固态锂离子传导氧化物中的点缺陷

doi:10.12028/j.issn.2095-4239.2016.0035

摘要/Abstract

摘要： 固态电解质能有效地解决液态电解质存在的易燃、易泄漏及化学稳定性差等问题，然而，固态电解质的锂离子电导率（105～103 S/cm）显著低于液态电解质电导率（102 S/cm），导致全固态锂离子电池的充放电性能比液态电池差。因此，进一步提高固态电解质的锂离子电导率成为改善全固态电池性能的关键，认知并调控材料中的点缺陷对于改善锂离子电导具有重要意义。本研究团队选用两种重要的固态锂离子传导氧化物材料：具有钙钛矿结构的Li3xLa2/3x□1/32xTiO3（0.04x0.16）和具有石榴石结构的Li7La3Zr2O12为研究对象，对其中存在的点缺陷及缺陷反应进行分析，并进一步阐述各种点缺陷对材料锂离子、氧离子和电子电导率的影响。

关键词: 固态电解质, 缺陷, 锂离子电导率, 氧离子电导率, 电子电导率

Abstract: Solid electrolytes do not have the common shortcomings of liquid electrolytes, such as flammability, leakage and low chemical stability. However, solid electrolytes also have a big disadvantage of relatively low lithium ion conductivity of 105～103 S/cm, as compared with the conductivity of liquid electrolytes (102 S/cm). Therefore, the properties of all-solid-state lithium ion batteries based on solid electrolytes are normally rather poor. To increase the lithium ion conductivity of solid electrolytes is a key issue for improving the performance of all-solid-state lithium ion batteries. As a matter of fact, point defects determine the lithium ion conductivity of oxides. To modulate the defect structure of lithium ion conducting oxides is an effective way to enhance the lithium ion conductivity. In this work, two oxides, i.e. perovskite Li3xLa2/3x□1/3-2xTiO3 (0.04x0.16) and garnet Li7La3Zr2O12 are evaluated from the point of view of defect chemistry, and the contributions of various defects to the lithium ion conductivity, the oxygen ion conductivity and the electronic conductivity are elucidated.

Key words: solid electrolyte, defects, lithium ion conductivity, oxygen ion conductivity, electronic conductivity

吴剑芳，郭新. 固态锂离子传导氧化物中的点缺陷[J]. 储能科学与技术, 2016, 5(5): 745-753.

Wu Jianfang, Guo Xin. Point defects in solid-state lithium ion conducting oxides[J]. Energy Storage Science and Technology, 2016, 5(5): 745-753.

参考文献

[1] YOSHINO A. The birth of the lithium-ion battery[J]. Angew. Chem. Int. Edit.，2012，51（24）：5798-5800.

[2] TARASCON J M，ARMAND M. Issues and challenges facing rechargeable lithium batteries[J]. Nature，2001，414：359-367.

[3] GOODENOUGH J B，KIM Y. Challenges for rechargeable Li batteries[J]. Chem. Mater.，2010，22（3）：587-603.

[4] THANGADURAI V，WEPPNER W. Li₆ALa₂Ta₂O₁₂(A=Sr, Ba)：Novel garnet-like oxides for fast lithium ion conduction[J]. Adv. Funct. Mater.，2005，15（1）：107-112.

[5] MURUGAN R，THANGADURAI V，WEPPNER W. Fast lithium ion conduction in garnet-type Li₇La₃Zr₂O₁₂[J]. Angew. Chem. Int. Edit.，2007，46（41）：7778-7781.

[6] GEIGER C A，ALEKSEEV E，LAZIC B，et al. Crystal chemistry and stability of “Li₇La₃Zr₂O₁₂” garnet：A fast lithium-ion conductor[J]. Inorg. Chem.，2011，50（3）：1089-1097.

[7] ZHANG Q，SCHMIDT N，LAN J，et al. A facile method for the synthesis of the Li_0.3La_0.57TiO₃ solid state electrolyte[J]. Chem. Commun.，2014，50（42）：5593-5596.

[8] INAGUMA Y，CHEN L，ITOH，et al. High ionic conductivity in lithium lanthanum titanate[J]. Solid State Commun.，1993，86（10）：689-693.

[9] STRAMARE S，THANGADURAI V，WEPPNER W. Lithium lanthanum titanates：A review [J]. Chem. Mater.，2003，15（21）：3974-3990.

[10] KNAUTH P. Inorganic solid Li ion conductors：An overview [J]. Solid State Ionics，2009，180（14/15/16）：911-916.

[11] TAKADA K. Progress and prospective of solid-state lithium batteries[J]. Acta Mater.，2013，61（3）：759-770.

[12] GOODENOUGH J B，HONG H Y P，KAFALAS J A. Fast Na⁺-ion transport in skeleton structures[J]. Mater. Res. Bull.，1976，11（2）：203-220.

[13] ALPEN U V，RABENAU A，TALAT G H. Ionic conductivity in Li₃N single crystals [J]. Appl. Phys. Lett.，1977，30（12）：621-623.

[14] DISSANAYAKE M A K L，WEST A R. Structure and conductivity of an Li₄SiO₄-Li₂SO₄ solid solution phase[J]. J. Mater. Chem.，1991，1（6）：1023-1025.

[15] THANGADURAI V，KAACK H，WEPPNER W J F. Novel fast lithium ion conduction in garnet-type Li₅La₃M₂O₁₂ (M=Nb, Ta)[J]. J. Am. Ceram. Soc.，2003，86（3）：437-440.

[16] KAMAYA N，HOMMA K，YAMAKAWA Y，et al. A lithium superionic conductor[J]. Nat. Mater.，2011，10（9）：682-686.

[17] SHIRAKI S，OKI H，TAKAGI Y，et al. Fabrication of all-solid-state battery using epitaxial LiCoO₂ thin films[J]. J. Power Sources，2014，267：881-887.

[18] OHTA S，SEKI J，YAGI Y，et al. Co-sinterable lithium garnet-type oxide electrolyte with cathode for all-solid-state lithium ion battery [J]. J. Power Sources，2014，265：40-44.

[19] KAWAI H，KUWANO J. Lithium ion conductivity of a-site deficient perovskite solid solution La_0.67_-_xLi_3xTiO₃[J]. J. Electrochem. Soc.，1994，141（7）：L78-L79.

[20] TERANISHI T，KOUCHI A，HAYASHI H，et al. Dependence of the conductivity of polycrystalline Li_0.33Ba_xLa_0.56–2/3xTiO₃ on Ba loading[J]. Solid State Ionics，2014，263（1）：33-38.

[21] MA C，CHEN K，LIANG C，et al. Atomic-scale origin of the large grain-boundary resistance in perovskite Li-ion-conducting solid electrolytes[J]. Energy Environ. Sci.，2014，7（5）：1638-1642.

[22] KINGERY W D. Plausible concepts necessary and sufficient for interpretation of ceramic grain-boundary phenomena：II, Solute segregation, grain-boundary diffusion, and general discussion[J]. J. Am. Ceram. Soc.，1974，57（2）：74-83.

[23] FRENKEL J. Kinetic theory of liquids[M]. New York：Oxford University Press，1946.

[24] AWAKA J，TAKASHIMA A，KATAOKA K，et al. Crystal structure of fast lithium-ion-conducting cubic Li₇La₃Zr₂O₁₂[J]. Chemistry Letters，2011，40（1）：60-62.

[25] ZEIER W G，ZHOU S，LOPEZBERMUDEZ B，et al. Dependence of the Li-ion conductivity and activation energies on the crystal structure and ionic radii in Li₆MLa₂Ta₂O₁₂[J]. ACS Appl. Mater. Interfaces，2014，6（14）：10900-10907.

[26] DU F，ZHAO N，LI Y，et al. All solid state lithium batteries based on lamellar garnet-type ceramic electrolytes[J]. J. Power Sources，2015，300：24-28.

[27] LI Y，WANG Z，CAO Y，et al. W-doped Li₇La₃Zr₂O₁₂ ceramic electrolytes for solid state Li-ion batteries[J]. Electrochimica Acta，2015，180（20）：37-42.

[28] WANG D，ZHONG G，PANG W K，et al. Towards understanding the lithium transport mechanism in garnet-type solid electrolytes：Li⁺ ions exchanges and their mobility at octahedral/tetrahedral sites[J]. Chem. Mater.，2015，27（19）：6650-6659.

[29] TONG X，THANGADURAI V，WACHSMAN E D. Highly conductive Li garnets by a multielement doping strategy[J]. Inorg. Chem.，2015，54（7）：3600-3607.

[30] JANANI N，RAMAKUMAR S，KANNAN S，et al. Optimization of lithium content and sintering aid for maximized Li⁺conductivity and density in Ta-doped Li₇La₃Zr₂O₁₂[J]. J. Am. Ceram. Soc.，2015，98（7）：2039-2046.

[31] DAVID I N，THOMPSON T，WOLFENSTINE J，et al. Microstructure and Li-ion conductivity of hot-pressed cubic Li₇La₃Zr₂O₁₂[J]. J. Am. Ceram. Soc.，2015，98（4）：1209-1214.

[32] WANG D，ZHONG G，DOLOTKO O，et al. The synergistic effects of Al and Te on the structure and Li⁺-mobility of the garnet-type solid electrolytes[J]. J. Mater. Chem. A，2014，2（47）：20271-20279.

[33] RANGASAMY E，SAHU G，KEUM J K，et al. A high conductivity oxide-sulfide composite lithium superionic conductor[J]. J. Mater. Chem. A，2014，2（12）：4111-4116.

[34] REN Y，DENG H，CHEN R，et al. Effects of Li source on microstructure and ionic conductivity of Al-contained Li_6.75La₃Zr_1.75Ta_0.25O₁₂ ceramics[J]. J. Eur. Ceram. Soc.，2015，35（2）：561-572.

[35] RAMAKUMAR S，JANANI N，MURUGAN R. Influence of lithium concentration on the structure and Li⁺transport properties of cubic phase lithium garnets[J]. Dalton Trans.，2014，44（2）：539-552.

[36] LI Y，WANG Z，LI C，et al. Densification and ionic-conduction improvement of lithium garnet solid electrolytes by flowing oxygen sintering[J]. J. Power Sources，2014，248：642-646.

[37] JANANI N，DEVIANNAPOORANI C，DHIVYA L，et al. Influence of sintering additives on densification and Li⁺conductivity of Al doped Li₇La₃Zr₂O₁₂lithium garnet[J]. RSC Adv.，2014，4（93）：51228-51238.

[38] HUANG M，SHOJI M，SHEN Y，et al. Preparation and electrochemical properties of Zr-site substituted Li₇La₃(Zr_2−xM_x)O₁₂ (M=Ta, Nb) solid electrolytes[J]. J. Power Sources，2014，261：206-211.

[39] DHIVYA L，MURUGAN R. Effect of simultaneous substitution of Y and Ta on the stabilization of cubic phase, microstructure, and Li conductivity of Li₇La₃Zr₂O₁₂lithium garnet[J]. ACS Appl. Mater. Interfaces，2014，6（20）：17606-17615.

[40] BERNUY C，MANALASTAS W，LOPEZ J M，et al. Atmosphere controlled processing of Ga-substituted garnets for high Li-ion conductivity ceramics[J]. Chem. Mater.，2014，26（12）：3610-3617.

[41] BAEK S W，LEE J M，KIM T Y，et al. Garnet related lithium ion conductor processed by spark plasma sintering for all solid state batteries[J]. J. Power Sources，2014，249：197-206.

[42] TADANAGA K，TAKANO R，ICHINOSE T，et al. Low temperature synthesis of highly ion conductive Li₇La₃Zr₂O₁₂-Li₃BO₃ composites[J]. Electrochem. Commun.，2013，33：51-54.

[43] SAKAMOTO J，RANGASAMY E，KIM H，et al. Synthesis of nano-scale fast ion conducting cubic Li₇La₃Zr₂O₁₂[J]. Nanotechnology，2013，24（42）：3532-3540.

[44] RASKOVALOV A A，IL'INA E A，ANTONOV B D. Structure and transport properties of Li₇La₃Zr₂_-_0.75xAl_xO₁₂ superionic solid electrolytes[J]. J. Power Sources，2013，238：48-52.

[45] RANGASAMY E，WOLFENSTINE J，ALLEN J，et al. The effect of 24c-site (A) cation substitution on the tetragonal-cubic phase transition in Li_7−xLa_3−xA_xZr₂O₁₂ garnet-based ceramic electrolyte[J]. J. Power Sources，2013，230：261-266.

[46] SHINAWI H E，JANEK J. Stabilization of cubic lithium-stuffed garnets of the type “Li₇La₃Zr₂O₁₂” by addition of gallium[J]. J. Power Sources，2013，225：13-19.

[47] DEVIANNAPOORANI C，DHIVYA L，RAMAKUMAR S，et al. Lithium ion transport properties of high conductive tellurium substituted Li₇La₃Zr₂O₁₂ cubic lithium garnets[J]. J. Power Sources，2013，240：18-25.

[48] WOLFENSTINE J，RATCHFORD J，RANGASAMY E，et al. Synthesis and high Li-ion conductivity of Ga-stabilized cubic Li₇La₃Zr₂O₁₂[J]. Mater. Chem. Phys.，2012，134（2/3）：571-575.

[49] WANG Y，LAI W. High ionic conductivity lithium garnet oxides of Li_7−xLa₃Zr_2−xTa_xO₁₂ compositions[J]. Electrochemical and Solid-State Letter，2012，15（5）：A68-A71.

[50] LI Y，HAN J T，WANG C A，et al. Optimizing Li⁺ conductivity in a garnet framework[J]. J. Mater. Chem.，2012，22（30）：15357-15361.

[51] HUANG M，DUMON A，NAN C W. Effect of Si, In and Ge doping on high ionic conductivity of Li₇La₃Zr₂O₁₂[J]. Electrochem. Commun.，2012，21：62-64.

[52] GUPTA A，MURUGAN R，PARANTHAMAN M P，et al. Optimum lithium-ion conductivity in cubic Li_7−xLa₃Hf_2−xTa_xO₁₂[J]. J. Power Sources，2012，209：184-188.

[53] ALLEN J L，WOLFENSTINE J，RANGASAMY E，et al. Effect of substitution (Ta, Al, Ga) on the conductivity of Li₇La₃Zr₂O₁₂[J]. J. Power Sources，2012，206：315-319.

[54] OHTA S，KOBAYASHI T，ASAOKA T. High lithium ionic conductivity in the garnet-type oxide Li₇_-_XLa₃(Zr₂_-_X, Nb_X)O₁₂ (X=0-2)[J]. J. Power Sources，2011，196：3342-3345.

[55] MURUGAN R，RAMAKUMAR S，JANANI N. High conductive yttrium doped Li₇La₃Zr₂O₁₂ cubic lithium garnet[J]. Electrochem. Commun.，2011，13（12）：1373-1375.

[56] LI Y，WANG C A，XIE H，et al. High lithium ion conduction in garnet-type Li₆La₃ZrTaO₁₂[J]. Electrochem. Commun.，2011，13（12）：1289-1292.

[57] KUMAZAKI S，IRIYAMA Y，KIM K H，et al. High lithium ion conductive Li₇La₃Zr₂O₁₂ by inclusion of both Al and Si[J]. Electrochem. Commun.，2011，13（5）：509-512.

[58] JIN Y，MCGINN P J. Al-doped Li₇La₃Zr₂O₁₂ synthesized by a polymerized complex method[J]. J. Power Sources，2011，196：8683-8687.

[59] WOLFENSTINE J，SAKAMOTO J，ALLEN J L. Electron microscopy characterization of hot-pressed Al substituted Li₇La₃Zr₂O₁₂[J]. J. Mater. Sci.，2012，47（10）：4428-4431.

[60] TENHAEFF W E，RANGASAMY E，WANG Y，et al. Resolving the grain boundary and lattice impedance of hot-pressed Li₇La₃Zr₂O₁₂garnet electrolytes[J]. ChemElectroChem，2014，1（2）：375-378.

[61] GUO X. Peculiar size effect in nanocrystalline BaTiO₃[J]. Acta Mater.，2013，61（5）：1748-1756.

[62] GUO X，ZHANG Z. Grain size dependent grain boundary defect structure：Case of doped zirconia[J]. Acta Mater.，2003，51（9）：2539-2547.