Polymer Electrolytes Based on Borane/Poly(ethylene glycol) Methyl Ether for Lithium Batteries

Abstract

This work presents a different approach to preparing polymer electrolytes having borate ester groups for lithium ion batteries. The polymers were synthesized by reaction between poly(ethylene glycol) methyl ether (PEGME) and BH 3 -THF complex. Molecular weight of PEGMEs was changed with different chain lengths. Then the polymer electrolytes comprising boron were prepared by doping of the matrices with CF 3 SO 3 Li at various molar ratios with respect to EO to Li and they are abbreviated as PEGMEX-B-. The identification of the PEGME-borate esters was carried out by FTIR and 1 H NMR spectroscopy. Thermal properties of these electrolytes were investigated via thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The ionic conductivity of these novel polymer electrolytes was studied by dielectric-impedance spectroscopy. Lithium ion conductivity of these electrolytes was changed by the length of PEGME as well as the doping ratios. They exhibit approximate conductivities of 10 −4 S⋅cm −1 at 30 ∘ C and 10 −3 S⋅cm

Organoboron‐Containing Polymer Electrolytes for High‐Performance Lithium Batteries

“…The most widely studied boron ester plasticizer has three branched EO chains, whose length can be changed to adjust the effect of boron ester on ionic conductivity of PE. [72,124,125] In this section, we will discuss the role of boron ester in facilitating the formation of SEI, high ionic conductivity, and ameliorating interfaces contacts in lithium batteries.…”

Methylboronic acid MIDA ester (ADM) as an effective additive in electrolyte to improve cathode electrolyte interlayer performance of LiNi0.8Co0.15Al0.05O2 electrode

“…The absorption peak for boron nitride (BN) bonding in ADM occured at 777–902 cm −1 and 1255–1329 cm −1 14 – 17 , and the peaks at 1086 cm −1 and 1135 cm −1 were the result of B–C and C–N vibrations, respectively 17 . The characteristic peaks related to boron occured at 1029 cm −1 for B–O–C bonding, and at 667 cm −1 and 1350 cm −1 for B–O asymmetric stretching peaks 18 – 20 . A careful analysis of the FTIR spectra showed clearly distinct absorption peaks at 1197 cm −1 and 728 cm −1 (EC-Li + coordination 21 ) for the electrolyte without ADM, whereas these peaks were absent for the additive-containing electrolyte, revealing the coordination effect of the Li + ion in the electrolyte additive.…”