Chen Xiaoyang, Fang Youlong, Tian Jiyu, Lu Haiyan, Ai Xinping, Yang Hanxi, Cao Yuliang
Engineering Research Center of Organosilicon Compounds & Materials of Ministry of Education, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China.
ACS Appl Mater Interfaces. 2021 Apr 28;13(16):18914-18922. doi: 10.1021/acsami.1c03748. Epub 2021 Apr 16.
Hard carbon (HC) has been actively investigated as a high-capacity and low-cost anode material for sodium-ion batteries (SIBs); however, its sodium-storage mechanism has remained controversial, which imposes great difficulties in the design and construction of better microstructured HC materials. To obtain a deeper understanding of the Na-storage mechanism, we comparatively investigated electrochemical behaviors of HC and graphite for Na- and Li-storage reactions. The experimental results reveal that the Na-storage reaction on HC at a low-potential plateau proceeds in a manner similar to the Li-insertion reaction on graphite but very differently from the Li-storage process on HC, suggesting that the Na-storage mechanism of HC at a low-voltage plateau operates through the Na intercalation into the graphitic layers for the formation of sodium-graphite intercalation compounds (Na-GICs) and is consistent with the "adsorption-intercalation" mechanism. Our work might provide new insight for designing better HC materials of high-energy density SIBs.
硬碳（HC）作为一种用于钠离子电池（SIB）的高容量、低成本负极材料，已受到广泛研究；然而，其储钠机制仍存在争议，这给设计和构建更优微观结构的硬碳材料带来了巨大困难。为了更深入地理解储钠机制，我们对比研究了硬碳和石墨在储钠和储锂反应中的电化学行为。实验结果表明，硬碳在低电位平台上的储钠反应与石墨上的锂嵌入反应方式相似，但与硬碳上的储锂过程有很大不同，这表明硬碳在低电压平台上的储钠机制是通过钠嵌入石墨层形成钠 - 石墨层间化合物（Na - GICs）来实现的，这与“吸附 - 嵌入”机制一致。我们的工作可能为设计具有高能量密度的钠离子电池的更优硬碳材料提供新的见解。
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