Conventional rechargeable batteries are formed using slurry-cast electrodes whose random nature and porosity limits both energy density and rate performance. As a general rule, such composite electrodes, consisting of a mixture of active material, solid electrolyte, and often conductive additives exhibit power and energy limitations due to the tortuosity of the ion and electron conduction pathways and lower than ideal energy densities due to the volume and mass of the additives. Slurry-cast electrodes also are generally incompatible with solid-state batteries unless the slurry contains solid electrolyte particles in addition to active material. Next generation batteries will require a paradigm shift from random composite electrodes to nearly dense, and either crystallographically oriented or deterministically structured cathodes and anodes. On the cathode side, I will present our work on electrodeposited LiCoO2, NaCoO2, LiMn2O4, and Al-doped LiCoO2 which provide near-theoretical capacities, and exceptional rate performances. A very attractive element of the electrodeposition process is control of the crystallographic orientation of the deposited film which is what enables the high-rate performance. For example, the electrode texture can be oriented such that the fast electron and ion conduction directions are perpendicular to the substrate. I will also present our work on CVD and electrodeposited silicon anodes, a system that offers potential for both good rate performance and high energy densities. Finally, I will discuss solid-state batteries built using electrodeposited electrodes and how the crystallography of the electrode | solid-electrolyte interface impacts interfacial reactions, rate performance, and cycle life.
Prof. Paul Braun is the Director of the Illinois Materials Research Laboratory, the Grainger Distinguished Chair in Engineering, Professor of Materials Science and Engineering, Chemistry, Chemical and Biomolecular Engineering, and Mechanical Sciences and Engineering at the University of Illinois Urbana-Champaign. Prof. Braun received his B.S. degree with distinction from Cornell University, and his Ph.D. in Materials Science and Engineering from the University of Illinois. Following a postdoctoral appointment at Bell Labs, Lucent Technologies, he joined the faculty of the University of Illinois. Prof. Braun has co-authored a book, about 350 peer-reviewed publications, been awarded multiple patents, and has co-founded four companies. Prof. Braun is a Fellow of the Materials Research Society, a AAAS Fellow, and a Fellow of the National Academy of Inventors.