Nitrile High Salt Concentration Electrolyte Promotes The Development Of High Specific Energy Lithium Metal Batteries

Recently, Recently, a research result published in the journal "Advanced Functional Materials" shows that scientists have  developed a nitrile electrolyte with high salt concentration for high specific energy lithium metal batteries firstly. 

Nitrile organics are a type of electrolyte system that has the advantages of high potential window, non-flammability, high flash point, wide liquid range, and low gas production. It has been widely used in supercapacitors, but due to the gap between the nitrile electrolyte and the metal lithium anode The inability to form an effective SEI film limits the application of nitrile solvents as electrolytes in lithium metal batteries.

In order to break through this limitation, many researchers have hoped to introduce a variety of lithium salts into the electrolyte system to adjust the composition of anions in the lithium salt and the concentration of lithium ions to form an effective SEI at the interface of the lithium metal anode and pass the high concentration Ion restricts the direct contact of free nitrile organics with lithium salts to obtain a highly safe electrolyte that is stable to lithium metal and does not contain traditional carbonate solvents.

In this study, the researchers proposed the use of basic film-forming additives, vinylene carbonate combined with the strong coordination effect of lithium salts and solvents in high-salt concentration systems, and prepared an optimization through the influence of salt concentration adjustment on the reduction process Acetonitrile high salt concentration electrolyte system (LiFSI: AN: VC, LAV system), and finally formed a stable interface film based on the crosslinking of polycarbonate and lithium fluoride on the surface of lithium metal.

This high-salt concentration electrolyte not only combines the high oxidation stability of the nitrile solvent, but also has a coulombic efficiency of more than 99.2% for lithium metal. It also has excellent high-current performance and a current density of 4 mAcm-2 To achieve dense lithium metal deposition.

The use of nitrile high-salt electrolyte can achieve a stable cycle of high-load (2 mAh cm-2 or more) 4.5 V lithium metal batteries, which is very important for the safe use of lithium metal anodes and the development of high specific energy Li metal batteries Meaning.

References:

Peng Zhe, Cao Xia, Gao Peiyuan, Jia Haiping, Ren Xiaodi, Swadip Roy, Li Zhendong, Zhu Yun, Xie Weiping, Liu Dianying, Li Qiuyan, Wang Deyu, * Wu Xu * and Zhang Jiguang * through high concentrations of acetonitrile High-power lithium metal battery realized by electrolyte and vinylene carbonate additives. Advanced function alma mater 2020, 2001285. DOI: 10.1002 / adfm.202001285