Constructing a Stable Interface Layer by Tailoring Solvation Chemistry in Carbonate Electrolytes for High‐Performance Lithium‐Metal Batteries

Abstract

Lithium‐metal batteries (LMBs) are considered as promising next‐generation batteries due to their high energy density. However, commercial carbonate electrolytes cannot be used in LMBs due to their poor compatibility with the lithium‐metal anode and detrimental hydrogen fluoride (HF) generation by lithium hexafluorophosphate decomposition. By introducing lithium nitrate additive and a small amount of tetramethylurea as a multifunctional cosolvent to a commercial carbonate electrolyte, NO3−, which is usually insoluble, can be introduced into the solvation structure of Li+ to form a conductive and stable solid electrolyte interface. At the same time, HF generation is suppressed by manipulating the solvation structure and a scavenging effect. As a result, the Coulombic efficiency (CE) of Li||Cu half cells using the designed carbonate electrolyte can reach 98.19% at room temperature and 96.14% at low temperature (−15 °C), and Li||LiFePO4 cells deliver a high capacity retention of 94.9% with a high CE of 99.6% after 550 cycles. This work provides a simple and effective way to extend the use of commercial carbonate electrolytes for next‐generation battery systems.

A nonflammable electrolyte for ultrahigh-voltage (4.8 V-class) Li||NCM811 cells with a wide temperature range of 100 °C

“…4 On the anode side, lithium metal with an ultrahigh specific capacity (3860 mA h g −1 ) and ultralow redox potential (−3.04 V vs. standard hydrogen electrode), is one of the ideal anodes to replace commercial graphite (372 mA h g −1 ). 3,5,6 On the cathode side, both increasing the cut-off voltage (>4.5 V) of the prevailing cathode materials (such as LiNi x Co y Mn z O 2 , x + y + z = 1) and developing novel materials such as Li-rich layer oxides and high-voltage spinel oxides with improved capacities (>250 mA h g −1 ) can significantly increase the energy density. 7,8 However, compared with developing novel materials, improving the cut-off voltages of commercial cathodes is easier and more effective.…”

Advancing to 4.6 V Review and Prospect in Developing High‐Energy‐Density LiCoO2 Cathode for Lithium‐Ion Batteries

“…Usually, the charged cathode materials, for example, LCO as concerned in this work, is highly oxidizing at a high valence state for the transition metal, and it is easy to react with the flammable electrolyte especially when the working voltage is extremely high. [55][56][57] Figure 3. a) Schematic of cracking degradation mechanism of twin boundary in LCO.…”

[tert-Butyl(diphenyl)silyl] trifluoromethanesulfonate acts as an effective additive for high-voltage lithium metal batteries

“…By analyzing the Coulombic efficiency (CE) of Cu8Li asymmetric batteries, it can effectively measure the degree of side reactions between lithium and the electrolyte during battery cycling. 39 Fig. 3a represents the variation curve of Coulombic efficiency at a current density of 0.5 mA cm À2 and a deposition capacity of 0.5 mA h cm À2 in different electrolytes.…”