Files
Piron_92292100_2026.pdf
Embargoed access from 2028-06-01 - Adobe PDF
- 4.45 MB
Details
- Supervisors
- Faculty
- Degree label
- Abstract
- The global energy transition requires safe, high-performance electrochemical storage, and solid-state batteries (SSBs) have emerged as a promising candidate by eliminating the thermal runaway, leakage, and fire risks of liquid-electrolyte systems. Among post-lithium charge carriers, calcium (Ca2+) is attractive due to its abundance, low cost, divalent nature, and reduction potential (−2.87 V vs. SHE) close to lithium, offering competitive theoretical energy densities. Yet Ca2+-conducting solid electrolyte development remains hindered by the ion’s large radius and high charge density, impeding mobility in solid matrices. In this context, complex metal hydrides such as closo-borate compounds based on the [B12H12]2- anion have attracted interest as candidate solid electrolytes, their quasi-spherical geometry facilitating Ca2+ migration through the paddle-wheel mechanism, whereby rapid anion rotation lowers the activation energy for cation hopping. Despite this, CaB12H12 (CaD) exhibits a low ionic conductivity of ~4 × 10-9 S cm-1 at 150 °C; this thesis thus aims to enhance it through incorporation of neutral ligands, drawing on strategies from related borohydride systems.