Mn掺杂TiO_2(101)提高锂空电池阴极催化活性的第一性原理研究
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摘要
本文基于密度泛函理论对TiO_2(101)和Mn_xTi_(1-x)O_2(101)作为锂空电池阴极催化材料进行了研究,发现其表面能够生成两种不同结构的Li_2O_2,进一步地研究了其中最稳定的生成结构并通过计算锂空电池首次充放电过程中的过电势来评价催化性能.结果表明,Mn掺杂进入Ti O_2(101)对充放电的过电势均有降低作用,深入分析发现掺杂Mn对TiO_2促进阴极催化反应的本质因素源于掺杂原子Mn的d态轨道的分布以及其平均能量.掺杂原子的d态轨道在费米能级处的峰态诱导了附近O的p态轨道,二者共同作用在Mn_xTi_(1-x)O_2(101)的总态密度的费米能级处形成多个新峰,改变了催化剂的导电方式.此外,由于掺杂原子Mn的d态轨道的平均能量高于Ti原子,使得O的p态轨道受到更多的激发,促使在Mn掺杂原子附近的氧空位形成能降低,为放电过程阴极催化反应的氧还原提供了更多的活性位点并且有利于氧气的吸附与还原.
Based on the density functional theory,pure and doped TiO_2(101)(Mn_xTi_(1-x)O_2(101))were investigated as cathode catalytic materials for lithium-oxygen batteries.It was found that Li_2O_2 was formed on the surface with two different structures.We chose the most stable structure to further explore,and the catalytic performance is evaluated by the overpotential during the first charging and discharging process of the lithium-oxygen batteries.The results show that the doping of Mn has a lowering effect on the overpotential of both charge and discharge.Through further calculation and analysis of electron state density,we found that the essential factor of Mn doping in TiO_2 to promote cathodic catalytic reaction is due to the distribution of d-state orbitals and the average energy of d-state orbitals of doped atom Mn.The distribution of the d-state orbital of the doping atom Mn at the Fermi level induces the p-state orbit of the nearby O atom,and these make the formation of new impurity peaks at the Fermi level of the total density of states of Mn_xTi_(1-x)O_2(101),which changes the conductivity of the catalyst.In addition,since the average energy of the d-state orbital of the doped atom Mn is higher than Ti atom,the p-state orbital of the oxygen atom is more excited,which promotes the formation of oxygen vacancies on the surface when Mn atom is doped.It provides more active sites for ORR of cathodic catalytic reaction in discharge process and is beneficial to oxygen adsorption and reduction.
Based on the density functional theory,pure and doped TiO_2(101)(Mn_xTi_(1-x)O_2(101))were investigated as cathode catalytic materials for lithium-oxygen batteries.It was found that Li_2O_2 was formed on the surface with two different structures.We chose the most stable structure to further explore,and the catalytic performance is evaluated by the overpotential during the first charging and discharging process of the lithium-oxygen batteries.The results show that the doping of Mn has a lowering effect on the overpotential of both charge and discharge.Through further calculation and analysis of electron state density,we found that the essential factor of Mn doping in TiO_2 to promote cathodic catalytic reaction is due to the distribution of d-state orbitals and the average energy of d-state orbitals of doped atom Mn.The distribution of the d-state orbital of the doping atom Mn at the Fermi level induces the p-state orbit of the nearby O atom,and these make the formation of new impurity peaks at the Fermi level of the total density of states of Mn_xTi_(1-x)O_2(101),which changes the conductivity of the catalyst.In addition,since the average energy of the d-state orbital of the doped atom Mn is higher than Ti atom,the p-state orbital of the oxygen atom is more excited,which promotes the formation of oxygen vacancies on the surface when Mn atom is doped.It provides more active sites for ORR of cathodic catalytic reaction in discharge process and is beneficial to oxygen adsorption and reduction.
引文
1 Gaurav A,Ng FTT,Rempel GL.Green Energy Environ,2016,1:62-74
2 Dunn B,Kamath H,Tarascon JM.Science,2011,334:928-935
3 Zhang X,Wang XG,Xie Z,Zhou Z.Green Energy Environ,2016,1:4-17
4 Zhang S.Green Energy Environ,2016,1:1-2
5 Lu Y.Green Energy Environ,2016,1:3
6 Li F,Zhang T,Zhou H.Energy Environ Sci,2013,6:1125
7 Christensen J,Albertus P,Sanchez-Carrera RS,Lohmann T,Kozinsky B,Liedtke R,Ahmed J,Kojic A.J Electrochem Soc,2011,159:R1-R30
8 Jung HG,Hassoun J,Park JB,Sun YK,Scrosati B.Nat Chem,2012,4:579-585
9 Girishkumar G,McCloskey B,Luntz AC,Swanson S,Wilcke W.J Phys Chem Lett,2010,1:2193-2203
10 H Li.Catalytic Mechanism and Application of Modified Titanium Dioxide in Lithium Air Batteries.Dissertation for the Master’s Degree.Shenzhen:Shenzhen University,2016(in Chinese)[李豪君.改性二氧化钛在锂空气电池中的催化机理与应用研究.硕士学位论文.深圳:深圳大学,2016]
11 Aschauer U,Chen J,Selloni A.Phys Chem Chem Phys,2010,12:12956
12 Wang J,Liu M,Lin M.Solid State Ion,2006,177:939-947
13 Ding WC,Gu XK,Su HY,Li WX.J Phys Chem C,2014,118:12216-12223
14 Li Z,Wang X,Xing X.J Atom Mol Phys,2019,2:305-311(in Chinese)[李宗宝,王霞,邢晓波.原子与分子物理学报,2019,2:305-311]
15 Lei M,Cao Y,Lin X,Yang X,Cai S,Yuan R,Zheng M,Dong Q.Sci Sin Chim,2017,47:663-670(in Chinese)[雷鸣,曹勇,林晓东,杨续来,蔡森荣,袁汝明,郑明森,董全峰.中国科学:化学,2017,47:663-670]
16 Lee M,Hwang Y,Yun KH,Chung YC.J Power Sources,2015,288:296-301
17 Lin X,Zhou L,Huang T,Yu A.Inter J Electrochem Sci,2012,7:9550-9559
18 Xie T,Wang XD,Yao M,Liu XS,Chen YG.RSC Adv,2016,6:20349-20356
19 Wang F,Li H,Wu Q,Fang J,Huang Y,Yin C,Xu Y,Luo Z.Electrochim Acta,2016,202:1-7
20 Hummelsh?j JS,Blomqvist J,Datta S,Vegge T,Rossmeisl J,Thygesen KS,Luntz AC,Jacobsen KW,N?rskov JK.J Chem Phys,2010,132:071101
21 Wei C,Feng Z,Scherer GG,Barber J,Shao-Horn Y,Xu ZJ.Adv Mater,2017,29:1606800
22 Ma L,Meng N,Zhang Y,Lian F.Nano Energy,2019,58:508-516
23 Lima FHB,Zhang J,Shao MH,Sasaki K,Vukmirovic MB,Ticianelli EA,Adzic RR.J Phys Chem C,2007,111:404-410
24 Hammer B,Norskov JK.Nature,1995,376:238-240
25 Bhattacharjee S,Waghmare UV,Lee SC.Sci Rep,2016,6:35916
2 Dunn B,Kamath H,Tarascon JM.Science,2011,334:928-935
3 Zhang X,Wang XG,Xie Z,Zhou Z.Green Energy Environ,2016,1:4-17
4 Zhang S.Green Energy Environ,2016,1:1-2
5 Lu Y.Green Energy Environ,2016,1:3
6 Li F,Zhang T,Zhou H.Energy Environ Sci,2013,6:1125
7 Christensen J,Albertus P,Sanchez-Carrera RS,Lohmann T,Kozinsky B,Liedtke R,Ahmed J,Kojic A.J Electrochem Soc,2011,159:R1-R30
8 Jung HG,Hassoun J,Park JB,Sun YK,Scrosati B.Nat Chem,2012,4:579-585
9 Girishkumar G,McCloskey B,Luntz AC,Swanson S,Wilcke W.J Phys Chem Lett,2010,1:2193-2203
10 H Li.Catalytic Mechanism and Application of Modified Titanium Dioxide in Lithium Air Batteries.Dissertation for the Master’s Degree.Shenzhen:Shenzhen University,2016(in Chinese)[李豪君.改性二氧化钛在锂空气电池中的催化机理与应用研究.硕士学位论文.深圳:深圳大学,2016]
11 Aschauer U,Chen J,Selloni A.Phys Chem Chem Phys,2010,12:12956
12 Wang J,Liu M,Lin M.Solid State Ion,2006,177:939-947
13 Ding WC,Gu XK,Su HY,Li WX.J Phys Chem C,2014,118:12216-12223
14 Li Z,Wang X,Xing X.J Atom Mol Phys,2019,2:305-311(in Chinese)[李宗宝,王霞,邢晓波.原子与分子物理学报,2019,2:305-311]
15 Lei M,Cao Y,Lin X,Yang X,Cai S,Yuan R,Zheng M,Dong Q.Sci Sin Chim,2017,47:663-670(in Chinese)[雷鸣,曹勇,林晓东,杨续来,蔡森荣,袁汝明,郑明森,董全峰.中国科学:化学,2017,47:663-670]
16 Lee M,Hwang Y,Yun KH,Chung YC.J Power Sources,2015,288:296-301
17 Lin X,Zhou L,Huang T,Yu A.Inter J Electrochem Sci,2012,7:9550-9559
18 Xie T,Wang XD,Yao M,Liu XS,Chen YG.RSC Adv,2016,6:20349-20356
19 Wang F,Li H,Wu Q,Fang J,Huang Y,Yin C,Xu Y,Luo Z.Electrochim Acta,2016,202:1-7
20 Hummelsh?j JS,Blomqvist J,Datta S,Vegge T,Rossmeisl J,Thygesen KS,Luntz AC,Jacobsen KW,N?rskov JK.J Chem Phys,2010,132:071101
21 Wei C,Feng Z,Scherer GG,Barber J,Shao-Horn Y,Xu ZJ.Adv Mater,2017,29:1606800
22 Ma L,Meng N,Zhang Y,Lian F.Nano Energy,2019,58:508-516
23 Lima FHB,Zhang J,Shao MH,Sasaki K,Vukmirovic MB,Ticianelli EA,Adzic RR.J Phys Chem C,2007,111:404-410
24 Hammer B,Norskov JK.Nature,1995,376:238-240
25 Bhattacharjee S,Waghmare UV,Lee SC.Sci Rep,2016,6:35916