Lithium Azide as an Electrolyte Additive for All‐Solid‐State Lithium–Sulfur Batteries

Abstract

Of the various beyond-lithium-ion battery technologies, lithium-sulfur (Li-S) batteries have an appealing theoretical energy density and are being intensely investigated as next-generation rechargeable lithium-metal batteries. However, the stability of the lithium-metal (Li°) anode is among the most urgent challenges that need to be addressed to ensure the long-term stability of Li-S batteries. Herein, we report lithium azide (LiN ) as a novel electrolyte additive for all-solid-state Li-S batteries (ASSLSBs). It results in the formation of a thin, compact and highly conductive passivation layer on the Li° anode, thereby avoiding dendrite formation, and polysulfide shuttling. It greatly enhances the cycling performance, Coulombic and energy efficiencies of ASSLSBs, outperforming the state-of-the-art additive lithium nitrate (LiNO ).

Understanding the Role of Nano‐Aluminum Oxide in All‐Solid‐State Lithium‐Sulfur Batteries

“…Despite the significant improvement on the Li anode/electrolyte interface by the addition of Al 2 O 3 has been demonstrated, it is still necessary to understand its interaction with PS in pursuit of its practical application Li−S cells. Figure b shows visual experiments where Al 2 O 3 nano‐particles added to a Li 2 S 6 containing 1,2‐dimethoxyethane (DME, with an analogous chemical structure to PEO) solution. The mixture was stirred 1 h prior removing of solid particles by centrifugation.…”

Key Aspects of Lithium Metal Anodes for Lithium Metal Batteries

“…[20,[22][23][24] For these reasons almost all electrolytes, including solid electrolytes, undergo decomposition as soon they come in contact with Li resulting in a variety of reduction products (Figure 3). [25][26][27][28][29] The extremely high reactivity of Li anode has been spectroscopically confirmed by Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and energy dispersive spectroscopy (EDS) measurements, [25,30] and electrochemically observed with the help of chronopotentiometry, chronoamperometry, cyclic voltammetry, electrochemical quartz crystal microbalance (EQCM), galvanostatic/potentiostatic intermittent titrations (GITT, PITT), and electrochemical impedance spectroscopy (EIS). [25,[31][32][33][34][35] The reactivity of Li anode has also been theoretically confirmed.…”

“…b) Schematic of the interaction of the Li surface with Li salts (e.g., LiTFSI, LiFSI) and additives (LiN 3 /LiNO 3 ) in DME solvent. Reproduced with permission . Copyright 2017, Wiley‐VCH.…”

“…[25,[31][32][33][34][35] The reactivity of Li anode has also been theoretically confirmed. [36][37][38] It has been found that the electrolyte salts ( Figure 3a) [29] and additives ( Figure 3b) [28] are repeatedly reduced/precipitated on the Li surface from solution. [39][40][41][42] Some of the aprotic salts, such as LiBF 4 , LiPF 6 , LiN(SO 2 CF 3 ) 2 , and LiSO 3 CF 3 are moisture sensitive and produce HF as the hydrolysis product due to the presence of trace moisture in the electrolyte solvents, which immediately react with Li metal anode until the electrolyte is vanished.…”

Structural Design of Lithium–Sulfur Batteries: From Fundamental Research to Practical Application

“…Preliminary research has developed a variety of polymers such as PEO, PEMO, and PEGDME and investigate the electrochemical performance with these SSEs in Li-S batteries [359,[402][403][404][405][406][407]. Furthermore, novel polymer electrolytes with nanostructure design, improved ionic conductivity and advanced characterizations were also conducted [396,408,409]. Many polymer electrolytes possess significant advantages in flexibility and chemical compatibility that are unrivaled by other SSEs.…”