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Title: Is alpha-V 2O 5 a cathode material for Mg insertion batteries?

Abstract

When designing a high energy density battery, one of the critical features is a high voltage, high capacity cathode material. In the development of Mg batteries, oxide cathodes that can reversibly intercalate Mg, while at the same time being compatible with an electrolyte that can deposit Mg reversibly are rare. Herein, we report the compatibility of Mg anodes with a-V 2O 5 by employing magnesium bis(trifluoromethane sulfonyl)imide in diglyme electrolytes at very low water levels. Electrolytes that contain a high water level do not reversibly deposit Mg, but interestingly these electrolytes appear to enable much higher capacities for an a-V 2O 5 cathode. Solid state NMR indicates that the major source of the higher capacity in high water content electrolytes originates from reversible proton insertion. In contrast, we found that lowering the water level of the magnesium bis(trifluoromethane sulfonyl)imide in diglyme electrolyte is critical to achieve reversible Mg deposition and direct evidence for reversible Mg intercalation is shown. Findings we report here elucidate the role of proton intercalation in water-containing electrolytes and clarify numerous conflicting reports of Mg insertion into a-V 2O 5.

Authors:
ORCiD logo; ; ; ; ; ORCiD logo; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science - Office of Basic Energy Sciences - Joint Center for Energy Storage Research (JCESR)
OSTI Identifier:
1325712
DOE Contract Number:
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Power Sources; Journal Volume: 323; Journal Issue: C
Country of Publication:
United States
Language:
English
Subject:
25 ENERGY STORAGE; Full cell; Mg anode; Mg battery; Non-aqueous Mg electrolyte; Proton intercalation; Solid state NMR

Citation Formats

Sa, Niya, Wang, Hao, Proffit, Danielle L., Lipson, Albert L., Key, Baris, Liu, Miao, Feng, Zhenxing, Fister, Timothy T., Ren, Yang, Sun, Cheng-Jun, Vaughey, John T., Fenter, Paul A., Persson, Kristin A., and Burrell, Anthony K. Is alpha-V2O5 a cathode material for Mg insertion batteries?. United States: N. p., 2016. Web. doi:10.1016/j.jpowsour.2016.05.028.
Sa, Niya, Wang, Hao, Proffit, Danielle L., Lipson, Albert L., Key, Baris, Liu, Miao, Feng, Zhenxing, Fister, Timothy T., Ren, Yang, Sun, Cheng-Jun, Vaughey, John T., Fenter, Paul A., Persson, Kristin A., & Burrell, Anthony K. Is alpha-V2O5 a cathode material for Mg insertion batteries?. United States. doi:10.1016/j.jpowsour.2016.05.028.
Sa, Niya, Wang, Hao, Proffit, Danielle L., Lipson, Albert L., Key, Baris, Liu, Miao, Feng, Zhenxing, Fister, Timothy T., Ren, Yang, Sun, Cheng-Jun, Vaughey, John T., Fenter, Paul A., Persson, Kristin A., and Burrell, Anthony K. Mon . "Is alpha-V2O5 a cathode material for Mg insertion batteries?". United States. doi:10.1016/j.jpowsour.2016.05.028.
@article{osti_1325712,
title = {Is alpha-V2O5 a cathode material for Mg insertion batteries?},
author = {Sa, Niya and Wang, Hao and Proffit, Danielle L. and Lipson, Albert L. and Key, Baris and Liu, Miao and Feng, Zhenxing and Fister, Timothy T. and Ren, Yang and Sun, Cheng-Jun and Vaughey, John T. and Fenter, Paul A. and Persson, Kristin A. and Burrell, Anthony K.},
abstractNote = {When designing a high energy density battery, one of the critical features is a high voltage, high capacity cathode material. In the development of Mg batteries, oxide cathodes that can reversibly intercalate Mg, while at the same time being compatible with an electrolyte that can deposit Mg reversibly are rare. Herein, we report the compatibility of Mg anodes with a-V2O5 by employing magnesium bis(trifluoromethane sulfonyl)imide in diglyme electrolytes at very low water levels. Electrolytes that contain a high water level do not reversibly deposit Mg, but interestingly these electrolytes appear to enable much higher capacities for an a-V2O5 cathode. Solid state NMR indicates that the major source of the higher capacity in high water content electrolytes originates from reversible proton insertion. In contrast, we found that lowering the water level of the magnesium bis(trifluoromethane sulfonyl)imide in diglyme electrolyte is critical to achieve reversible Mg deposition and direct evidence for reversible Mg intercalation is shown. Findings we report here elucidate the role of proton intercalation in water-containing electrolytes and clarify numerous conflicting reports of Mg insertion into a-V2O5.},
doi = {10.1016/j.jpowsour.2016.05.028},
journal = {Journal of Power Sources},
number = C,
volume = 323,
place = {United States},
year = {Mon Aug 01 00:00:00 EDT 2016},
month = {Mon Aug 01 00:00:00 EDT 2016}
}
  • Functional multivalent intercalation cathodes represent one of the largest hurdles in the development of Mg batteries. While there are many reports of Mg cathodes, many times the evidence of intercalation chemistry is only circumstantial. In this work, direct evidence of Mg intercalation into a bilayer structure of V2O5·nH2O xerogel is confirmed, and the nature of the Mg intercalated species is reported. The interlayer spacing of V2O5·nH2O contracts upon Mg intercalation and expands for Mg deintercalation due to the strong electrostatic interaction between the divalent cation and the cathode. A combination of NMR, pair distribution function (PDF) analysis, and X-ray absorptionmore » near edge spectroscopy (XANES) confirmed reversible Mg insertion into the V2O5·nH2O material, and structural evolution of Mg intercalation leads to the formation of multiple new phases. Structures of V2O5·nH2O with Mg intercalation were further supported by the first principle simulations. A solvent cointercalated Mg in V2O5·nH2O is observed for the first time, and the 25Mg magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy was used to elucidate the structure obtained upon electrochemical cycling. Specifically, existence of a well-defined Mg–O environment is revealed for the Mg intercalated structures. Information reported here reveals the fundamental Mg ion intercalation mechanism in a bilayer structure of V2O5·nH2O material and provides insightful design metrics for future Mg cathodes.« less
  • Batteries based on Mg metal anode can promise much higher specific volumetric capacity and energy density compared to Li-ion systems and are, at the same time, safer and more cost-effective. While previous experimental reports have claimed reversible Mg intercalation into beyond Chevrel phase cathodes, they provide limited evidence of true Mg intercalation other than electrochemical data. Transmission electron microscopy techniques provide unique capabilities to directly image Mg intercalation and quantify the redox reaction within the cathode material. Here, we present a systematic study of Mg insertion into orthorhombic V 2O 5, combining aberration-corrected scanning transmission electron microscopy (STEM) imaging, electronmore » energy-loss spectroscopy (EELS), and energy-dispersive X-ray spectroscopy (EDX) analysis. We compare the results from an electrochemically cycled V 2O 5 cathode in a prospective full cell with Mg metal anode with a chemically synthesized MgV 2O 5 sample. Results suggest that the electrochemically cycled orthorhombic V 2O 5 cathode shows a local formation of the theoretically predicted ϵ-Mg0.5V2O5 phase; however, the intercalation levels of Mg are lower than predicted. Lastly, this phase is different from the chemically synthesized sample, which is found to represent the δ-MgV 2O 5 phase.« less
  • The high-capacity cathode material V2O5·nH2O has attracted considerable attention for metal ion batteries due to the multielectron redox reaction during electrochemical processes. It has an expanded layer structure, which can host large ions or multivalent ions. However, structural instability and poor electronic and ionic conductivities greatly handicap its application. Here, in cell tests, self-assembly V2O5·nH2O nanoflakes shows excellent electrochemical performance with either monovalent or multivalent cation intercalation. They are directly grown on a 3D conductive stainless steel mesh substrate via a simple and green hydrothermal method. Well-layered nanoflakes are obtained after heat treatment at 300 °C (V2O5·0.3H2O). Nanoflakes with ultrathinmore » flower petals deliver a stable capacity of 250 mA h g-1 in a Li-ion cell, 110 mA h g-1 in a Na-ion cell, and 80 mA h g-1 in an Al-ion cell in their respective potential ranges (2.0–4.0 V for Li and Na-ion batteries and 0.1–2.5 V for Al-ion battery) after 100 cycles.« less