Dong Joon Lee
Energy Lab, Samsung Advanced Institute of Technology

While Li-air battery has recently become one of the most actively studied power sources for future electric vehicles, its short cycle life still remain a hurdle in the development of practical batteries. Li dendrite formation and electrolyte decomposition are frequently discussed as main causes of cell failure. We constructed a nonaqueous Li-air cell with protected Li anode employing two different nonaqueous electrolytes on cathode and anode sides respectively. With carefully designed cycling conditions, the discharge and charge of the cell could be repeated more than 100 times without significant degradation of performance. A post-mortem analysis of the eventually failed cell was performed and the tasks for further improvement of the cycle life will be discussed in the presentation.

Bryan D. McCloskey
Research Staff Member
IBM Almaden Research Center

Among many challenges being addressed to develop practical Li air batteries, relatively little attention has been devoted to the effects of atmospheric contamination on the active cathode chemistry in Li air cells, as most researchers discharge cells under either pure oxygen or zero air.  Reaction of Li2O2, the dominant discharge product in nonaqueous Li-O2 cells, with certain atmospheric gasses could lead to formation of products which require high overpotentials to oxidize, leading to losses in both energy efficiency and cyclability.  Even in aqueous Li-O2 cells, CO2 contamination is a critical issue, as it reacts with the dominant discharge product, lithium hydroxide, to form sparingly soluble lithium carbonate, which dramatically reduces the capacity of the cell. Furthermore, the deleterious effects of O2, N2, H2O and CO2 on a cyclable lithium metal anode have been extensively explored. Clearly, if rechargeable Li-air batteries are to ever achieve a specific and volumetric energy density significantly higher than Li-ion batteries, novel, compact, energy efficient air purification technologies will need to be developed.  One such possible system could be membrane-based.

This presentation will outline the effects of three atmospheric gasses- nitrogen, carbon dioxide, and water- on the Li-O2 electrochemistry.  Afterwards, the viability of using a compact membrane system to separate N2, CO2, and H2O from O2, with the end goal of providing the highest purity O2 for a Li-O2 cell, will be discussed.

Jun Liu
Pacific Northwest National Laboratory

Li metal is studied as the anode materials for Li-ion and Li-S batteries, but protection of the reactive Li surface is a significant challenge. In this presentation, we will discuss new strategies to avoid undesirable reactions on the electrode surfaces. Our new electrode design can significantly reduce the formation of the surface reaction products, and thus greatly improve the cycling stability.  Excellent high rate capability and long cycle stability are obtained as compared with traditional electrodes. Specific examples will be provided for Li-S batteries, and the fundamental reaction mechanisms will be discussed.

Rouven Scheffler & Angela Speidel
Volkswagen Research

Lithium oxygen batteries show a very high theoretical gravimetric energy density which makes them an attractive candidate for high energy batteries to enable long-distance electric driving and mass market penetration of electric vehicles. Before commercialization many challenges need to be solved. In our talk we discuss lithium (alkyl) carbonate formation as possible reason for the increasing overpotential during charge. Besides, we show that gas analytics during cycling is crucial for electrolyte research which is of fundamental importance to improve cycleability of lithium oxygen batteries.

Jay Whitacre
Carnegie Mellon University

This presentation will cover the scaling implementation of large-scale energy storage electrochemical batteries.  The core devices use an asymmetric/hybrid configuration wherein the anode consists of carbon and the cathode is an MnO2 – based alkali intercalation compound (either Na4Mn9O18 or cubic spinel -MnO).  Data will be presented showing that large scale industrially packaged individual batteries with over 30 Wh in capacity have be produced and qualified.  Further data will show that packs of these batteries in the kWh range have been effectively implemented in field-testing.  This will include support for both smaller off-grid applications with bus voltages in the in the 20 to 100 V range, as well as, grid compatible systems with bus voltages in excess of 1000 V.

Key topics to be addressed include: (1) a description of our path to scaled production of these devices, (2) lifetime performance of this system in temperatures ranging from minus 10˚C through 60˚C, (3) data from third party field tests in relevant applications showing the performance of our batteries under application specific load profiles, and (3) our vision for future implementation of this technology on a massive scale.