Unraveling the temperature-responsive solvation structure and interfacial chemistry for graphite anodes

Abstract

The variation of temperature induces a corresponding transformation of the primary solvation structure of Li+ due to the competition coordination of solvents and anions with Li+; however, the specific variations...

Non-Flammable Electrolyte Mediated by Solvation Chemistry toward High-Voltage Lithium-Ion Batteries

“…This result demonstrates that the PF 6 − location undergoes a process of moving away from and approaching Li + attributing to the different high and low steric hindrance of the EMC and EC solvent, respectively. Moreover, we observed that the chemical shift of 17 O NMR in DTD moved toward the higher values from 158.74 to 158.35 ppm, resulting from the increased shielding effect on the DTD by Li + (Figure 3f). This result further demonstrates that the DTD could move closer to the Li + gradually after adding the EMC and EC solvent in a TMP-based electrolyte, weakening the Li + -TMP interaction.…”

“…The molecular behaviors of each electrolyte component, such as the varied Li + solvation structure, in the as-designed electrolyte can be further characterized to bolster the rationale 7 Li-(LiPF 6 ), (d) 31 P-(TMP), (e) 19 F-(LiPF 6 ), and (f) 17 of our design. Subsequently, a correlation can be established between the electrolyte properties and battery performance.…”

“…Raman spectra of (a) P−O in TMP and (b) S�O in DTD of different electrolytes. (c)7 Li-(LiPF 6 ), (d)31 P-(TMP), (e)19 F-(LiPF 6 ), and (f)17 O-(DTD) NMR spectra of electrolytes. Radial distribution functions (RDF) and corresponding coordination numbers (N(r)) of (g) T 5 , (h) T 4 D, (i) T 2 EM 3 D, and (j) T 2 EM 2 E 1 D. (k) Schematics of varied interactions between Li + , solvents, and PF 6 − by adding DTD, EMC, and EC in different electrolytes.…”

“…These chemicals can capture the H • and/or HO • radicals (e.g., • P + • H → PH) produced from other flammable organic chemicals, thereby interrupting the chain reaction of combustion . For example, the fluorine substituted chemicals that contain a high proportion of fluorine atoms, such as fluoroethylene carbonate (FEC), , methyl (2,2,2-trifluoroetyl) carbonate (FEMC), ethyl difluoroacetate (DFEA), and particularly fluorinated ether solvents (e.g., bis­(2,2,2-trifluoroethyl) ether (BTFE), hydrofluoroethers (HFE), , bis­(2-fluoroethyl) ethers (BFE)), have been widely investigated as the additives or cosolvents. The fluorine-substituted carbonate solvent can be used in the commercial carbonate-based electrolyte.…”

Organic Electrode Materials for Energy Storage and Conversion: Mechanism, Characteristics, and Applications

“…Our previous investigation suggested that LIBs retain only approximately 10% of their room-temperature capacity at −40 °C in the 1 M LiPF 6 EC/DEC/DMC electrolyte. , The poor performance at low temperature mainly arises from the sluggish desolvation at the electrode/electrolyte interphase and the slow bulk diffusion rate in the rigid crystal lattice of IEMs. As shown in Figure a, IEMs for Li ion batteries generally have a rigid structure with limited internal space that cannot accommodate solvated Li ions, and the co-intercalation of solvent molecules leads to the structural collapse of electrode materials.…”