Infrared near-field nanospectroscopy of electrochemical interfaces in batteries

Description:
Li-ion and Li-metal batteries still must overcome performance limitations associated with electrode/electrolyte interfaces, such as high interfacial impedance, electrochemical instability, and inhomogeneous, Li plating and stripping. Battery performance is largely determined by thermodynamic, kinetic, and mechanical properties of electrochemical interfaces that operate far away from equilibrium. A thin passive film that forms st the electrode/electrolyte interface is critical for the system performance and lifetime. It provides sufficient electronic resistivity and ionic conductivity to inhibit side reactions with the electrolyte while still allowing ion transport. Additionally, the film’s inhomogeneous structure and chemistry influence localized current density distribution and the corresponding charge and mass transport processes.
A variety of instrumental techniques have been used to characterize the SEI, however, no methodology has been demonstrated thus far that can characterize interface and SEI nondestructively, within their undisturbed native environment, and with nanoscale resolution. In this work, we exploit the nanoscale spatial resolution, chemical selectivity, and surface sensitivity of near-field infrared nanospectroscopy to characterize electrode/liquid and solid electrolyte interfaces. Near-field infrared measurements can reveal that intrinsic molecular, structural, and chemical heterogeneities at the interface lead to the nonuniform current distribution and formation of a mosaic-like solid electrolyte interphase at the electrode/electrolyte interface on a similar length scale. This work provides a unique insight into the mechanisms of early-stage interphase formation at electrochemically active buried interfaces, and an experimental diagnostic means to aid in the development of methods to control local nanoscale variations in electrolyte chemistry, structure, and ionic conductivity at the surface of the electrode.

Speaker: Robert Kostecki - Lawrence Berkeley National Laboratory
Robert Kostecki is a Senior Scientist and Director of the Energy Storage and Distributed Resources Division in Lawrence Berkeley National Laboratory. He's been involved in multiple research projects focused on basic processes and fundamental phenomena that determine electrochemical performance of electrical energy storage/conversion systems and water treatment technologies. He is often recognized for his pioneering work in characterization of electrochemical interfaces and electrochemical systems engineering, which helped bridge the gap between basic and applied science for applications such as rechargeable batteries, fuel cells, photo-electrochemical reactors and desalination methods. Author of >140 papers in refereed journals, 15 papers in conference proceedings, >250 presentations at conferences and 17 patents. Fellow of the Electrochemical Society, past Vice President of International Society of Electrochemistry currently serves as Associated Editor of Electrochimica Acta.