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Li J, Luo H, Liu K, Zhang J, Zhai H, Su X, Wu J, Tang X, Tan G. Excellent Stability of Ga-Doped Garnet Electrolyte against Li Metal Anode via Eliminating LiGaO 2 Precipitates for Advanced All-Solid-State Batteries. ACS APPLIED MATERIALS & INTERFACES 2023; 15:7165-7174. [PMID: 36701379 DOI: 10.1021/acsami.2c21603] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Ga-doped garnet-type Li7La3Zr2O12 (Ga-LLZO) ceramics have long been recognized as ideal electrolyte candidates for all-solid-state lithium batteries (ASSLBs). However, in this study, it is shown that Ga-LLZO easily and promptly cracks in contact with molten lithium during the ASSLB assembly. This can be mainly ascribed to two aspects: (i) lithium captures O atoms and reduces Ga ions of the Ga-LLZO matrix, leading to a band-gap closure from >5 to <2 eV and a structural collapse from cubic to tetrahedral; and (ii) the in situ-formed LiGaO2 impurity phase has severe side reactions with lithium, resulting in huge stress release along the grain boundaries. It is also revealed that, while the former process consumes hours to take effect, the latter one is immediate and accounts for the crack propagation of Ga-LLZO electrolytes. A minute SiO2 is preadded during the synthesis of Ga-LLZO and found effective in eliminating the LiGaO2 impurity phase. The SiO2-modified Ga-LLZO solid electrolytes display excellent thermomechanical and electrochemical stabilities against lithium metals and well-reserved ionic conductivities, which was further confirmed by half-cells and full batteries. This study contributes to the understanding of the stability of garnet electrolytes and promotes their potential commercial applications in ASSLBs.
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Affiliation(s)
- Jun Li
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan430070, China
| | - Hao Luo
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan430070, China
- Nanostructure Research Center, Wuhan University of Technology, Wuhan430070, China
| | - Keke Liu
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan430070, China
| | - Jiaxu Zhang
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan430070, China
- International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan430070, China
| | - Huiyu Zhai
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan430070, China
- International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan430070, China
| | - Xianli Su
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan430070, China
| | - Jinsong Wu
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan430070, China
- Nanostructure Research Center, Wuhan University of Technology, Wuhan430070, China
| | - Xinfeng Tang
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan430070, China
| | - Gangjian Tan
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan430070, China
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Stockham MP, Dong B, Slater PR. High entropy lithium garnets – Testing the compositional flexibility of the lithium garnet system. J SOLID STATE CHEM 2022. [DOI: 10.1016/j.jssc.2022.122944] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Stockham MP, Griffiths AA, Dong B, Slater PR. Assessing the Importance of Cation Size in the Tetragonal-Cubic Phase Transition in Lithium-Garnet Electrolytes. Chemistry 2021; 28:e202103442. [PMID: 34851537 DOI: 10.1002/chem.202103442] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Indexed: 11/11/2022]
Abstract
Lithium garnets are promising solid-state electrolytes for next-generation lithium-ion batteries. These materials have high ionic conductivity, a wide electrochemical window and stability with Li metal. However, lithium garnets have a maximum limit of seven lithium atoms per formula unit (e.g., La3 Zr2 Li7 O12 ), before the system transitions from a cubic to a tetragonal phase with poor ionic mobility. This arises from full occupation of the Li sites. Hence, the most conductive lithium garnets have Li between 6-6.55 Li per formula unit, which maintains the cubic symmetry and the disordered Li sub-lattice. The tetragonal phase, however, forms the highly conducting cubic phase at higher temperatures, thought to arise from increased cell volume and entropic stabilisation permitting Li disorder. However, little work has been undertaken in understanding the controlling factors of this phase transition, which could enable enhanced dopant strategies to maintain room temperature cubic garnet at higher Li contents. Here, a series of nine tetragonal garnets were synthesised and analysed by variable temperature XRD to understand the dependence of site substitution on the phase transition temperature. Interestingly the octahedral site cation radius was identified as the key parameter for the transition temperature with larger or smaller dopants altering the transition temperature noticeably. A site substitution was, however, found to make little difference irrespective of significant changes to cell volume.
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Affiliation(s)
- Mark P Stockham
- School of Chemistry, University of Birmingham, Birmingham, B15 2TT., UK
| | - A Alice Griffiths
- School of Chemistry, University of Birmingham, Birmingham, B15 2TT., UK
| | - Bo Dong
- School of Chemistry, University of Birmingham, Birmingham, B15 2TT., UK
| | - Peter R Slater
- School of Chemistry, University of Birmingham, Birmingham, B15 2TT., UK
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Stockham MP, Dong B, James MS, Li Y, Ding Y, Kendrick E, Slater PR. Evaluation of Ga 0.2Li 6.4Nd 3Zr 2O 12 garnets: exploiting dopant instability to create a mixed conductive interface to reduce interfacial resistance for all solid state batteries. Dalton Trans 2021; 50:13786-13800. [PMID: 34517411 DOI: 10.1039/d1dt02474d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The next major leap in energy storage is thought to arise from a practical implementation of all solid-state batteries, which remain largely confined to the small scale due to issues in manufacturing and mechanical stability. Lithium batteries are amongst the most sought after, for the high expected energy density and improved safety characteristics, however the challenge of finding a suitable solid-state electrolyte remains. Lithium rich garnets are prime contenders as electrolytes, owing to their high ionic conductivity (>0.1 mS cm-1), wide electrochemical window (0-6 V) and stability with Li metal. However, the high Young's modulus of these materials, poor wetting of Li metal and rapid formation of Li2CO3 passivating layers tends to give a detrimentally large resistance at the solid-solid interface, limiting their application in solid state batteries. Most studies have focused on La based systems, with very little work on other lanthanides. Here we report a study of the Nd based garnet Ga0.2Li6.4Nd3Zr2O12, illustrating substantial differences in the interfacial behaviour. This garnet shows very low interfacial resistance attributed to dopant exsolution which, when combined with moderate heating (175 °C, 1 h) with Li metal, we suggest forms Ga-Li eutectics, which significantly reduces the resistance at the Li/garnet interface to as low as 67 Ω cm2 (much lower than equivalent La based systems). The material also shows intrinsically high density (93%) and good conductivity (≥0.2 mS cm-1) via conventional furnaces in air. It is suggested these garnets are particularly well suited to provide a mixed conductive interface (in combination with other garnets) which could enable future solid-state batteries.
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Affiliation(s)
- M P Stockham
- School of Chemistry, University of Birmingham, Birmingham B15 2TT, UK.
| | - B Dong
- School of Chemistry, University of Birmingham, Birmingham B15 2TT, UK.
| | - M S James
- School of Chemistry, University of Birmingham, Birmingham B15 2TT, UK.
| | - Y Li
- School of Chemical Engineering, University of Birmingham, Birmingham B15 2TT, UK
| | - Y Ding
- School of Chemical Engineering, University of Birmingham, Birmingham B15 2TT, UK
| | - E Kendrick
- School of Metallurgy and Materials, University of Birmingham, Birmingham B15 2TT, UK
| | - P R Slater
- School of Chemistry, University of Birmingham, Birmingham B15 2TT, UK.
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