锂二次电池正极材料LiMn_2O_4的制备及性能研究
摘要
本文报道了利用溶胶凝胶法，在空气条件下，400℃-750℃温度范围内烧结合成出不同Li／Mn加入比例的(Li／Mn=0.50，0.52，0.54)单相尖晶石型LiMn_2O_4材料。利用热分析仪(DTA-TG)、X射线衍射仪(XRD)、透射电镜(TEM)对材料的结构进行表征。利用物理性能测试系统(PPMS)对材料的低温电阻进行了研究。
研究结果如下：
(1) 溶胶凝胶法与固相反应方法相比，材料合成效率提高，合成温度降低，在400℃的较低温度下烧结即可得到尖晶石LiMn_2O_4材料。
(2) 低温烧结合成的材料为富氧型尖晶石材料，随着温度的升高，结构中多余的氧逐渐释放，系统能量降低，结合能增加，品格发生膨胀，样品向完整的尖晶石结构逐渐过渡。700℃得到的材料为化学量的LiMn_2O_4。烧结温度进一步提高材料的结构被破坏，形成了欠氧型尖晶石结构。
(3) 随着Li／Mn加入比例(Li／Mn=0.50，0.52，0.54)的增加，材料的品格发生收缩，晶体内部的结合能增大，结构稳定性增强。
(4) 化学量的LiMn_2O_4材料，在320K～280K的范围内Mn原子轨道电子态简并，电子处于无序状态，材料的电阻随温度的降低，缓慢增加。280K以后，Mn原子轨道电子态的简并被解除，电子由无序向有序状态转变，电阻随温度的降低，急剧增加，材料结构由立方相向四方相转变。
(5) 增加Li的加入量，八面体位的Mn~(+4)／Mn~(+3)比例增加，电子的无序程度减弱。使得材料在280K附近电子由无序状态向有序状态转变，在电阻特性曲线中表现得不很明显。
In this thesis the single-phase LiMn2O4 spinels with various Li/Mn ratios (Li/Mn=0. 50,0.52,0.54) synthesized by Sol-Gel method were sintered at 400 to 750 in the air and characterized by X-ray diffraction (XRD),Differential Thermal Analysis and Thermogravimetric Analysis (DTA-TG) and Transmission Electron Microscopy (TEM) .The low-temperature resistance was also investigated by Physical Property Measure System (PPMS).
The main results came as following:
(1) Compared to the Solid-State Reaction method the materials were synthesized with high efficiency at low temperature by Sol-Gel method and the LiMn2O4 spinel resulted when sintered at 400 .
(2) The oxygen-rich spinel material from sintering the precursor at low temperature changed into perfect spinel structure due to releasing the excess oxygen when raised the sintering temperature slowly ,which caused the lattice expanded and at the same time the system energy lowered and the bonding energy raised, and tansformed into the stoichiometric LiMn2O4 at 700 . When raised the sintering temperature further we got oxygen-poor LiMn2O4 spinel.
(3) The samples stabilized more because of the lattice parameter reduction and the crystalline bonding increase with the ratio Li/Mn increase (Li/Mn=0.50,0.52,0.54).
(4) The Mn electron orbits of stoichiometric LiMn2O4 became degenerated and the electrons settled in disordered states at 320K~280K and therefore the resistance of the material increased slowly with the temperature decrease. Below 280k the degenerated states were relieved and the electrons turned to the ordered states from the disordered , leading to the resistance increase suddenly and the transition from the cubic to the
tetragonal structure.
(5) The increase of Mn+4/Mn+3 in octahedron with the addition of Lithium tampered the disordered states , and the electrons around 280K tended ordered so that the resistance showed no significant changes.
研究结果如下：
(1) 溶胶凝胶法与固相反应方法相比，材料合成效率提高，合成温度降低，在400℃的较低温度下烧结即可得到尖晶石LiMn_2O_4材料。
(2) 低温烧结合成的材料为富氧型尖晶石材料，随着温度的升高，结构中多余的氧逐渐释放，系统能量降低，结合能增加，品格发生膨胀，样品向完整的尖晶石结构逐渐过渡。700℃得到的材料为化学量的LiMn_2O_4。烧结温度进一步提高材料的结构被破坏，形成了欠氧型尖晶石结构。
(3) 随着Li／Mn加入比例(Li／Mn=0.50，0.52，0.54)的增加，材料的品格发生收缩，晶体内部的结合能增大，结构稳定性增强。
(4) 化学量的LiMn_2O_4材料，在320K～280K的范围内Mn原子轨道电子态简并，电子处于无序状态，材料的电阻随温度的降低，缓慢增加。280K以后，Mn原子轨道电子态的简并被解除，电子由无序向有序状态转变，电阻随温度的降低，急剧增加，材料结构由立方相向四方相转变。
(5) 增加Li的加入量，八面体位的Mn~(+4)／Mn~(+3)比例增加，电子的无序程度减弱。使得材料在280K附近电子由无序状态向有序状态转变，在电阻特性曲线中表现得不很明显。
In this thesis the single-phase LiMn2O4 spinels with various Li/Mn ratios (Li/Mn=0. 50,0.52,0.54) synthesized by Sol-Gel method were sintered at 400 to 750 in the air and characterized by X-ray diffraction (XRD),Differential Thermal Analysis and Thermogravimetric Analysis (DTA-TG) and Transmission Electron Microscopy (TEM) .The low-temperature resistance was also investigated by Physical Property Measure System (PPMS).
The main results came as following:
(1) Compared to the Solid-State Reaction method the materials were synthesized with high efficiency at low temperature by Sol-Gel method and the LiMn2O4 spinel resulted when sintered at 400 .
(2) The oxygen-rich spinel material from sintering the precursor at low temperature changed into perfect spinel structure due to releasing the excess oxygen when raised the sintering temperature slowly ,which caused the lattice expanded and at the same time the system energy lowered and the bonding energy raised, and tansformed into the stoichiometric LiMn2O4 at 700 . When raised the sintering temperature further we got oxygen-poor LiMn2O4 spinel.
(3) The samples stabilized more because of the lattice parameter reduction and the crystalline bonding increase with the ratio Li/Mn increase (Li/Mn=0.50,0.52,0.54).
(4) The Mn electron orbits of stoichiometric LiMn2O4 became degenerated and the electrons settled in disordered states at 320K~280K and therefore the resistance of the material increased slowly with the temperature decrease. Below 280k the degenerated states were relieved and the electrons turned to the ordered states from the disordered , leading to the resistance increase suddenly and the transition from the cubic to the
tetragonal structure.
(5) The increase of Mn+4/Mn+3 in octahedron with the addition of Lithium tampered the disordered states , and the electrons around 280K tended ordered so that the resistance showed no significant changes.
引文
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[3] K.Mizushima et al,Solid State Ionics,3/4:171 (1981)
[4] Tsutomu Ohzuku.Lithium Batteries.Chapter 6,Pressed by Elsevier Science BV, the Netherlands, 1994
[5] News in Scientific American, No.5, 278(1998)
[6] T Nagaura, K Tozawa., Prog Batts Sol Cells, 9, 209(1990)
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[8] H.Arai, S.Okada, M.Ichimura and J.Yamaaki, Solid State Ionics,80: 261(1995)
[9] T.Iakada, H.Hayakawa and E.Akiba, J. Solid State Chem.,115: 420(1995)
[10] Y. Gao and J.R.Dahn, J. Electrochem.Soc, 143:100(1996)
[11] J R Dahn, E W Fukker, Solid State Ionics, 69:265-270(1994)
[12] W B White., B A Deangelis., Spectrochim. Acta., 23A:985-995(1967)
[13] J W Verwey., E W Hellmann., J.Chem.Phys., 15:174(1947)
[14] ViTins, physica B 180/181:97(1992)
[15] A Kock, M H Rossouw, M M Thackeray, Mat.. Res. Bull, 25: 657-664(1990)
[16] M M Thackeray, J Electrochem soc,142,2558(1995)
[17] M M Thackeray, J Electrochem soc,144,L100(1997)
[18] Y Gao,.J.R Dahn, J Electrochem soc,143,7183(1996)
[19] Mitsuharu Tabuchi,Christian Masquelier, J. Power Sources, 68: 623-628 (1997)
[20] I. Koostehau., M.N Richard., J.R Dahn., J Electrochem soc, 142: 2906(1995)
[21] Xingping Qiu, Xiaoguang Sun, Wanci Shen, Solid State Ionics, 93: 335-339 (1997)
[22] Lourdes Hernan, Julian Morales, Luis Sanchez, Solid State Ionics, 118: 179-185 (1999)
[23] B. Ammundsen, G..R. Burns, J.Phys. Chem.B, 103:5175—5180 (1999)
[24] W.J. Macklin, R. J. Neat, et al., J Power Sources, 24: 39—42 (1991)
[25] M M Yhckeray, J Electrochem soc, 144: L100—102(1997)
[26] B Ammundsen., G.. R. Burns., J.Phys. Chem.B, 103:5175—5180 (1999)
[27] W J Macklin., R J Neat.,et al. J Power Sources, 24:39—42 (1991)
[28] M. Yoshio, H. Noguchi, H. Nakamura, Denki Kagaku, 63: 941-946 (1995)
[29] M. Yoshio, H. Noguchi, Y. Xia, Denki Kagaku, 64: 388-393(1996)
[30] A. Kock, M H. Rossouw, et al., Mat. Res. Bull., 25:657-664(1990)
[31] M M. Thackeray, et al, J.Electrochem.Soc, 139:363-366(1992)
[32] 黄昆，韩汝琦编著，《固体物理学》，高等教育出版社，北京，49-53(1988)
[33] Y.Gao and J.R.Dahn,Solid State Ionics 84,33(1996)
[34] V.Massarotti, et al., J.Solid State Chem.131:94(1997)
[35] C.Masquelier et al., J.Solid State Chem.123:255(1996)
[36] A.Yamada. J.Solid State Chem.122,160(1996)
[37] A.Yamada. and M.Tanaka, Mater.Res.Bull.30,715(1995)
[38] Y. Shimakawa., T. Numata and J. Tabuchi, J. Solid State Chem.,131:138(1997)
[39] K. Oikawa et al., Solid State Ionics, 109:35(1998)
[40] H. Yamaguchi, A.Yamada and H.Uwe, Phys. Rew. B, 58:8(1998)
[41] P. Strobel et al., J. Solid State Chem.135,132(1998)
[42] Atsuo.Yamada, Masahiro. Tanaka, Mater Res. Bull., 30:715-721 (1995)
[43] Atsuo.Yamada, Masahiro. Tanaka, et.al., J. Power Sources, 81-82, 73-78(1999)
[44] Hirotaka Yamaguchi, et al..Phy.Rev.B.58:8-11(1998)
[45] J.Rodriguez-carvajal, et. al, Phy.Rev.Lett., 81:4660-4663(1998)
[2] M.Armand, in Mataerials in Advanced Batteries, Pienum Press, New York, 145(1980)
[3] K.Mizushima et al,Solid State Ionics,3/4:171 (1981)
[4] Tsutomu Ohzuku.Lithium Batteries.Chapter 6,Pressed by Elsevier Science BV, the Netherlands, 1994
[5] News in Scientific American, No.5, 278(1998)
[6] T Nagaura, K Tozawa., Prog Batts Sol Cells, 9, 209(1990)
[7] K Mizushima, P C Jones, P J Wiseman,et al. Mater Res Bull.,15:783(1980)
[8] H.Arai, S.Okada, M.Ichimura and J.Yamaaki, Solid State Ionics,80: 261(1995)
[9] T.Iakada, H.Hayakawa and E.Akiba, J. Solid State Chem.,115: 420(1995)
[10] Y. Gao and J.R.Dahn, J. Electrochem.Soc, 143:100(1996)
[11] J R Dahn, E W Fukker, Solid State Ionics, 69:265-270(1994)
[12] W B White., B A Deangelis., Spectrochim. Acta., 23A:985-995(1967)
[13] J W Verwey., E W Hellmann., J.Chem.Phys., 15:174(1947)
[14] ViTins, physica B 180/181:97(1992)
[15] A Kock, M H Rossouw, M M Thackeray, Mat.. Res. Bull, 25: 657-664(1990)
[16] M M Thackeray, J Electrochem soc,142,2558(1995)
[17] M M Thackeray, J Electrochem soc,144,L100(1997)
[18] Y Gao,.J.R Dahn, J Electrochem soc,143,7183(1996)
[19] Mitsuharu Tabuchi,Christian Masquelier, J. Power Sources, 68: 623-628 (1997)
[20] I. Koostehau., M.N Richard., J.R Dahn., J Electrochem soc, 142: 2906(1995)
[21] Xingping Qiu, Xiaoguang Sun, Wanci Shen, Solid State Ionics, 93: 335-339 (1997)
[22] Lourdes Hernan, Julian Morales, Luis Sanchez, Solid State Ionics, 118: 179-185 (1999)
[23] B. Ammundsen, G..R. Burns, J.Phys. Chem.B, 103:5175—5180 (1999)
[24] W.J. Macklin, R. J. Neat, et al., J Power Sources, 24: 39—42 (1991)
[25] M M Yhckeray, J Electrochem soc, 144: L100—102(1997)
[26] B Ammundsen., G.. R. Burns., J.Phys. Chem.B, 103:5175—5180 (1999)
[27] W J Macklin., R J Neat.,et al. J Power Sources, 24:39—42 (1991)
[28] M. Yoshio, H. Noguchi, H. Nakamura, Denki Kagaku, 63: 941-946 (1995)
[29] M. Yoshio, H. Noguchi, Y. Xia, Denki Kagaku, 64: 388-393(1996)
[30] A. Kock, M H. Rossouw, et al., Mat. Res. Bull., 25:657-664(1990)
[31] M M. Thackeray, et al, J.Electrochem.Soc, 139:363-366(1992)
[32] 黄昆，韩汝琦编著，《固体物理学》，高等教育出版社，北京，49-53(1988)
[33] Y.Gao and J.R.Dahn,Solid State Ionics 84,33(1996)
[34] V.Massarotti, et al., J.Solid State Chem.131:94(1997)
[35] C.Masquelier et al., J.Solid State Chem.123:255(1996)
[36] A.Yamada. J.Solid State Chem.122,160(1996)
[37] A.Yamada. and M.Tanaka, Mater.Res.Bull.30,715(1995)
[38] Y. Shimakawa., T. Numata and J. Tabuchi, J. Solid State Chem.,131:138(1997)
[39] K. Oikawa et al., Solid State Ionics, 109:35(1998)
[40] H. Yamaguchi, A.Yamada and H.Uwe, Phys. Rew. B, 58:8(1998)
[41] P. Strobel et al., J. Solid State Chem.135,132(1998)
[42] Atsuo.Yamada, Masahiro. Tanaka, Mater Res. Bull., 30:715-721 (1995)
[43] Atsuo.Yamada, Masahiro. Tanaka, et.al., J. Power Sources, 81-82, 73-78(1999)
[44] Hirotaka Yamaguchi, et al..Phy.Rev.B.58:8-11(1998)
[45] J.Rodriguez-carvajal, et. al, Phy.Rev.Lett., 81:4660-4663(1998)