A battery with unlimited shelf life is a dream that will never die out. Unless of course, someone actually makes the dream come true. While currently there are no unlimited batteries on the shelves, there are a number of ways to keep your current batteries going strong until a breakthrough is made on the whole battery-with-eternal-life thing.
The first solution to extended (if not infinite) battery life is rather obvious and has been around for a while. Buy a battery charger. That's right, these little doodads can be picked up at your local Wal-Mart for less than ten bucks and they allow you to charge a wide range of different types of batteries including AA, AAA, and so on. There are now eco friendly battery chargers, so if you want to look into a green solution that also helps you stop drowning in used batteries. An eco-friendly charger would be the way to go. You could even try your hand at either sugar powered batteries (which are said to last longer than lithium batteries), or biodegradable batteries (which really speak for themselves). These types of batteries are not only lightweight, they are also compact and have a more substantial life force than the batteries we're used to seeing on store shelves.
Researchers from MIT and Renesselaer Polytechnic Institute are responsible for the newest breakthrough in biodegradable batteries. With a combination of cellulose, electrolytes, silicon substrate, and carbon nanotubes, they have managed to create a flexible battery that's not only paper thin, but which also happens to be biodegradable.
Currently, scientists at the Technion Israel Institute of Technology think they may have created a battery that can power a host of devices for thousands of hours before it has to be replaced. That's not exactly an infinite battery, but it's certainly impressive and will help cut down on a lot of waste and pollution if it can become compact and portable enough to become mass produced. Right now the batteries are created from silicon and oxygen. Known uniquely enough as silicon air batteries, these batteries are lightweight and economically safe. How well these batteries actually do on the public stage we'll just have to wait and see, but so far it seems as if these batteries are the closest we've gotten to our pipedream of indefinite life.
There have been dozens of companies claiming to have made the breakthrough in longer lasting batteries. Each and every time the batteries in question were shown up by another battery manufacturer who had managed to lengthen the shelf life of his or her product. Now it's a leg race to see who can win the race and create the first battery that can last indefinitely. Whoever manages the deed will answer the prayers of many a battery user and will pave the way for new, more advanced technology in the years following the breakthrough. In the meantime, we'll just have to settle for the methods that we have now to extend the life of your average battery (methods that actually aren't too shabby).