Yolk-shell nanoarchitecture for stabilizing a Ce2S3 anode
Yolk-shell nanoarchitecture for stabilizing a Ce2S3 anode
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DOI：
10.1002/cey2.130
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发表时间：
2021-07-15
期刊：
影响因子：
20.5
通讯作者：
Tang, Mingxue
中科院分区：
文献类型：
--
作者：
Hui, Kanglong;Fu, Jipeng;Tang, Mingxue
稀土硫化物因其丰富的锂嵌锂中心和较低的氧化还原电压而成为锂离子电池的研究热点。然而，由于它们在电化学循环过程中导电性差、体积变化大，其电化学性能并不理想。本文采用自模板法制备了空心介孔碳纳米球(Ce2S3@HMCS)中包裹的γ-Ce2S3纳米结构，并将其作为LiB阳极进行了测试。Ce2S3核和碳纳米球外层之间的空隙经过适当的设计和调制，在电子导电性、可逆性和倍率能力方面获得了优异的电化学性能。Ce2S3@HMCS的可逆容量是纯Ce2S3阳极的2.6倍，在1A.g(-1)的电流密度下可以逐渐增加并保持282mAh.g(-1)的容量，即使在1000次循环后也可以获得高的库仑效率(接近100%)。这一良好的性能归功于独特的蛋黄壳纳米结构，具有高度结晶和稳定的Ce3S2核心，以及锂/脱锂后的体积膨胀缓冲空间。非原位X射线衍射和核磁共振结果表明，Ce2S3@HMCS的嵌锂过程为插层过程。这项研究代表了球内硫化精密结构设计的重要进展，并揭示了高性能锂存储的潜在方向。
Rare-earth sulfides are of research interest for lithium-ion batteries (LIBs) due to their abundant lithium intercalation sites and low redox voltage. However, their electrochemical performances are not satisfactory because of poor conductivity and volume change upon electrochemical cycling. Herein, nanoarchitectures of gamma-Ce2S3 encapsulated in a hollow mesoporous carbon nanosphere (Ce2S3@HMCS) are fabricated using the self-template strategy combined with the in-sphere sulfuration method and tested as an LIB anode. The void space between the Ce2S3 core and the outer layer of the carbon nanosphere has been properly designed and modulated to achieve excellent electrochemical performance in terms of electronic conductivity, reversibility, and rate capability. The reversible capacity of Ce2S3@HMCS is 2.6 times that of the pure Ce2S3 anode, which can gradually increase and maintain a capacity of 282 mAh.g(-1) at a current density of 1 A.g(-1), and a high Coulombic efficiency (similar to 100%) can be achieved even after 1000 cycles. This good performance is attributed to the unique yolk-shell nanostructure with a highly crystallized and stable Ce3S2 core and volume expansion buffer space upon lithiation/delithiation. Ex situ X-ray diffraction and nuclear magnetic resonance results indicate that the lithiation of Ce2S3@HMCS is an intercalation process. This study represents an important advancement in precise structural design with in-sphere sulfuration and sheds light on a potential direction for high-performance lithium storage.