Designing Reliable Operando TEM Experiments to Study (De)lithiation Mechanism of Battery Electrodes

Abstract

The unique capability of TEM to resolve the microstructural and chemical evolution of electrode materials during battery operation at high temporal and spatial resolution makes it the method of choice for operando battery experiments. However, the widely used open-cell setup, that uses oxidized lithium as the electrolyte due to its inherent design, does not allow Li-ions to be (de)inserted from every part of the electrode particle, which imposes restrictions on the (de)intercalation process. This may lead to the formation of a mechanistic hypothesis based on incomplete information about the (de)lithiation of the electrode material under investigation. Using LiFePO₄ as a model electrode material we propose here a MEMS based cell-on-a-chip design comprising of a thin coating of amorphous electrolyte, which can be utilized to overcome the said issue.