company is said to be working on a battery that will last 40% longer on a single charge.

Japanese newspaper Nikkei reports that Sony, the company that developed the first commercial Li-ion battery, is increasing the life of these new batteries by creating a power cell made from a sulfur compound, rather than the commonly used lithium.

The problem with sulfur-based batteries in the past has been that their capacity decreases after every charging cycle due to the electrode dissolving into the electrolyte. Nikkei says that Sony has found a way around this issue by reforming the electrolyte solution to create longer-lasting batteries that hold more power. Sony is now said to be verifying the safety of the batteries before starting mass production.

Sony wants to make sure that these batteries aren’t going to explode and turn your smartphones into a smoldering, stinking mess after a few charges, obviously, which is why the safety tests will be pretty extensive. In all likelihood, we won’t see these batteries until around 2020.

Another great thing about these sulfur batteries is that they’re 30 percent smaller than the lithium variety, which hopefully means we'll be using incredibly thin smartphones that can go several days without charging in a few years' time.

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