Improving the electrochemical cyclability of lithium manganese orthosilicate through the pillaring effects of gradient Na substitution
Improving the electrochemical cyclability of lithium manganese orthosilicate through the pillaring effects of gradient Na substitution
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通过梯度钠取代的支柱效应提高原硅酸锰锂的电化学循环性能
DOI：
10.1016/j.jpowsour.2017.03.023
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发表时间：
2017-05
影响因子：
9.2
通讯作者：
Weifeng Wei
中科院分区：
文献类型：
--
作者：
Zhengping Ding;Yiming Feng;Ran Ji;Datong Zhang;Libao Chen;Shuangbao Wang;Douglas G. Ivey;Weifeng Wei
正硅酸锂锰是一种有吸引力的阴极材料，提供高的理论比容量（约1000 mAh）。330 mAhg−1）和相当高的电位;然而，它在循环时遭受快速的容量/电压衰减。循环性能差的起源与Li 2 MnSiO 4多晶型物的结构不稳定性密切相关，包括在延长循环期间的层剥离和粉化。为了解决这些问题，采用梯度Na取代法制备了表面富Na+柱撑层和芯材适度Na+取代的Li 2 MnSiO 4正极材料。结果表明，柱撑层可以有效地抑制脱锂/锂化过程中层剥落/塌陷的发生，并防止延长循环时颗粒粉化。这对应于高的初始库仑效率（89.8%）和改善的可循环性，其中在Na取代的材料中在200次循环之后具有容量保持率（81.3%）。梯度Na取代过程还通过缩短Lisingle键Li距离来改善Na取代材料中的Li+扩散率和速率性能。这种梯度Na掺杂方法可以进一步应用于其他结构不稳定的聚阴离子型阴极材料，例如磷酸盐、氟磷酸盐和硼酸盐。
Lithium manganese orthosilicate is an attractive cathode material providing high theoretical specific capacity (ca. 330 mAhg−1) and reasonably high potential; however, it suffers from rapid capacity/voltage decay upon cycling. The origin of the poor cyclability is closely related to the structural instability of Li2MnSiO4polymorphs, including layer exfoliation and pulverization during extended cycling. To address these problems, a gradient Na substitution method was developed to prepare Li2MnSiO4cathode materials with a Na+-enriched surface pillaring layer and a moderately Na+-substituted core material. The results shows that the pillaring layer can effectively suppress the occurrence of layer exfoliation/collapse during delithiation/lithiation and prevent particle pulverization upon extended cycling. This corresponds to a high initial Coulombic efficiency (89.8%) and improved cyclability with a capacity retention (81.3%) after 200 cycles in Na-substituted materials. The gradient Na substitution process also results in improved Li+diffusivity and rate performance in Na-substituted materials by shortening Lisingle bondLi distances. This gradient Na-doping method can be further applied to other structure-unstable polyanion-type cathode materials, such as phosphates, fluorophosphates and borates.
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影响因子：
8.6
作者：
He, Guang;Popov, Guerman;Nazar, Linda F.
通讯作者：
Nazar, Linda F.
柠檬酸辅助溶胶-凝胶法合成Mo掺杂Li2MnSiO4/C纳米复合材料，具有增强的电化学性能
影响因子：
3
作者：
Chunyan Lai;Zhen Wang;Qunjie Xu
通讯作者：
Qunjie Xu
影响因子：
8.6
作者：
Hosik Lee;Soon‐Dong Park;Janghyuk Moon;Hoonkyung Lee;Kyeongjae Cho;M. Cho;Sung Youb Kim
通讯作者：
Hosik Lee;Soon‐Dong Park;Janghyuk Moon;Hoonkyung Lee;Kyeongjae Cho;M. Cho;Sung Youb Kim
影响因子：
27.8
作者：
Qing, Ren-Peng;Shi, Ji-Lei;Guo, Yu-Guo
通讯作者：
Guo, Yu-Guo
影响因子：
5.4
作者：
Arroyo-de Dompablo, M. E.;Armand, M.;Amador, U.
通讯作者：
Amador, U.