Design Principles and Routes for Calcium Alkoxyaluminate Electrolytes

• DOI: 10.1021/acs.jpclett.4c00969
• Publication Date: 2024-05-06T12:45:56Z
• Authors: Noel J. Leon; Stefan Ilic; Xiaowei Xie; Heonjae Jeong; Zhenzhen Yang; Bingning Wang; Evan Walter Clark...; Charlotte Stern; Nathan Hahn; Kevin Zavadil; Lei Cheng; Kristin A. Persson; Justin G. Connell; Chen Liao
• Keywords: Tetracoordinate

Multivalent-ion battery technologies are increasingly attractive options for meeting diverse energy storage needs. Calcium ion batteries (CIB) particularly appealing candidates their earthly abundance, high theoretical volumetric density, and relative safety advantages. At present, only a few Ca-ion electrolyte systems reported to reversibly plate at room temperature: example, aluminates borates, including Ca[TPFA]2, where [TPFA]− = [Al(OC(CF3)3)4]− Ca[B(hfip)4]2, [B(hfip)4]2– [B(OCH(CF3)2)4]−. Analyzing the structure of these salts reveals common theme: prevalent use weakly coordinating anion (WCA) consisting tetracoordinate aluminum/boron (Al/B) center with fluorinated alkoxides. Leveraging concept theory-aided design, we report an innovative, one-pot synthesis two new calcium-ion (Ca[Al(tftb)4]2, Ca[Al(hftb)4]2) (Ca[Al(hfip)4]2 Ca[TPFA]2) hfip (−OCH(CF3)2), tftb (−OC(CF3)(Me)2), hftb (−OC(CF3)2(Me)), [Al(OC(CF3)3)4]−. We also reveal dependence Coulombic efficiency on inherent propensity cation–anion coordination.