Three-dimensionally mesostructured Fe2O3 electrodes with good rate performance and reduced voltage hysteresis
Three-dimensionally mesostructured Fe2O3 electrodes with good rate performance and reduced voltage hysteresis
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DOI：
10.1021/cm504365s
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发表时间：
2015-04
影响因子：
8.6
通讯作者：
Junjie Wang;Hui-jie Zhou;J. Nanda;P. Braun
中科院分区：
文献类型：
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作者：
Junjie Wang;Hui-jie Zhou;J. Nanda;P. Braun
采用胶体模板法和脉冲电沉积法制备了镍支架三维介结构Fe2O3电极。该支架为活性相的锂离子和电子提供了短路径，从而实现了快速动力学和高功率密度。该支架还减少了电压迟滞。该电极在0.2 a g-1 （~ 0.2 C）下循环约20次的可逆容量为~ 1000 mAh g-1，在20 a g-1 （~ 20 C）的电流密度下，可交付容量约为450 mAh g-1。在0.1 A g-1 （~ 0.1 C）下，室温电压迟滞为0.62 V，明显小于文献中通常报道的迟滞。在45°C时，磁滞进一步降低到0.42 V。恒电位电化学阻抗谱（PEIS）研究表明，相对于传统的转换系统，在循环过程中电极中Li2O/Fe界面面积的减小可能是电压滞后小的原因。
Ni scaffolded mesostructured 3D Fe2O3 electrodes were fabricated by colloidal templating and pulsed electrodeposition. The scaffold provided short pathways for both lithium ions and electrons in the active phase, enabling fast kinetics and thus a high power density. The scaffold also resulted in a reduced voltage hysteresis. The electrode showed a reversible capacity of ∼1000 mAh g–1 at 0.2 A g–1 (∼0.2 C) for about 20 cycles, and at a current density of 20 A g–1 (∼20 C), the deliverable capacity was about 450 mAh g–1. The room-temperature voltage hysteresis at 0.1 A g–1 (∼0.1 C) was 0.62 V, which is significantly smaller than that normally reported in the literature. The hysteresis further reduced to 0.42 V at 45 °C. Potentiostatic electrochemical impedance spectroscopy (PEIS) studies indicated that the small voltage hysteresis may be due to a reduction in the Li2O/Fe interfacial area in the electrode during cycling relative to conventional conversion systems.