CPA Postdoc L(a)unch- May 19
Dr. Jacob Rothbaum, CCE
Lanthanide Chemodivergence
Dr. Tridip Das, CCE
New Solid-State Battery Materials Predicted from First Principles for Better Performance
Lunch will be provided starting 11:45 AM!
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Lanthanide Chemodivergence
Lanthanides (La-Lu), a group of heavy elements in the periodic table, typically exist in the trivalent oxidation state and it has long been assumed that they all exhibit similar chemical behavior as we move across the periodic table. This prior heurism is primarily based on the fact that their valence electrons, the electrons which interact with other chemicals, are considered core electrons and thus have limited interactions with other substances and ligands. In addition, pyridine, a nitrogen-containing heterocycle resembling benzene but with one carbon atom replaced by a nitrogen atom, is widely present in various structures found in pharmaceuticals, natural products, and catalysts. Interestingly, the presence of this nitrogen atom significantly alters the chemistry of pyridine and makes it considerably more challenging to modify or functionalize. In this talk, I will share our exciting journey of not only successfully functionalizing pyridine, but also uncovering the intriguing fact that lanthanides do, in fact, exhibit distinct reactivity from one another. By exploring these findings, we will gain a deeper understanding of the intricate interplay between pyridine and lanthanides, shedding light on the fascinating world of lanthanide chemistry and its applications.
New Solid-State Battery Materials Predicted from First Principles for Better Performance
Requirement for a high energy density, fast charging, safer battery technology with longer life span creates the market demand for all solid-state battery (ASSB). Among different chemistries available for ASSB, Li-ion batteries are at the forefront of research. The holy grail of lithium-ion batteries is to use lithium metal as the anode along with a fast lithium ion conducting electrolyte and an efficient cathode, chemically stable within the operating voltage range. In recent decades experimentalists have used structure-synthesis-stability-performance relationships for similar crystal (structural) families to design and develop new materials for application in lithium-ion batteries. This time-consuming and labor-intensive approach is not efficient because of non-productive searches and numerous available options with disordered compositions among similar structural classes of materials. Initial estimates for the material synthesis conditions and experimental search window could be narrowed if knowledge of the optimum atomic environments and corresponding processing conditions were available beforehand.
Among different class of Li-based solid state ceramics, several sulfide glasses or ceramics based on Li2S-P2S5 systems are being explored as solid-state electrolyte candidate due to high Li-ionic conductivity. Currently Li10GeP2S12 (LGPS) demonstrates one of the highest Li-ion conductivity, 12 mS/cm at room temperature but it is not stable with Li-metal electrode, and it is expensive due to the presence of Ge. Here, we studied ion diffusion mechanism, ionic conductivities and interfacial stability using Molecular dynamics in a promising alternative Li5(PS4)Cl2 based on Li2S-P2S5 system. The composition and crystal structure of Li5(PS4)Cl2 was predicted from the computational studies and this material is not yet experimentally realized.