[6] For example, the electrochemical window of Lithium bis- (trifluoromethanesulfonyl)imide, commercially known as LiTFSI is about 3.0 V because it can operate in the range of 1.9 -4.9 V.[7] On the other hand, for electrolytes that are characterized by narrow electrochemical window, they are prone to irreversible decomposition,[8] which in turn triggers the battery capacity decaying during subsequent battery cycling.
The electrochemical window of organic electrolyte depends on many factors that include temperature, molecular frontier orbitals such LUMO (Lowest Unoccupied Molecular Orbital) and HOMO (Highest occupied Molecular Orbital) because the mechanisms of reduction (electron gaining) and oxidation (electron loss) are governed by band gap between HOMO and LUMO.
[9] Solvation energy also plays an important role in defining the electrochemical window of the electrolyte.
[10] In order to safeguard the thermodynamic stability working conditions of the electrode materials in a given electrolyte, the electrochemical potentials of the electrode materials (anode and cathode) must be comprised within the electrochemical stability of the electrolyte.
[12][13] One of the shortcoming of electrochemical window (EW) in predicting the stability of the electrolyte towards anode or cathode materials ignores the voltage and the ionic conductivity, which are also important.