通过氧空位与Fe─C键的耦合作用抑制惰性转变实现铁基负极的长循环寿命,Advanced Materials

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通过氧空位与Fe─C键的耦合作用抑制惰性转变实现铁基负极的长循环寿命
Advanced Materials ( IF 27.4 ) Pub Date : 2023-07-26 , DOI: 10.1002/adma.202303360
Hongguang Fan ₁ , Jinyue Song ₁ , Yanpeng Wang ₁ , Yongcheng Jin ₁ , Shuang Liu ₁ , Tao Li ₁ , Qingping Li ₁ , Chenchen Shao ₁ , Wei Liu ₁

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具有许多法拉第反应位点的铁基电池型负极材料比碳基双层型材料具有更高的容量，可用于开发高能量密度的水系超级电容器。然而，作为不可克服的瓶颈，非活性转变导致的严重容量衰减和较差的循环性能阻碍了它们在非对称超级电容器（ASC）中的商业应用。在这项工作中，在“氧泵”机制的驱动下，开发了富含氧空位的Fe@Fe ₃ O ₄^(v) @Fe ₃ C@C纳米粒子，该纳米粒子由独特的“水果与石头”结构组成，它们表现出增强的比容量和快速充电/放电能力。实验和理论结果表明，传统铁基阳极的容量衰减在Fe@Fe ₃ O ₄^(v) @Fe ₃ C@C阳极中得到极大缓解，因为不可逆相变到不活泼的γ -Fe ₂ O氧空位和 Fe─C 键耦合形成的强大势垒可以抑制三相，从而提高循环稳定性（24 000 次循环后容量保持率为 93.5%）_。使用这种铁基负极制造的ASC还具有非凡的耐用性，在38000次循环后容量保持率为96.4%，并且在功率密度为981 W kg -1 时具有127.6 W h kg -1 的高^能量^密度。

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Inhabiting Inactive Transition by Coupling Function of Oxygen Vacancies and Fe─C Bonds achieving Long Cycle Life of an Iron-Based Anode

Fe-based battery-type anode materials with many faradaic reaction sites have higher capacities than carbon-based double-layer-type materials and can be used to develop aqueous supercapacitors with high energy density. However, as an insurmountable bottleneck, the severe capacity fading and poor cyclability derived from the inactive transition hinder their commercial application in asymmetric supercapacitors (ASCs). In this work, driven by the “oxygen pumping” mechanism, oxygen-vacancy-rich Fe@Fe₃O₄^(v)@Fe₃C@C nanoparticles that consist of a unique “fruit with stone”-like structure are developed, and they exhibit enhanced specific capacity and fast charge/discharge capability. Experimental and theoretical results demonstrate that the capacity attenuation in conventional iron-based anodes is greatly alleviated in the the Fe@Fe₃O₄^(v)@Fe₃C@C anode because the irreversible phase transition to the inactive γ-Fe₂O₃ phase can be inhibited by a robust barrier formed by the coupling of oxygen vacancies and Fe─C bonds, which promotes cycle stability (93.5% capacity retention after 24 000 cycles). An ASC fabricated using this Fe-based anode is also observed to have extraordinary durability, achieving capacity retention of 96.4% after 38 000 cycles, and a high energy density of 127.6 W h kg⁻¹ at a power density of 981 W kg⁻¹.

更新日期：2023-07-26

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