Publication Type:

Journal Article


Nano Letters, American Chemical Society, Volume 16, Number 6, p.3760-3767 (2016)



All-solid state batteries, Charge transfer, Electric batteries, Electrochemical systems, Electrodes, Electrolytes, Electron energy levels, Electron energy loss spectroscopy, Electron scattering, Energy dissipation, Energy storage, Energy storage and conversions, High resolution transmission electron microscopy, In-situ TEM, Interface states, Interfaces (materials), Interfacial phenomena, Ionic conduction in solids, Ions, Lithium, Lithium alloys, Lithium compounds, Lithium-ion batteries, Lithium-ion transport, scanning electron microscopy, Secondary batteries, Solid electrolytes, Solid state devices, Spectroscopic characterization, Thin film battery, Thin film lithium ion batteries, Thin films, transmission electron microscopy


Behaviors of functional interfaces are crucial factors in the performance and safety of energy storage and conversion devices. Indeed, solid electrode-solid electrolyte interfacial impedance is now considered the main limiting factor in all-solid-state batteries rather than low ionic conductivity of the solid electrolyte. Here, we present a new approach to conducting in situ scanning transmission electron microscopy (STEM) coupled with electron energy loss spectroscopy (EELS) in order to uncover the unique interfacial phenomena related to lithium ion transport and its corresponding charge transfer. Our approach allowed quantitative spectroscopic characterization of a galvanostatically biased electrochemical system under in situ conditions. Using a LiCoO2/LiPON/Si thin film battery, an unexpected structurally disordered interfacial layer between LiCoO2 cathode and LiPON electrolyte was discovered to be inherent to this interface without cycling. During in situ charging, spectroscopic characterization revealed that this interfacial layer evolved to form highly oxidized Co ions species along with lithium oxide and lithium peroxide species. These findings suggest that the mechanism of interfacial impedance at the LiCoO2/LiPON interface is caused by chemical changes rather than space charge effects. Insights gained from this technique will shed light on important challenges of interfaces in all-solid-state energy storage and conversion systems and facilitate improved engineering of devices operated far from equilibrium.


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Cite this Research Publication

Za Wang, Santhanagopalan, D., Zhang, Wc, Wang, Fc, Xin, H. Lc, He, Kc, Li, Jd, Dudney, Nd, and Meng, Y. Sa, “In situ STEM-EELS observation of nanoscale interfacial phenomena in all-solid-state batteries”, Nano Letters, vol. 16, pp. 3760-3767, 2016.