本文使用基于密度泛函理论(DFT)的超软赝势模拟法来对Li2ZnTi3O8、掺杂后的Li1.9Al0.1ZnTi3O8和Li1.9Ag0.1ZnTi3O8材料进行了电子结构与光学性质的研究。首先用CASTEP子程序对LZTO材料构建超晶胞并进行几何结构优化,并对优化后的电子结...本文使用基于密度泛函理论(DFT)的超软赝势模拟法来对Li2ZnTi3O8、掺杂后的Li1.9Al0.1ZnTi3O8和Li1.9Ag0.1ZnTi3O8材料进行了电子结构与光学性质的研究。首先用CASTEP子程序对LZTO材料构建超晶胞并进行几何结构优化,并对优化后的电子结构进行计算:包括能带结构、晶格常数、各原子的分波态密度以及总体态密度等。结果表明,LZTO晶格常数为a = b = c = 8.009 Å,Li1.9Al0.1ZnTi3O8晶格常数a = b = c = 8.837 Å,Li1.9Ag0.1ZnTi3O8晶格常数为a = b = c = 8.959 Å,与实验值接近。通过能带结构和态密度图得到Li2ZnTi3O8是一种直接带隙半导体材料,掺杂后电子的能量范围变窄,主要来自于Li、Ag、Zn和Al元素的贡献。最后计算和分析了LZTO的光学性质(光学吸收光谱),以期为锂离子电池电极材料的设计与优化提供理论指导。展开更多
Li_(2)ZnTi_(3)O_(8)(LZTO)co-doped with Mg^(2+)-W^(6+)(LM6ZTW3O)has been successfully prepared by a facile one-step solid-state route.A co-doping strategy improves ionic conductivity,reduces transfer resistance,interna...Li_(2)ZnTi_(3)O_(8)(LZTO)co-doped with Mg^(2+)-W^(6+)(LM6ZTW3O)has been successfully prepared by a facile one-step solid-state route.A co-doping strategy improves ionic conductivity,reduces transfer resistance,internal resistance and polarization,stabilizes the structure of LZTO and enables the LM6ZTW3O electrode to have a good electrical contact.展开更多
Li_(2)ZnTi_(3)O_(8)(LZTO)as an anode of lithium-ion batteries has been attracting great interest.However,its low electrical conductivity is the biggest obstacle to the practical application of LZTO.The presence of Ti^...Li_(2)ZnTi_(3)O_(8)(LZTO)as an anode of lithium-ion batteries has been attracting great interest.However,its low electrical conductivity is the biggest obstacle to the practical application of LZTO.The presence of Ti^(3+)can improve the electronic conductivity of LZTO via the introduction of oxygen vacancies(OVs).Nevertheless,excess OVs can cause severe lattice distortion and then worsen the electrochemical per-formance of LZTO.In this study,defective LZTO anodes with different concentrations of OVs are fabri-cated by a practical solid-state method.The effects of OVs on LZTO are investigated by experiments and first-principles calculations.The results show that the presence of OVs promotes random Zn/Ti distri-bution.LZTO with an appropriate concentration of OVs(LZTO-FA)can stabilize the structure,decrease the diffusion barriers of Li+ions and transfer resistance.Therefore,LZTO-FA has good electrochemical performance from 0 to 55℃.More importantly,compared with LZTO with a perfect structure,the inter-calation potential of LZTO-FA decreases as shown by the calculations.Therefore,the energy densities of the full cells can be improved using LZTO-FA as the anode.So,the findings can be instructive in the improvement of the electrochemical performance of LZTO via the introduction of OVs.展开更多
文摘本文使用基于密度泛函理论(DFT)的超软赝势模拟法来对Li2ZnTi3O8、掺杂后的Li1.9Al0.1ZnTi3O8和Li1.9Ag0.1ZnTi3O8材料进行了电子结构与光学性质的研究。首先用CASTEP子程序对LZTO材料构建超晶胞并进行几何结构优化,并对优化后的电子结构进行计算:包括能带结构、晶格常数、各原子的分波态密度以及总体态密度等。结果表明,LZTO晶格常数为a = b = c = 8.009 Å,Li1.9Al0.1ZnTi3O8晶格常数a = b = c = 8.837 Å,Li1.9Ag0.1ZnTi3O8晶格常数为a = b = c = 8.959 Å,与实验值接近。通过能带结构和态密度图得到Li2ZnTi3O8是一种直接带隙半导体材料,掺杂后电子的能量范围变窄,主要来自于Li、Ag、Zn和Al元素的贡献。最后计算和分析了LZTO的光学性质(光学吸收光谱),以期为锂离子电池电极材料的设计与优化提供理论指导。
基金supported by the Henan Joint Funds of the National Natural Science Foundation of China(U1504532)the Natural Science Foundation of Liaoning Shihua University(2018XJJ-012).
文摘Li_(2)ZnTi_(3)O_(8)(LZTO)co-doped with Mg^(2+)-W^(6+)(LM6ZTW3O)has been successfully prepared by a facile one-step solid-state route.A co-doping strategy improves ionic conductivity,reduces transfer resistance,internal resistance and polarization,stabilizes the structure of LZTO and enables the LM6ZTW3O electrode to have a good electrical contact.
基金supported by the National Natural Science Foundation of China(U1504532)the Liaoning Province Project Education Fund(LJKZ0408 and L2019043)+1 种基金the LiaoNing Revitalization Talents Program(XLYC1907025)the Natural Science Foundation of Liaoning Shihua University(2018XJJ-012).
文摘Li_(2)ZnTi_(3)O_(8)(LZTO)as an anode of lithium-ion batteries has been attracting great interest.However,its low electrical conductivity is the biggest obstacle to the practical application of LZTO.The presence of Ti^(3+)can improve the electronic conductivity of LZTO via the introduction of oxygen vacancies(OVs).Nevertheless,excess OVs can cause severe lattice distortion and then worsen the electrochemical per-formance of LZTO.In this study,defective LZTO anodes with different concentrations of OVs are fabri-cated by a practical solid-state method.The effects of OVs on LZTO are investigated by experiments and first-principles calculations.The results show that the presence of OVs promotes random Zn/Ti distri-bution.LZTO with an appropriate concentration of OVs(LZTO-FA)can stabilize the structure,decrease the diffusion barriers of Li+ions and transfer resistance.Therefore,LZTO-FA has good electrochemical performance from 0 to 55℃.More importantly,compared with LZTO with a perfect structure,the inter-calation potential of LZTO-FA decreases as shown by the calculations.Therefore,the energy densities of the full cells can be improved using LZTO-FA as the anode.So,the findings can be instructive in the improvement of the electrochemical performance of LZTO via the introduction of OVs.
