硝酸铜作为锂电池电解液添加剂的国内外研究进展

摘要: 锂金属是高能量密度锂电池的理想负极材料，然而，锂枝晶的生长严重阻碍了其实际应用. 文章介绍了锂枝晶的主要生长模型（固态电解质膜保护生长模型、电荷诱导生长模型、薄膜生长模型等）、影响因素（温度、电流密度、电极过电位、固态电解质膜、沉积基底等）和先进表征技术（原位表征），并综述了近年来抑制锂枝晶生长的方法及研究进展（稳定沉积主体及表面修饰、固体电解质膜改性、使用高盐浓度和纳米化电解液、固体电解质等），最后，对锂金属电池的应用进行了评价和展望.

锂金属具有低的氧化还原电位(-3.04 V vs 标准氢电极)和高比容量(3860 mAh/g)，是理想的锂二次电池负极材料。由金属锂负极/固态电解质/嵌锂正极组装的固态锂电池，有望成为未来航空航天、机器人、高端电子和电动汽车等相关技术产业的动力源。然而，在充放电过程中，由于锂的不均匀沉积-溶解造成锂与电解质接触面产生大量树枝状枝晶，并沿着电解质方向不断生长，最终造成电池内部短路而失效。使用较高杨氏模量的固态电解质，可以很大程度上阻挡锂枝晶的生长，但仍不能满足电池长循环和安全性的要求。此外，金属锂与固态电解质表面是固固接触，造成了界面电阻大以及金属锂与固态电解质的界面反应等问题，这严重阻碍了固态锂金属电池的发展与使用。本文综述了近年来基于固态电解质的金属锂电池抑制锂枝晶生长和提高固固界面相容性的相关策略，并对金属锂/固态电解质界面设计的发展趋势进行展望。

Abstract Li-metal batteries (LMBs) have attracted increasing attention because of the high energy density and low reduction potential of lithium metal. However, lithium dendrites generated by the uneven Li deposition during cycling seriously threaten the safety of the battery and limit its commercial application. Herein, we propose a novel and facile strategy by adding Cu(NO3)2 additive in carbonate electrolyte, which effectively inhibits the growth of lithium dendrites and prolongs the lifespan of LMBs based on LiMn2O4 as 4 V class cathode. Due to the contribution of Cu(NO3)2, the solid electrolyte interphase (SEI) is rapidly and stably formed attaching on lithium metal without evident lithium dendrites. Moreover, Cu ions can also participate in the formation of cathode electrolyte interphase (CEI), effectively suppressing the decomposition of electrolyte and dissolution of Mn in LiMn2O4. The Li|LiMn2O4 cell with additive maintains the capacity retention of 87.26% and an average coulombic efficiency of 99.40% when approching 1000 cycles at ~1.2 mA cm−2. Our findings shed light on understanding the role of transiton metal nitrate additive for stabilizing LMBs with long lifespan.

… In this work, under the guidance of density functional theory (DFT) calculations, copper nitrate (Cu(NO 3 ) 2 ), a cheap and functional inorganic additive, was demonstrated a good …

While lithium metal is highly desired as a next-generation battery material due to its theoretically highest capacity and lowest electrode potential, its practical application has been impeded by stability issues such as dendrite formation and short cycle life. Ongoing research aims to enhance the stability of lithium metal batteries for commercialization. Among the studies, research on N-based electrolyte additives, which can stabilize the solid electrolyte interface (SEI) layer and provide stability to the lithium metal surface, holds great promise. The NO3− anion in the N-based electrolyte additive causes the SEI layer on the lithium metal surface to contain compounds such as Li3N and Li2O, which not only facilitates the conduction of Li+ ions in the SEI layer but also increases its mechanical strength. However, due to challenges with the solubility of N-based electrolyte additives in carbonate-based electrolytes, extensive research has been conducted on electrolytes based on ethers. Nonetheless, the low oxidative stability of ether-based electrolytes hinders their practical application. Hence, a strategy is needed to incorporate N-based electrolyte additives into carbonate-based electrolytes. In this review, we address the challenges of lithium metal batteries and propose practical approaches for the application and development of N-based electrolyte additives.

… coupling with ternary metal oxide cathode show high energy density. However, the drastic … stability of Li metal battery. Here, we propose a strategy of NO 3 − consumption and short-…

Metallic Li is the ultimate choice for the anode of lithium batteries. However, the adverse effect retards the commercialization of Li-metal batteries (LMBs). Herein, by using Cu(NO3)2 to regulate the solvation behavior of the ester-based electrolyte without fluoroethylene carbonate (FEC), the properties of Li|NCM811 are improved evidently. The solvation degree and oxidation stability of the electrolyte are increased. The solvated NO3- and marginalized PF6- promote the formation of an inorganic-rich solid electrolyte interphase (SEI) film on the anode, effectively protecting the lithium metal. The voltage decay and the dissolution of transition metals in the Li|NCM811 cell are significantly suppressed. The cell exhibits a capacity retention as high as 95.73% after 600 cycles at room temperature and outstanding cycle performance for wide temperatures (0 and 50 °C). The cell also shows impressive cycle performance even under rigorous conditions. Our research elucidates the role of Cu(NO3)2 from the perspective of the solvation behavior and provides a new strategy for the application of nitrates in ester-based electrolytes for LMBs.