Reaction Mechanisms of the Degradation of Fluoroethylene Carbonate, an Additive of Lithium‐Ion Batteries, Unraveled by Radiation Chemistry

Abstract

Numerous additives are used in electrolytes of lithium-ion batteries, especially for the formation of efficient solid electrolyte interphase at the surface of the electrodes. The understanding of the degradation processes of these compounds is thus important. They can be obtained through radiolysis.In the case of fluoroethylene carbonate (FEC), picosecond pulse radiolysis experiments evidenced the formation of FEC •-. This radical is stabilized in neat FEC, whereas the ring opens to form more stable radical anions when FEC is a solute in other solvents, as confirmed by quantum chemistry calculations. In neat FEC, pre-solvated electrons primarily undergo attachment compared to solvation. At long timescales, produced gases (H2, CO, and CO2) were quantified. A reaction scheme for both the oxidizing and reducing pathways at stake in irradiated FEC was proposed. This work evidences that the nature of the primary species formed in FEC depends on the amount of FEC in the solution.

Time-Dependent Long-Range-Corrected Double-Hybrid Density Functionals with Spin-Component and Spin-Opposite Scaling: A Comprehensive Analysis of Singlet–Singlet and Singlet–Triplet Excitation Energies

“…Therein, we showed how the inclusion of a single parameter, which controls the interplay between the long- and short-range regimes, can improve long-range excitations such as Rydberg states and CT excitations without much loss in accuracy for local-valence transitions. We particularly note that both functionals delivered the best TD-DFT results to date for L a and L b transitions in PAHs, and that they have already been successfully used in applications to systems of biological or technological relevance. − …”

“…We particularly note that both functionals delivered the best TD-DFT results to date for L a and L b transitions in PAHs, 40 and that they have already been successfully used in applications to systems of biological or technological relevance. [58][59][60][61][62][63][64] Prior to mid-2020, most of the BLYPbased global DHDFAs studies had been carried out using the full TD-DHDFA scheme, whereas most of the studies using PBE-based global DHDFAs had used the TDA-DHDFA scheme, instead. 37,38,[65][66][67][68][69][70][71][72][73][74][75] Moreover, all previous benchmark studies and applications had been limited to singlet-singlet excitations, except for the original work by Grimme and Neese from 2007, 18 leaving out other spin multiplicities of crucial relevance, such as triplet excitations, most likely due to the lack of a code that could handle those transitions.…”

Time-Dependent Long-Range-Corrected Double-Hybrid Density Functionals with Spin-Component and Spin-Opposite Scaling: A Comprehensive Analysis of Singlet-Singlet and Singlet-Triplet Excitation Energies

“…We particularly note that both functionals delivered the best TD-DFT results to date for L a and L b transitions in PAHs, 40 and that they have already been successfully used in applications to systems of biological or technological relevance. [58][59][60][61][62][63][64] Prior to mid-2020, most of the BLYPbased global DHDFAs studies had been carried out using the full TD-DHDFA scheme, whereas most of the studies using PBE-based global DHDFAs had used the TDA-DHDFA scheme, instead. 37,38,[65][66][67][68][69][70][71][72][73][74][75] Moreover, all previous benchmark studies and applications had been limited to singlet-singlet excitations, except for the original work by Grimme and Neese from 2007, 18 leaving out other spin multiplicities of crucial relevance, such as triplet excitations, most likely due to the lack of a code that could handle those transitions.…”

Time-Dependent Long-Range-Corrected Double-Hybrid Density Functionals with Spin-Component and Spin-Opposite Scaling: A Comprehensive Analysis of Singlet-Singlet and Singlet-Triplet Excitation Energies

“…We particularly note that both functionals delivered the best TD-DFT results to date for L a and L b transitions in PAHs, 40 and that they have already been successfully used in applications to systems of biological or technological relevance. [59][60][61][62][63][64][65][66] Prior to mid-2020, most of the BLYPbased global DHDFAs studies had been carried out using the full TD-DHDFA scheme, whereas most of the studies using PBE-based 67 global DHDFAs had used the TDA-DHDFA scheme, instead. 37,38,[68][69][70][71][72][73][74][75][76][77][78] Moreover, all previous benchmark studies and applications had been limited to singlet-singlet excitations, except for the original work by Grimme and Neese from 2007, 18 leaving out other spin multiplicities of crucial relevance, such as triplet excitations, most likely due to the lack of a code that could handle those transitions.…”