Microcalorimetric Measurements of the Solvent Contribution to the Entropy Changes upon Electrochemical Lithium Bulk Deposition

Abstract

A strongly positive entropy of reaction for the bulk deposition of Li can be explained by the desolvation of Li+ ions, as revealed by microcalorimetric studies. From this the coordination number of Li+ can be derived. The positive entropy leads to cooling of the electrode, which may influence lithium plating in lithium‐ion batteries.

Concentration Effects on the Entropy of Electrochemical Lithium Deposition: Implications for Li+ Solvation

“…12 However, in our case this contribution is negligible due to the large Stokes radius of the lithium ion. 17 In order to extract the reversible contribution to the molar heat, i.e., the Peltier coeffient, from our experiment, the data from all measurements with different potential pulse amplitudes, i.e., overpotentials, was extrapolated to an overpotential of zero by linear regression. For the data of the 1 M solution of LiPF 6 in EC/DMC in Figure 2 a Peltier coefficient of 48.2 kJ·mol −1 mol was estimated.…”

“…Inside the glovebox LiPF 6 of the respective concentration in EC and DMC was used as electrolyte, and the reference and counter electrodes were changed to Li electrodes. In our previous experiments 17 we used platinum electrodes as counter electrode and pseudo reference electrode for all parts of the experiment. Using lithium electrodes, however, provides a better-defined reference potential.…”

Diglyme‐Based Thermoelectrochemical Cells Operable at Both Subzero and Elevated Temperatures

“…Δ S rxn (and thus S e ) is a critical factor to develop high‐performance TECs. In this regard, a Li + /Li redox couple is a promising system because it exhibits fairly high Δ S rxn (≈+165 J K −1 mol −1 and thus +1.71 mV K −1 in carbonate solutions) . In addition, Schmid et al reported that Δ S rxn on Li deposition reaction is affected by three parts: (i) entropy change pertaining to the fixation of immobilization of Li‐ions into solid phase, (ii) entropy change by immobilization of solvent molecules in the first solvation shell of Li‐ions, and (iii) entropy change from affecting solvent molecules beyond the first solvation shell through electrostatic interaction.…”

“…In addition, Schmid et al reported that Δ S rxn on Li deposition reaction is affected by three parts: (i) entropy change pertaining to the fixation of immobilization of Li‐ions into solid phase, (ii) entropy change by immobilization of solvent molecules in the first solvation shell of Li‐ions, and (iii) entropy change from affecting solvent molecules beyond the first solvation shell through electrostatic interaction. Importantly, entropy change of (ii) and (iii) parts depends on the nature of the solvent and Li salt concentration …”

Reações oscilatórias e a temperatura: dos efeitos em escala <i>bulk</i> ao monitoramento local

“…[150][151][152] Tais sensores são feitos a partir de materiais como o tantalato de lítio (LiTaO3) ou fluoreto de polivinilideno (PVDF) por exemplo. Tais materiais são expostos a um tratamento mecânico especial em um alto campo elétrico durante a sua fabricação.…”