Lithium nitrate (LiNO3) is often used in ether-based electrolytes as an effective additive for constructing stable solid-state electrolyte interfaces (SEIs), but its poor solubility in carbonate-based electrolytes limits the further application of lithium metal batteries (LMBs). Hu Renzong, South China University of TechnologyBy synthesizing a target covalent organic framework (EB-COF: NO3), NO3 was introduced into a carbonate-based electrolyte to modify the lithium anode to form a reliable SEI.
Fig.1 Schematic diagram of the synthesis and application of EB-COF:NO3
EB-Cof:NO3 synthesized from 1,3,5-tricarboxylresorcinol (TFP), ethidium bromide (EB), and LiNO3 can modify LIs and be used in situ cultivation of SEIs to stabilize the interface between LIs and electrolytes. This potent improvement is attributed to the purposeful composition of EB-COF:NO3, in which the desolvation process of Li+ is accelerated, as Li+ exhibits stronger ionic interactions with NO3- than the solvated sheath, while positively charged channels immobilize anion clusters. In addition, the released NO3- is involved in the construction of Li3N- and Linxoy-rich ideal SEIs to inhibit lithium dendrites and protect lithium anodes.
Fig.2 Theoretical calculation and electrochemical characterization of EB-COF:NO3 to improve the performance of lithium anode
Therefore, with the application of EB-CoF:NO3, the cycling and rate performance of (50 m) Li LiFePO4 whole battery under poor electrolyte and high load conditions have been comprehensively improved, and the capacity retention rate of 200 cycles has been significantly increased from 14% to 94%. And the high-voltage LI whole battery fluid exhibits excellent cycling stability, with a capacity retention rate of 92% after 600 cycles. This method can provide enlightening insights into the application of LiNO3 to carbonate-based electrolytes and the construction of SEIs by COFS for use in high-energy-density LMBS libs.
Figure 3 Full battery performance
introducing no3– into carbonate-based electrolytes via covalent organic framework to incubate stable interface for li-metal batteries. advanced functional materials 2021. doi: 10.1002/adfm.202109377