Crossover Effects in Lithium‐Metal Batteries with a Localized High Concentration Electrolyte and High‐Nickel Cathodes

Abstract

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Gas Generation in Lithium Cells with High-Nickel Cathodes and Localized High-Concentration Electrolytes

“…Meanwhile, the FSI salt anion naturally has SO 2 functional groups and has been shown to experience oxidation of its central nitrogen, suggesting the possibility of SO 2 or NO 2 formation. 36 Nevertheless, neither gas could be detected, even at 4.6 V (Figure S6). Evidently, FSI salt decomposition products are incorporated into the CEI (cathode-electrolyte interphase) or dissolved into the electrolyte as crossover products rather than released as SO 2 or NO 2 , although further work needs to be pursued to confirm this behavior.…”

“…In fact, it is surprising how little CO is produced in LHCE even at 4.6 V. Both the solvents in LP57 are carbonates containing CO 3 groups, for which CO 2 formation is easy to imagine (although, surprisingly, there are few reports on the mechanisms of CO 2 formation from carbonates). , Meanwhile, DME contains only single ether oxygens, so that a CO 2 formation pathway necessarily requires more steps than one for CO formation. Formates have been observed in the oxidative decomposition of DME in Li-O 2 cells and in Li-NMC batteries, and are an intuitive intermediate on the path to CO 2 formation, but further work will be necessary to determine a clear solvent decomposition and gas generation route in this electrolyte. , …”

“… However, no such species were detected in these experiments, even at a high 4.6 V cutoff. Meanwhile, the FSI salt anion naturally has SO 2 functional groups and has been shown to experience oxidation of its central nitrogen, suggesting the possibility of SO 2 or NO 2 formation . Nevertheless, neither gas could be detected, even at 4.6 V (Figure S6).…”

“…Formates have been observed in the oxidative decomposition of DME in Li-O 2 cells and in Li-NMC batteries, and are an intuitive intermediate on the path to CO 2 formation, but further work will be necessary to determine a clear solvent decomposition and gas generation route in this electrolyte. 35,36 Salt decomposition is also a major aspect of electrolyte reactivity, especially for an LHCE. While the oxidation of PF 6 cannot generate CO 2 etc., gaseous compounds such as POF 3 have previously been detected from PF 6 decomposition (Figure S6).…”

Juggling Formation of HF and LiF to Reduce Crossover Effects in Carbonate Electrolyte with Fluorinated Cosolvents for High‐Voltage Lithium Metal Batteries

“…[29,30] Nevertheless, numerous fluorides are not only expensive but also prone to thermal decomposition, resulting in the derivation of acidic products (e.g., HF) to deteriorate electrode interfaces through cathode-to-anode detrimental crossover effect. [31][32][33][34][35][36][37][38][39] Beyond possessing oxidative stability and firm-forming requirements, cost-effectiveness and stability during long-duration storage are the other two critical characteristics for realistic high-voltage LMBs. Considering these features, fluorobenzene (FB) and 1,3,5-trifluorobenzene (TFB) in ether-based diluted highly concentrated electrolyte (DHCE) express great potential to commercial application.…”