December 1 - 6, 2024
Boston, Massachusetts
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2024 MRS Fall Meeting & Exhibit
EN08.11.24

Heavier Alkali Metal Carbonphosphonitride Thermosets and Ternary Alkali Cyanides as Solid-State Electrolytes

When and Where

Dec 5, 2024
8:00pm - 10:00pm
Hynes, Level 1, Hall A

Presenter(s)

Co-Author(s)

Andrew Purdy1,Kaitlyn Talamantez1,2,Daniel Fragiadakis1,Hunter Ford1,3,Christopher Klug1,Mark Bovee1,3,Megan Sassin1,Brian Chaloux1

U.S. Naval Research Laboratory1,NREIP Intern2,NRC Postdoctoral Associate3

Abstract

Andrew Purdy1,Kaitlyn Talamantez1,2,Daniel Fragiadakis1,Hunter Ford1,3,Christopher Klug1,Mark Bovee1,3,Megan Sassin1,Brian Chaloux1

U.S. Naval Research Laboratory1,NREIP Intern2,NRC Postdoctoral Associate3
We already demonstrated that lithium dicyanamide (LiN(CN)<sub>2</sub>) reacts with phosphorus cyanides (P(CN)<sub>3</sub> or RP(CN)<sub>2</sub>) in a 2:1 or greater mole ratio in an anhydrous aprotic mutual solvent to form a resin, which then cures at temperatures of 200-300 °C to a non-flammable Li-P-C-N ion conductor. When fully cured, those films have a low ionic conductivity, probably due to rigid crosslinking of the thermoset. We found previously that the sodium version Na-P-C-N is substantially more conductive than the Li-P-C-N materials. Post-cure treatment with diglyme also causes a dramatic conductivity increase, presumably by complexing the mobile alkali ions and plasticizing the material. For this work, we completed the entire alkali metal series by preparing A-P-C-N materials through A= K, Rb, and Cs, prepared composites of Na-P-C-N and sodium beta-alumina, and made efforts to prepare ternary cyanides of A(CN) or AN(CN)<sub>2</sub> (A = Li, Na, K, Rb, Cs) with Al(CN)<sub>3</sub> and Ga(CN)<sub>3</sub>. The ratios of resin to ceramic and the conditions of preparation are varied to produce solid composite films for measurement, and the ionic conductivity and chain motions of these films are characterized by impedance and dielectric relaxation spectroscopy. Test cells with the heavier alkali metal are constructed and measured to evaluate electrochemical stability and transference numbers. Additionally, solid state NMR is used to examine the compositional stability of the composite and the ion mobility between different ionic conductors.

Keywords

electrical properties | inorganic

Symposium Organizers

Kelsey Hatzell, Vanderbilt University
Ying Shirley Meng, The University of Chicago
Daniel Steingart, Columbia University
Kang Xu, SES AI Corp

Session Chairs

Kelsey Hatzell
Daniel Steingart

In this Session