Chinese Acad Sci;
Peoples R China;
Shenzhen Inst Adv Technol;
Shenzhen 518055;
Beijing 100084;
Coll Chem;
Guangzhou 510006;
Zhengzhou Univ;
Zhengzhou 450001;
Fac Mat Sci & Engn;
Shenzhen Key Lab Power Battery Safety;
Sch Chem;
Shenzhen Geim Graphene Ctr;
Peoples R;
Peoples R China|Tsinghua Univ;
Sch Mat Sci & Engn;
Tsinghua Univ;
South China Normal Univ;
Tsinghua Shenzhen Int Grad Sch;
关键词：
electrode;
high voltage applications;
dual-anion aggregation;
lithium-metal batteries;
Li;
(+) solvation;
electrolyte interfaces;
期刊名称：
Advanced Materials
i s s n：
0935-9648
年卷期：
2021 年
33 卷
52 期
页 码：
2007945.1-2007945.11
页 码：
摘 要：
Lithium (Li)-metal batteries (LMBs) with high-voltage cathodes and limited Li-metal anodes are crucial to realizing high-energy storage. However, functional electrolytes that are compatible with both high-voltage cathodes and Li anodes are required for their developments. In this study, the use of a moderate-concentration LiPF6 and LiNO3 dual-salt electrolyte composed of ester and ether co-solvents (fluoroethylene carbonate/dimethoxyethane, FEC/DME), which forms a unique Li+ solvation with aggregated dual anions, that is, PF6- and NO3-, is proposed to stabilize high-voltage LMBs. Mechanistic studies reveal that such a solvation sheath improves the Li plating/stripping kinetics and induces the generation of a solid electrolyte interphase (SEI) layer with gradient heterostructure and high Young's modulus on the anode, and a thin and robust cathode electrolyte interface (CEI) film. Therefore, this novel electrolyte enables colossal Li deposits with a high Coulombic efficiency (approximate to 98.9%) for 450 cycles at 0.5 mA cm(-2). The as-assembled Li parallel to LiNi0.85Co0.10Al0.05O2 full batteries deliver an excellent lifespan and capacity retention at 4.3 V with a rigid negative-to-positive capacity ratio. This electrolyte system with a dual-anion-aggregated solvation structure provides insights into the interfacial chemistries through solvation regulation for high-voltage LMBs.
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