激进的
离子
电子顺磁共振
钠
光谱学
碳纤维
类金刚石
化学
纳米技术
化学工程
材料科学
分子
有机化学
核磁共振
工程类
复合材料
量子力学
复合数
物理
作者
Bin Wang,Yazhen Yao,Wanli Wang,Yang Xu,Yi Wan,Yi Sun,Qiang Li,Han Hu,Mingbo Wu
标识
DOI:10.1016/j.jcis.2024.03.068
摘要
Hard carbon (HC) has emerged as a highly promising anode material for sodium ion batteries, drawing tremendous interest in producing this material with low-cost and easily accessible precursors. The determination of the crucial parameters of precursors influencing the formation of key structures, such as closed pores, in the HC is of paramount importance. Considering the potential role of free radicals in the structural evolution of the precursors, we, for the first time, delve into the impact of radical species on the development of closed pores by electron paramagnetic resonance spectroscopy, with petroleum asphalt as the model system. Our findings reveal that carbon centred radicals, with the g value close to that of the free electron (2.0023), exhibit a propensity to form long-range, well-ordered graphitic structures with lower sodium storage capacity. Conversely, the deliberately incorporated oxygen radicals with the g value over 2.005 require a higher energy for ordering the graphitic structures, leading to the creation of closed pores. As a result, the optimal sample showcases a four-fold increase in plateau capacity for sodium ion storage due to the pore filling process. Our research underscores the pivotal role of employing electron paramagnetic resonance spectroscopy studying the critical structural evolution of functional carbon materials.
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