Investigation of Novel Tunnel Structured Zeta-V2O5 nanowire As a Potential Cathode for Li and Mg Ion Intercalation Using in Situ TEM and Aberration Corrected STEM
Authors: Mukherjee Arijita , Andrews Justin , Banerjee Sarbajit , Klie Robert F 
Published: February 2020

Li ion battery technology continues to be the leader in energy storage applications, however growing demand for higher capacity, longer lifetime and more cost effective options has motivated researchers to both improve existing Li ion technology and also explore multivalent battery technology. From consumer electronics to electric cars, designing better models for future calls for a vast improvement in the existing battery technology. [1] Of course, traditional intercalation compounds are drawing up interest as potential cathode candidates. V2O5 has been a promising cathode for Li ion batteries. Several first principle studies have also concluded that V2O5 could be a potential cathode for Mg ion intercalation.[2] The unique structure of V2O5 consisting of layers of VO5 square pyramids held by weak bonds along the interlayer direction facilitates ion intercalation between the layers. [3] According to a recent paper, a new tunnel structured polymorph of V2O5 [zeta-V2O5] has been stabilized which can accommodate both Li and Mg ions. [4]

In this talk, I will present results using in-situ TEM “open cell battery” approach to study in situ lithiation of these tunnel structured zeta-V2O5 nanowires to better understand the reaction kinetics and progression of lithiation as well as study lithiation induced changes in the structure at an atomic scale. I will compare these results with previous results we obtained studying in situ lithiation of orthorhombic alpha-V2O5 nanowires using electron diffraction and electron energy loss spectroscopy.[5] I will also use aberration corrected scanning transmission electron microscopy (STEM) imaging to study the magnesium intercalated beta structure and present the results as well, again comparing with previous results we have obtained studying electrochemically cycled thin film orthorhombic V2O5 with Mg metal anode.[6][7] Figure 1(a) shows typical TEM image of the zeta-V2O5 nanowire, electron diffraction pattern in Figure 1(b) can be indexed using XRD data for zeta-V2O5. The tunnel framework of zeta- V2O5 can be identified in the filtered High angle annular dark field (HAADF) image presented in Fig 1(c), and the electron energy loss spectra presented in Fig 1(d) establishes the valence state of Vanadium as V5+ (as expected in V2O5) by confirming the energy difference between V L3and O K edges as 9.8 eV.
References
1) Noorden, R V, The rechargeable revolution: A better battery, Nature, 2014, 507, 26-28
2) B. Zhou, H. Shi, R. Cao, X. Zhang, Z. Jiang, Theoretical study on the initial stage of a
magnesium battery based on a V2O5 cathode, Phys Chem Chem Phys, 2014,16,18578
3) G S Gautam, P. Canepa, A.Abdellahi, A.Urban, R.Malik, G. Ceder, The Intercalation Phase Diagram of Mg in V2O5 from First-Principles, Chem Mat, 2015
4) P.M Marley, T. A Abtew, K. E Farley, G.A Horrocks, R.V Dennis, P. Zhang, S Banerjee, Emptying and Filling a Tunnel Bronze, Chem. Sci, 2015, 6, 1712
5)A Mukherjee, H A Ardakani, T Yi, J Cabana, R S Yassar, R F Klie, Investigation of Li intercalation mechanism into V2O5nanowire cathode using in situ Transmission Electron Microscopy methods[Manuscript in preparation]
6) A. Mukherjee, N.Sa, P J Phillips, A Burrell, R F Klie.Investigation of Mg intercalation into thin film orthorhombic V2O5cathode using Aberration corrected STEM and EELS[Manuscript in preparation]
7) This work is supported by the Joint Center for Energy Storage Research (JCESR), an Energy Innovation Hub funded by the U.S. Department of Energy (DOE),Office of Science, Basic Energy Sciences.

Figure 1