A critical overview of the latest developments in the lithium ion batteries technology is reported. We first describe the evolution in the electrolyte area with particular attention to ionic liquids, discussing the expected application of these room temperature molten salts and listing the issues that still prevent their practical implementation. The attention is then focused on the electrode materials presently considered the most promising for enhancing the energy density of the batteries. At the anode side a discussion is provided on the status of development of high capacity tin and silicon lithium alloys. We show that the morphology that is the most likely to ensure commercial exploitation of these alloy electrodes is that involving carbon-based nanocomposites. We finally touch on super-high-capacity batteries, discussing the key cases of lithium-sulfur and lithium-air and attempting to forecast their chances to eventually reach the status of practically appealing energy storage systems. We conclude with a brief reflection on the amount of lithium reserves in view of its large use in the case of global conversion from gasoline-powered cars to hybrid and electric cars

Although dominating the consumer electronics markets as the power source of choice for popular portable devices, the common lithium battery is not yet suited for use in sustainable electrified road transport. The development of advanced, higher-energy lithium batteries is essential in the rapid establishment of the electric car market. Owing to its exceptionally high energy potentiality, the lithium-air battery is a very appealing candidate for fulfilling this role. However, the performance of such batteries has been limited to only a few charge-discharge cycles with low rate capability. Here, by choosing a suitable stable electrolyte and appropriate cell design, we demonstrate a lithium-air battery capable of operating over many cycles with capacity and rate values as high as 5,000 mAh g(carbon)(-1) and 3 A g(carbon)(-1), respectively. For this battery we estimate an energy density value that is much higher than those offered by the currently available lithium-ion battery technology.

Lithium-ion batteries are the power sources of choice for popular mobile devices, such as cellular phones and lap-top computers. However, to meet the user's demands, the consumer electronics market is in continuous evolution with the production of diversified multifeature devices that require constantly increasing power levels. Therefore, it is expected that even the lithium-ion battery will soon become inadequate to meet the expectations of this fast-growing market. In addition to the consumer electronics area, high-energy batteries are also urgently needed to face the great challenges of the new millennium, namely a change of energy policy and a more accurate control of the environment of the planet. In response to these needs, which, among others, call for a wide use of clean-energy sources and for the large-scale introduction of controlled-or zero-emission vehicles, it is now essential that high-energy, low-cost, and environmentally friendly storage systems are identified. Lithium batteries could still be the best candidates for all these applications, provided that their performance reaches a level higher than that presently offered.Generally, the performance of any device depends intimately on the properties of the materials of which it is formed; this also holds for lithium batteries. The chemistry of these batteries has not changed since their introduction in the market in the early nineties. Basically, a lithium-ion battery consists of a lithium-ion intercalation negative electrode (generally graphite) and a lithium-ion intercalation positive electrode (generally LiCoO 2 , or, occasionally, the spinel LiMn 2 O 4 ), these being separated by a lithium-ion conducting electrolyte, such as a solution of LiPF 6 in an ethylene carbonate-dimethylcarbonate (EC-DMC) mixture.[1]The new generation of rechargeable lithium batteries, designed not only for consumer electronics, but especially, for the storage of clean energy and for the power supply of electric or hybrid vehicles, may only be obtained by achieving a further step in performance, this in turn being related to a breakthrough in materials. In this respect, metals which store lithium, for example, lithium-tin alloys, have attracted much attention as improved anode materials because of their very high theoretical specific capacity.[2] Indeed, a number of metals and semiconductors, for example, Al, Sn, and Si, electrochemically react with lithium to form alloys having a large number of lithium atoms for formula units, thus providing a very high specific capacity. For instance, the lithium-tin alloy has, in its fully lithiated composition, Li 4.4 Sn, a theoretical specific capacity of 994 mA h g -1, that is, a value almost three times larger than that of conventional graphite (372 mA h g -1 ). A major drawback, however, affects these materials, that is, the large volume expansion-contraction that accompanies the lithium alloying-dealloying process. These volume variations result in severe mechanical strains that greatly limit the cycling life of the lithium-al...

A Li[Li(0.19)Ni(0.16)Co(0.08)Mn(0.57)]O(2) cathode was coated with AlF(3) on the surface. The AlF(3)-coating enhanced the overall electrochemical characteristics of the electrode while overcoming the typical shortcomings of lithium-enriched cathodes. This improvement was attributed to the transformation of the initial electrode layer to a spinel phase, induced by the Li chemical leaching effect of the AlF(3) coating layer.

gas. At the same time, the penetration of renewable energy sources has opened up the possibility of creating a CO 2 -neutral mobility system, where electric vehicles are powered by wind, hydro, and solar energy.Broad fi nancial efforts are being made at a governmental and industrial level to fund research into new areas of energy storage. The U.S. Department of Energy has allocated $20 million to energy storage research in 2012 and $15 million the following year, while the German government has committed itself to ¤200 million between 2011 and 2018; [ 1 ] similar schemes are also being promoted in Japan by the New Energy and Industrial Technology Development Organization (NEDO). The EU-backed "Horizon 2020" program aims at funding research into energy storage technologies, a fi eld where the European Union lags behind the U.S. and East Asia. [ 2 ] Lithium-ion technology has established itself as a type of reliable energy-storage chemistry over the past 20 years, fi rst being used in camcorders, then mobile phones, laptops, and more recently electric cars. However, as the size of the battery pack increases, so does the belief that the cost per kW h and its energy density are not suitable for practical vehicle applications. The Tesla Model S, which sports a 400 km driving range, does so with a whopping 85 kW h battery pack that alone has up to twice the price of a standard economy car. With a current cost higher than 400 $ kW h −1 , electric cars have so far only entered a niche, high-end market where users are willing to pay a premium. Resizing the battery pack, and so the total cost of an electric car, results in a limited driving range (typically 100-150 km) that automatically restricts the use for long-haul journeys and triggers the so-called "range anxiety" feeling. For these reasons, the need to develop energy-storage technologies that enable at least a 500 km driving range, while retaining the same battery pack volume at an affordable price, is of primary interest for governments and car manufacturers. A Brief History of Lithium/Air BatteriesOver the years, the scientifi c community has focused its interest on advanced lithium-ion and fuel cells with only incremental improvements being made. Lithium-ion technology in particular is predicted to reach an asymptotic limit in specifi c Lithium/air is a fascinating energy storage system. The effective exploitation of air as a battery electrode has been the long-time dream of the battery community. Air is, in principle, a no-cost material characterized by a very high specifi c capacity value. In the particular case of the lithium/air system, energy levels approaching that of gasoline have been postulated. It is then not surprising that, in the course of the last decade, great attention has been devoted to this battery by various top academic and industrial laboratories worldwide. This intense investigation, however, has soon highlighted a series of issues that prevent a rapid development of the Li/air electrochemical system. Although several breakthroughs have be...

The lithium-sulfur battery, based on the electrochemical reaction 16 Li + S 8 Q8 Li 2 S, has a theoretical specific energy and energy density of 2500 W h kg À1 and 2800 W h L À1 , respectively, much greater than those of any conventional lithium battery.[1] The Li-S battery has been investigated by many workers for several decades; however, such studies have been limited to the simplest cell configuration consisting of sulfur as the positive electrode, lithium metal as the negative electrode, and a solution of a lithium salt in an aprotic organic solvent as the electrolyte. [2][3][4][5][6] The practical development of the lithium-sulfur battery has been hindered to date by a series of shortcomings. A major hurdle is the high solubility in the organic electrolyte of the polysulfides Li 2 S x (1 x 8) that form as intermediates during both charge and discharge processes. This high solubility results in a loss of active mass, which is reflected in a low utilization of the sulfur cathode and in a severe capacity decay upon cycling. The dissolved polysulfide anions, by migration through the electrolyte, may reach the lithium metal anode, where they react to form insoluble products on its surface; this process also negatively impacts the battery operation. [7] Various strategies to address the solubility issue have been explored. They include the design of modified organic liquid electrolytes [8][9][10] and the use of ionic-liquidbased electrolytes [11] and polymer electrolytes.[12] However, although interesting, the results are still far from marking real breakthroughs in the field.Important progress was recently made by Nazar and coworkers, who showed that by fabricating cathodes based on an intimate mixture of nanostructured sulfur and mesoporous carbon, high reversible capacity and good rates can be obtained. [13] However, this battery is also based on conventional chemistry in terms of anode and electrolyte, as it contains a lithium metal foil anode and an organic liquid electrolyte. Lithium metal is very reactive in common lithium battery electrolyte media: the organic solution readily decomposes at the metal surface, thus forming a passivating layer. [14] Nonuniformities in this layer result in dendrite deposition that may eventually extend to short the cell, with negative repercussion for the cycle life of the battery and also for its safety. For this reason, commercial "lithium" batteries do not use a lithium metal anode but rather a material capable of hosting and releasing lithium ions (e.g., graphite) in order to operate by lithium ion transfer only, thus carefully avoiding any lithium metal deposition. It is then surprising that all the strategies attempted to date to achieve progress with the Li-S battery have been concentrated on the cathode problems, totally neglecting those associated with the anode.The key challenge is then to totally renew the chemistry of this battery such as to achieve an advanced configuration that can consistently provide high capacity, a long cycle life, and safe operation. Herei...

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This paper describes the synthesis and the properties of a kinetically improved LiFePO 4 cathode material. The novel aspect of the synthesis is based on a critical step involving the dispersion of metal ͑e.g., copper or silver͒ at a very low concentration ͑1 wt %͒. This metal addition does not affect the structure of the cathode but considerably improves its kinetics in terms of capacity delivery and cycle life. Such an enhancement of the electrochemical properties has been ascribed to a reduction of the particle size and to an increase of the bulk intra-and interparticle electronic conductivity of LiFePO 4 , both effects being promoted by the finely dispersed metal powders. This improved conductivity favors the response of LiFePO 4 , thus substantiating its interest as new cathode for advanced lithium ion batteries.