Operando bulk and interfacial characterization for electrochemical energy storage: Case study employing isothermal microcalorimetry and X-ray absorption spectroscopy

Wenzao Li,Nahian Sadique,Kenneth J Takeuchi,Steve Ehrlich,David C Bock,Esther S Takeuchi,Amy C Marschilok,Lisa M Housel,Mallory N Vila,Genesis D Renderos,Lei Wang

doi:10.1557/s43578-021-00350-y

Abstract

The global shift to electricity as the main energy carrier will require innovation in electrochemical energy storage (EES). EES systems are the key to the “electron energy economy,” minimizing losses and increasing reliability between energy supply and demand. However, steep challenges such as cost, cycle/calendar life, energy density, material availability, and safety limit widespread adoption of batteries for large-scale grid and vehicle applications. Battery innovation that meets today’s challenges will require new chemistries, which can originate from understanding charge transport phenomena at multiple time and length scales. The advancement of operando characterization can expedite this progress as changes can be observed during battery function. This article highlights progress in bulk and interfacial operando characterization of batteries. Specifically, a case study involving Fe3O4 is provided demonstrating that combining X-ray absorption spectroscopy and isothermal microcalorimetry can provide real-time characterization of productive faradaic redox processes and parasitic interfacial reactions during (de)lithiation.Graphic abstract

Highlights

Operando characterization of electrochemical energy storageElectrochemical energy storage is critical to achieve an “electron energy economy,” where electricity generated by renewable resources powers all end-use applications
The majority of operando battery characterization relies on electromagnetic (X-rays, optical) or particle radiation including angle and energy dispersive X-ray diffraction (ADXRD, EDXRD), X-ray absorption spectroscopy (XAS), transmission X-ray microscopy (TXM), X-ray microfluorescence (μ-XFM), neutron powder diffraction (NPD), transmission electron microscopy (TEM), nuclear magnetic resonance (NMR), and Raman spectroscopy
For the fluoroethylene carbonate (FEC) cell (Fig. 6b), total heat flow is ~ 20 mW/g greater than the polarization and entropic heat flow contributions before 2 ee of lithiation, indicating earlier onset of the parasitic reactions relative to ethylene carbonate (EC), which is consistent with reports indicating FEC reduction and solid electrolyte interphase (SEI) formation occurs at higher potential [5, 33]

Summary

Introduction

Operando characterization of electrochemical energy storageElectrochemical energy storage is critical to achieve an “electron energy economy,” where electricity generated by renewable resources powers all end-use applications. Heat flow peaks in both EC (Fig. 4e) and FEC (Fig. 4f) heat flow profiles are observed at the same lithiation states where differential capacity peaks and discharge plateaus appear, suggesting real-time heat flow can indicate phase transitions in electroactive materials and structural changes account for a part of thermal output released from the Li/Fe3O4 cells.

Results

Conclusion