Boron nitride nanotubes move lithium ions 31 times faster than expected

Scientists used boron nitride, a synthetic crystalline compound, to build membranes containing millions of microscopic tubes that move lithium ions far faster than other charged particles. Lithium transport was observed at up to 31 times the rate expected from standard diffusion.

The paper, “Anomalous ultrafast lithium-ion transport through boron nitride nanotube membranes,” was recently published in Nature Nanotechnology. The research was led by Semih Cetindag of Rutgers University and Aaditya Pendse of the University of Illinois Chicago.

Sangil Kim, associate professor of chemical engineering at University of Illinois Chicago and a corresponding author of the paper, compared the mechanism to the way an electric eel generates electricity through ion channels in specialized cells, and said the ion transport observed was much higher than the theoretical estimation and also higher than existing experimental systems.

To test the membranes, the researchers placed them between ionic solutions of different salinities. The membranes powered small electronics, including a watch, a calculator, and LEDs, using only salt-solution gradients.

The paper reports per-pore power densities of up to 15,300 W per square meter and energy-conversion efficiency approaching the theoretical limit of 50% at pH 5.5.

The team said potential applications include lithium recovery from waste batteries and blue energy generation, in which power is harvested from the convergence of salt and fresh water.