High‐Performance Tubular Electricity Generators Operated by Magnetically Driving Movement of Droplet

Abstract Electricity generators by driving movement of liquid droplet or flow on the surface of nanocarbon materials represent an emerging means to harvest energy from nature and environment, which have widely potential applications in the fields of sensors, biomedicine, energy conversion, and so on. Herein, a tubular electricity generator with magnetic droplet encapsulated in a continuous graphene tube is developed. The droplet in tubular electricity generators can be easily driven by magnetic force, during which a potential difference ranging from 196 to 419 mV can be realized by tuning the salt species in the droplet. The value of the generated potential difference is among the highest range, compared with other electricity generators reported previously. In addition, in‐series connecting effect could be achieved with multi‐droplet encapsulated in one single electricity generator, resulting in multifold output voltage of device with one droplet. The work provides a powerful strategy to build electricity generator with high output voltage and easy manipulation, and the tubular devices are promising to be used for biomedical and/or wearable electronics.