Alloying-type metals with high theoretical capacity are promising anode materials for sodium ion batteries, but suffer from large volume expansion and sluggish reaction kinetics. Dispersing alloying-type metal into a buffer matrix with interfacial anionic covalent bonding is an effective method to solve the above issues. Here, this bifunctional structural unit is designed by incorporating high-capacity Sb metal into a rigid CrSe framework for fast-charging applications. The high-capacity and high-rate sodium storage can be synergistically realized in the bifunctional SbCrSe system, where the rigid CrSe framework endows the SbCrSe₃ anodes with superior structural stability and improved intercalative redox pseudocapacitance. Moreover, the volume expansion of Sb during discharge can be buffered by the CrSe chain-like matrix. The novel SbCrSe₃ anode delivers a high charge capacity of 472 mAh g⁻¹ at a current density of 0.4 C and retains ≈100% capacity at 60 C over 10 000 cycles. Further in situ and ex situ characterization reveal the multistep reaction mechanism, and the breakage and formation of reversible SbSe bonds during (dis)charge. The proposed bifunctional structural unit that combines alloying type anodes and intercalative anodes is expected to pave a new road for the development of high capacity and high rate anode materials.

中文翻译：

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通过促进插层氧化还原赝电容实现极快充电：用于大型和快速钠存储的 SbCrSe3 阳极

具有高理论容量的合金型金属是很有前途的钠离子电池负极材料，但存在体积膨胀大和反应动力学缓慢的问题。将合金型金属分散到具有界面阴离子共价键的缓冲基质中是解决上述问题的有效方法。在这里，这种双功能结构单元是通过将高容量 Sb 金属结合到用于快速充电应用的刚性 Cr  Se 框架中而设计的。在双功能 Sb  Cr  Se 系统中可以协同实现高容量和高速率的钠存储，其中刚性 Cr  Se 框架赋予 SbCrSe ₃具有优异结构稳定性和改进的插层氧化还原赝电容的阳极。此外，放电过程中 Sb 的体积膨胀可以通过 Cr  Se 链状基质进行缓冲。新型 SbCrSe ₃阳极在 0.4 C 的电流密度下提供 472 mAh g ⁻¹的高充电容量，并在 60 C 下超过 10000 次循环后保持≈100% 的容量。进一步的原位和非原位表征揭示了多步反应机制，以及（放电）充电过程中可逆 Sb-Se 键的断裂和形成。所提出的结合合金型负极和插层负极的双功能结构单元有望为开发高容量和高倍率负极材料铺平道路。