Synergistic theoretical and experimental study on the ion dynamics of bis(trifluoromethanesulfonyl)imide-based alkali metal salts for solid polymer electrolytes

Abstract

Combining experimental and computational techniques to perform a model validation study of a well-known class of solid polymer electrolyte (SPE) towards predicting the performance of alternative alkali metal-based SPEs for solid-state alkali metal batteries.

Effect of Zwitterionic Additives on Solvation and Transport of Sodium and Potassium Cations in (Ethylene Oxide)10: A Molecular Dynamics Simulation Study

“…Table 2 and Table 3 show the calculated coordination numbers of cation–O(EO10) (N cation-O(EO10) ), cation–O([TFSI] − ) (N cation-O([TFSI]− ), and cation–O(ZW) (N cation-O(ZW) ) and their sums for Na + and K + in the eight electrolytes listed in Table 1 . The total cation–O coordination number was higher for K + (7.03–7.15) than for Na + (6.52–6.70), which is consistent with the literature [ 44 , 45 ].…”

“…) and their sums for Na + and K + in the eight electrolytes listed in Table 1. The total cation-O coordination number was higher for K + (7.03-7.15) than for Na + (6.52-6.70), which is consistent with the literature [44,45]. The highest coordination number was observed for cation-O(EO 10 ).…”

“…The decrease in cation-ZW molecule lifetime with increased cationic size correlated with the weakened preference of the cation to coordinate with ZW molecules. The reduced cation-O interaction lifetime for K + compared to Na + agrees with the literature [44] and can be attributed to the weaker cation-O interactions.…”

“…Meanwhile, the K + –O([TFSI] − ) and K + –O(EO 10 ) RDFs showed high peaks at a further distance of around 0.27 nm. Previous studies [ 38 , 41 , 42 , 43 , 44 , 45 ] also reported that the K⁺–O RDF peaks were at a greater distance at around 0.28 nm, indicating weaker K⁺–O interactions compared to Na + –O interactions. The high RDF peaks suggested a strong coordination between Na + and K + ions with [TFSI] − , EO 10 , and ZW molecules.…”

Weak Electrostatic Force on K+ in Gel Polymer Electrolyte Realizes High Ion Transference Number for Quasi Solid‐State Potassium Ion Batteries

“…Correspondingly, the energy barrier to be overcome for K + migration in K-UVGPE is the lowest compared with that of Li + in Li-UVGPE and Na + in Na-UVGPE (Figure S12, Supporting Information). [58,59] As mentioned above, K-UVGPE has great advantages as a GPE for PIBs, but in-depth research is still needed to meet the application requirements of high-performance SSPIBs. More importantly, the K-UVGPE with different precursor components (different liquid electrolytes/monomer ratios of 9:1, 8:2, 5:5, and 3:7, respectively) are prepared (Figure S13, Supporting Information), and the ionic conductivity and mechanical properties at room temperature are compared (Figure 2a).…”