Local Structure and Entropic Stabilization of Ca-Based Molten Salt Electrolytes
Artikel i vetenskaplig tidskrift, 2024

Here molten salt electrolytes (MSEs) and specifically their physico-chemical properties as a function of composition are reported on, with a special emphasis on the compositional entropy and targeting calcium battery application. By using MSEs, several problematic issues associated with organic electrolytes, such as the blocking of Ca2+ transfer at the electrode/electrolyte interfaces and electrolyte flammability, are avoided. Ca(FSI)2 salt in combination with the analogous Li-, Na-, and KFSI salts are used in equimolar compositions to first create several ternary MSEs, melting at (ca.) 60–75 °C, a melting temperature which is further reduced to (ca.) 55 °C for the unique quaternary MSE. This is ascribed to an increased entropy of mixing, which also contributes to an improved stability (re−)crystallization, as shown by Raman spectroscopy. Furthermore, molecular dynamics simulations of the quaternary MSE alongside density functional theory calculations targeting the ion-ion interactions are used to elucidate the local structure in more detail, demonstrating that both the ionic radii and valence influence the coordination and solvation of the cations. These MSEs are stepping-stones towards completely solvent-free, semi-solid, and ideally room-temperature Ca-conducting electrolytes.

calcium batteries

solvent-free electrolytes

local structure

molten salt electrolytes

high entropy electrolytes

Författare

Johanna Timhagen

Chalmers, Fysik, Materialfysik

Carolina Cruz Cardona

Chalmers, Fysik, Materialfysik

Jonathan Weidow

Chalmers, Fysik, Materialfysik

Patrik Johansson

Centre national de la recherche scientifique (CNRS)

Chalmers, Fysik, Materialfysik

Batteries and Supercaps

25666223 (eISSN)

Vol. In Press

Elektrolyter för Metallorganiska Multivalenta Batterier

Energimyndigheten (50638-1), 2021-01-01 -- 2024-12-31.

Vetenskapsrådet (VR) (2020-03988), 2021-01-01 -- 2024-12-31.

Nästa generations batterier

Vetenskapsrådet (VR) (2021-00613), 2021-12-01 -- 2032-12-31.

Ämneskategorier

Oorganisk kemi

Fysikalisk kemi

Materialkemi

Styrkeområden

Produktion

Energi

DOI

10.1002/batt.202400297

Mer information

Senast uppdaterat

2024-07-29