I came across an article for an energizer phone that states it can do 50 days standby or 2 days of video per full charge. But the thing is 18mm Thick.. It may never come to fruition, but this would last all you guys in the field.... And supposedly it can recharge other devices. Here's the article, if you're bored.
https://arstechnica.com/gadgets/2019/02/energizers-beastly-smartphone-has-an-18000mah-battery/
https://arstechnica.com/gadgets/2019/02/energizers-beastly-smartphone-has-an-18000mah-battery/