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Lithium-ion intercalation and deintercalation behaviors of graphitized carbon nanospheres†
Journal of Materials Chemistry A ( IF 11.9 ) Pub Date : 2017-12-22 00:00:00 , DOI: 10.1039/c7ta07902h
Shohei Maruyama 1, 2, 3, 4 , Tomokazu Fukutsuka 1, 2, 3, 4, 5 , Kohei Miyazaki 1, 2, 3, 4, 5 , Yumi Abe 1, 2, 3, 4 , Noriko Yoshizawa 4, 6, 7 , Takeshi Abe 1, 2, 3, 4, 5
Affiliation  

As negative electrode materials for lithium-ion batteries, graphitized carbon nanospheres (GCNSs) exhibit excellent capacity retention and high-rate capability. GCNSs with diameters less than 1 μm possess core–shell structures with a low graphitized core and an outer graphitized shell arranged in a concentric orientation. In the present work, the structural changes in GCNSs with various sizes and heat-treatment temperatures during lithium-ion intercalation and deintercalation were examined. Charge–discharge measurements and in situ Raman spectroscopy were used to investigate the origin of the specific electrochemical properties of GCNSs. The results indicated that GCNSs with small sizes and low heat-treatment temperatures did not exhibit the formation of stages 4 and 3 during lithium-ion intercalation and deintercalation. In addition, phase transition between different stage structures was ambiguous. This behavior was related to the disordered stacking structures of the outer graphene layers. In addition to the decreased size that increased the specific surface area and reduced the lithium-ion diffusion length within a particle, the high-rate capability of GCNSs can be ascribed to the monotonous and moderate structural changes. The excellent capacity retention can also be attributed to the specific structure of GCNSs.

中文翻译:

石墨化碳纳米球的锂离子嵌入和脱嵌行为

石墨化碳纳米球(GCNSs)作为锂离子电池的负极材料,具有出色的容量保持率和高倍率容量。直径小于1μm的GCNS具有核壳结构,其石墨化度低,而外部石墨化壳呈同心排列。在本工作中,研究了在锂离子嵌入和脱嵌过程中,各种尺寸和热处理温度的GCNS的结构变化。充放电测量和原位拉曼光谱用于研究GCNSs特定电化学性质的起源。结果表明,具有较小尺寸和较低热处理温度的GCNS在锂离子嵌入和脱嵌过程中未显示出阶段4和3的形成。另外,不同阶段结构之间的相变是模棱两可的。此行为与外部石墨烯层的无序堆叠结构有关。除了减小尺寸以增加比表面积并减小颗粒内的锂离子扩散长度外,GCNS的高速率能力还可以归因于单调和适度的结构变化。出色的容量保持能力还可以归因于GCNS的特定结构。
更新日期:2017-12-22
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