Designing Better Li Metal Anodes for Next-Generation Batteries

Abstract

Li metal batteries have the potential to significantly advance battery technology due to their substantially higher energy densities. However, robust high-capacity Li metal anodes are necessary to realize this approach, and current Li metal anode designs suffer from significant degradation over time due to non-uniform Li plating/stripping during cycling, which can lead to dead Li and/or Li dendrite growth. Carbon scaffold hosts can help mitigate this problem by creating a uniform electric field and providing abundant Li nucleation sites, but the relationship between the host architecture and performance is not well understood. We investigated the effect of scaffold architecture and chemistry on the resulting Li morphology and electrochemical performance using a combined experiment/theory approach. Carbon scaffolds with well-controlled geometries and varied porosities were fabricated using 3D printing and then characterized by SEM, Raman, and XPS before cycling in cells to evaluate their performance as hosts for uniform Li plating/stripping with both liquid and solid electrolytes. Atomistic and mesoscale modeling were used to predict how scaffold chemistry and microstructure affect Li nucleation probability and the formation of current density/stress hotspots that can lead to dendrite growth, and these results were used to help guide scaffold design. This work provides further insight into the relationship between anode architecture and Li metal cycling stability, which will facilitate the development of high-energy-density batteries in the future.Lawrence Livermore National Laboratory is operated by Lawrence Livermore National Security, LLC, for the U.S. Department of Energy, National Nuclear Security Administration under Contract DE-AC52-07NA27344.