Using biology as fuel

>TL;DR will be at bottom
Anons i have a retarded question, please forgive my autism.
Artificial life, power armor, and those dog robots that boston dynamics makes all suffer from the problem of fuel. from my perspective it seems like evolution over centries has allowed most mammals and more specifically humans the ability to work longer and more efficiently compared to any known robot of equal weight and size (with equal abilities).
We have small machines that can simulate almost every action a human can do, but due to entropy, they could not be combined into one machine and work nearly as effectively. changing battries/fuel cells is quick but very cumbersome and wastefull. charging battries is more cost effective but slow to transfer.
> my actual question
Sci, has anyone tried to simulate lungs to produce energy for machines the way it produces temporary energy for humans? is it possible? to me it seems like mechanical lungs that could collect energy from air and release carbon dioxide as exaust? wouldnt that make robots and machines hyper efficient?
could estute biologists and robotics engineers work together to simulate something like this?
My autistic idea was that said breathing engines could effectively power things like exoskeletons, power armor, cordless robots and other machines. Could a hybrid power system allow these machines to operate for much longer periods of time using say 60%-90% air and 40%-10% fuel similar to RAMJET missiles (yes i know thats not exactly how ramjet works)

>tl;dr
can we make breathing machines, if so, would it be better than traditional fuel?

There is a type of batteries that take in oxygen from the air. There are also fuel cells that use stored fuel and again air from the outside. Both provide electricity.

That is the closest realistic solution that I know of.

>There is a type of batteries that take in oxygen from the air.

i am infatuated with this idea. please provide any articles or sources for me to read. perhaps artificial carbon based life running on pure chemical energy, but without unecissary components like reproduction

I'm not convinced it's plausible.
Lungs just take in oxygen to burn fuel so breathing robots would still need to carry burnable fuel around. Pretty much anything with an engine already does this.
The main advantage of traditional machines is high efficiency and huge power output, eg. dozers can dig the holes of 10 men in 1/10 the time. But if they had to breathe like humans do they would need 100x the lungs to get the energy they need.
Humans can work longer than machines because we carry hundreds of pounds of burnable fat around with us for energy and use it relatively slowly. Duplicate that in robots you just get heavy, low power robots.

pretty much already do this, but there's not any way to change the chemical ratios of oxygen to fuel without adding immense amounts of energy (which itself costs fuel).

Google and other companies are using natural gas fuel cells for their buildings.

forgot image

>can we make breathing machines
Yes it's called giving birth.

>The main advantage of traditional machines is high efficiency and huge power output, eg
but thats not more effecient. those engines and machines weigh more, use more fuel and take up more space than its lifting equivalent in humans.

Define efficient? In terms of conversion of chemical to useful mechanical energy and waste heat I think engines are more efficient.
In terms of efficient resource/space use idk humans probably are better.

>Define efficient? In terms of conversion of chemical to useful mechanical energy and waste heat I think engines are more efficient.
really what im looking for is a machine that takes up the same amount of space as a human would with the same fuel cost and endurance using air ((i say air because there are other gasses that most mammals and these hypothetical machines benefit from, which is why you cant breathe in a room filled with absolutley pure oxygen.))

yes trucks produce more torque than a group of men of the same volume, but im talking about mammal sized machines, that could utilize this chemical energy to produce almost as much work. obviously nothing man made with the same volume could ever compete with a human, because nanotech is no where near capable of that.
another issue with humanoid and mammal-sized robots is that they weigh to much, and even if we mastered making robots that walk, run, and get themselves up when they fall, the computing power required to do anything close has been proven very very inefficient compared to bipeds and quadropeds. if we some how solved that issue, these machines are often so heavy that the weight being distributed onto their feet breaks the ground beneath it/sinks into the soil.
My concept for this thread really could be simplified into a android or mammal sized robot running on chemical energy but could be boosted by traditional means of power production. i dont expect it to be better than humans, just nearly as capable considering entropy.