Visualization of electrochemical reactions in all-solid-state li-ion batteries by spatially resolved electron energy-loss spectroscopy and electron holography

Abstract

Lithium-ion rechargeable batteries (LIBs) have become essential for business, industry, and daily life. All-solid-state LIBs with incombustible solid electrolytes are expected as next-generation batteries that are safe, long lasting, and have high energy density. The electrochemical battery reactions commonly occur around the electrode/electrolyte interfaces on a nanometer scale; thus, local-scale analysis and observation are important to improve battery performance. Transmission electron microscopy (TEM) is an appropriate technique for such localscale analysis inside batteries. Here, we introduce two TEM techniques and explain the results of visualizing the dynamics of electrochemical reactions in all-solid-state LIBs. From the results using ex situ spatially resolved electron energy-loss spectroscopy and in situ electron holography, we reveal how Li-ions move in batteries and how they affect the crystal structures, electronic structures, and electric potential during the charge-discharge reactions.