Lithium-sulfur battery

The Hthium-sulfur (Li-S) battery has been under intense scrutiny for over two decades, as it offers the possibility of high gravimetric capacities and theoretical energy densities. Sulfur has a high specific capacity of 1673 mAh g , but the rapid 

These reactions are analogous to those in the Na/8 battery. Octasulfur has three forms a-sulfur, p-sulfur, and y-sulfur the p-sulfur and y-sulfur are metastable as they convert to a-sulfur in storage at ambient temperature. A typical discharge and charge voltage profile of the first cycle of Li//8 cells is shown in Fig. 2.12. 

The theoretical energy density of a lithium-sulfur electrochemical system is 2500 Wh/kg or 2800 Wh/1, which makes it immensely attractive for the development of a chemical power source. This attractiveness is also enhanced by the ready availability and cheapness of sulfur and the absence of environmentally harmful components. And, indeed, attempts of developing a battery using this electrochemical system were made yet in the end of the 1960s of the previous century, at the rise of the studies of electrochemical lithium systems. It was suggested in the beginning to use the negative electrode made of metallic lithium and the positive one of elementary sulfur supported directly on the current collector. The characteristics of these first layouts were clearly unsatisfactory, partly, because sulfur is an insulator. Later, the positive electrode came to be made of a mixture of sulfur and a carbon material (carbon black). 

The current-producing process in a lithium-sulfur battery is very simple as regards stoichiometry lithium and sulfur form lithium sulfide Li2S. However, the mechanism of this process, same as the mechanism of the reverse charging process is very complicated. 

Under charging (after discharge), the sulfur electrode potential jumps very fast to the value of about 2.2 V and then two, not very pronounced though, steps can also be distinguished in the discharge curve the first one is almost horizontal at the potential in the range of 2.2-23 V and the second one corresponds to the potentials of about 2.4 V. 

The processes on the metallic lithium electrode are simple anodic dissolution with the formation of Li ions under discharge and cathodic deposition under charging. In a freshly assembled battery, the lithium surface is covered by SEI (see Chapter 11) that includes the products of interaction between lithium and components of electrolyte. Under cycling, the SEI composition changes in the course of the first several 

Reduction of dissolved polysulfides on fhe negative (lifhium) elecfrode is equivalent to internal short circuit and results in a decrease in the Coulombic efficiency under cycling and self-discharge under sforage. 

With a theoretical capacity of 1675 mAh g elemental sulfur has been considered as one of the most promising alternative cathode materials for high-capacity energy storage. The lithium-sulfur (Li-S) battery system uses conversion chemistry instead of the topotactic reactions [1]  

Through this reaction, each sulfur atom hosts two lithium atoms without the need of extra atoms to maintain a crystal structure that is required by Li-ion batteries using transition metal oxides or phosphates as the cathode materials. The simple electrochemical reaction represented in Equation 24.1 shows that every atom in the Li-S battery contributes to electrical energy storage. Therefore, for the same quantity of electrons transferred in the electrochemical reactions the weight of active materials in the Li-S battery is significantly reduced. Although Li-S batteries have an emf of about two-thirds of that offered by conventional cathode materials, sulfur 

Handbook of Battery Materials, Second Edition. Edited by Claus Daniel and Jurgen O. Besenhard. 

Polysuffide shuttle is a phenomenon unique to Li-S batteries with liquid electrolytes. This phenomenon is responsible for high self-discharge, low coulombic efficiency, severe sulfur migration, and fast capacity decay. The polysulfide shutde 

Chemical reduction of high-order poly sulfides that diffuse to the anode  

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Kolosnitsyn VS, Karaseva EV (2008) Lithium-Sulfur batteries Problems and solutions. Russ J Electrochem 44 506-509... 

Reactions of lithium with various oxidizing agents have been examined for use in batteries. A particularly well-studied case is that of the lithium-sulfur battery. Determine the potential that is possible for a battery that operates on the reaction of Li(s) with S(s). 

What makes the sodium-sulfur cell possible is a remarkable property of a compound called beta-alumina, which has the composition NaAlnOiy. Beta-alumina allows sodium ions to migrate through its structure very easily, but it blocks the passage of polysulfide ions. Therefore, it can function as a semipermeable medium like the membranes used in osmosis (see Section 11.5). Such an ion-conducting solid electrolyte is essential to prevent direct chemical reaction between sulfur and sodium. The lithium-sulfur battery operates on similar principles, and other solid electrolytes such as calcium fluoride, which permits ionic transport of fluoride ion, may find use in cells based on those elements. 

The development of lithium-sulfur batteries began in 1967 as a small basic research effort at Argonne National Laboratory (J). Since then,... 

Kyle, M. L., et al.y Lithium/Sulfur Batteries for Off-Peak Energy Storage, ... 

Heredy, L. A., Parkins, W. E., Lithium-Sulfur Battery Plant for Power... 

Lithium-Sulfur Battery - A battery that uses lithium in the negative electrode and a metal sulfide in the positive electrode, and the electrolyte is molten salt can store large amounts of energy per unit weight. 

Zhang, Y., Zhao, Y, Gosselink, D., Chen, P. (2014). Synthesis of poly-(ethylene-oxide)/nanoclay solid polymer electrotyte for all solid-state lithium/sulfur battery,DOI 10.1007/sll581-014-1176-2. 

Development of lithium ion batteries proved to be a power factor of technical advance. While at present such batteries form the base for portable electronics, in the near future, one could look forward to wide application of larger devices based on lithium ion batteries, including their application in electric transport and smart grids. However, many researchers at present have already started attempting to predict the further development of batteries that fundamentally differ from lithium ion batteries. One can identify three electrochemical systems against various possible new battery variants (i) lithium-air batteries, (ii) lithium-sulfur batteries, and (iii) sodium ion batteries. 

At present, lithium-sulfur batteries are at the pilot production stage. Flat batteries in flexible cases ( coffee bag ) are produced wifh the capacity of several ampere-hours and energy density of 350 - 400 Wh/kg. 

Xi, K., Kidambi, P. R, Chen, R, Gao, C., Peng, X., Ducati, C., Hofmann, S., Kumar, R V. (2014]. Binder free three-dimensional sulfur/few-layer graphene foam cathode with enhanced high-rate capability for rechargeable lithium sulfur batteries. Nanoscale, 6, pp. 5746-5753. 

Park JW, Yamauchi K, Takashima E, Tachikawa N, Ueno K, Dokko K, Watanabe M (2013) Solvent effect of room temperature ionic liquids on electrochemical reactions in lithium-sulfur batteries. J Phys Chem C 117 4431 440... 

Zheng J, Gu M, Chen H, Meduri P, Engelhard MH, Zhang J-G, Liu J, Xiao J (2013) Ionic liquid-enhanced solid state electrolyte interface (SEI) for lithium-sulfur batteries. J Mater Chem A l(29) 8464-8470. doi 10.1039/c3tal 1553d... 

Winston is a Shenzen-based Chinese company producing lithium-yttrium and lithium-sulfur batteries. They offer cells with capacities between 40 and 3000 Ah. Moreover, they offer electric vehicles, energy storage systems and EV charge stations. 

Lithium-Sulfur Batteries, Fig. 1 Typical discharge-charge curves of sulfur in organic electrolyte and the schematic illustration of redox-shuttle mechanism... 

Lithium-Sulfur Batteries, Fig. 2 Initial discharge and charge profiles for NiS2 and MS samples cells at 175 (0.2C) and 177 mA-g (0.3C), respectively... 

Lithium-Sulfur Batteries, Table 1 Selected reports for S-C composites ... 

Liang X, Wen Z, Liu Y, Wu M, Jin J, Zhang H, Wu X (2011) Improved cycling performances of lithium sulfur batteries with LiN03 - modified electrolyte. J Power Soiffces 196 9839-9843... 

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