Flame-retardant electrolyte with boosted interfacial stability for practical Li metal batteries

Developing Li metal batteries (LMBs) with high-voltage cathodes is crucial for realizing high energy storage systems. Thus, advanced electrolytes that can derive stable interphases for both Li anode and high-voltage cathodes are highly desired. LiNO 3 has been widely used as an efficient additive fo...

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Bibliographic Details
Published in:Science China materials 2024-03, Vol.67 (3), p.804-815
Main Authors: Kou, Xiaohang, Zhang, Jiaolong, Li, Chaolin, Li, Ruhong, Ruan, Tingting, Wang, Wenhui
Format: Article
Language:English
Subjects:
Cathodes
Chemistry and Materials Science
Chemistry/Food Science
Electrolytes
Electrolytic cells
Energy storage
Flame retardants
High voltages
Interface stability
Lithium batteries
Materials Science
Solid electrolytes
Solubility
Storage systems
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Summary:Developing Li metal batteries (LMBs) with high-voltage cathodes is crucial for realizing high energy storage systems. Thus, advanced electrolytes that can derive stable interphases for both Li anode and high-voltage cathodes are highly desired. LiNO 3 has been widely used as an efficient additive for solid electrolyte interphases in ether-based electrolytes, but its poor solubility in carbonate-based electrolytes limits its application in high-voltage LMBs. Herein, trimethyl phosphate was proposed as co-solvent in ethyl methyl carbonate/fluoroethylene carbonate electrolyte to endow the electrolyte with high LiNO 3 solubility and flame-retardant properties. Additionally, lithium bis(oxalato) borate was added to improve the interfacial stability at both the anode and the cathode sides. As a result, the obtained electrolyte exhibited high compatibility towards both Li metal anode and high-voltage layered cathodes. After cycled between 2.8–4.3 V at a current density of 1.2 mA cm −2 for 300 times, Li∣LiCoO 2 and Li∣LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) full cells delivered high capacity retention of 80.2% and 84.2%, respectively. More amazingly, the Li∥NCM811 cell with a negative-to-positive capacity ratio of 3.33 still remained a capacity retention of ∼80% after 150 cycles under the same charge/discharge conditions. The understanding of this fire-retardant, high-voltage electrolyte enriched with LiNO 3 inspires the development of safe and high energy LMBs through interphases regulation.
ISSN:2095-8226
2199-4501
DOI:10.1007/s40843-023-2745-x