Tortuosity Anisotropy in Porous Lithium-Ion Batteries

The ability to engineer electrode microstructures to increase power and energy densities is critical to the development of high-energy density lithium-ion batteries. Because high tortuosities in porous electrodes are linked to lower delivered energy and power densities, in this project, we study tortuosity and consider possible approaches to decrease it. We investigate the effect of electrode processing on the tortuosity of in- house fabricated porous electrodes, using three-dimensionally reconstructed microstructures obtained by synchrotron x-ray tomography. Computer- generated electrodes are used to understand the experimental findings and assess the impact of particle morphology, size distribution and particle packing on tortuosity and reactive area density. We highlight the limitations and tradeoffs of reducing tortuosity and develop a practical set of guidelines for active material manufacture and electrode preparation.