Elucidating the Mechanism of Fast Na Storage Kinetics in Ether Electrolytes for Hard Carbon Anodes,Advanced Materials

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Elucidating the Mechanism of Fast Na Storage Kinetics in Ether Electrolytes for Hard Carbon Anodes
Advanced Materials ( IF 27.4 ) Pub Date : 2021-07-30 , DOI: 10.1002/adma.202008810
Ruiqi Dong ₁ , Lumin Zheng ₁ , Ying Bai ₁ , Qiao Ni ₁ , Yu Li ₁ , Feng Wu _{1,

2} , Haixia Ren ₁ , Chuan Wu _{1,

2}

Affiliation

The sodium storage performance of a hard carbon (HC) anode in ether electrolytes exhibits a higher initial Coulombic efficiency (ICE) and better rate performance compared to conventional ester electrolytes. However, the mechanism behind faster Na storage kinetics for HC in ether electrolytes remains unclear. Herein, a unique solvated Na⁺ and Na⁺ co-intercalation mechanism in ether electrolytes is reported using designed monodispersed HC nanospheres. In addition, a thin solid electrolyte interphase film with a high inorganic proportion formed in an ether electrolyte is visualized by cryo transmission electron microscopy and depth-profiling X-ray photoelectron spectroscopy, which facilitates Na⁺ transportation, and results in a high ICE. Furthermore, the fast solvated Na⁺ diffusion kinetics in ether electrolytes are also revealed via molecular dynamics simulation. Owing to the contribution of the ether electrolytes, an excellent rate performance (214 mAh g⁻¹ at 10 A g⁻¹ with an ultrahigh plateau capacity of 120 mAh g⁻¹) and a high ICE (84.93% at 1 A g⁻¹) are observed in a half cell; in a full cell, an attractive specific capacity of 110.3 mAh g⁻¹ is achieved after 1000 cycles at 1 A g⁻¹.

中文翻译：

阐明硬碳阳极醚电解质中快速储钠动力学的机制

与传统的酯电解质相比，硬碳 (HC) 阳极在醚电解质中的储钠性能表现出更高的初始库仑效率 (ICE) 和更好的倍率性能。然而，醚电解质中 HC 更快的 Na 储存动力学背后的机制尚不清楚。在此，使用设计的单分散 HC 纳米球报道了醚电解质中独特的溶剂化 Na ⁺和 Na ⁺共嵌入机制。此外，通过低温透射电子显微镜和深度剖面 X 射线光电子能谱观察在醚电解质中形成的具有高无机比例的薄固体电解质界面膜，这有助于 Na ⁺运输，并导致高 ICE。此外，还通过分子动力学模拟揭示了醚电解质中快速溶剂化的 Na ⁺扩散动力学。由于醚电解质的贡献，优异的倍率性能（10 A g ^-1时为214 mAh g ^-1，具有 120 mAh g ^-1的超高平台容量）和高 ICE（1 A g ^{-1 时为}84.93% ) 在半电池中观察到；在一个完整的电池中，在 1 A g ^{-1 下}循环 1000 次后获得了 110.3 mAh g ^-1的有吸引力的比容量。

更新日期：2021-09-10

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