氮掺杂Ti_(3)C_(2)T_(x)MXene纳米片包覆的SiO_(x)实现储锂性能提升

N-doped Ti_(3)C_(2)T_(x)MXene sheet-coated SiO_(x)to boost lithium storage for lithium-ion batteries

构建具有快速反应动力学和优异循环稳定性的SiO_(x)基负极材料是获取高性能锂离子电池的关键和挑战.本文中,我们利用三聚氰胺辅助的球磨和退火方法,合成了氮掺杂的Ti_(3)C_(2)T_(x)MXene超薄片层(NTS)包覆的SiO_(x)复合材料.通过对比实验和理论计算,我们论证了三聚氰胺剥离MXene的作用机理.SiO_(x)与NTS之间强烈的界面相互作用(Si-O-Ti键)可以有效地增强电子转移,确保电极的稳定性.此外,具有丰富表面基团的NTS使复合材料具有赝电容性能,有利于快速储锂.因此,该复合材料展现出了长循环寿命(在1.0 A g^(-1)的电流密度下,循环800次后比容量保持为~700 mA h g^(-1))和优越的倍率性能(在5 A g^(-1)的电流密度下,比容量为596.4 mA h g^(-1)).更重要的是,在高负载量下,该复合材料在半电池和全电池中均表现出较高的面积比容量和良好的循环稳定性,展现出了良好的应用潜力.

Constructing SiO_(x)-based composite materials with fast reaction kinetics and high stability is crucial but challenging for high-performance lithium-ion batteries.Herein,we developed the N-doped Ti_(3)C_(2)T_(x)MXene ultrathin sheet(NTS)-coupled SiO_(x)nanoparticles using a melamineassisted ball milling and annealing procedure.The principle of melamine in exfoliating MXene was demonstrated by contrast experiments and theoretical calculations.The strong interfacial interactions between SiO_(x)and the NTS(Si-O-Ti bond)can effectively enhance the electron transfer and ensure electrode stability.Moreover,the NTS with rich surface groups endowed the composite with a pseudocapacitive behavior,beneficial for fast lithium storage.As a result,the composite delivered a long lifespan(~700 m A h g^(-1)over 800 cycles a t1.0 A g^(-1))and a superior rate performance(596.4 m A h g^(-1)at 5 A g^(-1)).More importantly,the composite in half and full cells exhibited high areal capacity and good cycling stability at high mass loadings,revealing a promising application prospect.