Non-flammable organic liquid electrolyte for high-safety and high-energy density Li-ion batteries

Robust Solid‐Electrolyte Interphase Enables Near‐Theoretical Capacity of Graphite Battery Anode at 0.2 C in Propylene Carbonate‐Based Electrolyte

“…Additionally, new peaks at 1277 and 1084 cm À 1 are attributed to v(CÀ F) of À CF 3 and À CF 2 -functionalities of DFDEC decomposition products. [16,19,27,32] Upon the use of 1 wt% FEC additive (Figure 6a-iv), the same spectral features are shown but at the reduced peaks absorbance from the one without additive, which is associated with relatively thinner SEI layer consistent with impedance spectral analysis.…”

“…PC-based electrolyte [1 M LiPF 6 (Aldrich) in PC (Lichem Co., Ltd.)/ DFDEC (Lichem Co., Ltd.), 3 : 7 v/v] was prepared by dissolving the LiPF 6 salt in the PC/DFDFEC solvent mixture. [19] Fluoroethylene carbonate (FEC, 1 wt%; Lichem Co., Ltd.) was utilized as an additive. The viscosities of 1 M LiPF 6 in PC/DFDEC and commercial electrolytes, which were measured by using a rotational viscometer (Brookfield, DV3TLV) at room temperature, were 7.85 cP and 3.28 cP, respectively.…”

“…We developed a solution for the use of PC in LIBs; the effective replacement of a linear carbonate solvent with a fluorinated one enables the prevention of graphene exfoliation and the formation of a stable SEI, and moreover, being nonflammable PC-based organic liquid electrolyte, making the realization of high performance and safer LIBs. [14][15][16][17][18][19] Conventional perception on graphite anode is that high capacity close to theoretical value (372 mAh g À 1 ) of graphite is attainable only at a very slow charge-discharge condition usually below 0.05 C (taking 20 h for charge) due to the slow Li + -diffusion kinetics at both bulk and surface of graphite during stepwise staging-destaging processes. However, our PCbased electrolyte enables the graphite anode to deliver 370 mAh g À 1 , which is closely the theoretical capacity, at 4-fold faster rate, 0.2 C (taking 5 h for charge), than usual.…”

Recent Advances in Non-Flammable Electrolytes for Safer Lithium-Ion Batteries

“…The study reported that the addition of di-(2,2,2 trifluoroethyl) carbonate (DFDEC) enabled the cathode to charge to 5.0 V and to deliver a significantly increased capacity of 250 mAh•g −1 or higher. To overcome the risk of battery fires and explosions, Pham et al developed a novel non-flammable electrolyte composed of 1 M Li-hexafluorophosphate salt, propylene carbonate, and fluorinated linear carbonate co-solvents with high voltage stability [28]. The full batteries with the electrolyte with 1 wt.% FEC additive displayed high energy density, and stable cyclability performance at high voltages up to 5 V. Figure 6 shows the comparison between the fire tests of various compositions of electrolytes.…”

Thermal runaway of Lithium-ion batteries employing LiN(SO2F)2-based concentrated electrolytes

“…Thus, nonflammable electrolytes are considered and thought to improve battery safety. Concentrated electrolytes and localized or aqueous concentrated electrolytes have been receiving considerable attention in recent years, due to their high electrochemical performance, low volatility, and low flammability [20][21][22][23][24][25][26][27] . Many fundamental studies revealed that the unique solution structure, where all the solvent molecules and even anions are involved in the solvation sheath, endow concentrated electrolytes with different properties in comparison with the same compositional but traditional 1 M electrolytes.…”