新加坡国立大学Jun Song Chen团队开发了Sb-Cu合金纳米阵列中双梯度浓度分布用于稳健钠离子存储。相关研究成果于2024年7月31日发表在《德国应用化学》。

合金型材料因其高理论容量和总体性能而对钠离子电池（SIBs）中的阳极具有吸引力。然而，在重复循环过程中应力/应变的累积会导致电极粉碎，导致容量迅速衰减并最终分解，从而阻碍了它们的实际应用。

该文中，研究人员报告了一种具有两种元素梯度分布的3D珊瑚状Sb-Cu合金纳米阵列。该阵列具有富锑底部和富铜顶部，从上到下Sb浓度增加，Cu浓度降低。前者是提供高容量的活性成分，而后者则是一种惰性添加剂，可以对抗体积变化。

电极内成分的逐渐转变引入了梯型体积膨胀效应，促进了应力的平稳分布和有效释放，从而确保了所需的机械稳定性和结构完整性。所开发的纳米阵列具有高可逆容量（0.5C下460 mAh g^-1）、稳定的循环（1.0C下120次循环保持89%）和优异的倍率性能（10C下354 mAh g^-1)。

浓度双梯度策略为SIBs合金型材料的设计开辟了新途径。

附：英文原文

Title: Dual-gradient Concentration Distribution in Sb-Cu Alloy Nanoarrays for Robust Sodium-ionStorage

Author: Xinyan Li, Chao Li, Xin Zhang, Jianguo Sun, Ximeng Liu, Kepeng Song, Jiuhui Han, John Wang, Jun Song Chen

Issue&Volume: 2024-07-31

Abstract: Alloy-type materials are attractive for anodes in sodium-ion batteries (SIBs) owing to their high theoretical capacities and overall performance. However, the accumulation of stress/strain during repeated cycling results in electrode pulverization, leading to rapid capacity decay and eventual disintegration, thus hindering their practical applications. Herein, we report a 3D coral-like Sb-Cu alloy nanoarray with gradient distribution of both elements. The array features a Sb-rich bottom and a Cu-rich top with increasing Sb and decreasing Cu concentrations from top to bottom. The former is the active component that provides the high capacity, whereas the latter serves as an inert additive that acts against volume variation. The gradual transition in composition within the electrode introduces a ladder-type volume expansion effect, facilitating a smooth distribution and effective release of stress, thereby ensuring the wanted mechanical stability and structural integrity. The as-developed nanoarray affords a high reversible capacity (460 mAh g1 at 0.5 C), stable cycling (89% retention over 120 cycles at 1.0 C), and superior rate capability (354 mAh g1 at 10 C). The concentration dual-gradient strategy paves a new pathway of designing alloy-type materials for SIBs.

DOI: 10.1002/anie.202412533

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202412533