Chinese researchers recently unveiled a groundbreaking achievement in drone technology. They have successfully developed the world's smallest and lightest solar-powered drone, a marvel of engineering that could revolutionize the field.

Developed by a team at Beihang University, the CoulombFly drone weighs just 4.21 grams and boasts a wingspan of just 20 centimeters. Unlike its predecessors, which typically struggle with limited flight times, the CoulombFly can soar indefinitely as long as the sun shines.

The secret to this remarkable feat lies in its innovative electrostatic motor. Unlike traditional electromagnetic motors, which suffer from efficiency losses at smaller scales, the electrostatic motor enables the tiny drone to generate sufficient lift.

What's more, the team invented a lightweight boost converter that can boost the voltage from less than 100 volts to as high as 9,000 volts, with its step-up ratio 92 percent higher than similar technology developed at Stanford University. The high-voltage current is then used to drive the voltage-thirsty electrostatic motor.

Researchers envision a future where swarms of these "micro aerial vehicles" (MAVs) – insect- and bird-sized aircraft – could be deployed for various applications, including photography, disaster relief and environmental monitoring.

While the current prototype can carry limited payloads, the team is optimistic about future advancements that could increase the drone's capacity.

The team's work has been published online in the journal Nature.

Next, the team will try building an even smaller drone that weighs only 9 milligrams and has a wingspan of just 8 centimeters.