A Steric-Hindrance-Induced Weakly Solvating Electrolyte Boosting the Cycling Performance of a Micrometer-Sized Silicon Anode

Abstract

The application of micrometer-sized silicon (mSi) is challenging due to the severe volume change during cycling, resulting in serious pulverization of the mSi and detachment of active materials from the current collector and consequently causing a capacity loss. Here, a new LiPF 6compatible ether electrolyte is developed to enhance the cycling performance of the mSi anode. Ethylene glycol dibutyl ether (EGDE) with large steric hindrance renders PF 6 − -rich solvation complexes in the electrolyte, which are favorable for rapidly passivating the mSi anode surface and forming a LiF-rich, thin, and stratified solid electrolyte interphase (SEI). As a result, the mSi anode displays a high capacity retention of 1901 mAh g −1 after 500 cycles and a high CE of 99.92% in a mediumconcentration EGDE-LiPF 6 -based electrolyte. This work provides an effective strategy for extending the cycling life of the mSi anode by designing a new LiPF 6 -ether electrolyte system.

Long‐cycling and High‐voltage Solid State Lithium Metal Batteries Enabled by Fluorinated and Crosslinked Polyether Electrolytes

“…Figure 2g and Figure S9 exhibit the radial distribution function (RDFs) of Li + to DFOB − and TFSI − in different electrolytes. The Li−O(DFOB − ) and Li−O(TFSI − ) present higher frequencies (the absolute value of g(r)) in FGPE than in GPE, demonstrating that the anions are more probable to enter the first solvation sheath of Li + in FGPE [20] . The anion‐rich solvation structure in FGPE can promote the formation of an inorganic‐rich and stable SEI on the anode, which contributes to the enhanced lithium metal stability.…”

Tuning the End Alkyl Chain of the Ether Solvent to Stabilize the Electrode/Electrolyte Interfaces in the NCM-Li Battery

“…The 2 M LiFSI +DIGDBE and 2 M LiFSI+TEGDBE electrolytes are rich in contact ion pairs (CIPs) and ionic aggregates (AGGs), which play a significant role in the formation of anion-derived and well-structured CEI. 32 In addition, we also avoided the + and Li(TEGDBE) 2 + . This indicates that the chelating ability of short-carbon-chain ethers with Li + is stronger than that of long-carbon-chain ethers.…”

Novel Binder with Cross-Linking Reconfiguration Functionality for Silicon Anodes of Lithium-Ion Batteries

“…This causes fragmentation of silicon electrodes, instability of the solid electrolyte interface (SEI), loss of electrical contact within the electrode film, and ultimately, a rapid deterioration of capacity, hindering the large-scale applicability of silicon anodes. 4,5 To resolve the aforementioned issues, the stable structure of the silicon anode can be maintained from both the material and electrode aspects by designing nanostructures, 6 modifying the carbon coating, 7 or introducing an artificial SEI layer and high-performance binders. 8,9 To address the significant volume expansion incurred by the alloying process, the stable electrode structure is the key factor to exert the performance of the material after having excellent electrode materials, which are modified from the material scale.…”

“…Silicon is recognized as a conceivable anode material for high-energy-density lithium-ion batteries owing to its high theoretical capacity (4200 mAh g –1 , Li 4.4 Si), low working potential, and abundant reserves. , Nevertheless, unlike the insertion/extraction mechanism of lithium-ion storage in graphite, silicon anodes undergo alloying/dealloying transformations during electrochemical reactions, leading to significantly higher volume expansion and shrinkage (>300%) upon cycling than the insertion/extraction process. This causes fragmentation of silicon electrodes, instability of the solid electrolyte interface (SEI), loss of electrical contact within the electrode film, and ultimately, a rapid deterioration of capacity, hindering the large-scale applicability of silicon anodes. , …”