Thursday, 1 June 2017: 08:00
Grand Salon C - Section 18 (Hilton New Orleans Riverside)
In the past two decades, lithium ion batteries have become the workhorse of the portable energy storage industry. Despite the progress which has been made in regards to improving lithium ion batteries, there is strong need to improve the safety and efficiency of this technology. So far, studies have focused on improving the electrodes or on optimizing the electrolyte composition. However, very few studies have focused on characterizing the structure and dynamics of the electrolytes at the molecular level. In this work, we have utilized both steady-state and time-dependent infrared spectroscopies to characterize the structure and dynamics of lithium ion electrolytes composed of linear organic carbonates with different structures. Specifically, we present the effects of increasing the alkyl chain length of the linear organic carbonate on the structure and dynamics of lithium ion solvation shell. Surprisingly, the lithium ion shows a tetrahedral solvation structure in the various linear carbonates in which little effect is observed from increasing alkyl chain length. However, the time-resolved studies reveal a clear slowdown of the solvation shell motions when the alkyl chain length of the linear organic carbonate is increased. Thus, our studies reveal that the molecular structure of the carbonate solvent has far reaching consequences on the structure and dynamics of the electrolyte formed and direct implication on the macroscopic properties of the electrolyte.