闪锌矿结构AlSb的嵌脱锂机理

Lithiation/delithiation mechanism of AlSb with zinc-blende structure

利用第一原理赝势平面波计算方法研究具有闪锌矿结构AlSb的嵌脱锂机理。通过计算不同嵌锂相Lix(AlSb)(0≤x≤2)或Li2+yAl1-ySb(0≤y≤1)的形成能(ΔE),并结合相应的热力学原理便可得出当Li嵌入AlSb时的电压—比容量曲线图,由此进一步确认了锂在嵌入AlSb的结构时,首先是占据AlSb中的间隙位置,然后随着Li嵌入量的增加,可以逐步取代AlSb中的Al位置从而形成Li3Sb相。通过分析Li嵌入AlSb前后的能带结构及态密度图可以发现,AlSb的导电性能首先随Li嵌入量的增加而增加,当Li占据AlSb全部间隙位置后达到峰值,当Li进一步替代Al时导电性能随之降低。

The lithiation/delithiation mechanism of AlSb with zinc-blende structure was investigated by the first-principles pseudopotential plane wave method. The plot of potential vs specific capacity of Li intercalated into AlSb can be drawn by calculating the formation energies （△E） of different types of lithiated phases of Lix（AlSb）（0≤x≤2） or Li2＋yAl1-ySb（0≤y≤1） in combination with the corresponding thermodynamic principles. It is found that Li first occupies the interstitial sites when intercalated into AlSb, and followed by substituting for Al sites with the increase of Li intercalation capacity to form the phase of Li3Sb. Through analyzing the band structure and the density of states of AlSb before and after lithiation, it is shown that the conductibility of AlSb increases with the increase of Li intercalation capacity, and reaches the peak value when Li occupies all the interstitial sites of AlSb, followed by decreasing when Li begins to substitute for Al.