I'd love to see you try just so I can learn from your experience. I'm getting a LiFePO4 battery for my e-bike after lots of research into their safety and longevity (both much better than the LiIon batteries in phones).
I also still occasionally do backpacking and I think the tradeoff between cost and something being lightweight is personal and I really value quality lightweight gear of any kind.
In the interest of encouraging you, I found this that you may have already seen.
http://www.jenericramblings.com/2017...ng-to-lithium/
BTW, just because I want them to be a good idea doesn't mean they necessarily are
I'll be considering them when we replace our batteries. So please report back on how you decided and why.