Introducing NO3- into Carbonate-Based Electrolytes via Covalent Organic Framework to Incubate Stable Interface for Li-Metal Batteries

作者：Wen, Yucheng; Ding, Jieying; Yang, Yan; Lan, Xuexia; Liu, Jun; Hu, Renzong^*; Zhu, Min

来源：Advanced Functional Materials, 2022, 32(15): 2109377.

DOI：10.1002/adfm.202109377

• covalent organic framework
• high voltage cathode
• Li metal anode
• lithium nitrate

Lithium nitrate (LiNO3) as an effective additive to construct stable solid electrolyte interface (SEI) is generally applied in ether-based electrolytes, but its poor solubility in carbonate-based electrolytes limits further application for Li metal batteries (LMBs). Therefore, an engineering of introducing NO3- into carbonate-based electrolytes by synthesizing targeted covalent organic framework (EB-COF:NO3) to modify Li anode for incubating a reliable SEI is reported. Its unique structure not only facilitates the desolvation process of lithium ions (Li+) to accelerate the transport of Li+, but also releases NO3- to form beneficial Li3N, LiNxOy species to in situ construct a stable SEI. With the application of EB-COF:NO3, the cycling and rate performance of (50 mu m) Li//LiFePO4 full cell is comprehensively improved under the conditions of poor electrolyte and high loading, significantly increasing capacity retention from 14% to 94% after 200 cycles. And the high voltage Li//LiNi0.5Mn1.5O4 full cell still demonstrates excellent cycling stability with the capacity retention of 92% after 600 cycles. Accordingly, this strategy shares a prospect for the application of covalent organic frameworks (COFs) to build a stable SEI for high-energy-density LMBs, and also broadens the application of LiNO3 in carbonate-based electrolytes.