Mitigation of grain boundary resistance in La 2/3-x Li 3x TiO 3 perovskite as an electrolyte for solid-state Li-ion batt
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Mitigation of grain boundary resistance in La2/3-xLi3xTiO3 perovskite as an electrolyte for solid-state Li-ion batteries Tomasz Polczyk1, Wojciech Zaja˛c1,*
´ wierczek1,3 , Magdalena Zia˛bka2, and Konrad S
1
Faculty of Energy and Fuels, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Kraków, Poland Faculty of Materials Science and Ceramics, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Kraków, Poland 3 AGH University of Science and Technology, AGH Centre of Energy, ul. Czarnowiejska 36, 30-054 Kraków, Poland 2
Received: 20 June 2020
ABSTRACT
Accepted: 15 September 2020
In this work, we report that modification of the chemical composition of grain boundaries of La2/3-xLi3xTiO3 double perovskite, one of the most promising Liion conducting solid electrolytes, can be a convenient and versatile way of controlling the space charge potential, leading to a mitigated electrical resistance of the grain boundaries. Two groups of additives are investigated: lithiumenriching agents (Li3BO3, LiF) and 3d metal ions (Co2?, Cu2?), both expected to reduce the Schottky barrier. It is observed that Li-containing additives work effectively at a higher sintering temperature of 1250 °C. Regarding copper, it shows a much stronger positive impact at lower temperature, 1150 °C, while the addition of cobalt is always detrimental. Despite overall complex behavior, it is documented that the decreased space charge potential plays a more important role in the improvement of lithium conduction than the thickness of the grain boundaries. Among the proposed additives, modification of La2/3-xLi3xTiO3 by 2 mol.% Cu2? results in the space charge potential reduction by 32 mV in relation to the reference sample, and the grain boundary specific conductivity increase by 80%, as measured at 30 °C. Introduced additive allows to obtain a similar effect on the conductivity as elevating the sintering temperature, which can facilitate manufacturing procedure.
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The Author(s) 2020
Handling Editor: Joshua Tong.
Address correspondence to E-mail: [email protected]
https://doi.org/10.1007/s10853-020-05342-7
J Mater Sci
GRAPHIC ABSTRACT
Introduction Due to a rapidly increasing number of electric vehicles and a growing share of renewable energy sources in the power generation mix, the development of effective and reliable electrochemical energy storage systems has become very urgent. Among commercial reversible batteries, the highest performance is achieved for lithium-ion cells; however, it is believed that regrettably the Li-ion technology is close to the physical limits, and increasing safety requirements are not fully met. Solid-state lithium batteries, i.e., with the solid-state electrolyte, are considered to be a promising alternative for the state-of-the-art Li-ion batteries, as they would mitigate issues related to the presence of liquid organic electrolytes: flammability, chemical instability and risk of leakage, as well as possible dendritic growth of lithium during charging. In recent years
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