Carbon encapsulated 3D hierarchical Fe3O4 spheres as advanced anode materials with long cycle lifetimes for lithium-ion batteries
Carbon encapsulated 3D hierarchical Fe3O4 spheres as advanced anode materials with long cycle lifetimes for lithium-ion batteries
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DOI：
10.1039/c4ta01511h
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发表时间：
2014-08
影响因子：
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通讯作者：
Xiulin Fan;Jie Shao;Xuezhang Xiao;Lixin Chen;Xinhua Wang;Shou-quan Li;Hongwei Ge
中科院分区：
文献类型：
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作者：
Xiulin Fan;Jie Shao;Xuezhang Xiao;Lixin Chen;Xinhua Wang;Shou-quan Li;Hongwei Ge
金属氧化物作为锂离子电池的负极材料，具有很大的存储容量。然而，它们的循环寿命和倍率能力仍然不适合商业应用。在本论文中，我们设计并制备了具有5-10 nm碳壳结构的三维分层Fe3O4微球。在所构建的结构中，较薄的碳壳可以避免包裹的Fe3O4直接暴露在电解液中，保持球体的结构和电化学完整性，并在电化学循环过程中抑制粉状Fe3O4的聚集。自下而上的自组装方法形成的层次化结构可以有效地适应Fe3O4在锂-脱锂过程中由于体积变化而产生的机械应力。此外，碳壳与结构的完整性和耐用性一起赋予了良好的高导电性和高效的离子传输。所有这些功能对于高性能阳极至关重要，因此能够实现出色的锂存储性能和较长的循环寿命。例如，这样的电极即使在600次循环后仍能提供910 mA h g−1的容量，放电充电率为1 A g−1。此外，这一有效的策略可以很容易地扩展到构建许多其他类型的高性能锂离子电池的杂化电极材料。
As anode materials for lithium ion batteries, metal oxides have large storage capacity. However, their cycle life and rate capability are still not suitable for commercial applications. Herein, 3D hierarchical Fe3O4 spheres associated with a 5–10 nm carbon shell were designed and fabricated. In the constructed architecture, the thin carbon shells can avoid the direct exposure of encapsulated Fe3O4 to the electrolyte and preserve the structural and electrochemical integrity of spheres as well as inhibit the aggregation of pulverized Fe3O4 during electrochemical cycling. The hierarchical structure formed by the bottom-up self-assembly approach can efficiently accommodate the mechanical stress induced by the severe volume variation of Fe3O4 during lithiation–delithiation processes. Moreover, the carbon shell together with the structure integrity and durability endows the favorable high conductivity and efficient ion transport. All these features are critical for high-performance anodes, therefore enabling an outstanding lithium storage performance with a long cycle lifespan. For instance, such an electrode could deliver a capacity of 910 mA h g−1 even after 600 cycles with a discharge–charge rate of 1 A g−1. In addition, this effective strategy may be readily extended to construct many other classes of hybrid electrode materials for high-performance lithium-ion batteries.