All solid-state Li-ion battery (LIB) technology will be a breakthrough for the next generation energy storage devices, which are free from a thermal runaway risk of current LIBs. However, instability of electrode–electrolyte interface is challenging the commercialization of the solid-state LIB. For example, to achieve good adhesion and ionic conductivity between ceramic components of the cells, sintering process in high-temperature is unavoidable. This heat-treatment often results in undesired chemical reactions at electrode-electrolyte interfaces, which lead to a formation of secondary phase and an impedance growth at the interfaces (i.e., sluggish Li-ion transport). However, phase stability data between solid electrolytes and cathodes is not readily available due to their complicated phase evolution behaviors involving multiple elements. In this study, we performed a systematic investigation on the thermal stability between Li1.4Al0.4Ti1.6(PO4)3 (LATP) solid electrolyte and conventional cathode materials including LiCoO2, LiNiO2, LiNi1/3Mn1/3Co1/3O2, LiNi0.5Mn1.5O4, and LiFePO4. We characterized their phase stabilities in a temperature range of 500 – 900 oC using X-ray diffraction (XRD) and Rietveld refinement. From the results, we identified the crystal structures, on set temperatures of the secondary phases, and their evolutions with temperatures. By comparing the overall phase evolution behaviors, we will present the fundamental reaction mechanism between LATP and cathode materials. Moreover, we will discuss an important relationship between the phase stability and electrochemical performances by characterizing solid-state LIBs. Outcome of this study suggests that understanding the fundamental reaction mechanisms between solid electrolyte and cathode materials would be crucial in developing strategies for improving the cathode–solid electrolyte interfaces in solid-state LIBs.

Interface stability between Li1.4Al0.4Ti1.6(PO4)3 and cathode for all solid-state lithium-ion batteries

2019 Fall National Meeting

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