Storing energy in plants with electronic roots

By watering bean plants (Phaseolus vulgaris) with a solution that contains conjugated oligomers, researchers have shown that the roots of the plant become electrically conducting and can store energy.

The researchers here have used a trimer, which is polymerised by a natural process in the plant. A conducting film of polymer is formed on the roots of the plant, which causes the complete root system to function as a network of readily accessible conductors.

The bean plant roots remained electrically conducting for at least four weeks, with a conductivity in the roots of approximately 10 Siemens/cm.

Supercapacitors based on conducting polymers and cellulose are an eco-friendly alternative for energy storage.

The root-based supercapacitor worked well, and could store 100 times more energy than previous experiments with supercapacitors in plants that used the plant stem. The device can also be used over extended periods of time since the bean plants in the experiments continued to live and thrive.

The plant develops a more complex root system, but is otherwise not affected: it continues to grow and produce beans.

The results, are highly significant, not just for the development of sustainable energy storage, but also for the development of new biohybrid systems, such as functional materials and composites. The electronic roots are also a major contribution to the development of seamless communication between electronic and biological systems.