NMR Spectroscopic Investigation of LiNO3 - Induced SEI Modification in Li-S Batteries: A Concentration-Dependent Study

The growing demand for sustainable energy has intensified efforts to develop safer, high-performance batteries. Lithium metal offers exceptional energy density but is limited by safety concerns and short cycle life. Electrolyte additives such as LiNO3 are known to enhance battery performance, yet their specific mechanism remains unclear. Nuclear magnetic resonance (NMR) spectroscopy provides a powerful and non-destructive means to probe Li metal batteries, offering a unique insight into the Li species and interfacial processes. Among the different NMR methods, operando 7Li NMR measurements of the Li-S battery enable time-resolved and quantitative monitoring of electrochemical Li metal deposition, thereby linking electrochemical performance to changes in the metallic Li environment. In this work, we systematically investigate the influence of LiNO3 concentration in the ubiquitous Li-S electrolyte, a 1 M LiTFSI DOL:DME, using a combination of operando 7Li NMR and ex situ SEM to elucidate its influence on anode performance and interfacial processes. This data collection includes the operando 7Li NMR data and corresponding SEM data.