Lithium-ion batteries are everywhere and in such common use. Since they are so ubiquitous, scientists have long been looking to improve their output by experimenting with the various micro-structures inside them. What they’ve found is that they can manage better capacity if their micro-scale electrodes have pores and channels. As a result, these structures allow lithium to transport through the battery efficiently. Now, scientists are looking to create high efficiency batteries with electrodes connected in 3D printed microlattices with controllable porosity.
The research is a collaboration between Carnegie Mellon University and Missouri University of Science and Technology. Using complex geometries, the researchers boosted both the capacity and the discharge rates. Another great feature is that the electrodes maintained their geometric structure without deforming even after forty electrochemical cycles. The system is now more robust and can manage far better efficiency characteristics for the same weight.
“In the case of lithium-ion batteries, the electrodes with porous architectures can lead to higher charge capacities,” says Rahul Panat, associate professor of mechanical engineering at Carnegie Mellon University. “This is because such architectures allow the lithium to penetrate through the electrode volume leading to very high electrode utilization, and thereby higher energy storage capacity. In normal batteries, 30-50% of the total electrode volume is unutilized. Our method overcomes this issue by using 3D printing where we create a microlattice electrode architecture that allows the efficient transport of lithium through the entire electrode, which also increases the battery charging rates.”
Printing Better Batteries
One can see the integration of the structure in the image above, weaving in through the battery’s solid form. The lattice creates channels for effective transportation of electrolyte inside the volume of material. The researchers achieved this micro-scale feat with the use of Aerosol Jet 3D printing. Aerosol Jet methods allow for droplet deposition and higher control at a smaller scale while typical extrusion methods would not be able to manage at this level.
“Because these droplets are separated from each other, we can create these new complex geometries,” says Panat. “If this was a single stream of material, as is in the case of extrusion printing, we wouldn’t be able to make them. This is a new thing. I don’t believe anybody until now has used 3-D printing to create these kinds of complex structures.”
Featured image courtesy of Rahul Panat, Carnegie Mellon University College of Engineering. Retrieved via Science Daily.