Vanadium Doping Enhanced Electrochemical Performance of Molybdenum Oxide in Lithium-Ion Batteries
Vanadium Doping Enhanced Electrochemical Performance of Molybdenum Oxide in Lithium-Ion Batteries
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钒掺杂增强锂离子电池中氧化钼的电化学性能
DOI：
10.1002/adfm.201805227
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发表时间：
2019-01-01
影响因子：
19
通讯作者：
Wang, Zhongchang
中科院分区：
文献类型：
--
作者：
Qu, Gan;Wang, Jun;Wang, Zhongchang
三氧化钼(MoO_3)在锂离子电池中存在导电性差、倍率低、循环稳定性差等问题。等价离子掺杂可能为改善MoO_3的电化学性能提供了一种有效的途径。通过第一性原理计算表明，掺杂12.5%的V可以显著地调制MoO_3的电子结构，并为提高MoO_3的电化学性能提供一个小的扩散势垒。制备了超长的Mo0.88V0.12O2.94纳米结构，它保留了h-MoO_3结构，由于V的替代而表现出极高的导电性和快速的离子扩散，促进了锂/脱硫化行为，并诱导出了体积变化较小的精细纳米结构。结果表明，锂离子插层/脱插层过程中的应力和应变得到了缓解，提高了循环稳定性和倍率性能。电化学性质的如此大的改善可以归因于V的稳定作用、较小的迁移能垒和较短的扩散路径。独特的工程策略和简便的合成路线为修饰和开发其他种类的电极材料开辟了一条新的途径。
Molybdenum trioxide (MoO3) suffers from poor conductivity, a low rate capability, and unsatisfactory cycling stability in lithium-ion batteries. The aliovalent ion doping may present an effective way to improve the electrochemical performances of MoO3. Here, it is shown, by first-principle calculations, that doping MoO3 with V by 12.5% can modulate significantly electronic structure and provide a small diffusion barrier for enhancing the electrochemical performance of MoO3. The ultralong Mo0.88V0.12O2.94 nanostructures, which retain the h-MoO3 structure and present an exceptionally high conductivity and fast ionic diffusion due to the substitution of V, facilitating lithiation/delithiation behavior, and induce a fine nanosized structure with a reduced volume change are prepared. As a result, the stress and strain are alleviated during the Li-ion intercalation/deintercalation processes, improving the cycling stability and rate capability. Such a large improvement in the electrochemical properties can be ascribed to the stabilizing effect of V, the small migration energy barrier, and short diffusion path, which arise from the introduction of V into MoO3. The unique engineering strategy and facile synthesis route open up a new avenue in modifying and developing other species of electrode materials.