Abstract Electrochemical conversion reaction offers plenty of material options for high-capacity Na-ion battery anodes; however, the poor long-term cyclability is seriously blocking their practical utilization. In the present study, a new amino-terminated hyperbranched polyamide (AHP) is employed to construct a unique twin-daffodil shaped Cu2S anode for Na-ion batteries. First as a reaction template, the AHP regulates the formation of a special hierarchical twin-daffodil structure for Cu2S. Secondly and more importantly, the AHP acts as an additive remaining in the Cu2S, offering an elastic framework to prevent the nanograin aggregation and effectively enhanced the cycling stability. This Cu2S twin-daffodil shows a remarkable capacity of 370 mAh g−1 at 100 mA g−1 and a superior cyclability without obvious fading within 1000 cycles. Further investigation demonstrates fast solid-state Na+ diffusion kinetics in such Cu2S twin-daffodil, which leads to an outstanding rate capability of 170 mAh g−1 at 20 A g−1. This research not only provides a potential electrode for Na-ion batteries, but also introduces a new method to improve the performance of conversion materials for Na-ion batteries.

中文翻译：

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端氨基超支化聚酰胺调节 Cu2S 双水仙花，增强储钠性能

摘要 电化学转化反应为高容量钠离子电池负极提供了丰富的材料选择；然而，较差的长期循环性能严重阻碍了它们的实际应用。在本研究中，采用一种新的端氨基超支化聚酰胺 (AHP) 来构建独特的双水仙花状 Cu2S 负极，用于钠离子电池。首先作为反应模板，层次分析法调节了 Cu2S 特殊分层双水仙结构的形成。其次，更重要的是，AHP 作为残留在 Cu2S 中的添加剂，提供弹性框架以防止纳米颗粒聚集并有效提高循环稳定性。这种 Cu2S 双水仙花在 100 mA g-1 下显示出 370 mAh g-1 的显着容量和优异的循环性能，在 1000 次循环内没有明显褪色。进一步的研究表明，这种 Cu2S 双水仙花具有快速的固态 Na+ 扩散动力学，这导致在 20 A g-1 下具有 170 mAh g-1 的出色倍率能力。该研究不仅为钠离子电池提供了一种潜在的电极，而且为提高钠离子电池转换材料的性能引入了一种新方法。