Synergistic Effects of Bisalt Additives in High-Voltage Rechargeable Lithium Batteries

• Published in: ChemSusChem p. e202400636
• Main Authors: Pham, Thuy Duong, Kim, Junam, Oh, Hye Min, Kwak, Kyungwon, Lee, Kyung-Koo
• Format: Journal Article
• Language: English
• Published: Germany 10.07.2024
• Subjects: suppressing Li-dendrite; suppressing Al corrosion; bisalts; bisalts additive; high-voltage cathode; lithium secondary batteries; high-voltage; Al corrosion; additive
• ISSN: 1864-5631; 1864-564X; 1864-564X
• DOI: 10.1002/cssc.202400636

The stability of high-energy-density lithium metal batteries (LMBs) heavily relies on the composition of the solid electrolyte interphase (SEI) formed on lithium metal anodes. In this study, the inorganic-rich SEI layer was achieved by incorporating bisalts additives into carbonate-based electrolytes. Within this SEI layer, the presence of LiF, polythionate, and Li N was observed, generated by combining 1.0 м lithium bis(trifluoromethanesulfonyl)imide in ethylene carbonate: ethyl methyl carbonate:dimethyl carbonate in a 1 : 1 : 1 volume ratio, with the addition of 2 wt% lithium difluorophosphate and 2 wt% lithium difluoro(oxalato)borate additives (EL-DO). Furthermore, this formulation effectively mitigated corrosion of aluminum current collectors. EL-DO exhibited outstanding performance, including an average coulombic efficiency of 98.2 % in Li||Cu cells and a stable discharge capacity of approximately 162 mAh g after 200 cycles in a Li||LiNi Co Mn O (NCM811) configuration. Moreover, EL-DO displayed the potential to enhance the performance not only of LMBs but also of lithium-ion batteries. In the case of Gr||NCM811 cell using EL-DO, it consistently maintained high discharge capacities, even achieving around 135 mAh g after the 100 cycle, surpassing the performance of other electrolytes. This study underscores the synergistic impact of bisalts additives in elevating the performance of lithium batteries.