The development of advanced unmanned robots is of great significance to promote scientific progress and innovation, expand application fields, and improve efficiency and safety. Complex perception, motion, and navigation systems consisting of numerous sensors and powerful processors enable robots to monitor various sophisticated environments. However, the available commercial batteries cannot satisfy the long endurance and safety requirements of robots. Herein, we propose the application of metal–air batteries to power robot devices considering their advantages of higher energy density, lower cost, and better safety compared to lithium-ion batteries. Furthermore, the technological development of metal–air batteries in terms of specific energy, cycle life, fast charging, environmental adaptability and flexibility has increased the possibility of their application in next-generation unmanned devices. Accordingly, we present an outlook on the application of metal–air batteries in all fields of robotics, including land, air and sea, embodying the temporal and spatial infinities of these batteries. It is expected that the application of metal–air batteries will promote the advancement of the robot industry.