Energizer Ultra Lithium AA

With this pack of L91 / AA-type Lithium/Ion batteries you'll always have enough energy for your flashgun, digital camera and other types of photographic equipment

Their output output voltage is 1.5v and they have an unopened shelf life of up to 20 years at room temperature (approx 21deg), which means you can store them for a long time before using them and they will keep their power for when you need them