Ni-Sn合金量子点镶嵌在多孔纳米碳片复合物的合成及其优异的储钠性能

Synthesis and excellent sodium storage performance of Ni-Sn alloy quantum dots embedded in porous carbon nanosheets composites

锡基合金负极材料由于其在储钠过程中拥有高的比容量和低工作电压而备受瞩目,但其在嵌钠/脱钠过程中却易造成原子体积膨胀,从而引起电极材料在储钠时的容量衰减。为了解决这些问题,利用简单的模板法制备出了Ni-Sn合金量子点镶嵌在多孔纳米碳片的复合物(Ni-Sn@PNC),并对比了Ni-Sn的常见两种合金Ni3Sn4@PNC、Ni3Sn2@PNC和PNC的形貌结构和电化学性能。当它们作为负极材料应用到储钠研究时,Ni3Sn4@PNC表现出明高的容量(在100 mA/g的电流密度下进行100圈充放电循环后比容量保持232.7 mAh/g)和出色的循环稳定性(在400 mA/g电流下循环1000圈后具有高达81.6%的容量保持率);PNC拥有较好的倍率性能,而Ni3Sn2@PNC却表现出较差的性能。研究结果表明,Ni3Sn4作为Ni-Sn合金负极材料的首选,可以利用材料纳米化和多孔纳米碳复合来实现优异的电化学性能。为抑制Sn、Sb和Bi等负极材料在储钠过程中的体积膨胀和性能提升指明了可行的方向。

The Sn-based alloy anode materials have attracted wide interest due to their excellent capacity and lower voltage platform during the sodium storage process.Unfortunately,a huge volume change causes the Sn-based anode materials to be easily broken during the charging/discharging processes,resulting in capacity degradation.Herein,the composites composed of Ni-Sn alloy quantum dots embedded in porous carbon nanosheets(Ni-Sn@PNC)have been synthesized by a simple template method.And the morphological structure and electrochemical performance of the composites Ni3Sn4@PNC,Ni3Sn2@PNC and PNC have been investigated using structural characterization techniques and electrochemical measurements.The results show that the Ni3Sn4@PNC exhibits the best performance among the samples as anodes for sodium-ion batteries.The Ni3Sn4@PNC anode delivers a high capacity of 232.7 mAh/g after 100 cycles at 100 mA/g,and the outstanding cycle stability with a capacity retention rate of 81.6%over 1000 cycles at 400 mA/g.The superior electrochemical performance of Ni-Sn alloy anode materials is attributed to the synergistic effect of Ni3Sn4 quantum dot and porous carbon nanoplates,shortening the transport distance of charged species,providing high contact area of the electrolyte and active materials,and increasing the reaction active sites.This work provides a feasible strategy for the exploration of new alloy anodes for sodium-ion batteries.