Liu Lu, Zhu Jianhua, Chen Guohui, Wang Zhuosen, Wang Liu, Guo Chengkun, Chao Yunfeng, Cui Xinwei, Wang Caiyun
Institute of Advanced Technology, Zhengzhou University Zhengzhou 450052 P. R. China
ARC Ctr. Excellence Electromat Sci., University of Wollongong Innovation Campus, North Wollongong NSW 2500 Australia.
Chem Sci. 2025 Aug 26. doi: 10.1039/d5sc04111b.
Hard carbon is the most commercially viable anode material for sodium-ion batteries (SIBs), yet its application in ester-based electrolytes is hindered by sluggish interfacial ion diffusion and limited sodium nucleation kinetics. After comprehensive evaluation, an interfacial chemistry regulation strategy was proposed based on orbital hybridization between bismuth and electrolyte ions, which was realized through the introduction of ammonium bismuth citrate. The surface bismuth particles regulate the formation of a NaF-rich SEI through improved anion affinity. In collaboration with the generated highly ion-conductive NaN, a thin, compact and homogeneous SEI was constructed to enable fast and stable interfacial Na migration kinetics. Moreover, the Bi atoms can diffuse into the hard carbon structures, expanding the carbon interlayers to facilitate ion diffusion and intercalation as well as enhancing the sodiophilicity in closed pores to lower the nucleation barrier. Benefiting from these merits, the resulting T2-BiN exhibits superior sodium-storage kinetics with outstanding rate capability (185.6 mA h g at 0.5 A g) and long-term cycling stability (84.4% after 400 cycles at 0.5 A g) in the ester-based electrolyte. Even the practical full cell showed no capacity decay over 400 cycles at 2C. This work provides a simple and effective interfacial modification strategy, offering new insights into the advancement of hard carbon anodes for high-performance SIBs.
硬碳是钠离子电池（SIBs）中最具商业可行性的负极材料，然而其在酯基电解质中的应用受到界面离子扩散缓慢和成核动力学受限的阻碍。经过综合评估，基于铋与电解质离子之间的轨道杂化提出了一种界面化学调控策略，这通过引入柠檬酸铋铵得以实现。表面铋颗粒通过提高阴离子亲和力来调节富含NaF的固体电解质界面（SEI）的形成。与生成的高离子导电性NaN协同作用，构建了一层薄而致密且均匀的SEI，以实现快速且稳定的界面Na迁移动力学。此外，Bi原子可扩散到硬碳结构中，扩大碳层间距以促进离子扩散和嵌入，并增强封闭孔隙中的亲钠性以降低成核势垒。得益于这些优点，所得的T2 - BiN在酯基电解质中表现出优异的储钠动力学，具有出色的倍率性能（在0.5 A g下为185.6 mA h g）和长期循环稳定性（在0.5 A g下循环400次后为84.4%）。甚至实际的全电池在2C下循环400次也没有容量衰减。这项工作提供了一种简单有效的界面修饰策略，为高性能SIBs的硬碳负极的发展提供了新的见解。
