Enhanced Interphase Stability and Longevity of Sodium-Ion Pouch Cells by Compound Additive Engineering

作者：Yalong Wen, Jingkai Gao, Lei Xu, Simin Li, Bowen Zhu, Zhiyuan Cheng, Jiahao Xing, Linlin Wu, Jie Li, Zhian Zhang, Yanqing Lai · 发表于：ACS Applied Energy Materials · 年份：2025 · DOI：10.1021/acsaem.5c01236 · 被引用次数：7 · 研究领域：Advancements in Battery Materials、Advanced Battery Materials and Technologies、Advanced Battery Technologies Research

Sodium-ion batteries (SIBs) have emerged as promising candidates for energy storage applications due to the abundant availability and low cost of sodium resources. However, the instability of the electrolyte–electrode interphase in pouch cells remains a significant challenge, negatively impacting the cycle life and overall performance of the batteries. In this study, we address this issue by developing a compound electrolyte additive system, which includes inorganic sodium salt additives, like sodium bis(fluorosulfonyl)imide (NaFSI), sodium difluorophosphate (NaDFP), and sodium difluoro(oxalate)borate (NaDFOB), combined with the organic ester additive vinylidene carbonate (VC). This system promotes the preferential reduction of additives on the anode and oxidation on the cathode, leading to the formation of uniform, dense, and ultrathin solid electrolyte interphase (SEI) and cathode electrolyte interphase (CEI) layers enriched with inorganic components. To assess the effectiveness of these additives, a 2.6 Ah Na x Cu 0.11 Ni 0.11 Fe 0.3 Mn 0.48 O 2 (CNFM)/hard carbon (HC) sodium-ion pouch cell is assembled. The cell demonstrates remarkable performance when using the compound additive electrolyte, achieving 84% capacity retention after 150 cycles at 25 °C, which is a significant improvement compared to the 57% retention observed in the baseline electrolyte without additives. Additionally, the additive system effectively mitigates cathode transition metal dissolution and anode ...