锂在不锈钢表面吸附与扩散的第一性原理计算

doi:10.7523/j.ucas.2024.039

摘要/Abstract

摘要：

偏滤器材料的选择一直是核聚变领域的热门问题之一，近年来的实验结果表明，采用液态锂作为偏滤器中面对等离子体的材料不仅可以有效解决传统固体材料所面临的难题，还可以显著提升等离子体的约束性能。然而，液态锂在多数固体材料表面的润湿性和铺展性并不理想。鉴于此，采用第一性原理方法模拟计算锂原子在不锈钢表面的占位和扩散特性，分析镍、钨、铬、锰4种合金元素的影响。结果显示4种合金元素可以显著地改变锂原子在（100）晶面上的吸附能。在镍和钨元素周围，锂原子的吸附能随着距离的增加先增大后减小，表现出先吸引后排斥的效果；而在铬和锰元素周围，吸附能随着距离的增加单调降低，全程具有排斥作用。4种合金元素对锂原子的扩散行为具有类似的影响规律，对于镍和钨而言，锂原子在一定范围内具有向靠近合金元素的方向进行扩散的趋势，超过此范围后则更易向外移动；对于铬和锰而言，锂原子始终更易向外扩散。该结果有助于在微观尺度上更好地理解液态锂在不锈钢表面的润湿和铺展特性。

关键词: 第一性原理, 吸附能, 扩散势垒, 液态锂, 不锈钢

Abstract:

The selection of divertor materials has always been one of the hot issues in the field of nuclear fusion. The experimental results in recent years show that using liquid lithium as plasma facing materials in divertor can not only effectively solve the problems faced by traditional solid materials， but also significantly improve the confinement property of plasma. However， the wettability of liquid lithium on the surface of most solid materials is not ideal. In view of this， the first-principles method was used to simulate and calculate the occupation and diffusion characteristics of lithium atoms on the surface of stainless steel， and the effects of nickel， tungsten， chromium and manganese were analyzed. The results show that the four alloying elements can significantly change the adsorption energy of lithium atoms on the （100） crystal plane. Around nickel and tungsten， the adsorption energy of lithium atom first increases and then decreases with the increase of distance， showing the effect of first attraction and then repulsion. However， around chromium and manganese， the adsorption energy decreases monotonously with the increase of distance， and it has a repulsive effect in the whole process. For nickel and tungsten， lithium atoms tend to diffuse in the direction close to alloy elements within a certain range， and move outward more easily beyond this range. For chromium and manganese， lithium atoms are always more likely to diffuse outward. The results of this paper are helpful to better understand the wetting and spreading characteristics of liquid lithium on the surface of stainless steel at the micro scale.

Key words: first-principles, adsorption energy, diffusion barrier, liquid lithium, stainless steel

中图分类号:

O485

申雷, 余新刚. 锂在不锈钢表面吸附与扩散的第一性原理计算[J]. 中国科学院大学学报, 2026, 43(4): 463-470.

Lei SHEN, Xingang YU. First principles calculation of lithium adsorption and diffusion on stainless steel surface[J]. Journal of University of Chinese Academy of Sciences, 2026, 43(4): 463-470.

图/表 9

图1 原子模型示意图

Fig.1 Schematic diagram of atomic model

图2 Li原子在α-Fe （100）表面上的3种占位点

Fig.2 Three types of adsorption sites of Li atom on α-Fe （100） surface

表1 Li原子在α-Fe （100）表面上的吸附能

Table 1 Adsorption energy of Li atom on α-Fe （100） surface

吸附点	覆盖率	吸附能/eV
吸附点	覆盖率	本文计算结果	文献数据
Hollow	1∶9	-0.24	-0.23^[26]
	1∶16	-0.32	—
	1∶36	-0.35	—
Bridge	1∶9	-0.11	-0.11^[26]
	1∶16	-0.23	—
	1∶36	-0.26	—
On-Top	1∶9	-0.02	-0.03^[26]
	1∶16	-0.17	—
	1∶36	-0.19	—

图3 Li原子在α-Fe （100）表面上的2种扩散路径

Fig.3 Two diffusion paths of Li atom on α-Fe （100）surface

图4 Li原子沿α-Fe （100）表面2种扩散路径的能量分布曲线

Fig.4 Energy distribution of Li atom along two diffusion paths on α-Fe （100） surface

图5 Li原子在包含合金元素的α-Fe （100）晶面上的占位点示意图

Fig.5 Adsorption sites of Li atoms on α-Fe （100） surface with an alloy element

表2 Li原子在包含合金元素的Fe表面不同占点的吸附能

Table 2 Adsorption energy of Li atom on α-Fe （100） surface with different substitutional alloy elements

吸附点	吸附能/eV
吸附点	Ni	W	Cr	Mn
H1	-0.41	-0.35	-0.26	-0.28
B	-0.34	-0.26	-0.08	—
O	-0.32	-0.04	0.13	0.18

图6 Li原子在合金元素附近Hollow点位的吸附能

Fig.6 Adsorption energy of Li atom at Hollow sites near the substitutional alloy element

图7 Li原子在含有合金元素的α-Fe表面的扩散能量曲线

Fig.7 Energy curve of Li atom on α-Fe （100） surface with a substitutional alloy element

参考文献 27

[1]	Federici G， Skinner C H， Brooks J N， et al. Plasma-material interactions in current tokamaks and their implications for next step fusion reactors［J］. Nuclear Fusion， 2001， 41（12R）： 1967-2137. DOI： 10.1088/0029-5515/41/12/218 .
[2]	Roth J， Tsitrone E， Loarte A， et al. Recent analysis of key plasma wall interactions issues for ITER［J］. Journal of Nuclear Materials， 2009， 390-391： 1-9. DOI： 10.1016/j.jnucmat.2009.01.037 .
[3]	Nygren R E， Tabarés F L. Liquid surfaces for fusion plasma facing components：a critical review. Part I： Physics and PSI［J］. Nuclear Materials and Energy， 2016， 9： 6-21. DOI： 10.1016/j.nme.2016.08.008 .
[4]	Hu J S， Ren J， Sun Z， et al. An overview of lithium experiments on HT-7 and EAST during 2012［J］. Fusion Engineering and Design， 2014， 89（12）： 2875-2885. DOI： 10.1016/j.fusengdes.2014.06.015 .
[5]	Ono M， Bell M G， Kaita R， et al. Recent progress of NSTX lithium program and opportunities for magnetic fusion research［J］. Fusion Engineering and Design， 2012， 87（10）： 1770-1776. DOI： 10.1016/j.fusengdes.2011.10.011 .
[6]	Kugel H W， Allain J P， Bell M G， et al. NSTX plasma operation with a Liquid Lithium Divertor［J］. Fusion Engineering and Design， 2012， 87（10）：1724-1731. DOI： 10.1016/j.fusengdes.2011.07.010 .
[7]	S􀅡nchez J， Tabarés F L， Tafalla D， et al. Impact of lithium-coated walls on plasma performance in the TJ-II stellarator［J］. Journal of Nuclear Materials， 2009， 390： 852-857. DOI： 10.1016/j.jnucmat.2009.01.224 .
[8]	Wang H Y， Hu J S， Gao X， et al. Influence of Li and B coatings of metal walls on deuterium retention and plasma confinement in HT-7［J］. Nuclear Fusion， 2012， 52（10）： 103002. DOI： 10.1088/0029-5515/52/10/103002 .
[9]	Zuo G Z， Hu J S， Zhen S， et al. Comparison of various wall conditionings on the reduction of H content and particle recycling in EAST［J］. Plasma Physics and Controlled Fusion， 2011， 54（1）： 015014. DOI： 10.1088/0741-3335/54/1/015014 .
[10]	Kugel H W， Mansfield D， Maingi R， et al. Evaporated lithium surface coatings in NSTX［J］. Journal of Nuclear Materials， 2009， 390-391： 1000-1004. DOI： 10.1016/j.jnucmat.2009.01.262 .
[11]	Bell M G， Kugel H W， Kaita R， et al. Plasma response to lithium-coated plasma-facing components in the National Spherical Torus Experiment［J］. Plasma Physics and Controlled Fusion， 2009， 51（12）： 124054. DOI： 10.1088/0741-3335/51/12/124054 .
[12]	Lu W， Wang W H， Jiang H Y， et al. Investigation of wetting property between liquid lead lithium alloy and several structural materials for Chinese DEMO reactor［J］. Journal of Nuclear Materials， 2017， 494： 303-310. DOI： 10.1016/j.jnucmat.2017.07.055 .
[13]	Fiflis P， Press A， Xu W， et al. Wetting properties of liquid lithium on select fusion relevant surfaces［J］. Fusion Engineering and Design， 2014， 89（12）： 2827-2832. DOI： 10.1016/j.fusengdes.2014.03.060 .
[14]	Wang J Y， Wang H S， Xie J， et al. Fundamental study on the wetting property of liquid lithium［J］. Energy Storage Materials， 2018， 14： 345-350. DOI： 10.1016/j.ensm.2018.05.021 .
[15]	Hammouti S， Holybee B， Christenson M， et al. Wetting of liquid lithium on fusion-relevant materials microtextured by femtosecond laser exposure［J］. Journal of Nuclear Materials， 2018， 508： 237-248. DOI： 10.1016/j.jnucmat.2018.05.051 .
[16]	Cicero G， Calzolari A， Corni S， et al. Anomalous wetting layer at the Au（111） surface［J］. The Journal of Physical Chemistry Letters， 2011， 2（20）： 2582-2586. DOI： 10.1021/jz200989n .
[17]	Cui Y T， Liang F， Xu S， et al. Interfacial wetting behaviors of liquid Ga alloys/FeGa₃ based on metallic bond interaction［J］. Colloids and Surfaces A： Physicochemical and Engineering Aspects， 2019， 569： 102-109. DOI： 10.1016/j.colsurfa.2019.01.079 .
[18]	Yi S， Li G， Liu Z， et al. First-principles calculations on the wettability of Li atoms on the （111） surfaces of W and Mo substrates［J］. Plasma Physics Reports， 2018， 44（7）： 692-701. DOI： 10.1134/s1063780x18070097 .
[19]	Skinner C H， Capece A M， Roszell J P， et al. Spreading of lithium on a stainless steel surface at room temperature［J］. Journal of Nuclear Materials， 2016， 468： 26-30. DOI： 10.1016/j.jnucmat.2015.10.059 .
[20]	Kresse G， Joubert D. From ultrasoft pseudopotentials to the projector augmented-wave method［J］. Physical Review B， 1999， 59（3）： 1758-1775. DOI： 10.1103/PhysRevB.59.1758 .
[21]	Kresse G， Furthmüller J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set［J］. Physical Review B， 1996， 54（16）： 11169-11186. DOI： 10.1103/PhysRevB.54.11169 .
[22]	Kresse G， Furthmüller J. Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set［J］. Computational Materials Science， 1996， 6（1）： 15-50. DOI： 10.1016/0927-0256（96）00008-0 .
[23]	Blöchl P E. Projector augmented-wave method［J］. Physical Review B， 1994， 50（24）： 17953-17979. DOI： 10.1103/physrevb.50.17953 .
[24]	Perdew J P， Ruzsinszky A， Tao J M， et al. Prescription for the design and selection of density functional approximations： more constraint satisfaction with fewer fits［J］. The Journal of Chemical Physics， 2005， 123（6）： 62201. DOI： 10.1063/1.1904565 .
[25]	Monkhorst H J， Pack J D. Special points for Brillouin-zone integrations［J］. Physical Review B， 1976， 13（12）： 5188-5192. DOI： 10.1103/PhysRevB.13.5188 .
[26]	Xu Y， Zhang Y， Li X， et al. The adsorption and dissolution properties of iron surfaces in liquid lithium and lead under a fusion environment［J］. Journal of Nuclear Materials， 2019， 524： 200-208. DOI： 10.1016/j.jnucmat.2019.06.033 .
[27]	Henkelman G， Uberuaga B P， Jónsson H. A climbing image nudged elastic band method for finding saddle points and minimum energy paths［J］. The Journal of Chemical Physics， 2000， 113（22）： 9901-9904. DOI： 10.1063/1.1329672 .