Published Papers

The Role of Li3ClO-Based Electrolyte in Li-S Batteries

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Symposium G: Next-Generation Electrochemical Energy Storage and Conversion Systems—Synthesis, Processing, Characterization and Manufacturing

Andrew Murchison 2; Jorge Ferreira 3; Maria Helena Braga 1

Affiliations

1, Engineering Physics Department, University of Porto – FEUP, Porto, Portugal
2, Pathion, Los Gatos, California, United States
3, Energy and Geology National Laboratory, Porto, Portugal

Materials Research Society 2015 Spring Meeting

Copyright © 2015 Materials Research Society

ABSTRACT:

The lithium-sulfur chemistry is a potential breakthrough solution to the enduring battery performance problem of inexpensive portable energy storage. A lithium-sulfur battery could achieve specific energy levels up to 800 Wh/kg, while lithium-ion cells today delivery only 250 Watt-hours per kilogram (Wh/kg), with potential improvement to 400 Wh/kg in the future. Lithium and sulfur are inexpensive raw materials, enabling lower cost batteries, and the cells can be produced in the same factories that are making lithium-ion cells today.
Although the operation principle of Li-S batteries has been known for decades, unfortunately they have not been commercialized on a large scale to date. The major problems connected with a fast capacity fading (stability) and low cycling efficiency are mainly due to a complicated reaction mechanism which involves different soluble lithium polysulfides.
It has been proposed that a high surface area, porous carbon materials enable confinement of sulfur and polysulfides and have an impact on the Li-S battery cycling properties (capacity and efficiency). However, some literature reports to have showed that the use of carbons with a designed morphology is insufficient for long cycling stability. Additional stability can be gained by utilizing a doped or optimized Li3ClO-based glass electrolyte [1] as a barrier to halt the diffusion of polysulfides into the lithium.
In this study, we present our recent results on the role of LiRAP (lithium rich anti-perovskite) – as a solid state Li-S electrolyte. Besides using our doped or optimized Li3ClO-based glass electrolyte, we have also prepared a highly efficient sulfur cathode which allows for an increased sulfur loading of up to 6.9 mgcm-2. The use of the here reported electrolyte has resulted in a significant improvement in coloumbic efficiency and in a longer cycle life. The impact of an optimized electrolyte/cathode on the mechanisms proceeding in Li-S batteries were studied using 2.5 x (2.5 or 3.5) cm2 cells and potentio – galvanostatic measurements.
[1] M.H. Braga, J.A. Ferreira, V. Stockhausen, J.E. Oliveira, A. El-Azab, Novel Li3ClO based glasses with superionic properties for lithium batteries, J. Mater. Chem. A 2014, 2, 5470-5480.
[2] A. Murchison, J.A. Ferreira, M.H. Braga, Superionic solid electrolyte for Li-S batteries, in preparation.

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Superionic Conductivity in Lithium-Rich Anti-Perovskites

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Yusheng Zhao*’^ and Luke L. Daemen*

 Department of Physics and Astronomy, University of Nevada, Las Vegas, Nevada 89154, United States

 Los Alamos Neutron Science Center, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States

J. Am. Chem. Soc.2012134 (36), pp 15042–15047

DOI: 10.1021/ja305709z

Publication Date (Web): July 30, 2012

Copyright © 2012 American Chemical Society

 

ABSTRACT: Lithium ion batteries have shown great promise in electrical energy storage with enhanced energy density, power capacity, charge—discharge rates, and cycling lifetimes. However common fluid electrolytes consisting of lithium salts dissolved in solvents are toxic, corrosive, or flammable. Solid electrolytes with superionic conductivity can avoid those shortcomings and work with a metallic lithium anode, thereby allowing much higher energy densities. Here we present a novel class of solid electrolytes with three-dimensional conducting pathways based on lithium-rich anti-perovskites (LiRAP) with ionic conductivity of  σ > 10-3 S/cm at room temperature and activation energy of 0.2—0.3 eV. As temperature approaches the melting point, the ionic conductivity of the anti-perovskites increases to advanced superionic conductivity of  σ > 10-2 S/cm and beyond. The new crystalline materials can be readily manipulated via chemical, electronic, and structural means to boost ionic transport and serve as high-performance solid electrolytes for superionic Li+ conduction in electrochemistry applications.

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Novel Anti-Perovskite Electrolytes for Superionic Lithium Transport

Luc L. Daemen 20110139ER

FY11 Annual Progress Report Published in the LANL FY11- Annual Progress Report  Page 157-160

Copyright © 2011 Los Alamos National Lab Press

Lithium ion batteries have shown great promise in terms of electric energy storage parameters such as energy density, power capacity, charge-discharge rates, and cycling lifetimes. However many fluid electrolytes consisting of lithium salts dissolved in solvents are toxic, corrosive, or flammable. They tend to work poorly with lithium anodes. Solid electrolytes with superionic conductivity can avoid those shortcomings, and can work much better with a metallic lithium anode, allowing for much higher energy densities. We propose a novel class of superionic solid electrolytes with 3D conducting pathways based on anti-perovskites of high lithium content.

The new crystalline materials can form adaptable solid solutions and lend themselves to structural and chemical modifications to boost ionic transporting. We have measured the ionic conductivities of the order of 10-2 S/m for the anti-perovskites Li30CI and Li30CI0.5Br0.5, respectively, and the high temperature measurements derive the activation energies of range 0.3-0.5 eV corresponding, well within the superionic transporting region. These initial studies demonstrate that the anti-perovskites can serve as a solid electrolyte material for superionic conduction of Li-ion battery.

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The Role of Defects in Li3CIO Solid Electrolyte: Calculations and Experiments

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M. Helena Braga, Verena Stockhausen, Joana Oliverira, Jorge A. Ferreira, Engineering Physics Department, FEUP, Porto University, R. Dr. Roberto Frias, s/n, 4200-465, Porto, Portugal and CEMUCa and CFPb.

2Energy and Geology National Laboratory, LNEG, R. da Amieira, S. Mamede Infesta, Portugal.

Materials Research Society 2012 Fall Meeting

Copyright © 2012 Materials Research Society

ABSTRACT:

We have analyzed the hopping movement of a new ionic solid electrolyte by calculating defect formation energies and activation barriers. The role of the lattice during diffusion was established. Thermodynamic properties were determined by means of first principles and phonon calculations at working temperatures. The new solid electrolyte, an antiperovskite, Li3.2XMxAO (in which M is a higher valent cation like Ca2+ or Mg2+ and A is a halide like Cl- or Br- or a mixture of halides), was studied either pure or doped. Moreover, we present experimental ionic conductivity data for these novel solid state ionic conductors for the doped and the pure solid electrolyte from room temperature and up to -253 °C. In this paper, we compare the ionic conductivity of the latter solid electrolyte with other fast ionic conductors.

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Ab initio study of the stabilities of and mechanism of superionic transport in lithium-rich anti-perovskites

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Yi Zhang, Yusheng Zhao, and Changfeng Chen

Department of Physics and High Pressure Science and Engineering Center, University of Nevada, Las Vegas, Nevada 89154, USA

PHYSICAL REVIEW B 87,134303 (2013)

Copyright © 2013 Physical Review – APS Physics

 

Recently, a family of halogen-based Li-rich anti-perovskites were synthesized [J. Am. Chem. Soc. 134,15042 (2012)], and the measured superionic conductivity makes these materials promising candidates as solid electrolytes for applications in Li-ion and Li-air batteries. This discovery raises several pressing issues on the fundamental physics concerning the thermodynamic and electrochemical stability of the synthesized materials and the mechanism of the observed superionic Li+ transport. Here, we study the reported anti-perovskites Li3OCl,

Li3OBr, and their mixed compounds using first-principles density functional theory and molecular dynamics simulations. Our calculations show that these materials are thermodynamically metastable. Their large electronic band gaps and chemical stability against electrodes suggest the excellent electrochemical performance, which bodes well for the use in potentially harsh working conditions in practical battery applications. The calculated low activation enthalpy for Li-ion migration well below the crystal melting temperature and superionic transport near the Li sublattice melting state explain the experimentally observed phenomena. Our study identifies mobile Li vacancies and anion disorder as the primary driving mechanisms for superionic Li+ conductivity in the anti-perovskites. This work unveils essential working principles of the Li-rich anti-perovskites, which are crucial to further exploration, development, and application of these and other charge-inverted materials with tailored properties.

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Novel Li3ClO based glasses with superionic properties for lithium batteries

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Royal Society of Chemistry – Journals of Material Chemistry A

M. H. Braga,*3 J. A. Ferreira,b V. Stockhausen,c J. E. Oliveirad and A. El-Azabe

J. Mater. Chem. A, 2014,2, 5470-5480

DOI: 10.1039/C3TA15087A

 

Received 08 Dec 2013, Accepted 26 Jan 2014
First published online 07 Mar 2014

Copyright © 2014 Royal Society of Chemistry

 

Three types of next generation batteries are currently being envisaged among the international community: metal-air batteries, multivalent cation batteries and all-solid-state batteries. These battery designs require high-performance, safe and cost effective electrolytes that are compatible with optimized electrode materials. Solid electrolytes have not yet been extensively employed in commercial batteries as they suffer from poor ionic conduction at acceptable temperatures and insufficient stability with respect to lithium-metal. Here we show a novel type of glasses, which evolve from an anti-perovskite structure and that show the highest ionic conductivity ever reported for the Li-ion (25 mS cm-1 at 25 °C). These glassy electrolytes for lithium batteries are inexpensive, light, recyclable, non-flammable and non-toxic. Moreover, they present a wide electrochemical window (higher than 8 V) and thermal stability within the application range of temperatures.

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Phase Stability and Transport Mechanisms in Anti-perovskite Li3OCl and Li3OBr Superionic Conductors

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Alexandra Emly , Emmanouil Kioupakis †, and Anton Van der Ven *†‡

 Materials Science & Engineering, University of Michigan, Ann Arbor, Michigan, United States

 Materials Department, University of California, Santa Barbara, California, United States

Chem. Mater., 201325 (23), pp 4663–4670

DOI: 10.1021/cm4016222

Publication Date (Web): November 26, 2013

Copyright © 2013 American Chemical Society

 

We investigate phase stability and ionic transport mechanisms in two recently discovered superionic conductors, Li3OX (X = Cl, Br), from first principles. These compounds, which have an antiperovskite crystal structure, have potential applications as solid electrolytes in Li-ion batteries. We identify a low-barrier three-atom hop mechanism involving Li interstitial dumbbells. This hop mechanism is facile within the (001) crystallographic planes of the perovskite crystal structure and is evidence for the occurrence of concerted motion, similar to ionic transport in other solid electrolytes. Our first-principles analysis of phase stability predicts that antiperovskite Li3OCl (Li3OBr) is metastable relative to Li2O and LiCl (LiBr) at room temperature. We also find that although the band gap of Li3OCl exceeds 5 eV, the metastable antiperovskite becomes susceptible to decomposition into Li2O2, LiCl and LiClO4 above an applied voltage of 2.5 V, suggesting that these compounds are most suited for low-voltage Li batteries provided the formation of Li2O can be suppressed.

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Li-rich anti-perovskite Li3OCl films with enhanced ionic conductivity†

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Xujie Lu¨,*ab   Gang Wu, a John W. Howard, ab   Aiping Chen, a  Yusheng Zhao,*b   Luke L. Daemen a   and Quanxi Jia*a

DOI:10.1039/c4cc05372a

Received July 11th 2014

Accepted August 13th 2014

Publication Date (Web): August 13, 2014

Copyright © 2014 Royal Society of Chemistry

Abstract: Anti-perovskite solid electrolyte films were prepared by pulsed laser deposition, and their room-temperature ionic conductivity can be improved by more than an order of magnitude in comparison with its bulk counterpart. The cyclability of Li3OCl films in contact with lithium was evaluated using a Li/Li3OCl/Li symmetric cell, showing self-stabilization during cycling test.

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