FeSe_(2)/Ti_(3)C_(2)Tx复合材料的制备及其钠存储性能

Preparation of FeSe_(2)/Ti_(3)C_(2)T_(x)Composites with Sodium Storage Properties

硒化物常被应用于钠离子电池负极材料,具有更高可逆容量和合适的工作电位,然而,循环过程中的体积变化较大,电导率较低,限制了其实际应用。通过简单的水热反应制备了FeSe_(2)/Ti_(3)C_(2)T_(x)复合材料作为钠离子电池负极材料。Fe^(2+)首先与乙二胺四乙酸配位并形成螯合物,经过水热反应,Ti_(3)C_(2)T_(x)和Fe^(2+)螯合物之间产生静电作用,合成了FeSe_(2)/Ti_(3)C_(2)T_(x)复合材料。FeSe_(2)/Ti_(3)C_(2)T_(x)呈开放式的“花瓣”结构,Ti_(3)C_(2)T_(x)为材料提供了强导电网络并且缓解了一定的体积膨胀。电化学测试表明:FeSe_(2)/Ti_(3)C_(2)T_(x)电极在0.5 A/g下经过150次循环后容量达到455 m A·h/g,相同电流密度下,FeSe_(2)电极循环100圈后的容量仅为335 m A·h/g,并且在随后的循环中容量迅速衰减,以上结果表明合理的结构设计使得FeSe_(2)/Ti_(3)C_(2)T_(x)电极具有优异的电化学储钠性能和循环稳定性。

Selenides have a higher reversible capacity and a suitable working potential.However,their large volume change during cycling and low conductivity restrict their practical applications.In this paper,FeSe_(2)/Ti_(3)C_(2)T_(x)composites were synthesized as anode materials for sodium-ion batteries by a simple hydrothermal method.Fe^(2+)were firstly coordinated with ethylene diamine tetraacetie acid to form chelates,and then FeSe_(2)/Ti_(3)C_(2)T_(x)composites were synthesized via the electrostatic interaction between Ti_(3)C_(2)T_(x)and Fe^(2+)chelates after the hydrothermal reaction.FeSe_(2)/Ti_(3)C_(2)T_(x)has an open‘flower petal’structure,and Ti_(3)C_(2)T_(x)in the composite provides an intense conductive network for the material and relieves volume expansion.According to the results of the electrochemical test,Ti_(3)C_(2)T_(x)electrode has a capacity of 455 mA·h/g after 150 cycles at 0.5 A/g,while the capacity of FeSe_(2)electrode at the same current density is only 335 mA·h/g after 100 cycles,and the capacity decays rapidly in the subsequent cycles.It is indicated that FeSe_(2)/Ti_(3)C_(2)T_(x)electrode has superior electrochemical sodium storage performance and cycling stability.