摘要
基于密度泛函理论(DFT)的第一原理方法计算了四方相和立方相中2种不同的Li_(7)La_(3)Zr_(2)O_(12)(LLZO)固体电解质材料的能带结构,晶格参数,态密度和成键特性。基于理论计算结果,通过电子结构特性解释了四面体相的离子电导率低于立方相的离子电导率的原因。基于LLZO的第一性原理计算,设计了2种晶体结构的LLZO材料,并通过高温固相法制备并分析了不同烧结时间的LLZO颗粒的性能。探索了合成工艺参数对Li_(7)La_(3)Zr_(2)O_(12)性能的影响。立方晶Li_(7)La_(3)Zr_(2)O_(12)(C-LLZO)的平均晶格大小为a=b=c=1.302 246 nm,而四方Li_(7)La_(3)Zr_(2)O_(12)(T-LLZO)的平均晶格大小为a=b=1.313 064 nm,c=1.266 024 nm。在1000℃下烧结12 h的C-LLZO为纯立方相,在室温(25℃)下最大离子电导率为9.8×10^(-5) S·cm^(-1)。T-LLZO在室温(25℃)下的离子电导率为5.96×10^(-8) S·cm^(-1),在800℃下烧结6 h具有纯的四方相结构,与计算结果基本吻合。
The band structures, lattice parameters, densities of states and bond characteristics of two different Li_(7)La_(3)Zr_(2)O_(12)(LLZO)solid electrolyte materials in tetragonal and cubic phases were calculated by the first-principles method based on density functional theory(DFT). The reason why the ionic conductivity of the tetrahedral phase is lower than that of cubic phase was explained by the electronic structural characteristics based on the theoretical calculation results. Two kinds of crystalline structure LLZO materials were designed based on first principles calculation of LLZO and prepared by the high temperature solid phase method, and the properties of LLZO pellets with different sintering time were analysed. The effect of the synthesis process parameters on the properties of Li_(7)La_(3)Zr_(2)O_(12) was explored. Results show that the average lattice size of cubic Li_(7)La_(3)Zr_(2)O_(12)(C-LLZO) is a=b=c=1.302 246 nm, while that of tetragonal Li_(7)La_(3)Zr_(2)O_(12)(T-LLZO) is a=b=1.313 064 nm, c=1.266 024 nm. The C-LLZO sintered at1000 ℃ for 12 h has a pure cubic phase and a maximum ionic conductivity of 9.8×10^(-5) S·cm^(-1) is realized at room temperature(25 ℃).The ionic conductivity of T-LLZO at room temperature(25 ℃) is 5.96×10^(-8) S·cm^(-1), which has a pure tetragonal phase structure after sintering at 800 ℃ for 6 h, basically in agreement with the calculation results.
作者
梁兴华
吴希
吴秋满
李鑫旗
毛杰
方志杰
Liang Xinghua;Wu Xi;Wu Qiuman;Li Xinqi;Mao Jie;Fang Zhijie(Guangxi Key Laboratory of Automobile Components and Vehicle Technology,Guangxi University of Science&Technology,Liuzhou 545006,China;National Engineering Laboratory for Modern Materials Surface Engineering Technology,Guangdong Institute of New Materials,Guangdong Academy of Science,Guangzhou 510650,China)
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2021年第6期1956-1963,共8页
Rare Metal Materials and Engineering
基金
Fund Project of the GDAS Special Project of Science and Technology Development
Guangdong Academy of Sciences Program (2020GDASYL-20200104030)
Innovation Project of Guangxi University of Science and Technology Graduate Education (YCSW2020217)
Guangxi Innovation Driven Development Project (AA18242036-2)
Fund Project of the Key Lab of Guangdong for Modern Surface Engineering Technology (2018KFKT01)。
