Magnetism in lithium-oxygen discharge product.

Nonaqueous lithium-oxygen batteries have a much superior theoretical gravimetric energy density compared to conventional lithium-ion batteries, and thus could render long-range electric vehicles a reality. A molecular-level understanding of the reversible formation of lithium peroxide in these batteries, the properties of major/minor discharge products, and the stability of the nonaqueous electrolytes is required to achieve successful lithium-oxygen batteries. We demonstrate that the major discharge product formed in the lithium-oxygen cell, lithium peroxide, exhibits a magnetic moment. These results are based on dc-magnetization measurements and a lithium-oxygen cell containing an ether-based electrolyte. The results are unexpected because bulk lithium peroxide has a significant band gap. Density functional calculations predict that superoxide-type surface oxygen groups with unpaired electrons exist on stoichiometric lithium peroxide crystalline surfaces and on nanoparticle surfaces; these computational results are consistent with the magnetic measurement of the discharged lithium peroxide product as well as EPR measurements on commercial lithium peroxide. The presence of superoxide-type surface oxygen groups with spin can play a role in the reversible formation and decomposition of lithium peroxide as well as the reversible formation and decomposition of electrolyte molecules.

[1]  P. Bruce,et al.  Reactions in the rechargeable lithium-O2 battery with alkyl carbonate electrolytes. , 2011, Journal of the American Chemical Society.

[2]  Yang Shao-Horn,et al.  The discharge rate capability of rechargeable Li–O2 batteries , 2011 .

[3]  Hun‐Gi Jung,et al.  An improved high-performance lithium-air battery. , 2012, Nature chemistry.

[4]  K. Lau,et al.  Density Functional Investigation of the Thermodynamic Stability of Lithium Oxide Bulk Crystalline Structures as a Function of Oxygen Pressure , 2011 .

[5]  J. Read.  Ether-Based Electrolytes for the Lithium/Oxygen Organic Electrolyte Battery , 2006 .

[6]  Fuminori Mizuno,et al.  Rechargeable Li-Air Batteries with Carbonate-Based Liquid Electrolytes , 2010 .

[7]  J. Nørskov,et al.  Twin Problems of Interfacial Carbonate Formation in Nonaqueous Li-O2 Batteries. , 2012, The journal of physical chemistry letters.

[8]  R M Shelby,et al.  Solvents' Critical Role in Nonaqueous Lithium-Oxygen Battery Electrochemistry. , 2011, The journal of physical chemistry letters.

[9]  B. McCloskey,et al.  Lithium−Air Battery: Promise and Challenges , 2010 .

[10]  K. M. Abraham,et al.  A Polymer Electrolyte‐Based Rechargeable Lithium/Oxygen Battery , 1996 .

[11]  Dh Shin Dong Hyeop Shin,et al.  Control of the Preferred Orientation of Cu(In,Ga)Se2 Thin Film by the Surface Modification of Mo Film , 2011 .

[12]  Yair Ein-Eli,et al.  Review on Liair batteriesOpportunities, limitations and perspective , 2011 .

[13]  Jun Lu,et al.  Increased Stability Toward Oxygen Reduction Products for Lithium-Air Batteries with Oligoether-Functionalized Silane Electrolytes , 2011 .

[14]  Yuhui Chen,et al.  The lithium-oxygen battery with ether-based electrolytes. , 2011, Angewandte Chemie.

[15]  K. Lau,et al.  Electronic Structure of Lithium Peroxide Clusters and Relevance to Lithium–Air Batteries , 2012 .

[16]  Kai Xie,et al.  Investigation of oxygen reduction chemistry in ether and carbonate based electrolytes for Li–O2 batteries , 2012 .

[17]  Yang-Kook Sun,et al.  Evidence for lithium superoxide-like species in the discharge product of a Li-O2 battery. , 2013, Physical chemistry chemical physics : PCCP.

[18]  Peter G. Bruce,et al.  Die Lithium‐Sauerstoff‐Batterie mit etherbasierten Elektrolyten , 2011 .

[19]  Linda F. Nazar,et al.  Screening for superoxide reactivity in Li-O2 batteries: effect on Li2O2/LiOH crystallization. , 2012, Journal of the American Chemical Society.

[20]  Burke,et al.  Generalized Gradient Approximation Made Simple. , 1996, Physical review letters.

[21]  D. M. Lindsay,et al.  ESR spectra of matrix-isolated lithium superoxide , 1987 .

[22]  Boris Kozinsky,et al.  Identifying Capacity Limitations in the Li/Oxygen Battery Using Experiments and Modeling , 2011 .

[23]  G. Kresse,et al.  From ultrasoft pseudopotentials to the projector augmented-wave method , 1999 .

[24]  Jasim Ahmed,et al.  A Critical Review of Li/Air Batteries , 2011 .

[25]  Yuyan Shao,et al.  Electrocatalysts for Nonaqueous Lithium–Air Batteries: Status, Challenges, and Perspective , 2012 .

[26]  L. J. Lyons,et al.  Highly conductive trimethylsilyl oligo(ethylene oxide) electrolytes for energy storage applications , 2008 .

[27]  Jean-Marie Tarascon,et al.  Li-O2 and Li-S batteries with high energy storage. , 2011, Nature materials.

[28]  Bruno Scrosati,et al.  Investigation of the O2 electrochemistry in a polymer electrolyte solid-state cell. , 2011, Angewandte Chemie.

[29]  Donald J. Siegel,et al.  Lithium peroxide surfaces are metallic, while lithium oxide surfaces are not. , 2012, Journal of the American Chemical Society.

[30]  N. Seriani.  Ab initio thermodynamics of lithium oxides: from bulk phases to nanoparticles , 2009, Nanotechnology.

[31]  J. Bass,et al.  Communication: strong excitonic and vibronic effects determine the optical properties of Li2O2. , 2011, The Journal of chemical physics.

[32]  X. Sun,et al.  Soft X-ray XANES studies of various phases related to LiFePO4 based cathode materials , 2012 .

[33]  G. Kresse,et al.  Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set , 1996 .

[34]  J. Nørskov,et al.  Communications: Elementary oxygen electrode reactions in the aprotic Li-air battery. , 2010, The Journal of chemical physics.

[35]  Tejs Vegge,et al.  The role of transition metal interfaces on the electronic transport in lithium–air batteries , 2011 .

[36]  Rajeev S. Assary,et al.  Computational Studies of Polysiloxanes: Oxidation Potentials and Decomposition Reactions , 2011 .

[37]  Blöchl,et al.  Projector augmented-wave method. , 1994, Physical review. B, Condensed matter.

[38]  Shyue Ping Ong,et al.  Low hole polaron migration barrier in lithium peroxide , 2012 .

[39]  Gi‐Heon Kim,et al.  P-type doping of lithium peroxide with carbon sheets , 2012 .

[40]  D. Bethune,et al.  On the efficacy of electrocatalysis in nonaqueous Li-O2 batteries. , 2011, Journal of the American Chemical Society.

[41]  P. Bruce,et al.  A Reversible and Higher-Rate Li-O2 Battery , 2012, Science.

[42]  Kresse,et al.  Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. , 1996, Physical review. B, Condensed matter.

[43]  D. Bethune,et al.  Limitations in Rechargeability of Li-O2 Batteries and Possible Origins. , 2012, The journal of physical chemistry letters.

[44]  J. Nørskov,et al.  Electrical conductivity in Li2O2 and its role in determining capacity limitations in non-aqueous Li-O2 batteries. , 2011, The Journal of chemical physics.

[45]  Sanjeev Mukerjee,et al.  Rechargeable Lithium/TEGDME- LiPF6 ∕ O2 Battery , 2011 .

[46]  P. Bruce,et al.  Rechargeable LI2O2 electrode for lithium batteries. , 2006, Journal of the American Chemical Society.