Quantifying the ion coordination strength in polymer electrolytes

Abstract

Quantitative determination of the cation coordination strength to the ligands in polymer electrolytes and its correlation to the ion transport.

Carbonyl-Containing Solid Polymer Electrolyte Host Materials: Conduction and Coordination in Polyketone, Polyester, and Polycarbonate Systems

“…This calls into question the validity of the FT-IR measurements on the polycarbonate electrolyte and may hint toward more general quantification problems for this and possibly also related polymer systems using vibrational spectroscopy, as has previously been observed for nitrile solvents. 38 The low Li + to TFSI oxygen coordination number for POHM suggests that it actually has a better solvating ability for LiTFSI as compared to the polyester and polycarbonate, which can also be seen in snapshots from Figure 5b. The Li + transport is affected by both the local coordination environment and the coordination strength.…”

“…It can be observed that the Li + to carbonyl oxygen coordination number for PCL is in good agreement with the coordination number from FT-IR; however, a difference in coordination number for PTeMC can be observed. This calls into question the validity of the FT-IR measurements on the polycarbonate electrolyte and may hint toward more general quantification problems for this and possibly also related polymer systems using vibrational spectroscopy, as has previously been observed for nitrile solvents . The low Li + to TFSI oxygen coordination number for POHM suggests that it actually has a better solvating ability for LiTFSI as compared to the polyester and polycarbonate, which can also be seen in snapshots from Figure b.…”

Investigating the abnormal conductivity behaviour of divalent cations in low dielectric constant tetraglyme-based electrolytes

“…Nonetheless, it has long been considered that glymebased solutions are not ideal electrolytes for batteries as they possess a low dielectric constant and would poorly dissociate the ions. Depending on the chain length, glyme molecules can actually act as multidentate ligands, 47 and the solvated ions are highly stabilised through a chelating effect facilitated by the relatively low mechanical stress associated with the glyme strain. Long-chain glyme-based molecules, e.g., triglyme and tetraglyme, can thus dissolve a significant amount of salts, which can be used as electrolytes for rechargeable batteries.…”

Improving the Electrochemical Stability of a Polyester–Polycarbonate Solid Polymer Electrolyte by Zwitterionic Additives

“…However, without more samples and data points, it is not possible to assuredly draw firm conclusions from these parameters, and for this reason, further discussion will not be dealt with in this paper. Furthermore, FTIR spectra of PCL-PTMC:LiTFSI with and without zwitterions were recorded (see Figure S2), showing a change in the interaction between the carbonate and ester groups with the Li + but no apparent change in the 700 cm –1 region, which can be used to probe changes in the ion coordination …”

“…Furthermore, FTIR spectra of PCL-PTMC:LiTFSI with and without zwitterions were recorded (see Figure S2), showing a change in the interaction between the carbonate and ester groups with the Li + but no apparent change in the 700 cm −1 region, which can be used to probe changes in the ion coordination. 41 Voltammetric Measurements. The electrochemical stability of an electrolyte is conventionally evaluated with voltammetric measurements.…”