Designing Advanced In Situ Electrode/Electrolyte Interphases for Wide Temperature Operation of 4.5 V Li||LiCoO₂ Batteries

Abstract

Figure 4. The CEI structures on cycled LCO cathodes in different electrolytes by HR-STEM characterizations. a,b) After 100 cycles in the BL-carbonate electrolyte. c,d) After 300 cycles in the AD-ether electrolyte. a,c) The ABF-STEM images. b,d) The HAADF-STEM images.

Quasi‐Ionic Liquid Enabling Single‐Phase Poly(vinylidene fluoride)‐Based Polymer Electrolytes for Solid‐State LiNi0.6Co0.2Mn0.2O2||Li Batteries with Rigid‐Flexible Coupling Interphase

“…[2] Consequently, lithium metal batteries cycle with low Coulombic efficiency (CE), formation of lithium dendrite, short-circuit risk, and continuous consumption of both electrolytes and electrodes. [3] Various strategies have been applied in the lithium metal batteries, like highconcentration electrolytes, [4] all-fluorinated electrolytes, [5] electrolytes additives, [6] solid inorganic electrolytes, [7] and polymer electrolytes. [8] Among them, employing polymer electrolytes instead of liquid electrolytes is a promising approach due to low flammability, excellent processability, and desirable flexibility.…”

“…Figure S26 of the Supporting Information plots the corresponding wide XPS spectra, and related narrow spectra are provided in Figure S27 of the Supporting Information. With respect to C 1s spectra, the group CO 3 arises at 288.8 eV, [4][5][6] which is generated from decomposition of [Li(DMF) 3 ][TFSI] and further oxidation of as-existing OCO (≈286.6 eV) and CO (≈285.5 eV) on LiNi 0.6 Co 0.2 Mn 0.2 O 2 . The appearance of CO 3 is also predominant in O 1s spectra.…”

“…Based on C 1s, the cycled Li anode is covered by CC/CH, COC, COOR, and poly(CO 3 ), which is further identified by O 1s spectra. [4][5][6] At the surface of Li anode without sputtering, Li salts (56 eV) and Li 2 CO 3 (54.5 eV) constitute the major component of SEI. However, Li 2 O (52.9 eV) and LiF/Li x N (55.7 eV) dominate the surface after sputtering.…”

“…However, Li 2 O (52.9 eV) and LiF/Li x N (55.7 eV) dominate the surface after sputtering. [4][5][6] As regards to F 1s spectra, signal of decomposed PVDF-HFP segments is pronounced at 689.1 eV, while LiF (685 eV) overwhelms the surface upon sputtering. [5] Similarly, the major component in N 1s spectra is associated with Li x N (398.5 eV) upon sputtering, [6] arising from decomposition of DMF and TFSI − .…”

“…Various strategies have been applied in the lithium metal batteries, like high‐concentration electrolytes, [ 4 ] all‐fluorinated electrolytes, [ 5 ] electrolytes additives, [ 6 ] solid inorganic electrolytes, [ 7 ] and polymer electrolytes. [ 8 ] Among them, employing polymer electrolytes instead of liquid electrolytes is a promising approach due to low flammability, excellent processability, and desirable flexibility.…”