@SilviaFox@cutie.space @mallaidh@witches.town here's a article about it: https://butyoudontlooksick.com/articles/written-by-christine/the-spoon-theory/
the gist is that you have a finite amount of motivation to do stuff per day (your spoons), and you use it up as you do more things between resting
the battery emoji are just a different metaphor