Enhancing electrochemical properties of PNb9O25 anodes at elevated temperature via surface modification by nitrogen-doped carbon

• Published in: Journal of power sources 2025-02, Vol.629, p.235969, Article 235969
• Main Authors: Liu, Xinghua, Li, Jinsong, Wang, Shuyu, Diao, Xungang, Zhao, Lijiang, Zhang, Junying
• Format: Article
• Language: English
• Subjects: Cycling stability; High operating temperature; Lithium-ion batteries; Nitrogen-doped carbon; PNb9O25; Surface chemical reactivity
• ISSN: 0378-7753
• DOI: 10.1016/j.jpowsour.2024.235969

Improving the performance of electrode materials is a crucial step for enhancing the intrinsic safety of batteries, especially during high operating temperature conditions and rapid charge/discharge processes. The aggravation of side reactions caused by electro-thermal behaviors especially at high operating temperature is the main factor causing the instability of surface structure. In this work, we focus on the titanium-free, coarse-grained PNb9O25 (PNO) anode and enhance its electrochemical performance at an elevated temperature of 45 °C using a nitrogen-doped carbon (N-C) surface modification strategy. The homogeneous N-C passivation layer provides favorable electronic conductivity and fast Li+ diffusion kinetics, significantly reducing chemical reactivity and improving the interfacial charge transfer capability. As a result, PNO@N-C demonstrates exceptional high-rate capacity retention (249 mAh g−1 at 0.1 A g−1 and 173 mAh g−1 at 6 A g−1 under 45 °C) and superior cycling stability, maintaining a high capacity of 147 mAh g−1 after 1000 rapid charging cycles at a current density of 4 A g−1 (∼20 C, 45 °C). This approach provides a practical strategy for further development of electrode materials for high-rate lithium-ion batteries operating at high temperatures. Structural engineering is a crucial step to enhance the safety and electrochemical performance of electrode materials, especially during high operating temperature and rapid charge/discharge processes. Here, we develope a titanate-free, coarse-grained anode (PNb9O25) modified with N-C layer to overcome the catalyst issue of the interface at high operating temperature (45 °C). The N-C passivation layer significantly reduced the chemical reactivity and improved interfacial charge transfer process, leading to elevated electrochemical properties. [Display omitted] •A N-C passivation layer has been cocated on PNO surface.•The N-C layer reduces chemical reactivity and improves interfacial charge transfer.•The PNO@N-C anode shows higer electrochemical performance than PNO at 45 °C.