Fuels generally have higher energy density than batteries. Research like ([0]) can, in time, result in systems which are on par or exceed biological ones. [0]:

Fuels generally have higher energy density than batteries. Research like ([0]) can, in time, result in systems which are on par or exceed biological ones. [0]: https://www.researchgate.net/publication/235043961_Fuel-Powered_Artificial_Muscles_for_the_Robotic_Soldier https://www.researchgate.net/publication/235043961_Fuel-Powe...