Electrode Design from Atomistic to Mesoscale Dimensions*

The invention of rechargeable batteries has dramatically changed our landscapes and lives, underpinning the explosive worldwide growth of consumer electronics. Unfortunately, current battery technologies suffer from a myriad of challenges. Mechanistic understanding of compositional and electronic structure heterogeneities is imperative to facilitate the design of high-performing electrodes. X-ray microscopy observations indicate the formation of lithiation gradients in a Li_xV₂O₅ nanowire that arise from electron localization coupled to local structural distortions, giving rise to small polarons. I will also discuss the first direct visualization of patterns of compositional inhomogeneities within cathode materials. Two patterns are evidenced: core—shell separation and striping modulations. 3D compositional maps have been developed and translated to stress and strain maps, providing a hitherto unprecedented visualization of stress and strain inhomogeneities. Moreover, a cluster of interlaced Li_xV₂O₅ nanoparticles is evaluated, where increased heterogeneity at the interfaces suggest the exchange of Li-ions, implying a “winner-takes-all” behavior. Finally, I will discuss prospects for “beyond-Li” batteries.