Disproportionation in Li-O2 batteries based on a large surface area carbon cathode.

In this paper we report on a kinetics study of the discharge process and its relationship to the charge overpotential in a Li-O2 cell for large surface area cathode material. The kinetics study reveals evidence for a first-order disproportionation reaction during discharge from an oxygen-rich Li2O2 component with superoxide-like character to a Li2O2 component. The oxygen-rich superoxide-like component has a much smaller potential during charge (3.2-3.5 V) than the Li2O2 component (∼4.2 V). The formation of the superoxide-like component is likely due to the porosity of the activated carbon used in the Li-O2 cell cathode that provides a good environment for growth during discharge. The discharge product containing these two components is characterized by toroids, which are assemblies of nanoparticles. The morphologic growth and decomposition process of the toroids during the reversible discharge/charge process was observed by scanning electron microscopy and is consistent with the presence of the two components in the discharge product. The results of this study provide new insight into how growth conditions control the nature of discharge product, which can be used to achieve improved performance in Li-O2 cell.

[1]  Linda F. Nazar,et al.  Current density dependence of peroxide formation in the Li–O2 battery and its effect on charge , 2013 .

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

[3]  Stefan A Freunberger,et al.  The carbon electrode in nonaqueous Li-O2 cells. , 2013, Journal of the American Chemical Society.

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

[5]  Duncan Graham,et al.  Oxygen reactions in a non-aqueous Li+ electrolyte. , 2011, Angewandte Chemie.

[6]  Yuyan Shao,et al.  Making Li‐Air Batteries Rechargeable: Material Challenges , 2013 .

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

[8]  Yang Shao-Horn,et al.  Influence of Li2O2 morphology on oxygen reduction and evolution kinetics in Li–O2 batteries , 2013 .

[9]  Yang Shao-Horn,et al.  Probing the Reaction Kinetics of the Charge Reactions of Nonaqueous Li-O2 Batteries. , 2013, The journal of physical chemistry letters.

[10]  L. Nazar,et al.  The role of vacancies and defects in Na0.44MnO2 nanowire catalysts for lithium–oxygen batteries , 2012 .

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

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

[13]  W. Bennett,et al.  Hierarchically porous graphene as a lithium-air battery electrode. , 2011, Nano letters.

[14]  In-Hwan Oh,et al.  A transmission electron microscopy study of the electrochemical process of lithium-oxygen cells. , 2012, Nano letters.

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

[16]  Jun Lu,et al.  Synthesis, Characterization, and Structural Modeling of High‐Capacity, Dual Functioning MnO2 Electrode/Electrocatalysts for Li‐O2 Cells , 2013 .

[17]  Bryan D. McCloskey,et al.  On the Mechanism of Nonaqueous Li–O2 Electrochemistry on C and Its Kinetic Overpotentials: Some Implications for Li–Air Batteries , 2012 .

[18]  Linda F Nazar,et al.  The role of catalysts and peroxide oxidation in lithium-oxygen batteries. , 2013, Angewandte Chemie.

[19]  Sanjeev Mukerjee,et al.  Elucidating the Mechanism of Oxygen Reduction for Lithium-Air Battery Applications , 2009 .

[20]  D. Qu.  Investigation of oxygen reduction on activated carbon electrodes in alkaline solution , 2007 .

[21]  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.

[22]  Yang-Kook Sun,et al.  Compatibility of lithium salts with solvent of the non-aqueous electrolyte in Li-O2 batteries. , 2013, Physical chemistry chemical physics : PCCP.

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

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

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

[26]  Jun Lu,et al.  The effect of oxygen crossover on the anode of a Li-O(2) battery using an ether-based solvent: insights from experimental and computational studies. , 2013, ChemSusChem.

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

[28]  N. Seaton,et al.  A new analysis method for the determination of the pore size distribution of porous carbons from nitrogen adsorption measurements , 1989 .

[29]  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.

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

[31]  Betar M. Gallant,et al.  All-carbon-nanofiber electrodes for high-energy rechargeable Li–O2 batteries , 2011 .

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

[33]  Xin-bo Zhang,et al.  Graphene Oxide Gel‐Derived, Free‐Standing, Hierarchically Porous Carbon for High‐Capacity and High‐Rate Rechargeable Li‐O2 Batteries , 2012 .

[34]  Sanjeev Mukerjee,et al.  Influence of Nonaqueous Solvents on the Electrochemistry of Oxygen in the Rechargeable Lithium−Air Battery , 2010 .

[35]  Shyue Ping Ong,et al.  A Facile Mechanism for Recharging Li2O2 in Li–O2 Batteries , 2013 .

[36]  Gbolahan O. Shitta-Bey,et al.  The Electrochemical Performance of Phenol-Formaldehyde Based Activated Carbon Electrodes for Lithium/Oxygen Batteries , 2012 .

[37]  M. Balasubramanian,et al.  Fe/N/C composite in Li-O2 battery: studies of catalytic structure and activity toward oxygen evolution reaction. , 2012, Journal of the American Chemical Society.

[38]  T. Enoki,et al.  Gas adsorption effects on structural and electrical properties of activated carbon fibers , 1998 .