Al2O3 coated metal sulfides: one-pot synthesis and enhanced lithium storage stability via localized in situ conversion reactions
Al2O3 coated metal sulfides: one-pot synthesis and enhanced lithium storage stability via localized in situ conversion reactions
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Al2O3涂覆的金属硫化物：一锅合成并通过局部原位转化反应增强锂储存稳定性
DOI：
10.1039/c6dt04467k
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发表时间：
2017
影响因子：
4
通讯作者：
Qian Xuefeng
中科院分区：
文献类型：
--
作者：
Liu Yuanyuan;Zai Jiantao;Li Xiaomin;Ma Zi-feng;Qian Xuefeng
高比容量的过渡金属硫化物在锂的储存中受到越来越多的研究兴趣。然而，金属硫化物的低可逆性通常导致Li 2S氧化成多硫化物。多硫化物的溶解会由于Li 2S的损失而抑制硫化物的再生，这通常导致硫化物的循环稳定性差。本文采用合理设计的方法，通过一锅水热法制备了Al_2O_3包覆的Ni_3S_4纳米粒子（Ni_3S_4@Al_2O_3）。硫化镍的再生是硫化物循环稳定性的关键，由于Al 2 O3层可以阻止多硫化物的扩散和溶解，因此可以通过从金属到金属硫化物的局部转化来促进。Al 2 O3向离子导电AlF 3的转化可以增强锂离子插入/拔出反应的快速电荷转移过程。此外，Al 2 O3/AlF 3层还可以防止Ni 3S 4纳米颗粒的生长和聚集，从而在循环过程中保持电极的结构。如此制备的Ni3S4@Al2O3即使在400次循环后也表现出在500 mA g-1下651 mA h g-1的高可逆容量。该方法也可推广到其他金属硫化物的电化学改性。
Transition metal sulfides with high specific capacity have received increasing research interest in lithium storage. However, the low reversibility of metal sulfides usually leads to the oxidation of Li2S into polysulfides. The dissolution of polysulfides will suppress the regeneration of sulfides due to the loss of Li2S, which usually leads to poor cycling stability of sulfides. Herein, Al2O3 coated Ni3S4 nanoparticles (Ni3S4@Al2O3) have been rationally designed and fabricated via a one-pot hydrothermal process. The regeneration of nickel sulfides, which is the key to cycling stability of sulfides, can be promoted by the localized conversion from metal to metal sulfides because the Al2O3 layer can prevent the diffusion and dissolution of polysulfides. The conversion of Al2O3 to ion-conductive AlF3 can enhance the quick charge transfer process of the lithium ion insertion/extraction reaction. Furthermore, the Al2O3/AlF3 layer can also prevent the growth and aggregation of Ni3S4 nanoparticles to retain the structure of the electrodes during the cycling process. The as-prepared Ni3S4@Al2O3 exhibits a high reversible capacity of 651 mA h g−1 at 500 mA g−1 even after 400 cycles. This method can also be extended to other metal sulfides for improving electrochemical performances.