A new wallpaper can turn the humidity in your home into electricity. Here is how the clever design works.

Each unit is a small 2 by 2 centimetre square of paper with three zones. The outer edge carries glycerol, a syrupy liquid that grabs water vapour from the air and turns it into liquid.

The middle zone holds a material called PVP that grips water tightly and pulls it inward through tiny pores. The centre is treated with wax, which repels liquid water but lets vapour escape.

This creates a constant one-way flow: moisture enters at the edge and leaves through the centre as vapour. The movement of water releases charged particles, and the imbalance between edge and centre drives an electric current.

Each unit makes about 0.34 volts. Linked together, 1,596 units produced enough power to run a wireless keyboard. The system also dehumidifies, cutting room humidity from 38 to 32 per cent in tests.

What it cannot do: the power is in microwatts, so it will not run a fridge. But it could keep small sensors and smart gadgets going without batteries.