Disordered Battery Materials and Systems—Insights via Extended X-Ray Absorption Fine Structure Analysis

Batteries based on highly ordered intercalation materials such as graphite and lithium cobalt oxide undergo well defined and specific crystallographic changes upon electrochemical cycling and are suitable for characterization via diffraction-based methods. In contrast, conversion batteries based on nanocrystalline materials possess less long-range order and may be too amorphous for diffraction based study. Understanding the local coordination environment of such materials and their evolution upon electrochemical cycling can be very beneficial for the materials designer. This presentation will highlight the benefits of extended x-ray absorption fine structure analysis for determining specific coordination environment changes within disordered battery materials. For example, determination and differentiation between octahedral and tetrahedral coordination sites, idealized and distorted environments (i.e. Jahn-Teller) can be deciphered in a specific way using this approach. As conversion batteries provide the opportunity for higher capacities and incorporation of more earth abundant elements, these methods can help support progress toward a green energy future.