-
在能源结构转型背景下, 开发高效储热材料是提升太阳能热发电技术的关键. 硝酸熔盐因热稳定性优异、储热密度高而被广泛应用, 但其性能优化多依赖传统实验与模拟方法, 存在效率低、成本高等问题. 本研究引入固体与分子经验电子理论(EET), 系统分析了硝酸盐MNO3 (M = Li, Na, K)及其分解产物亚硝酸盐MNO2的价电子结构、结合能和熔点, 揭示了其物性与价电子结构之间的关联机制. 计算的键长、结合能和熔点与实验相符. 结果表明: 其结合能与价电子成正相关; 熔融源于M—O键的断键, 其价电子对数与熔点呈显著正相关. 研究了二元硝酸盐的液相线与价电子结构的关联性, 计算的液相线与实验相符. 通过优化价电子结构, 可调控液化温度. 应用热动力学理论预测二元硝酸熔盐的结合黏度、电导率和热导率. 通过物性综合优化, 筛选出0.5LiNO3-0.5NaNO3等低液化温度、低黏度、高电导率、高热导率的二元硝酸盐成分. 本研究为硝酸熔盐成分设计提供了电子结构层面的依据.Nitrate molten salt is widely used as an efficient thermal storage material for improving concentrated solar power (CSP) technology, which is due to their many excellent properties such as thermal stability, high energy density, low viscosity and liquefaction temperature. However, it is not convenient to measure the performance of nitrate for a long time in a high temperature molten state, which can cause the storage containers made of stainless steel to be corroded by nitrate salt. Simulations also face huge challenges in optimizing the performance of nitrate molten salts, with models being complex and calculation time being long. In this study, an empirical electron theory (EET) of solids and molecules is used to investigate the valence electron structure, cohesive energy, and melting points of MNO3 (M = Li, Na, K) and their decomposition byproducts (nitrites) systematically for revealing the mechanisms of these properties. The calculated bond lengths, cohesive energy, and melting points of nitrate molten salt are in agreement with their corresponding measurements. This study reveals the strong dependence of physical properties on the valence electron structure. The bonding strength and ability strongly depend on the covalent electron pairs $ {n}_{\alpha } $. The cohesive energy exhibits a positive correlation with the number of valence electrons $ {n}_{\mathrm{c}} $. The melting mechanism originates from the melting-broken M—O (M = Li, Na, K) bond by the vibrating of thermal phonon at melting temperature. It is suggested that the atomic cluster of NO3 is still stabilized in the melting process. In binary nitrate molten-salts, the calculated liquidus lines match the measured ones in their binary phase diagrams well. The liquid temperatures show significant positive correlation with the weighted average number of covalent electron pairs ($ {n}_{{\mathrm{M}}—{\mathrm{O}}} $) on M—O bond. The thermodynamic simulation models are used systematically to predict the viscosity, electrical conductivity, and thermal conductivity of the binary nitrate molten-salts. Based on the calculations of EET and thermodynamic simulations, the composition of binary nitrate molten salts is optimized as 0.5LiNO3-0.5NaNO3, 0.5LiNO3-0.5KNO3, and 0.6NaNO3-0.4KNO3, which are considered as good candidates for advanced molten salts with high thermal conductivity, high electrical conductivity, low viscosity, and low liquefaction temperature.
-
Keywords:
- nitrates /
- valence electron structure /
- melting point /
- cohesive energy
-
图 1 单元硝酸熔盐的晶体结构示意图 (a) LiNO3; (b) NaNO3; (c) KNO3; (d) NaNO2; (e) KNO2
Fig. 1. Diagram of the crystal structure of the unit nitrate molten salt: (a) LiNO3; (b) NaNO3; (c) KNO3; (d) NaNO2; (e) KNO2.
图 2 键能$ {E}_{\alpha } $和共价电子对数$ {n}_{\alpha } $变化趋势
Fig. 2. Variation trends of bond energy $ {E}_{\alpha } $ and covalent electron pair numbers $ {n}_{\alpha } $.
图 3 MNOx (M = Li, Na, K)的熔点$ {T}_{\mathrm{m}} $和M—O键的$ {n}_{\alpha } $变化趋势
Fig. 3. Variation trends of melting points $ {T}_{\mathrm{m}} $ and M—O covalent electron pair numbers $ {n}_{\alpha } $ in MNOx (M = Li, Na, K).
图 4 二元硝酸盐的液相线与共价电子对数$ {n}_{M—\mathrm{O}} $变化趋势 (a) (1–x)NaNO3-xKNO3; (b) (1–x)LiNO3-xKNO3; (c) (1–x)LiNO3-xNaNO3
Fig. 4. Variation trends of liquidus temperatures and M—O covalent electron pair numbers $ {n}_{M—\mathrm{O}} $ in binary nitrate molten salts: (a) (1–x)NaNO3-xKNO3; (b) (1–x)LiNO3-xKNO3; (c) (1–x)LiNO3-xNaNO3.
图 5 LiNO3-NaNO3, LiNO3-KNO3, NaNO3-KNO3的黏度
Fig. 5. Viscosity of LiNO3-NaNO3, LiNO3-KNO3, NaNO3-KNO3 systems.
图 6 二元硝酸熔盐体系的电导率和热导率 (a) LiNO3-NaNO3; (b) LiNO3-KNO3; (c) NaNO3-KNO3
Fig. 6. Electrical and thermal conductivities of binary nitrate molten salts: (a) LiNO3-NaNO3; (b) LiNO3-KNO3; (c) NaNO3-KNO3.
图 7 黏度、电导率和热导率关系图 (a) (1–x)LiNO3-xNaNO3; (b) (1–x)LiNO3-xKNO3; (c) (1–x)NaNO3-xKNO3
Fig. 7. Correlation diagram of viscosity, electrical conductivity, and thermal conductivity for binary nitrate molten salts: (a) (1–x)LiNO3-xNaNO3, (b) (1–x)LiNO3-xKNO3; (c) (1–x)NaNO3-xKNO3 systems.
表 1 MNO3 (M = Li, Na, K)和MNO2 (M = Na, K)的熔点和结合能计算结果
Table 1. Calculation results of melting points and cohesive energy for MNO3 (M = Li, Na, K) and MNO2 (M = Na, K).
MNOx $ {T}_{m} $/K[41] $ {\overline{T}}_{m} $/K $ \dfrac{\left|\Delta{T}_{m}\right|}{{T}_{m}} $/% $ {n}_{\mathrm{M}—\mathrm{O}} $/atom–1 $ {E}_{c}/ $( eV·atom–1)[42] $ {\overline{E}}_{c}/( $eV·atom–1) $ \dfrac{\left|\Delta{E}_{c}\right|}{{E}_{c}} $/% LiNO3 527.5 518.56 1.6 0.1795 14.350 13.986 2.5 NaNO3 579.1 586.00 1.2 0.2009 13.833 13.821 0.1 KNO3 612.2 640.27 4.6 0.2779 13.654 12.683 7.1 NaNO2 554.0 563.54 1.7 0.1859 11.233 11.582 3.1 KNO2 713.0 691.66 3.0 0.2159 11.054 10.936 1.1 
下载: 导出CSV
表 2 二元共晶熔盐体系的计算和观测的液化温度和混合能
Table 2. Calculated and observed liquidus temperatures and mixing energy for binary eutectic molten salt systems.
共晶成分 $ {T}_{\mathrm{m}}/\mathrm{K} $[41] $ {\overline{T}}_{\mathrm{m}}/\mathrm{K} $ $ \dfrac{\left|\Delta{T}_{\mathrm{m}}\right|}{{T}_{\mathrm{m}}}/{\text{%}} $ $ {E}_{\mathrm{c}}/ $( eV·atom–1)[42] $ {\overline{E}}_{\mathrm{c}}/( $eV·atom–1) $ \dfrac{\left|\Delta{E}_{\mathrm{c}}\right|}{{E}_{\mathrm{c}}}/{\text{%}} $ 0.5NaNO3-0.5KNO3 494.0 497.77 0.8 13.743 13.629 0.8 0.44LiNO3-0.56KNO3 410.5 406.49 1.0 13.948 13.179 5.5 0.537LiNO3-0.463NaNO3 473.5 439.77 7.1 14.111 13.671 3.1
下载: 导出CSV
表 3 (1–x)NaNO3-xKNO3二元复合熔盐体系的计算和观测的液化温度和混合能
Table 3. Calculated and observed liquidus temperatures and mixing energy for (1–x)NaNO3-xKNO3 binary molten salt system.
x $ {T}_{\mathrm{m}} $/K[41] $ {\overline{T}}_{\mathrm{m}} $/K $ \dfrac{\left|\Delta{T}_{\mathrm{m}}\right|}{{T}_{\mathrm{m}}} $/% $ {n}_{\mathrm{M}—\mathrm{O}} $/atom–1 $ {E}_{\mathrm{c}}/ $(eV·atom–1)[42] $ {\overline{E}}_{\mathrm{c}}/( $eV·atom–1) $ \dfrac{\left|\Delta{E}_{\mathrm{c}}\right|}{{E}_{\mathrm{c}}} $/% 0.1 563 566.42 0.6 0.199 13.815 13.705 0.8 0.2 546 556.96 2.0 0.1908 13.797 12.762 7.5 0.3 528 537.35 1.8 0.1763 13.779 12.924 6.2 0.4 512 522.50 2.1 0.1522 13.761 13.687 0.5 0.5 494 497.77 0.8 0.1479 13.743 13.629 0.8 0.6 514 509.20 0.9 0.1564 13.726 13.481 1.8 0.7 540 549.02 1.7 0.1769 13.708 13.209 3.6 0.8 565 558.5 1.2 0.1865 13.690 13.022 4.9 0.9 588 558.72 5.0 0.1947 13.672 12.812 6.3
下载: 导出CSV
表 4 (1–x)LiNO3-xKNO3二元复合熔盐体系的计算和观测的液化温度和混合能
Table 4. Calculated and observed liquidus temperatures and mixing energy for (1–x)LiNO3-xKNO3 binary molten salt system.
x $ {T}_{\mathrm{m}} $/K[41] $ {\overline{T}}_{\mathrm{m}} $/K $ \dfrac{\left|\Delta{T}_{\mathrm{m}}\right|}{{T}_{\mathrm{m}}} $/% $ {n}_{\mathrm{M}—\mathrm{O}} $/atom–1 $ {E}_{\mathrm{c}}/ $(eV·atom–1)[42] $ {\overline{E}}_{\mathrm{c}}/( $eV·atom–1) $ \dfrac{\left|\Delta{E}_{\mathrm{c}}\right|}{{E}_{\mathrm{c}}} $/% 0.1 514.3 493.85 4.0 0.1788 14.280 13.831 3.1 0.2 497.7 474.34 4.7 0.1766 14.211 12.952 8.9 0.3 477.9 481.83 0.8 0.1693 14.141 13.166 6.9 0.4 453.6 452.15 0.3 0.158 14.072 13.205 6.2 0.5 427.2 418.89 1.9 0.1471 14.002 13.195 5.8 0.56 410.5 406.49 1.0 0.1429 13.948 13.179 5.5 0.6 437.6 429.44 1.9 0.1472 13.932 12.678 9.0 0.7 476 458.42 3.7 0.1528 13.863 12.633 8.9 0.8 524.4 521.35 0.6 0.172 13.793 12.558 9.0 0.9 572.8 575.54 0.5 0.1964 13.724 12.878 6.2
下载: 导出CSV
表 5 (1–x)LiNO3-xNaNO3二元复合熔盐体系的计算和观测的液化温度和混合能
Table 5. Calculated and observed liquidus temperatures and mixing energy for (1–x)LiNO3-xNaNO3 binary molten salt system.
x $ {T}_{\mathrm{m}} $/K[41] $ {\overline{T}}_{\mathrm{m}} $/K $ \dfrac{\left|\Delta{T}_{\mathrm{m}}\right|}{{T}_{\mathrm{m}}} $/% $ {n}_{\mathrm{M}—\mathrm{O}} $/atom–1 $ {E}_{\mathrm{c}}/ $(eV·atom–1)[42] $ {\overline{E}}_{\mathrm{c}}/( $eV·atom–1) $ \dfrac{\left|\Delta{E}_{\mathrm{c}}\right|}{{E}_{\mathrm{c}}} $/% 0.1 517.9 503.94 2.7 0.1773 14.298 13.97 2.3 0.2 507.1 485.17 4.3 0.1737 14.247 13.88 2.6 0.3 495.2 467.32 5.6 0.1702 14.195 13.796 2.8 0.4 482 450.07 6.6 0.1667 14.143 13.718 3.0 0.463 473.5 439.77 7.1 0.1645 14.111 13.671 3.1 0.5 482.5 469.06 2.8 0.1787 14.091 13.608 3.4 0.6 499.4 485.9 2.7 0.1827 14.04 14.255 1.5 0.7 520.1 512.96 1.4 0.179 13.988 13.799 1.4 0.8 538.7 564.38 4.8 0.1835 13.936 14.084 1.1 0.9 558.7 566.4 1.4 0.1881 13.885 13.986 0.7
下载: 导出CSV
-
[1] 许丹, 于彩莲, 李芬, 杨莹, 李博琳, 芦柳, 蔺宇晨 2024 材料导报 38 33
Xu D, Yu C L, Li F, Yang Y, Li B L, Lu L, Lin Y C 2024 Mater. Rep. 38 33
[2] 张宏韬, 赵有璟, 张萍, 时历杰, 李锦丽, 康为清, 黄培锦, 王敏 2015 材料导报 29 54
Zhang H T, Zhao Y J, Zhang P, Shi L J, Li J L, Kang W Q, Huang P J, Wang M 2015 Mater. Rep. 29 54
[3] 陈冬, 吕洪坤, 丁历威, 来振亚, 肖刚, 祝培旺 2024 太阳能学报 45 432
Chen D, Lv H K, Ling L W, Lai Z Y, Xiao G, Zhu P W 2024 Acta Energ. Sol. Sin. 45 432
[4] 范刚, 宋健, 宫啸宇, 傅子隽, 张嘉耕, 戴义平 2024 太阳能学报 45 590
Fan G, Song J, Gong X Y, Fu Z J, Zhang J G, Dai Y P 2024 Acta Energ. Sol. Sin. 45 590
[5] Bajaj I, Peng X, Maravelias C T 2024 RSC Sustain. 2 943
Google Scholar
[6] 孙华, 苏兴治, 张鹏, 王建强 2017 腐蚀科学与防护技术 29 282
Sun H, Su X Z, Zhang P, Wang J Q 2017 Corros. Sci. Prot. Technol. 29 282
[7] Li B, Zheng Y, Shao X, Jiang Z, Zhang X, Wang W, Lu J, Li Y 2023 Int. J. Refract. Met. Hard Mater. 112 106162
Google Scholar
[8] Mohammad M B, Cadusch P, Brooks G A, Rhamdhani M A 2018 Metall. Mater. Trans. B 49 3580
Google Scholar
[9] Wang T, Mantha D, Reddy R G 2012 Sol. Mat. 100 162
[10] Kramer C M, Wilson C J 1980 Thermochim. Acta 42 253
Google Scholar
[11] Greis O, Bahamdan K M, Uwais B M 1985 Thermochim. Acta 86 343
Google Scholar
[12] Maeso M J, Largo J 1993 Thermochim. Acta 223 145
Google Scholar
[13] Zang X J, Tian J, Xu K C, Gao Y C 2003 J. Phase Equilib. 24 441
Google Scholar
[14] 陈静, 曾德文, 李东东, 王军涛, 韩海军, 郭立江 2015 无机盐工业 47 38
Chen J, Zeng D W, Li D D, Wang J T, Han H J, Guo L J 2015 Inorg. Chem. Ind. 47 38
[15] Mochinaga J, Ohtani H, Igarashi K 1981 Bunseki Kagaku 49 19
[16] Bonk A, Braun M, Bauer T 2022 Sol. Energy 231 1061
Google Scholar
[17] Zhong Y, Wang M, Wang H Y, Yuan J S 2021 Sol. Energy Mater. Sol. Cells 230 111148
Google Scholar
[18] Li X 2019 Ph. D. Dissertation (Shanghai: Shanghai Institute of Applied Physics) [李想 2019 博士学位论文 (上海: 中国科学院上海应用物理研究所)]
Li X 2019 Ph. D. Dissertation (Shanghai: Shanghai Institute of Applied Physics)
[19] 罗海华, 沈强, 林俊光, 张艳梅, 徐云柯 2020 储能科学与技术 9 1755
Luo H H, Shen Q, Lin J G, Zhang Y M, Xu Y K 2020 Energ. Storage Sci. Technol. 9 1755
[20] Wang X Z, Guo Y Q, Li B Y, Feng Y C, Tang W 2025 Phys. E: Low-Dimens. Syst. Nanostructures 165 116124
Google Scholar
[21] Yang Z Y, Guo Y Q, Zhang X P, Tang W, Li B Y, Feng Y C 2024 J. Energy Storage 91 111963
Google Scholar
[22] Lv M Z, Xu B, Cai L C, Jia F, Yuan X D 2019 Chin. Phys. Lett. 36 013101
Google Scholar
[23] Li B, Zheng Y, Shao X, Jiang Z Y, Zhang X, Wang W W, Lu J, Li Y F 2023 Int. J. Refract. Met. Hard Mater. 112 106162
Google Scholar
[24] Fu B Q, Liu W, Li Z L 2009 Appl. Surf. Sci. 255 8511
Google Scholar
[25] Fu B Q, Liu W, Li Z L 2010 Appl. Surf. Sci. 256 6899
Google Scholar
[26] Li S, Ma C L, Hou X H, Wang H L, Shi C X, Guo R, Zhou Y 2022 J. Alloys Compd. 907 164409
Google Scholar
[27] Yin L H, Guo Y Q, Guo X P 2022 Inorg. Chem. 61 2402
Google Scholar
[28] Feng Y C, Guo Y Q, Yao Y, Liu W, Li B Y, Yin L H, Wang T 2023 J. Phys. Chem. C 127 21328
Google Scholar
[29] Wang T, Guo Y Q, Wang C 2021 Chin. Phys. B 30 043101
Google Scholar
[30] Guo Y Q, Su T, Zhang J, Wang X Q, Chen Y, Zhao X 2020 ACS Appl. Energy Mater. 3 5361
Google Scholar
[31] Li B Y, Guo Y Q, Yang Z Y, Wang X Z, Feng Y C, Tang W, Peng S Q, Su T 2024 Phys. Chem. Chem. Phys. 26 25819
Google Scholar
[32] 张晓鹏, 杨震宇, 唐玮, 李博洋, 冯奕晨, 赵兴, 郭永权, 李宝让 2024 兵器材料科学与工程 1 11
Zhang X P, Yang Z Y, Tang W, Li B Y, Feng Y C, Zhao X, Guo Y Q, Li B R 2024 Ordn. Mater. Sci. Eng. 1 11
[33] Guo Y Q, Yü R H, Zhang R L, Zhang X H, Tao K 1998 J. Phys. Chem. B 102 9
[34] Yu R H 1978 Sci. Bull 23 217
[35] Rao C, Prakash B, Natarajan M 1975 Crystal Structure Transformations in Inorganic Nitrites Nitrates and Carbonates (1st Ed. ) (Washington, D. C. : U. S. Government Printing Office) p3
[36] Benages-Vilau R, Calvet T, Cuevas-Diarte M A 2014 Crystallogr. Rev. 20 25
Google Scholar
[37] Zachariasen W H 1929 GFF 51 123
[38] Gonschorek G, Weitzel H, Miehe G, Fuess H, Schmahl W W 2000 Z. Kristallogr. - Cryst. Mater. 215 752
Google Scholar
[39] Solbakk J K, Strømme K O, Rasmussen S E, Smidsrød O, Lindberg A A, Jansen G, Lamm B, Samuelsson B 1969 Acta Chem. Scand. 23 20
[40] Schiebel P, Altenburger W, Hoser A, Prandl W, Hiller W 1990 Z. Kristallogr. - Cryst. Mater. 190 63
Google Scholar
[41] Predel F, Predel B 2016 Phase Equilibria, Crystallographic and Thermodynamic Data of Binary Alloys (Volume 12D) (Berlin: Springer) p1
[42] Kittel, C 2004 Introduction to Solid State Physics (8th Edition) (New York: John Wiley & Sons) p1
[43] Mohammad M B, Cadusch P, Brooks G A, Rhamdhani M A 2018 Metall. Mater. Trans. B 49 3580
Google Scholar
[44] Janz G J 1968 Molten Salts 1 139
[45] Abe Y, Kosugiyama O, Nagashima A 1981 J. Nucl. Mater. 99 173
Google Scholar
[46] Wakao M, Minami K, Nagashima A 1991 Int. J. Thermophys. 12 223
Google Scholar
[47] Sato Y, Fukasawa M, Yamamura T 1997 Int. J. Thermophys. 18 1123
Google Scholar
[48] Bloomfield V A, Dewan R 1971 J. Phys. Chem. 75 3113
Google Scholar
[49] Fujiwara S, Inaba M, Tasaka A 2010 J. Power Sources 195 7691
Google Scholar
[50] Fujiwara S, Inaba M, Tasaka A 2011 J. Power Sources 196 4012
Google Scholar
[51] Gheribi A E, Torres J A, Chartrand P 2014 Sol. Energy Mater. Sol. Cells 126 11
Google Scholar
[52] Li Y Y, Xu X K, Wang X X, Li P W, Hao Q, Xiao B 2017 Sol. Energy 152 57
Google Scholar
[53] Hossain M Z, Kassaee M H, Jeter S, Teja A S 2014 Int. J. Thermophys. 35 246
Google Scholar
[54] Hu C X 2018 M. S. Thesis (Beijing: Beijing University of Technology) [胡春旭 2018硕士学位论文 (北京: 北京工业大学)]
Hu C X 2018 M. S. Thesis (Beijing: Beijing University of Technology)
[55] Murgulescu I G, Zuca S 1969 Electrochim. Acta 14 519
Google Scholar
[56] Murgulescu I G, Zuca S 1966 Electrochim. Acta 11 1383
Google Scholar
[57] Stern K H 1972 J. Phys. Chem. Ref. Data 1 747
Google Scholar
下载:
计量
- 文章访问数: 378
- PDF下载量: 3
- 被引次数: 0
