锂离子电池正极材料Li_2MnO_3稀土掺杂的第一性原理研究
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摘要
掺杂是锂离子电池电极材料优化改性的一种有效的方法.稀土元素因其具有高的电子电荷、大的离子半径以及强的自极化能力,成为掺杂改性的重要选择.本文利用基于密度泛函理论的第一性原理方法研究了稀土元素(La, Ce, Pr, Sm)掺杂的锂离子电池正极材料Li_2MnO_3的性质.通过稀土元素的掺杂, Li_2MnO_3材料的晶格常数和晶胞体积都有不同程度的增大.由于稀土原子的价态不同,导致掺杂后的Li_2MnO_3的电子结构性质不同. La掺杂的Li_2MnO_3表现出金属性,而Ce, Pr, Sm掺杂的结构为半导体性质,但带隙与未掺杂情况下相比有所减小. Li_2MnO_3中的Li离子迁移在La和Ce掺杂后展示出复杂的能垒变化.在远离稀土离子处,Li离子迁移势垒比未掺杂时减小,但在靠近稀土离子处则表现为势垒变化的多样性.当Li离子在离稀土离子最近的位置处进行迁移,势垒有明显的增加,这一结果与稀土离子周围的局域结构变化大密切相关.
Although Li-ion batteries(LIBs) have had great success in portable electronic devices and electrical vehicles, the improvement of the performances has received intensive attention. Generally, doping is an effective method to modify the battery performance, such as cycling performance. Appropriate doping can effectively reduce the structural deformation of electrode materials during charging and discharging, thus improving the cycling performace of LIBs. Because of the large radius, large charge and strong self-polarization ability of rare earth ions, rare earth element is a promising candidate for doping modification. Motivated by this, we study the structural, electronic and ionic diffusion properties of rare-earth-doped cathode material Li_2MnO_3 by using firstprinciples calculations based on density functional theory as implemented in Vienna ab initio simulation package. After the doping of rare earth elements(La, Ce, Pr, Sm), the lattice constants and cell volumes increase with respect to the undoped one. The cell volume of La-doped Li_2MnO_3 has the biggest change, while the cell volume of Sm-doped one has the smallest change. Due to the different ionic valence states, the electronic structures of the doped Li_2MnO_3 are various. La-doped Li_2MnO_3 exhibits metallic characteristic,whereas Ce-, Pr-, and Sm-doped structures are semiconducting with smaller band gap than that of the undoped case. The Li diffusion energy barrier in Li_2MnO_3 shows complicated variation when the La and Ce are doped.At the sites far away from the rare earth ions, the Li diffusion barriers are lower than that of undoped one. The reason is that the diffusion channels, which are determined by the distance between neighboring O-layers, are enlarged due to the implantment of rare earth ions. However, the situations are various at the sites close to the rare earth ions. The Li diffusion barriers increase essentially when Li ions diffuse from the nearest sites to rare earth ions. Such a result is closely related to the huge changes of local structures around the rare earth ions. In addition, the effect of La doping on the Li diffusion barrier is more obvious than that of Ce doping, which is due to the local structure change around rare earth ions.
Although Li-ion batteries(LIBs) have had great success in portable electronic devices and electrical vehicles, the improvement of the performances has received intensive attention. Generally, doping is an effective method to modify the battery performance, such as cycling performance. Appropriate doping can effectively reduce the structural deformation of electrode materials during charging and discharging, thus improving the cycling performace of LIBs. Because of the large radius, large charge and strong self-polarization ability of rare earth ions, rare earth element is a promising candidate for doping modification. Motivated by this, we study the structural, electronic and ionic diffusion properties of rare-earth-doped cathode material Li_2MnO_3 by using firstprinciples calculations based on density functional theory as implemented in Vienna ab initio simulation package. After the doping of rare earth elements(La, Ce, Pr, Sm), the lattice constants and cell volumes increase with respect to the undoped one. The cell volume of La-doped Li_2MnO_3 has the biggest change, while the cell volume of Sm-doped one has the smallest change. Due to the different ionic valence states, the electronic structures of the doped Li_2MnO_3 are various. La-doped Li_2MnO_3 exhibits metallic characteristic,whereas Ce-, Pr-, and Sm-doped structures are semiconducting with smaller band gap than that of the undoped case. The Li diffusion energy barrier in Li_2MnO_3 shows complicated variation when the La and Ce are doped.At the sites far away from the rare earth ions, the Li diffusion barriers are lower than that of undoped one. The reason is that the diffusion channels, which are determined by the distance between neighboring O-layers, are enlarged due to the implantment of rare earth ions. However, the situations are various at the sites close to the rare earth ions. The Li diffusion barriers increase essentially when Li ions diffuse from the nearest sites to rare earth ions. Such a result is closely related to the huge changes of local structures around the rare earth ions. In addition, the effect of La doping on the Li diffusion barrier is more obvious than that of Ce doping, which is due to the local structure change around rare earth ions.
引文
[1]Tarascon J M, Armand M 2001 Nature 414 359
[2]Liu H, Cao Q, Fu L J, Li C, Wu Y P, Wu H Q 2006Electrochem. Commun. 8 1553
[3]Xiao P H, Deng Z Q, Manthiram A, Henkelman G 2012 J.Phys. Chem. C 116 23201
[4]Hou Y H, Huang Y L, Liu Z W, Zeng D C 2015 Acta Phys.Sin. 64 037501(in Chinese)[候育花,黄有林,刘仲武,曾德长2015物理学报64 037501]
[5]Ghosh P, Mahanty S, Basu R N 2009 Electrochim. Acta 541654
[6]Liao C F, Chen H H, Chen Z P 2004 Jiangxi Nonferrous Metals 18 33(in Chinese)[廖春发,陈辉煌,陈子平2004江西有色金属18 33]
[7]Wei J P, Cao X Y, Pan G L, Ye M, Yan J 2003 J. Rare Earths 21 466
[8]Balaji S, Manichandran T, Mutharasu D 2012 Bull. Mater.Sci. 35 471
[9]Iqbal M J, Ahmad Z 2008 J. Power Sources 179 763
[10]Khedr A M, Abou-Sekkina M M, El-Metwaly F G 2013 J.Electron. Mater. 42127 5
[11]Tang Z Y, Zhang N, Lu X H 2005 J. Rare Earths 23 120
[12]Ye L, Zhang H L 2012 Rare Metal Mater. Eng. 41 636(in Chinese)[叶兰,张海朗2012稀有金属材料与工程41 636]
[13]Luo S H, Tian Y, Li H, Shi K J, Tang Z L, Zhang Z T 2010J. Rare Earths 28 439
[14]Chen H, Xiang K X, Gong W Q, Liu J H 2011 Rare Metal Mater. Eng. 40 1936(in Chinese)[陈晗,向楷雄,龚文强,刘建华2011稀有金属材料与工程40 1936]
[15]Zhang Y J, Xia S B, Zhang Y N, Dong P, Yan Y X, Yang R M 2012 Chin. Sci. Bull. 57 4181
[16]Yang S T, Jia J H, Zheng L Q, Cao Z X 2003 J. Chin. Rare Earth Soc. 21 413(in Chinese)[杨书廷,贾俊华,郑立庆,曹朝霞2003中国稀土学报21 413]
[17]Sun H B, Chen Y G, Xu C H, Zhu D, Huang L H 2012 J.Solid State Electrochem. 16 1247
[18]Tian Y W, Kang X X, Liu L Y 2008 J. Rare Earths 26 279
[19]Ding Y H, Zhang P, Jiang Y, Gao D S 2007 Solid State Ionics178 967
[20]Zhao S X, Guo S T, Deng Y F, Xiong K, Xu Y H, Nan C W2017 J. Chin. Ceram. Soc. 45 495(in Chinese)[赵世玺,郭双桃,邓玉峰,熊凯,徐亚辉,南策文2017硅酸盐学报45 495]
[21]He P, Yu H J, Li D, Zhou H S 2012 J. Mater. Chem. 22 3680
[22]Gao Y R, Ma J, Wang X F, Lu X, Bai Y, Wang Z X, Chen L Q 2014 J. Mater. Chem. A 2 4811
[23]Wang Z Q, Wu M S, Xu B, Ouyang C Y 2016 J. Alloy Compd. 658 818
[24]Shi S, Gao J, Liu Y, Zhao Y, Wu Q, Ju W, Ouyang C, Xiao R 2016 Chin. Phys. B 25 018212
[25]Kresse G, Furthmüller J 1996 Phys. Rev. B 54 11169
[26]Bl?chl P E 1994 Phys. Rev. B 50 17953
[27]Perdew J P, Chevary J A, Vosko S H, Jackson K A, Pederson M R, Singh D J, Fiolhais C 1992 Phys. Rev. B 46 6671
[28]Anisimov V I, Zaanen J, Andersen O K 1991 Phys. Rev. B 44943
[29]Koyama Y, Tanaka I, Nagao M, Kanno R 2009 J. Power Sources 189 798
[30]Zhou F, Cococcioni M, Marianetti C A, Morgan D, Ceder G2004 Phys. Rev. B 70 235121
[31]Ning F H, Xu B, Shi J, Wu M S, Hu Y Q, Ouyang C Y 2016J. Phys. Chem. C 120 18428
[32]Monkhorst H J, Pack J D 1976 Phys. Rev. B 13 5188
[33]Henkelman G, Jónsson H 2000 J. Chem. Phys. 113 9978
[34]Henkelman G, Uberuaga B P, Jónsson H 2000 J. Chem. Phys.113 9901
[35]Zheng L M, Wang H W, Luo M, Wang G Q, Wang Z Q,Ouyang C Y 2018 Solid State Ionics 320 210
[36]Strobel P, Lambert-Andron B 1988 J. Solid State Chem. 7590
[37]Xiao R J, Li H, Chen L Q 2012 Chem. Mater. 24 4242
[38]Zhu Y, Li J, Ji X, Li T, Jin M, Ou X, Shen X, Wang W,Huang F 2018 AIP Adv. 8 105014
[2]Liu H, Cao Q, Fu L J, Li C, Wu Y P, Wu H Q 2006Electrochem. Commun. 8 1553
[3]Xiao P H, Deng Z Q, Manthiram A, Henkelman G 2012 J.Phys. Chem. C 116 23201
[4]Hou Y H, Huang Y L, Liu Z W, Zeng D C 2015 Acta Phys.Sin. 64 037501(in Chinese)[候育花,黄有林,刘仲武,曾德长2015物理学报64 037501]
[5]Ghosh P, Mahanty S, Basu R N 2009 Electrochim. Acta 541654
[6]Liao C F, Chen H H, Chen Z P 2004 Jiangxi Nonferrous Metals 18 33(in Chinese)[廖春发,陈辉煌,陈子平2004江西有色金属18 33]
[7]Wei J P, Cao X Y, Pan G L, Ye M, Yan J 2003 J. Rare Earths 21 466
[8]Balaji S, Manichandran T, Mutharasu D 2012 Bull. Mater.Sci. 35 471
[9]Iqbal M J, Ahmad Z 2008 J. Power Sources 179 763
[10]Khedr A M, Abou-Sekkina M M, El-Metwaly F G 2013 J.Electron. Mater. 42127 5
[11]Tang Z Y, Zhang N, Lu X H 2005 J. Rare Earths 23 120
[12]Ye L, Zhang H L 2012 Rare Metal Mater. Eng. 41 636(in Chinese)[叶兰,张海朗2012稀有金属材料与工程41 636]
[13]Luo S H, Tian Y, Li H, Shi K J, Tang Z L, Zhang Z T 2010J. Rare Earths 28 439
[14]Chen H, Xiang K X, Gong W Q, Liu J H 2011 Rare Metal Mater. Eng. 40 1936(in Chinese)[陈晗,向楷雄,龚文强,刘建华2011稀有金属材料与工程40 1936]
[15]Zhang Y J, Xia S B, Zhang Y N, Dong P, Yan Y X, Yang R M 2012 Chin. Sci. Bull. 57 4181
[16]Yang S T, Jia J H, Zheng L Q, Cao Z X 2003 J. Chin. Rare Earth Soc. 21 413(in Chinese)[杨书廷,贾俊华,郑立庆,曹朝霞2003中国稀土学报21 413]
[17]Sun H B, Chen Y G, Xu C H, Zhu D, Huang L H 2012 J.Solid State Electrochem. 16 1247
[18]Tian Y W, Kang X X, Liu L Y 2008 J. Rare Earths 26 279
[19]Ding Y H, Zhang P, Jiang Y, Gao D S 2007 Solid State Ionics178 967
[20]Zhao S X, Guo S T, Deng Y F, Xiong K, Xu Y H, Nan C W2017 J. Chin. Ceram. Soc. 45 495(in Chinese)[赵世玺,郭双桃,邓玉峰,熊凯,徐亚辉,南策文2017硅酸盐学报45 495]
[21]He P, Yu H J, Li D, Zhou H S 2012 J. Mater. Chem. 22 3680
[22]Gao Y R, Ma J, Wang X F, Lu X, Bai Y, Wang Z X, Chen L Q 2014 J. Mater. Chem. A 2 4811
[23]Wang Z Q, Wu M S, Xu B, Ouyang C Y 2016 J. Alloy Compd. 658 818
[24]Shi S, Gao J, Liu Y, Zhao Y, Wu Q, Ju W, Ouyang C, Xiao R 2016 Chin. Phys. B 25 018212
[25]Kresse G, Furthmüller J 1996 Phys. Rev. B 54 11169
[26]Bl?chl P E 1994 Phys. Rev. B 50 17953
[27]Perdew J P, Chevary J A, Vosko S H, Jackson K A, Pederson M R, Singh D J, Fiolhais C 1992 Phys. Rev. B 46 6671
[28]Anisimov V I, Zaanen J, Andersen O K 1991 Phys. Rev. B 44943
[29]Koyama Y, Tanaka I, Nagao M, Kanno R 2009 J. Power Sources 189 798
[30]Zhou F, Cococcioni M, Marianetti C A, Morgan D, Ceder G2004 Phys. Rev. B 70 235121
[31]Ning F H, Xu B, Shi J, Wu M S, Hu Y Q, Ouyang C Y 2016J. Phys. Chem. C 120 18428
[32]Monkhorst H J, Pack J D 1976 Phys. Rev. B 13 5188
[33]Henkelman G, Jónsson H 2000 J. Chem. Phys. 113 9978
[34]Henkelman G, Uberuaga B P, Jónsson H 2000 J. Chem. Phys.113 9901
[35]Zheng L M, Wang H W, Luo M, Wang G Q, Wang Z Q,Ouyang C Y 2018 Solid State Ionics 320 210
[36]Strobel P, Lambert-Andron B 1988 J. Solid State Chem. 7590
[37]Xiao R J, Li H, Chen L Q 2012 Chem. Mater. 24 4242
[38]Zhu Y, Li J, Ji X, Li T, Jin M, Ou X, Shen X, Wang W,Huang F 2018 AIP Adv. 8 105014