Enhancing the performance of LiNi0.8Mn0.1Co0.1O2-based pouch cells through advanced electrolyte additive systems for high-temperature lithium-ion batteries

• Published in: Journal of power sources 2024-12, Vol.623, p.235470, Article 235470
• Main Authors: Tesatchabut, Panpanat, Muangkasem, Panida, Kunanusont, Nattanai, Limthongkul, Pimpa, Eiamlamai, Priew
• Format: Article
• Language: English
• Subjects: Electrolyte additive; Lithium difluorophosphate; Lithium-ion batteries; NMC811; p-Toluenesulfonyl isocyanate; Structural stability
• ISSN: 0378-7753
• DOI: 10.1016/j.jpowsour.2024.235470

Next-generation lithium-ion batteries, which achieve high energy densities and prolonged cycle performance, require cathode materials with high operating voltages and specific capacities. Because of their high capacity and operating voltage, nickel-rich layered oxides like LiNi0.8Mn0.1Co0.1O2 (NMC811) are attractive cathodes; nevertheless, they have drawbacks such capacity loss, poor cycle performance, structural instability, and thermal instability. Enhancing the stability of the NMC811 cathode-electrolyte interphase demands improvements in both cathode materials and electrolytes. This study explores the enhancement of NMC811-based battery systems through electrolyte modification, focusing on mixed additive combinations to evaluate their synergistic effects at elevated temperatures, relevant for tropical climates. A ternary additive system comprising vinylene carbonate (VC), lithium difluorophosphate (LiPO2F2), and p-toluenesulfonyl isocyanate (PTSI) in a LiPF6-based electrolyte showed significant improvements. This system mitigated capacity fading for cells cycled over 3 V–4.2 V at both 25 °C and 45 °C, outperforming the baseline electrolyte. The designed electrolyte stabilized the electrode-electrolyte interface, enhancing cell performance and the cathode's structural integrity. Notably, the graphite/NMC811 pouch cell's cycling performance showed an increase in capacity retention from 82.4% to 90.2% after 150 cycles at C/2 at 45 °C. Moreover, the deactivation of PF5 by PTSI can help to suppress the side reaction from the instability of LiPF6-based electrolytes, especially at elevated temperatures. These findings carried out from this strategic electrolyte additive system can substantially improve nickel-rich LIBs, especially in challenging thermal environments. •Ternary additive system improves elevated temperature cycling of NMC811/graphite cell.•CEI film formed by designed additive combination reduces cracking of NMC cathodes.•PTSI incorporation enhances the thermal stability of LiPF6-based electrolytes.