Structure characterization and electrochemical properties of new lithium salt LiODFB for electrolyte of lithium ion batteries

Abstract

Lithium difluoro(axalato)borate (LiODFB) was synthesized in dimethyl carbonate (DMC) solvent and purified by the method of solventing-out crystallization. The structure characterization of the purified LiODFB was performed by Fourier transform infrared (FTIR) spectrometry and nuclear magnetic resonance (NMR) spectrometry. The electrochemical properties of the cells using 1 mol/L LiPF 6 and 1 mol/L LiODFB in ethylene carbonate (EC)/DMC were investigated, respectively. The results indicate that LiODFB can be reduced at about 1.5 V and form a robust protective solid electrolyte interface (SEI) film on the graphite surface in the first cycle. The graphite/LiNi 1/3 Mn 1/3 Co 1/3 O 2 cells with LiODFB-based electrolyte have very good capacity retention at 55 , ℃ and show very good rate capability at 0.5C and 1C charge/discharge rate. Therefore, as a new salt, LiODFB is a most promising alternative lithium salt to replace LiPF 6 for lithium ion battery electrolytes in the future.

Recent Progress on Spray Pyrolysis for High Performance Electrode Materials in Lithium and Sodium Rechargeable Batteries

“…[133,134] SP has turned out to be useful in stabilizing Ni-rich compounds by spontaneous core-shell composite formation including protecting shell layer as well as uniform TM mixing. [135][136][137] [136] In the SP step, ethylene glycol, citric acid, and N-N-dimethlyformamide (a 40 cycles.…”

Ethylene carbonate adsorption on the major surfaces of lithium manganese oxide Li1−xMn2O4spinel (0.000 <x< 0.375): a DFT+U-D3 study

“…A number of methods have attempted to mitigate the manganese dissolution, including (i) cation doping [17,18]; (ii) the replacement of commercially used LiPF6 as the electrolyte ionic conductor to limit the production of the scavenging hydrofluoric acid produced by its degradation [19,20,21];…”

Electrolytes for Lithium (Sodium) Batteries Based on Ionic Liquids: Highlighting the Key Role Played by the Anion

“…The unsymmetric hybrid anion difluorooxalatoborate, [DFOB] − , was introduced by Zhang et al and Gao et al with the intention of combining the advantages of [BOB] − and [BF 4 ] − , that is, excellent SEI formation on graphite anodes ([BOB] − ), better low temperature performance ([BF 4 ] − ) than that of [PF 6 ] − , and protection against overcharge ([BOB] − and [BF 4 ] − )(we have noticed an error in a reference given for the latter in the Zhang paper). Indeed, graphite/LiNi 1‐ x ‐ y M x N y O 2 (M and N are metal atoms not further defined in the original literature) Li‐ion cells assembled with Li[DFOB] PC/EC/EMC electrolytes showed excellent cycling behavior over a wide temperature range and retained about 90 % of the initial capacity after 200 cycles at 60 °C.…”