Understanding the role of crystallographic shear on the electrochemical behavior of niobium oxyfluorides. Issue 25 (17th June 2020)

• Record Type: Journal Article
• Authors: Bashian, Nicholas H.; Preefer, Molleigh B.; Milam-Guerrero, JoAnna; Zak, Joshua J.; Sendi, Charlotte; Ahsan, Suha A.; Vincent, Rebecca C.; Haiges, Ralf; See, Kimberly A.; Seshadri, Ram; Melot, Brent C.
• Is Part Of: Journal of materials chemistry. Volume 8:Issue 25(2020)
• Page Start: 12623
• Page End: 12632
• Publication Date: 2020-06-17
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d0ta01406k
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : The effects of shear planes in perovskitic materials have been studied in order to identify their role in the electrochemical behavior and structural evolution of Li + intercalation hosts. Abstract : The effects of shear planes in perovskite materials have been studied in order to identify their role in the electrochemical behavior of Li + intercalation hosts. These planes modulate the structural stability and ionic transport pathways and therefore play an intimate role in the characteristics and performance of shear compounds. Herein, two Nb-based compounds, NbO2 F and Nb3 O7 F, were chosen as representative perovskite and shear derivatives respectively to investigate the role of crystallographic shear. A series of operando measurements, including X-ray diffraction and X-ray absorption spectroscopy, in conjunction with structural analysis, Raman spectroscopy, and detailed electrochemical studies identified the effect of shear planes. It was found that shear planes led to increased structural stability during Li + (de)intercalation with shear layers being maintained, while perovskite layers were seen to degrade rapidly. However, disordering in the shear plane stacking introduced during delithiation ultimately led to poor capacity retention despite structural maintenance as Li + diffusion channels are disrupted.