Growth of lithium-indium dendrites in all-solid-state lithium-based batteries with sulfide electrolytes

All-solid-state lithium-based batteries with inorganic solid electrolytes are considered a viable option for electrochemical energy storage applications. However, the application of lithium metal is hindered by issues associated with the growth of mossy and dendritic Li morphologies upon prolonged cell cycling and undesired reactions at the electrode/solid electrolyte interface. In this context, alloy materials such as lithium-indium (Li-In) alloys are widely used at the laboratory scale because of their (electro)chemical stability, although no in-depth investigations on their morphological stability have been reported yet. In this work, we report the growth of Li-In dendritic structures when the alloy material is used in combination with a Li 6 PS 5 Cl solid electrolyte and Li(Ni 0.6 Co 0.2 Mn 0.2 )O 2 positive electrode active material and cycled at high currents (e.g., 3.8 mA cm −2 ) and high cathode loading (e.g., 4 mAh cm −2 ). Via ex situ measurements and simulations, we demonstrate that the irregular growth of Li-In dendrites leads to cell short circuits after room-temperature long-term cycling. Furthermore, the difference between Li and Li-In dendrites is investigated and discussed to demonstrate the distinct type of dendrite morphology. Li-In alloys are widely used as reference materials in the research field of solid-state lithium-based batteries. Here, the authors report and discuss the instability of Li-In electrodes towards sulfide solid electrolytes in all-solid-state batteries.