(A) study on the improvement in stability of lithium metal anode via Li3N-rich interphase in carbonate-based electrolytes

Abstract

Full cell using lithium cobalt oxide (LCO) cathode with an AgNO3/PAN interlayer shows an excellent capacity retention of 85.8% with a high Coulombic efficiency (CE) of 99.6% after 100 charge-discharge cycles (@0.54 C). 2. Lithium nitrate is a widely used additive in LMBs, recently, researchers have shifted their focus to other nitrates. Many agree that NO3- involve in Li+ solvation structure and participate in N-rich SEI formation. However, the effect of cations remains to be explored, especially in carbonate-based electrolyte with very limited solubility. Here, we compare the electrochemical performance of different metal nitrate additives (LiNO3, AgNO3, RbNO3) and their role in SEI formation. The experimental results indicate that the cell with AgNO3 has thin Li deposition layer and anion derived SEI. The cell with RbNO3 has limited capacity due to saturation of Rb ions. Among the metal nitrate additives, LiNO3 additive has the longest cycle life. By optimizing the ratio of different metal nitrate additives, the cycle stability of Li metal anode has been improved.

1) utilizing AgNO3 as an electrolyte additive in carbonated-based electrolyte using polyacrylonitrile nanofiber support to enhance Li deposition morphology and SEI stability, 2) enhancing electrochemical performance of Li metal anode through different metal nitrate additives and understanding sustainable release mechanism of the additives. 1. Li dendrite formation increases irreversible Li reaction with electrolyte and decreases Coulombic efficiency of the cell. Unstable SEI layer by reduction of carbonate-based electrolyte deteriorates the problem and limit cycle life of Li metal anodes. In order to address these issues, we adopted AgNO3-containing polyacrylonitrile (PAN) interlayer to prevent dendrite formation and enhance SEI stability. The strategy to support AgNO3 on PAN overcome the solubility limitation of AgNO3 in carbonate-based electrolytes. Slowly released Ag+ reduce on Li surface acting as a nucleation seed and induce uniform Li deposition. At the same time, NO3- react with Li to form Li3N-rich SEI. Li metal anode with AgNO3/PAN shows excellent Li plating morphology and electrochemical performance

The conventional lithium-ion batteries (LIBs) have long relied on graphite anodes and transition metal oxide cathodes since their initial commercialization. However, the persistent demand for higher energy density has highlighted the intrinsic limitations of these electrode materials. Graphite, as a dependable anode material, faces capacity constraints, necessitating the exploration of alternatives to meet escalating energy storage needs. Simultaneously, transition metal oxide cathodes, while effective, encounter challenges related to energy density and overall performance. To address these limitations, ongoing research endeavors focus on innovating new electrode materials capable of surpassing existing constraints and pushing the boundaries of energy density. This pursuit is crucial to meet the evolving requirements of applications such as electric vehicles and portable electronic devices, propelling the exploration of advanced electrode materials beyond conventional graphite anodes and transition metal oxide cathodes. The lithium (Li) metal anode is considered as a critical constituent in advanced electrochemical energy storage systems. Despite its inherent attributes of high theoretical capacity and low electrode potential, the practical application of Li metal anode confronts formidable impediments, prominently stemming from challenges associated with irreversible reaction with electrolyte and dendritic growth of Li. To overcome these challenges, a careful electrolyte design is necessary to create stable solid electrolyte interphase (SEI) and to control morphology of Li deposition. In this study, different types of additives are adopted based on following strategies