In a significant stride towards advancing large-scale energy storage solutions, researchers have unveiled a comprehensive study on the failure mechanisms of high-performance, large-format prismatic sodium-ion batteries. The research, led by Yinglai Wang from the College of Materials Science and Technology at Nanjing University of Aeronautics and Astronautics and the Lithium Battery Research Institute at Narada Power Source Co., Ltd., was recently published in the journal “Next Materials” (translated to English).
The study focuses on the O3-NaNi1/3Fe1/3Mn1/3O2 (NFM) layered oxide cathode/hard carbon anode system, which demonstrates impressive electrochemical performance. The battery maintains a remarkable 98.07% coulombic efficiency during charge-discharge cycling and retains 75.45% of its capacity at a high discharge rate of 5C. Even at freezing temperatures of -30°C, the battery retains 84.79% of its capacity, and after 1502 cycles at room temperature, it still holds 85.45% of its initial capacity.
However, the battery’s performance significantly degrades under high-temperature and high-rate accelerated cycling conditions, with a capacity retention rate of only 77.6% over 111 cycles at 2C/2C. To understand these limitations, the researchers conducted a thorough analysis of the battery’s microscopic morphology, structure, impedance, and elemental composition at both the beginning and end of its life.
“We employed a range of techniques, including SEM, XRD, EIS, and ICP, to characterize the electrodes,” Wang explained. “Additionally, we analyzed the residual gas at the end of life using GC-MS to gain insights into the failure mechanisms.”
The findings reveal that the NFM single-crystal undergoes cracking and dissolution of transition metal ions, while the anode experiences cracking and exfoliation. Sodium precipitation, along with the degradation of the solid electrolyte interphase (SEI) and cathode electrolyte interphase (CEI) layers, and ongoing adverse side reactions with the electrolyte, collectively contribute to the battery’s cycle failure.
This research holds substantial implications for the energy sector, particularly in the development of large-scale energy storage systems. Sodium-ion batteries offer a promising alternative to lithium-ion batteries due to their lower cost, abundance of raw materials, and improved safety. Understanding the failure mechanisms of these batteries is crucial for enhancing their performance and longevity, ultimately driving the adoption of renewable energy sources.
As the world transitions towards cleaner energy solutions, the insights gained from this study could pave the way for more robust and efficient sodium-ion batteries. “Our findings provide a roadmap for optimizing the design and manufacturing of sodium-ion batteries, ensuring their reliability and performance in real-world applications,” Wang stated.
The research published in “Next Materials” not only advances our understanding of sodium-ion battery technology but also underscores the importance of continued innovation in the field. As the energy sector evolves, such breakthroughs will be instrumental in shaping a sustainable and resilient energy future.