The Li-O2 battery is generating a great deal of interest because theoretically it possesses a specific energy 5-10 times that of a conventional Li-ion battery. Very little is known about the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) in lithium-air battery cathodes based on aprotic organic electrolytes. A systematic study using both traditional RDE measurements as well as cell level measurements in conjunction with various characterization techniques will be presented. We begin by drawing analogies between the oxygen electrode reactions in the aqueous electrolyte, in particular alkaline electrolyte, and the aprotic (Li+ free) non-aqueous electrolytes. Employing extended surfaces of Au we will demonstrate that the ORR in these electrolytes is governed by the same principles that dictate the reaction mechanisms in protic solvents. We will also employ R(R)DE techniques to both quantitatively and qualitatively determine the reaction products namely the superoxide and peroxide. This will be used to determine the stability of the various ethers and carbonate solvents toward the superoxide species. Extending this study to Li+ based solvents will be used to further determine the products formed, their stability, their strength of adsorption to the electrode surface, and the measure of reversibilities achieved using RDE measurements. Furthermore, using an electrochemical voltammetric finger printing technique, we will aim to understand the nature of products formed in the presence of Li+ cations and the ease of their re-chargeability. Extending this approach to study carbonaceous materials will help us better delineate the role of morphology, nature of carbon and the relative geometry effects on observed reversibility of Li-O¬2 cathode interfaces. A careful study on the role of surface active groups and their impact on both the reduction and oxidation reactions will be studied both in a traditional three-electrode setup as well as our in-house design battery cell design (KF cell). The presence of side reactions that can occur at the cathode interfaces, particularly related to electrolyte oxidation will be discussed briefly. This will help us to understand the reaction that determines the observed charging plateaus. The KF cell then allows us to both determine the potentials at which gasses are generated/consumed using a pressure-change measurement, which can then in conjunction with DEMS be used to identify the nature of products formed during the charging process. Also, using the “expected products” in the battery directly we determine the expected voltages at which they can be oxidized and correlate them with the real battery charging potentials. This helps us to draw a conclusion regarding the nature of products formed during discharge and the potential charging reactions.

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.

Bio coming soon…

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.

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.

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.

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.

In the U.S., Canada and Mexico, the Bosch Group manufactures and markets automotive original equipment and aftermarket products, industrial drives and control technology, power tools, security and communication systems, packaging technology, thermo-technology, household appliances, solar energy, healthcare telemedicine and software solutions. Having established a regional presence in 1906, Bosch employs over 23,000 associates in more than 100 locations, with sales of $9.8 billion in fiscal year 2011.  For more information, visit www.boschusa.com.

The Bosch Group is a leading global supplier of technology and services. In the areas of automotive and industrial technology, consumer goods, and building technology, more than 300,000 associates generated sales of 51.5 billion euros in fiscal 2011. The Bosch Group comprises Robert Bosch GmbH and its roughly 350 subsidiaries and regional companies in some 60 countries. If its sales and service partners are included, then Bosch is represented in roughly 150 countries. This worldwide development, manufacturing, and sales network is the foundation for further growth. Bosch spent some 4.2 billion euros for research and development in 2011, and applied for over 4,100 patents worldwide. With all its products and services, Bosch enhances the quality of life by providing solutions which are both innovative and beneficial.  Further information is available online at www.bosch.com and www.bosch-press.com.

With locations in Palo Alto, Calif.,  Pittsburgh, Pa. and Cambridge, Mass., Bosch Research and Technology Center (RTC) in North America covers a wide spectrum of research topics ranging from user interaction, software, advanced circuits and wireless systems to energy technologies, and maintains strong relationships with leading U.S. universities.

Li-metal based cells, including Li/air, are attractive due to their high gravimetric energy density, but safely recharging Li metal over hundreds of cycles remains a significant challenge.  This is due in part to the fact that Li metal electrodes are chemically and morphologically unstable in most, if not all, liquid electrolytes and must be protected with a solid electrolyte, for which there are few working prototypes.  Here we examine the principle requirements of such a protection layer from a systems perspective.  In addition to possessing high ionic conductivity, mechanical strength, and chemical stability against both lithium and the positive electrode constituents, these materials must be thin (< 50 µm,) cheap (< $100/m2), and defect free.  We conclude that further fundamental materials and processing research and development are needed to attain these objectives.

For a Li/O2 battery system to achieve a high energy per mass and volume and thereby enable long-range electric vehicles, a technology is needed to handle the gases entering and exiting the cell.  Such a technology should be light weight and compact and both supply contaminant-free O2 during discharge and prevent the loss of any volatile cell components during charge.  While the highest energy per mass and volume may ultimately be obtained with a technology that allows the use of ambient air, another option is the use of an oxygen tank, which would create a completely closed system. In this talk I will give an overview of the requirements for gas handling in a Li/O2 battery system, including acceptable mass and volume as well as energy use.  Calculations for an oxygen tank will be presented.

The lithium-air battery is a promising alternative to existing rechargeable batteries. However, there are substantial challenges, such as poor reversibility, cyclability, rate capability, and energy efficiency, which limit commercialization. Currently, the charge and discharge mechanisms and their relationship to the battery parameters are not clearly understood.

In this talk, we present our study of the mechanisms of the oxygen evolution reaction (OER) and electronic conduction in lithium peroxide (Li2O2) using first-principles calculations. Li2O2, the primary product during discharging, is an insulator and is suspected to increase the charging overpotential, thereby deteriorating the Li-air battery performance. We show that i) the OER process on low-index surfaces of Li2O2 is kinetically limited by the oxygen evolution, not by the extraction of Li+ ions and/or electrons, and that ii) the formation and migration of hole polaron VLi+ pairs is a possible electronic conduction mechanism in Li2O2.

Renewable fuels are a long-term solution to the world’s energy needs.  It is a significant challenge to find efficient ways to harness solar and wind energy that are cost-competitive with fossil fuels.  Because renewable sources are intermittent, energy storage is essential to renewable fuel production.  In this work, we discuss modular approaches to making solar fuels.  We use back-of-the-envelope calculations to evaluate production schemes, including energy storage with batteries.  A relationship that predicts the required sales price of energy storage is also discussed.

Daikin Industries is a large global company with over $10B in sales generated from four main operating divisions.  The Chemicals Division is approximately $1B in sales and is a world leading manufacturer of fluoropolymers, fluoroelastomers, and fluorochemical products.  Daikin produces a wide range of fluoropolymers products (PTFE, PFA, FEP, ETFE, EFEP, CTFE, and CPT).  These products are used in a wide variety of high-performance demanding applications including fluorinated ethylene carbonate, fluoro-ether, and other fluorinated solvents and additives used in lithium ion batteries.  Daikin also produces fluorinated cathode and anode binders for use in high-temperature, high energy density lithium ion battery applications.  Other Daikin products are also used in demanding aerospace, electronic, medical, and automotive applications.  Daikin’s fluoropolymer and fluorochemical products are known globally as technologically advanced and typically are the key enabling components in their field of use.

Lithium-air secondary batteries with a lithium metal anode and an air cathode are an attractive energy storage system because they have high theoretical energy density. Two types of lithium-air batteries have been developed, namely, non-aqueous and aqueous types. We have studied aqueous type of lithium-air batteries, which consist of a lithium electrode, an aqueous electrolyte with LiCl, and an air electrode. A protected lithium electrode, Li/PEO18LiTFSI/Li1+xTi2-xAlx(PO4)3 was stable in a saturated LiOH with 10 M LiCl aqueous electrolyte, which showed a pH value of ca. 9.

In this study, applicability of air electrodes in this moderately alkaline aqueous solution were examined. Carbon electrodes with perovskite-type oxide catalysts were used as air electrodes. The catalytic activity for oxygen reduction and evolution, and chemical, electrochemical stabilities were evaluated for these perovskites. Various carbon materials are studied for the long term polarization in the LiOH-LiCl electrolyte. The effect of ion exchange membranes is also investigated which are applied to avoid direct deposition of solid LiOH on the air electrode.

Battery systems based on lithium metal as the negative electrode could lead to gains in specific energy over Li-ion technologies.  This is particularly the case in lithium sulfur (Li/S) and lithium/air (Li/air) batteries, which are increasingly gaining the attention of the scientific community.  However, there are major technical obstacles which have thwarted this advancement for two decades.  These include shape change and dendrite formation, which lead to short cycle lifes and, potentially, to short-circuits that severely compromise the safety of the device.  This is in addition to side reactions with liquid electrolytes, which consume charge and generally lead to poorer performance with time.

A solution that has been long explored is that of using solid state electrolytes.1  More recently, battery systems with dual liquid-solid electrolytes have been proposed.2  In this case, a thin solid layer acts as a barrier layer between lithium and the liquid electrolyte.  It must be ionically conductive and mechanically stable in order to prevent dendritic growth.  A number of inorganic crystalline and amorphous phases are known to have suitable electrical properties.3  However, they pose the challenge of processing into a thin pinhole-free membrane.  Further, most of them contain a transition metal, making them highly susceptible to reduction.  During this presentation, strategies toward membranes based on ceramic conductors that can be used as protective layers for the lithium electrode will be discussed.  Emphasis will be placed on sintering and composite architectures, as well as on the interfacial redox stability against metallic Li of the resulting structures.  Electrochemical testing in Li symmetric cells will be used to evaluate the desired figures of merit.

Acknowledgements
This work was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

References:
J.W. Fergus, J. Power Sources 195 (2010) 4554.
M-Y Chu, S. Visco, L.C. De Jonghe, U.S. Patent No. 6402795, 2004.
P. Knauth, Solid State Ionics 180 (2010) 911.

Although current Lithium-ion batteries dominate the portable electrochemical storage market, there is limited room for improvement. They have a theoretical energy density approaching 1 kWh/kg, but in practice deliver no more than 200 Wh/kg. Similarly within a year they will be delivering close to 1 kWh/liter, over 30% of theoretical.

Metal (lithium) oxygen and Lithium sulfur have the capability to exceed these values on a weight basis, and indeed Li/S already does. However, their volumetric capacities are likely to be significantly lower than Li-ion even if all the technical challenges are overcome. I will discuss the opportunities and challenges.
This work is being supported by NYSERDA.

Li-ion batteries are now penetrating the automotive market, and this will increase at a rate largely dependent on liquid fuel prices and the cost of automotive Li-ion battery systems.  As a first step in determining what is “beyond Li-ion”, we will project cell weight, volume, and cost reductions achievable through successful implementation of advanced Li-ion materials.  We will then consider the potential for Li-air and Li-S chemistries to enable automotive systems that surpass advanced Li-ion-based systems.

Si and S have an ultrahigh capacity of lithium storage and suitable voltage as anodes and cathodes, respectively, for future high energy batteries. The combination of Si-S can generate  four times  specific energy of the  existing C-LiCoO2 system. However, Si and S has many materials challenges to be overcome. The development of nanotechnology in the past two decades has generated great capability of controlling materials at the nanometer scale and has enabled exciting opportunities to design materials to overcome these challenges.  In this talk, I will show how to develop fundamental principles through single nanostructure measurement and how to design rationally nanostructured materials to address all those materials challenges. I will show the excitingly high performance on both Si and S electrodes.

Rechargeable lithium batteries represent one of the most important developments in electrical energy storage and application. However, the energy density of state-of-the-art Li-ion batteries is still too small for some practical applications. Recently, Li-air batteries (LABs) have received new attention as a promising energy storage system beyond Li-ion batteries because their specific energy densities could be 5-10 times greater than those of the Li-ion batteries. However, although LABs offer the promise of very high energy density, its utilizations are hindered by both poor rate capability and significant polarization in cell voltage, primarily due to the formation of Li₂O₂ in the air cathode and poor electron conductivity in Li₂O₂. Here, using hybrid density functional theory, we demonstrate that the self-trapping of electrons in small polarons could be the origin of the low electron mobility in Li₂O₂. The low electron mobility is an intrinsic property of Li₂O₂ that originates from the molecular nature of the conduction band states of Li₂O₂ and the strong spin polarization of the O 2p state. We will discuss in detail how the low electron mobility affects the performance of LABs. Furthermore, based on our understanding of the mechanism, we will propose approaches to improve the performance of LABs at high current densities, such as selecting optimal growth direction of Li₂O₂ via substrate control, designing alternative carrier conduction paths for the cathode reaction, and/or introducing electron-deficient nano boron-carbon sheets to enhance the conductivity.

The rise of global environmental concerns is pushing science and industry toward the development and realization of improved electrochemical storage systems for a more efficient and effective use of energy. This is especially true in the mobility field where the present use of energy is, in fact, based on the immediate but rather inefficient and polluting conversion of fossil fuels because of the lack of effective energy storage systems.

Present high-energy battery technologies, namely Li-ion batteries, do not allow the realization of electric vehicles capable of a 500 km driving range with one battery charge. In fact, even considering the most optimistic estimation on the development of Li-Ion batteries (250 Wh/kg), which would correspond to more than 33% of the theoretical specific energy calculated on the active material weight only, it is clear that the 500 km range cannot be achieved with Li-ion (the battery weight would be more than 400 kg).

Much higher specific capacities can be achieved using lithium metal/element chemistries (Li/S, Li/O2 etc.). However, the long-term cycling stability of lithium metal anodes has been, so far, preventing the development of lithium metal-based battery chemistries.

In this work the improvements obtained by using battery electrolytes containing ionic liquids (ILs) will be presented