The batteries we are using in the smartphones right now are made with Lithium-ion. These batteries offer limited battery backup and most of the times if we are not used them properly they may cause accidents.
Numerous battery technologies are surfacing on the internet time to time. Here is another one, which has exciting features. Harward University researchers developed a battery which gives a battery life of 10 years.
The battery is completely water based. It loses the battery power once in 1000 chargings. The battery is developed by flow battery technology.
It runs on two chemicals dissolved in liquids. Even though the battery is leaked on the floor nothing will happen, it is completely safe. We have to wait for the upcoming batteries.