A fluorinated electrolyte stabilizing high-voltage graphite/NCM811 batteries with an inorganic-rich electrode-electrolyte interface

Simultaneous Prelithiation and Compatible Modification toward Ultrafast and Ultrastable Lithium-Ion Capacitors

“…30,31 In addition, the highest HOMO energy level of the LiDFOB additive suggests that the LiDFOB additive is prone to be oxidatively decomposed to form the thin and uniform LiDFOB-promoted CEI layer on the Li 2 S@ NPCNF cathode, resulting in enhanced high-voltage durability of the ester electrolyte. 31,32 The LiDFOB-derived CEI layer also acts as a barrier to mitigate the undesirable side reactions between the ester electrolyte and polysulfide. 28 The electrochemical performances of the Li 2 S@NPCNF cathode in the corresponding electrolytes were examined in half cells, and the mass ratio of Li 2 S to NPCNF is controlled to be 1:1.…”

“…Figure S3 shows the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of the solvents and lithium salts. As indicated by the lowest LUMO energy level, the LiDFOB additive tends to undergo preferential reduction on the surface of the anode and contribute to the formation of a mechanically robust and LiF-rich SEI layer, owing to the strong electron affinity of the LiDFOB additive. , In addition, the highest HOMO energy level of the LiDFOB additive suggests that the LiDFOB additive is prone to be oxidatively decomposed to form the thin and uniform LiDFOB-promoted CEI layer on the Li 2 S@NPCNF cathode, resulting in enhanced high-voltage durability of the ester electrolyte. , The LiDFOB-derived CEI layer also acts as a barrier to mitigate the undesirable side reactions between the ester electrolyte and polysulfide …”

In Situ Inorganic-Rich Electrode–Electrolyte Interphases for Safer 4.5 V Gr||NCM811 Batteries Enabled by an Ethylene Carbonate-Free Electrolyte

“…Besides, the polycrystalline material exhibits worse thermal stability during cycling due to the existence of an internal crystal gap, which leads to higher lithium ion transfer impedance and a lower ion diffusion coefficient. The lower specific surface area of the single-crystal material can effectively reduce the occurrence of side reactions and produce fewer mechanical cracks and gases, resulting in better cycling performance. − Moreover, the in situ formed robust inorganic-rich EEIs are a very promising approach to further improve the electrochemical performance and safety performance. − …”

Electrolyte Solvation Engineering toward High-Rate and Low-Temperature Silicon-Based Batteries

“…15 Moreover, F introduction leads to a decrease in both the lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) energy levels, endowing the electrolyte with better SEI formation capability on the anode side and a higher oxidative stability on the cathode side. 16,17 The decomposition products from fluorinated solvents, either in the form of inorganic LiF or organic F-containing moieties, are known to efficaciously passivate the anode surface against subsequent electrolyte decompositions. 18,19 By taking such advantages, Fan et al proposed an all-fluoride electrolyte composed of fluoroethylene carbonate (FEC)/methyl (2,2,2-trifluoroethyl) carbonate (FEMC) dispersed into a highly fluorinated ethane, enabling wide temperature operation of the Li-Ni 0.8 Co 0.15 Al 0.05 O 2 /Li batteries with low desolvation energy and a LiF-rich interphase established on both the anode and cathode.…”

“…Fluorination has been recognized as an effective strategy to tailor the solvent binding energy with Li + , where the electron-withdrawing effect produced by F atoms effectively reduces the solvating power of the solvents . Moreover, F introduction leads to a decrease in both the lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) energy levels, endowing the electrolyte with better SEI formation capability on the anode side and a higher oxidative stability on the cathode side. , The decomposition products from fluorinated solvents, either in the form of inorganic LiF or organic F-containing moieties, are known to efficaciously passivate the anode surface against subsequent electrolyte decompositions. , By taking such advantages, Fan et al proposed an all-fluoride electrolyte composed of fluoroethylene carbonate (FEC)/methyl (2,2,2-trifluoroethyl) carbonate (FEMC) dispersed into a highly fluorinated ethane, enabling wide temperature operation of the LiNi 0.8 Co 0.15 Al 0.05 O 2 /Li batteries with low desolvation energy and a LiF-rich interphase established on both the anode and cathode . More recently, Chen’s group adopted a fluorinated form of methyl propionate (MP), methyl 3,3,3-trifluoropionate (MTFP), as a major solvent; by coupling with 10 vol % FEC, they achieved a discharge capacity of 161 mAh g –1 at −40 °C in Li/NMC811 full cells under a rate of 0.1 C .…”