Depending on the robot's work, sustainability could look different from machine to machine. In general, making a more sustainable robot starts with ethically sourced recycled or sustainable materials, functioning as energy efficiently as possible. Then the robot has to be repairable if broken and recyclable when it's time to retire. While some sensors or computer chips might not currently be recyclable or reusable, those pieces wouldn't make up a large percentage of the machine. Some definitions of sustainability include the robot's function.

The climate emergency brooks no compromise: every human activity or artefact is either part of the solution or it is part of the problem. I've worried about the sustainability of consumer electronics for some time, and, more recently, the shocking energy costs of big AI. But the climate emergency has also caused me to think hard about the sustainability of robots. And, I'm ashamed to say, very little robotics research is focused on the development of sustainable robots. A search on google scholar throws up a handful of excellent papers detailing work on upcycled and sustainable robots (2018), sustainable robotics for smart cities (2018), green marketing of sustainable robots (2019), and sustainable soft robots (2020).