Electrolyte Additive-Controlled Interfacial Models Enabling Stable Antimony Anodes for Lithium-Ion Batteries

Abstract

Most electrolyte additives can improve lithium-ion batteries’ performance by forming a solid electrolyte interphase (SEI) layer on the electrode surface. However, the influences of such additives on the lithium-ion (Li+) solvation structure, particularly on the Li+ desolvation process and its relationship with the attained electrode performance, are mostly overlooked. Herein, we designed a novel ether-based electrolyte to stabilize the alloying anode (e.g., Sb, antimony) by introducing LiNO3 as an additive, where a new interfacial model was constructed to show the additive effect on the kinetic and thermodynamic properties of Li+–solvent–anion complex in the electrolyte. We find that the NO3 – anion can weaken the Li+–solvent interaction, promote the Li+ desolvation, particularly mitigate electrolyte decomposition by tuning the location of the Li+–solvent–anion complex on the electrode surface, and then improve electrolyte stability. This is the first time to show that the LiNO3 additive can contribute to a far distance of the Li+–solvent–anion complex from the Sb anode surface rather than the role of forming SEI. Eventually, an extremely high capacity of 664 mAh g–1, extraordinary rate capability over 5C, and good cycle performance over hundreds of cycles were obtained. This work provides new insight into understanding the role of additives more comprehensively and offers guidance in designing electrolytes for stable lithium-ion batteries using alloying anodes.

Weak Solvent–Solvent Interaction Enables High Stability of Battery Electrolyte

“…In this way, the redox properties of the electrolyte components, including solvent, additive, and anion during the polarization, − as well as the recently proposed M + –solvent–anion complex formed during the desolvation process on the electrode surface, − have been widely studied to evaluate the electrolyte, since they can be highly influenced by the widely existing electrostatic interactions between M + , anions, and solvent molecules with uneven charge distribution. Then, varying the interactions of M + –solvent, M + –anion pair, and anion–solvent by changing the type and quantity of solvents, anions, additives, etc., have received significant attention recently to tune the electrolyte properties. − It is worth noting that solvent–solvent interaction has rarely been mentioned before, as such interaction is considered to be very weak, 1–2 orders of magnitude weaker than the ion–ion interaction between M + –anion and the ion-dipole interaction between M + –solvent .…”

Retuning Solvating Ability of Ether Solvent by Anion Chemistry toward 4.5 V Class Li Metal Battery

“…The peak shift of FSI − in the Blank electrolyte is opposite to the LNO one, which is consistent with the 7 Li NMR results. Moreover, 13 C and 1 H NMR spectra further assist in analyzing the role of NO 3 − in the solvated structure of different electrolytes (see details in Figures S4 and S5, Supporting Information). The combined Raman and NMR results show that the interaction of FSI − and DME with Li + in the LNO system is weakened due to the effective NO 3 − regulation, producing a weakly solvated electrolyte.…”

“…[11] It is believed that a good solid-electrolyte interphase (SEI) can effectively prevent interfacial parasitic reactions, enhancing the stability of the ether-based electrolyte. [12,13] And 1 m lithium bis(fluorosulfonyl)imide (LiFSI) in1,2dimethoxyethane (DME), as a typical ether-based electrolyte, DOI: 10.1002/adfm.202310516 has a solvent-dominated solvation structure that enables a solvent-dominated interfacial film and a poor de-solvation process.…”

Structure Property and Reaction Mechanism of Boron-Based High-Voltage Electrolyte Additives via First-Principles Calculations

“…First-principles calculations were implemented using the Gaussian16 package and the VASP . The structures were optimized using B3LYP combined with the basis set of 6-311+G­(d,p) . Added DFT-D3 dispersion correction in the calculation process to obtain more accurate weak interaction.…”

“…34 The structures were optimized using B3LYP combined with the basis set of 6-311+G(d,p). 35 Added DFT-D3 36 dispersion correction in the calculation process to obtain more accurate weak interaction. According to the optimized coordinates, the vibration calculation and frequency analysis were performed under the same basis set.…”