摘要
By taking tetragonal tungsten bronze(TTB)phase Nb_(18)W_(16)O_(93)as an example,an improved solid-state sintering method at lower temperature of 1000℃for 36 h was proposed via applying nanoscale raw materials.XRD,SEM and XPS confirm that the expected sample was produced.GITT results show that the lithium-ion diffusion coefficient of Nb_(18)W_(16)O_(93)(10−12 cm^(2)/s)is higher than that of the conventional titanium-based anode,ensuring a relatively superior electrochemical performance.The lithium-ion diffusion mechanism was thoroughly revealed by using density functional theory simulation.There are three diffusion paths in TTB phase,among which the interlayer diffusion with the smallest diffusion barrier(0.46 eV)has more advantages than other typical anodes(such as graphite,0.56 eV).The relatively smaller lithium-ion diffusion barrier makes TTB phase Nb_(18)W_(16)O_(93)become a potential highspecific-power anode material.
使用改进的固态烧结方法(1000℃,36 h)成功合成四方钨青铜(TTB)相Nb_(18)W_(16)O_(93),并通过XRD,SEM和XPS对其进行表征与分析。GITT结果表明,Nb_(18)W_(16)O_(93)(10−12cm^(2)/s)的锂离子扩散系数高于传统的Ti基负极。使用密度泛函理论模拟计算揭示锂离子的扩散机制。TTB相有3种扩散路径,其中扩散能垒最小的层间扩散(0.46 eV)比其他典型负极(例如,石墨0.56 eV)更具有优势,使TTB相Nb_(18)W_(16)O_(93)成为潜在的高特定功率阳极材料。
基金
the Key R&D Program of Shaanxi Province,China(No.2019ZDLGY04-05)
the Natural Science Foundation of Shaanxi Province,China(No.2019JLZ-01)
the Fundamental Research Funds for the Central Universities of China(Nos.19GH020302,3102019JC005,3102021ZD0401,3102021TS0406)
the Science,Technology,and Innovation Commission of Shenzhen Municipality,China(No.JCYJ20180508151856806).
