Modification of Nitrate Ion Enables Stable Solid Electrolyte Interphase in Lithium Metal Batteries

Abstract

The lifespan of high‐energy‐density lithium metal batteries (LMBs) is hindered by heterogeneous solid electrolyte interphase (SEI). The rational design of electrolytes is strongly considered to obtain uniform SEI in working batteries. Herein, a modification of nitrate ion (NO3−) is proposed and validated to improve the homogeneity of the SEI in practical LMBs. NO3− is connected to an ether‐based moiety to form isosorbide dinitrate (ISDN) to break the resonance structure of NO3− and improve the reducibility. The decomposition of non‐resonant −NO3 in ISDN enriches SEI with abundant LiNxOy and induces uniform lithium deposition. Lithium–sulfur batteries with ISDN additives deliver a capacity retention of 83.7 % for 100 cycles compared with rapid decay with LiNO3 after 55 cycles. Moreover, lithium–sulfur pouch cells with ISDN additives provide a specific energy of 319 Wh kg−1 and undergo 20 cycles. This work provides a realistic reference in designing additives to modify the SEI for stabilizing LMBs.

Revealing Lithium Nitrate-Mediated Solid-Electrolyte Interphase of Lithium Metal Anode via Cryogenic Transmission Electron Microscopy

“…36,37 In combined consideration of the strong oxidation of NO 3 − , LiNO 3 decomposition would take precedence over salt and solvent decomposition. 16,38 This explains why all the SEI layers have an interior Li 2 O-rich region. Though crystalline Li 3 N and partial reduction products such as LiNO 2 are not found, their existence and distribution are reflected from sharp contrasts of N maps (Figure S8).…”

Comonomer-Tuned Gel Electrolyte Enables Ultralong Cycle Life of Solid-State Lithium Metal Batteries

“…SSEs can eliminate the leakage concerns of flammable organic liquid electrolytes. In addition, SSEs generally have a large electrochemical window which enables the use of Li metal anodes and high-voltage cathodes, contributing to a high energy density of the energy storage system. − Despite these beneficial characteristics, the practical application of SSEs is confronted with several obstacles. As a group of SSEs with high ionic conductivity (10 –2 –10 –4 S cm –1 ), most inorganic SSEs have interphase contacting problems between the electrolyte and Li metal, a high tendency to fracture, and a high reactivity against Li .…”