Compact-Nanobox Engineering of Transition Metal Oxides with Enhanced Initial Coulombic Efficiency for Lithium-Ion Battery Anodes
Compact-Nanobox Engineering of Transition Metal Oxides with Enhanced Initial Coulombic Efficiency for Lithium-Ion Battery Anodes
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用于锂离子电池阳极的具有增强初始库仑效率的过渡金属氧化物的紧凑纳米盒工程
DOI：
10.1021/acsami.7b19379
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发表时间：
2018
影响因子：
9.5
通讯作者：
Chen Xiaohua
中科院分区：
文献类型：
--
作者：
Zhu Yanfei;Hu Aiping;Tang Qunli;Zhang Shiying;Deng Weina;Li Yanhua;Liu Zheng;Fan Binbin;Xiao Kuikui;Liu Jilei;Chen Xiaohua
提出了一种构建由不规则纳米颗粒(平均直径≈为10 nm)组成的致密纳米盒结构的新策略，旨在限制电极-电解液接触面积并提高过渡金属氧化物阳极的初始库仑效率。为了验证这一尝试的有效性，本文以碳热还原法合成了CoO-CNB为例。由于结构紧凑，电解液只能接触纳米盒的外表面，使内部的CoO纳米颗粒保持不变。因此，减少了固体电解质界面(SEI)的形成。此外，内腔为锂化和脱氢时的体积变化留下了足够的空间，从而使CNB结构具有优异的机械稳定性，并减少了新鲜SEI的生成。因此，SEI保持稳定和空间受限而不会降解，因此，CoO-CNB电极提供了82.2%的增强ICE，这是已报道的锂离子电池中TMO基阳极的最高值之一。此外，CoO-CNB电极还表现出良好的循环性能，其可逆容量为811.6 mA h g-1(100次循环后容量保持率为90.4%)。这些发现为设计高ICE电极开辟了一条新途径，促进了TMO阳极的实际应用。
A novel strategy is proposed to construct a compact-nanobox (CNB) structure composed of irregular nanograins (average diameter ≈ 10 nm), aiming to confine the electrode–electrolyte contact area and enhance initial Coulombic efficiency (ICE) of transition metal oxide (TMO) anodes. To demonstrate the validity of this attempt, CoO-CNB is taken as an example which is synthesized via a carbothermic reduction method. Benefiting from the compact configuration, electrolyte can only contact the outer surface of the nanobox, keeping the inner CoO nanograins untouched. Therefore, the solid electrolyte interphase (SEI) formation is reduced. Furthermore, the internal cavity leaves enough room for volume variation upon lithiation and delithiation, resulting in superior mechanical stability of the CNB structure and less generation of fresh SEI. Consequently, the SEI remains stable and spatially confined without degradation, and hence, the CoO-CNB electrode delivers an enhanced ICE of 82.2%, which is among the highest values reported for TMO-based anodes in lithium-ion batteries. In addition, the CoO-CNB electrode also demonstrates excellent cyclability with a reversible capacity of 811.6 mA h g–1(90.4% capacity retention after 100 cycles). These findings open up a new way to design high-ICE electrodes and boost the practical application of TMO anodes.