A synergistic duo for enhanced cathode stability in high-voltage lithium-ion batteries

Abstract

Lithium-ion batteries with high-nickel cathode materials are promising candidates for achieving significantly higher energy densities. However, when Ni-rich subjected to higher charging cutoff voltages accelerates both electrolyte decomposition and structural degradation, leading to compromised cycling stability and reduced lifespan. In this study, we have developed a dual-additive strategy using lithium difluoro bisoxalate phosphate (LiDFBOP), and 1,3-divinyl-1,1,3,3-tetramethyldisilazane (DTDS) to address these challenges and improve the battery's performance. Theoretical calculations and experimental results indicate that the LiDFBOP regulates Li⁺ solvation for robust CEI formation, while DTDS scavenges impurities and promotes the formation of an inorganic/organic interphase. The synergistic effect of these additives combination allows Li||NCM811 coin cell to retain a capacity retention 87.9 % at 4.6 V and Graphite||NCM811full cell achieved 90.5 % capacity retention at 4.5 V. Moreover, the 1Ah pouch full cells exhibit excellent cycling stability, with a capacity retention of 91.4 % after 610 cycles at a constant current of 500 mA and voltage of 4.5 V. This work offers guidance on designing multifunctional additives to achieve synergistic electrolyte engineering for high-energy lithium-ion batteries.