Jusef Hassoun

Lithium-ion batteries. A look into the future

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.

An improved high-performance lithium-air battery

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.

A Novel Concept for the Synthesis of an Improved LiFePO4 Lithium Battery Cathode

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 silver) 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.

The Role of AlF3 Coatings in Improving Electrochemical Cycling of Li‐Enriched Nickel‐Manganese Oxide Electrodes for Li‐Ion Batteries

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.

A High-Performance Polymer Tin Sulfur Lithium Ion Battery†

The lithium–sulfur battery, based on the electrochemical reaction 16 Li + S8Q8Li2S, has a theoretical specific energy and energy density of 2500 Wh kg 1 and 2800 WhL , respectively, much greater than those of any conventional lithium battery. 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. 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 Li2Sx (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. Various strategies to address the solubility issue have been explored. They include the design of modified organic liquid electrolytes and the use of ionic-liquidbased electrolytes and polymer electrolytes. 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. 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. 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. Herein, we report an example of a lithiummetal-free new battery version and demonstrate that, to a large extent, it can effectively meet these targets. In contrast to most of the Li–S batteries proposed to date, which are fabricated in the “charged” state, that is, using a carbon–sulfur composite cathode that necessarily requires a lithium metal counter electrode (anode) to assure the 16 Li + S8!8Li2S discharge process, we propose to fabricate the battery in the “discharged” state by using a carbon lithium sulfide composite as the cathode. The battery may be activated by reversing the above process, that is, by converting lithium sulfide back to lithium and sulfur (8Li2S!16 Li + S8). We show herein that the charging process may be reversibly turned into a reverse discharge process and that the entire charge–discharge cycle can be efficiently repeated several times. We also renewed the electrolyte component by replacing the common liquid organic solutions with a gel-type polymer membrane, formed by trapping an ethylene carbonate /dimethylcarbonate lithium hexafluorophosphate (EC:DMC LiPF6) solution saturated with lithium sulfide in a polyethylene oxide / lithium trifluoromethanesulfonate (PEO/ LiCF3SO3) polymer matrix. [15] A dispersed zirconia ceramic filler enhances the mechanical properties of the gel and improves liquid retention within its bulk. For simplicity, we refer to this composite gel polymer electrolyte as CGPE. The photograph in Figure 1a demonstrates the plastic appearance of the CGPE polymer electrolyte. We can describe this electrolyte as a membrane with liquid zones contained within a polymer envelope. It is expected that when the membrane is used as electrolyte in the cell, the external polymer layer may act as a physical barrier preventing the direct contact of the electrode components with the internal liquid solution. This barrier function will help to control the dissolution of the sulfide anions from the cathode and to prevent the attack of the same anions at the anode. Bearing in mind that the solubility of the sulfide anions is one of the key factors affecting cell life and performance, we have further enforced its control by supplementing the electrolyte with lithium sulfide up to saturation, which leads to a combined physical and chemical barrier to block most the dissolution. [*] Dr. J. Hassoun, Prof. B. Scrosati Dipartimento di Chimica Universit degli Studi di Roma La Sapienza Piazzale Aldo Moro, 5, 00185 Roma (Italy) Fax: (+ 39)06-491-769 E-mail: bruno.scrosati@uniroma1.it

An advanced lithium ion battery based on high performance electrode materials.

In this paper we report the study of a high capacity Sn-C nanostructured anode and of a high rate, high voltage Li[Ni(0.45)Co(0.1)Mn(1.45)]O(4) spinel cathode. We have combined these anode and cathode materials in an advanced lithium ion battery that, by exploiting this new chemistry, offers excellent performances in terms of cycling life, i.e., ca. 100 high rate cycles, of rate capability, operating at 5C and still keeping more than 85% of the initial capacity, and of energy density, expected to be of the order of 170 Wh kg(-1). These unique features make the battery a very promising energy storage for powering low or zero emission HEV or EV vehicles.

Moving to a Solid-State Configuration: A Valid Approach to Making Lithium-Sulfur Batteries Viable for Practical Applications

DOI: 10.1002/adma.201002584 Although established products in the consumer electronics, common lithium batteries are not yet ready to fulfi ll the requirements of key emerging markets such as those directed to the progress of sustainable road transport. To assure the use of lithium ion batteries for applications that extend beyond the electronic market, such as for electric or hybrid vehicles, improvements in energy density and safety are urgently required. A very promising approach for achieving this goal is to move from the traditional insertion chemistry to an innovative conversion chemistry. [ 1 ] A good example is provided by the lithium-sulfur system that, on the basis of its electrochemical process, 16Li + S 8 → 8Li 2 S, theoretically provides a signifi cantly higher energy by mass than that offered by conventional lithium ion batteries, namely 2,500 Wh kg − 1 versus 500 Wh kg − 1 . [ 2 ]

A high-rate long-life Li4Ti5O12/Li[Ni0.45Co0.1Mn1.45]O4 lithium-ion battery

Lithium batteries are receiving considerable attention as storage devices in the renewable energy and sustainable road transport fields. However, low-cost, long-life lithium batteries with higher energy densities are required to facilitate practical application. Here we report a lithium-ion battery that can be cycled at rates as high as 10 C has a life exceeding 500 cycles and an operating temperature range extending from -20 to 55 °C. The estimated energy density is 260 W h kg(-1), which is considerably higher than densities delivered by the presently available Li-ion batteries.

An advanced lithium-ion battery based on a graphene anode and a lithium iron phosphate cathode.

We report an advanced lithium-ion battery based on a graphene ink anode and a lithium iron phosphate cathode. By carefully balancing the cell composition and suppressing the initial irreversible capacity of the anode in the round of few cycles, we demonstrate an optimal battery performance in terms of specific capacity, that is, 165 mAhg(-1), of an estimated energy density of about 190 Wh kg(-1) and a stable operation for over 80 charge-discharge cycles. The components of the battery are low cost and potentially scalable. To the best of our knowledge, complete, graphene-based, lithium ion batteries having performances comparable with those offered by the present technology are rarely reported; hence, we believe that the results disclosed in this work may open up new opportunities for exploiting graphene in the lithium-ion battery science and development.

Advanced Na[Ni0.25Fe0.5Mn0.25]O2/C-Fe3O4 sodium-ion batteries using EMS electrolyte for energy storage.

While much research effort has been devoted to the development of advanced lithium-ion batteries for renewal energy storage applications, the sodium-ion battery is also of considerable interest because sodium is one of the most abundant elements in the Earths crust. In this work, we report a sodium-ion battery based on a carbon-coated Fe3O4 anode, Na[Ni0.25Fe0.5Mn0.25]O2 layered cathode, and NaClO4 in fluoroethylene carbonate and ethyl methanesulfonate electrolyte. This unique battery system combines an intercalation cathode and a conversion anode, resulting in high capacity, high rate capability, thermal stability, and much improved cycle life. This performance suggests that our sodium-ion system is potentially promising power sources for promoting the substantial use of low-cost energy storage systems in the near future.