LiNO₃‐Based Electrolytes via Electron‐Donation Modulation for Sustainable Nonaqueous Lithium Rechargeable Batteries

Abstract

LiPF6 as a dominant lithium salt of electrolyte is widely used in commercial rechargeable lithium‐ion batteries due to its well‐balanced properties, including high solubility in organic solvents, good electrochemical stability, and high ionic conductivity. However, it suffers from several undesirable properties, such as high moisture sensitivity, thermal instability, and high cost. To address these issues, herein, we propose an electron‐donation modulation (EDM) rule for the development of low‐cost, sustainable, and electrochemically compatible LiNO3‐based electrolytes. We employ high donor‐number solvents (HDNSs) with strong electron‐donation ability to dissolve LiNO3, while low donor‐number solvents (LDNSs) with weak electron‐donation ability are used to regulate the solvation structure to stabilize the electrolytes. As an example, we design the LiNO3‐DMSO@PC electrolyte, where DMSO acts as an HDNS and PC serves as an LDNS. This electrolyte exhibits excellent electrochemical compatibility with graphite anodes, as well as the LiFePO4 and LiCoO2 cathodes, leading to stable cycling over 200 cycles. Through spectroscopy analyses and theoretical calculation, we uncover the underlying mechanism responsible for the stabilization of these electrolytes. Our findings provide valuable insights into the preparation of LiNO3‐based electrolytes using the EDM rule, opening new avenues for the development of advanced electrolytes with versatile functions for sustainable rechargeable batteries.

Rational Molecular Engineering via Electron Reconfiguration toward Robust Dual-Electrode/Electrolyte Interphases for High-Performance Lithium Metal Batteries

“…With further understanding at the molecular level, it can be seen that the issues of current additives are related to electron structure. The insolubility of LiNO 3 stems from the strong bonding between nitrate and lithium ions, coexisting with the lack of electron-donating capacity of the electrolyte system. , The low reducibility of NO 3 – is associated with the high resonance electron cloud structure, containing large π bonds with four centers and six electrons. , In addition, the narrow oxidation window of ether implicates the removal of lone pair electrons from the ether-oxygen functional group, accompanied by H-abstraction and radical intermediates. , …”

Trace ethylene carbonate-mediated low-concentration ether-based electrolytes for high-voltage lithium metal batteries

“…Note that traditional HOESY is often used to qualitatively illustrate the existence of ion–molecule interactions, but cannot quantitatively compare the strength of ion–molecule interactions in two electrolytes. 21,51,52 Herein, the electrolyte of LiPF 6 in FEC/PC (in a 1 : 5 : 7 mol ratio) was utilized, with deuterated benzene (C 6 D 6 ) sealed together in a coaxial tube as the external calibration solution. This calibration solution presents a fixed strength signal (indicated within the black box) representing solvent–solvent interactions between molecules of distinct polarities ( i.e.…”

Designing Advanced Electrolytes for High-Safety and Long-Lifetime Sodium-Ion Batteries via Anion–Cation Interaction Modulation

“…Sodium-ion batteries (SIBs) have been considered a promising technology for large-scale energy storage applications because of the natural abundance and low cost of sodium resources . As an indispensable component of the battery, the electrolyte plays an important role in determining the electrochemical performance of SIBs. , However, traditional carbonate and ether electrolytes used in SIBs are highly volatile and flammable, , which will combust and eventually lead to thermal runaway when the batteries are subjected to abusive conditions (e.g., crash, heat treatment, and short circuit). To address the safety hazards of batteries, functional electrolytes such as aqueous systems, ionic liquids, and phosphates are alternatives owing to their intrinsic nonflammability. , Among them, aqueous electrolytes are cost-effective, but their electrochemical window is too narrow to be compatible with different electrode materials, while the ionic liquids are too costly.…”