In 2008:

The iPhone had an 1150mAh battery and, according to anandtech [0], 284 minutes of talk time (3G) and 400 minutes of web browsing time (WiFi). It weighed 133 grams.

In 2016:

The iPhone SE has a 1,624mAh battery and gets 556.2[1] minutes of web browsing time on WiFi.

It weighs 113 grams.

Of course, I have no idea what percentage of weight made up the battery for either of these phones. I also have no idea what percentage of the cost to manufacture the battery made up for either of these phones. But I do know the iPhone SE @ 16GB is $100 cheaper than the iPhone 3G @ 16GB was, not accounting for inflation.

We're seeing some improvement, most definitely. But unless someone has data to compare the two batteries directly, we can't say by how much.

The smartphone world has been much more keen on improving power consumption of the hardware in question rather than power storage. At the scale of power that an automobile uses, the opposite is true.

0. http://www.anandtech.com/show/2571/18 1. http://www.anandtech.com/show/10285/the-iphone-se-review/3

They say that battery tech has been improving at 2% a year.

That would mean we should see a ~37% improvement between 2008 and 2016. Seems about right.

That's not a "fivefold improvement". A fivefold improvement is 400% more.

Maybe the battery form factors that are being improved aren't appropriately sized for use in smartphones? :)

1.02^8=1.17, or ~17% improvement

errr, oops. I did ^16 by accident. Damn you human error!

Do you work at NASA?

Yeah we are. But phones are more powerful, with bigger screens and power hungry electronics. Plus consumers want smaller, lighter phones, so with the higher density they make the batteries smaller. It's a balance.

Thats exactly why I was disappointed that all the top of the line phones went with 1440p or 4k displays. I have a 27" monitor that is 1440p, I don't need that kind of resolution on my Note 5. I wish it was still 1080p display and better battery life.

Are you sure?