At most times smart phones don't have a long battery life and you have to recharge the phone often. My requirement is to have a phone with advanced computing capabilities and also a long time battery life. Is there a phone like this available in the market?
I don't think so. What you could do would be to buy an extra battery and when needed, connect it to the phone. There are solar chargers too, so you can charge your phone wherever you go and for free.
Long ago, you can get high capacity batteries for your mobile phones. I don't think this option is available anymore. The only solution is an external battery pack. I have recently seen one that's rather unobtrusive. It's just like a small dry cell battery. Something like this:
I recommend the Note II if you're looking for just battery life. The Note II is pretty large in size, but the battery lasts long. You can use it for two days straight before recharging your battery which is really convenient if you use your phone a lot. It comes with a stylus as well.
I have an iPhone and as much as I love it, if long lasting battery is important for anyone then don't even think about buying it lol, literally have to charge every night