SnS@Ti_3C_2复合材料的制备及其储锂性能研究

MXene是一类新型二维过渡金属碳化物晶体,该类材料具有一些优异的性质,如高的电导率、低的锂离子扩散能垒、独特的金属离子吸附特性等等,但是,作为锂离子电极材料时,MXene材料容量较低,限制了它在锂离子电池领域的进一步应用。本文以Ti_3C_2(最具代表性的一种MXene材料)为基体材料,通过液相插层、水热合成以及高温热处理,成功制备出二维SnS@Ti_3C_2复合材料。研究发现,当Ti_3C_2:L-半胱氨酸的质量比为1:3时(L-半胱氨酸:Na2Sn O3·4H2O=1:4),合成出来的Sn S@Ti_3C_2在0.1 A×g~(-1)的电流密度下循环50次之后,容量达到735.8 m Ah×g~(-1),且保持稳定;在3 A×g~(-1)的电流密度下,其容量能达到525.4 m Ah g~(-1);而当电流恢复到0.1 A×g~(-1)时,其容量能恢复到689.2 m Ah×g~(-1),展现出了优异的倍率性能。

Synthesis and Lithium Storage Properties of Two-Dimensional SnS@Ti3C2 Composites

MXene is a kind of two dimensional early transition metal carbides/carbonatrides. These materials have many good properties, such as remarkable electrical conductivity, low Li+ diffusion barrier and unique metal-ion adsorption behavior, etc. Although they have many good properties, the capacity of MXene-based electrodes are low, which confines the further application of MXene in the fields of lithium-ion batteries. In this paper, Ti3C2 (one of the most representative MXene) was used as the matrix. The two dimensional (2D) SnS@Ti3C­2 composite was successfully synthesized by liquid intercalation, hydrothermal, and the high temperature heat treatment. It was found that the capacity of synthesized SnS@Ti3C2(S2) can reach 735.8 mAh×g-1 after 50 cycle at 0.1 A×g-1 when the mass ratio of Ti3C2: L-cysteine is 1:3 (the mole ratio of L-cysteine: Na2SnO3 = 1:4). The capacity remains stable. When the current density reached at 3 A×g-1, the capacity of composite was 520 mAh×g-1. When the current density returned to 0.1 A×g-1, the capacity can be restored to 689.2 mAh×g-1, showing the good rate performance of SnS@Ti3C2.