Lithium ion-batteries

Rechargeable lithium ion batteries are of great importance at the present time due to their superiority in terms of volumetric and gravimetric energy density and cycle life, in comparison with their traditional counterparts including value regulated lead acid (VRLA), nickel cadmium (Ni-Cd), and nickel metal hybrid 

For a LIB made of LiCo02 as positive electrode and graphite-like carbon as negative electrode, the chemical reactions for charge and discharge are expressed as shown below  

Note that the LiCo02//C-type cell operates at high voltages, around 4 V, due to the big difference [/ (LiCo02) yw(C)] between the chemical potentials of the electrodes (Eq. 1.2). 

Acronym Cathode Anode Cell voltage (V) Energy density (Wh kg ) 

The elementary electrochemical cell of the lithium-ion battery is based on the assembly of three main components. This cell comprises two reversible electrodes that are slurry deposited onto metallic current collector the anode provides lithium 

Currently most portable electronic devices, including cell phones and laptop computers, are powered by rechargeable lithium-ion (Li-ion) batteries. Because lithium 

What is the oxidation state of lead in the cathode of this battery  

Lead grid filled with spongy lead (anode) 

Lead grid filled with Pb02 (cathode) 

When a Li-ion battery is fuiiy discharged the cathode has an empirical formula of LiCo02. What is the oxidation number of cobalt in this state Does the oxidation number of the cobalt increase or decrease as the battery charges  

The band gap of Ti02 does not overlap with the solar spectrum. Dyes that absorb the sunhght must be added to the electrolyte as sensitizers. The photostabiUty of these dyes is a serious problem. The liquid phase is another obstacle and there is now a trend to develop an all solid-state cell. All materials must be optimized, especially the Ti02. So far, nanosized particles have shown the hest performance.  

A comprehensive, systematic work related to Li-sulfur battery systems has been presented, covering the Li-anode challenges. 

Sulfiphihc cathode materials w ith a strong affinity for lithium polysulfides are a promising group of candidates to control the dissolution and precipitation reactions in the cell, where the improvement of conductivity and the areal sulfur loading is an important objective. A metallic CogSs material has been described with an interconnected graphene-like nano-architecture that realizes this issue (28). 

Li alloying materials, such as Si and Ge nanowires, are interesting to replace the relatively low-capacity carbonaceous-based Li-ion anodes. Since the initial report of binder-free nanowire electrodes, much research has been carried out in which the performance and cycle life has significantly progressed (30). 

The study of such electrodes has provided invaluable insights into the cycling behavior of Si and Ge, as the effects of repeated 

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The rechargeable lithium-ion battery is one of a number of new battery technologies which have been developed in the last ten years. TTiis battery system, operating at room temperature, offers several advantages compared to conventional aqueous battery technologies, for example,... 

L2 Why is carbon a suitable candidate for the anode of a Lithium-ion Battery ... 

One criterion for the anode material is that the chemical potential of lithium in the anode host should be close to that of lithium metal. Carbonaceous materials are therefore good candidates for replacing metallic lithium because of their low cost, low potential versus lithium, and wonderful cycling performance. Practical cells with LiCoOj and carbon electrodes are now commercially available. Finding the best carbon for the anode material in the lithium-ion battery remains an active research topic. 

The work presented in this chapter involves the study of high capacity carbonaceous materials as anodes for lithium-ion battery applications. There are hundreds and thousands of carbonaceous materials commercially available. Lithium can be inserted reversibly within most of these carbons. In order to prepare high capacity carbons for hthium-ion batteries, one has to understand the physics and chemistry of this insertion. Good understanding will ultimately lead to carbonaceous materials with higher capacity and better performance. 

Carbons deseribed in sections 3 and 5 have already been used in practical lithium-ion batteries. We review and briefly describe these earbon materials in seetion 6 and make a few coneluding remarks. 

Graphitic carbon is now used as the anode material in lithium-ion batteries produced by Moli Energy (1990) Ltd., Matsushita, Sanyo and A+T battery. It is important to understand how the structures and properties of graphitic carbons affect the intercalation of lithium within them. 

In lithium-ion battery applications, it is important to reduce the cost of electrode materials as much as possible. In this section, we will discuss hard carbons with high capacity for lithium, prepared from phenolic resins. It is also our goal, to collect further evidence supporting the model in Fig. 24. 

Chapter 11 reports the use of carbon materials in the fast growing consumer eleetronies applieation of lithium-ion batteries. The principles of operation of a lithium-ion battery and the mechanism of Li insertion are reviewed. The influence of the structure of carbon materials on anode performance is described. An extensive study of the behavior of various carbons as anodes in Li-ion batteries is reported. Carbons used in commereial Li-ion batteries are briefly reviewed. 

To avoid this problem for lithium-ion batteries consisting out of non-overcharge-able cells, computer-controlled charging systems regulate the voltage for each single cell. 

The variety of practical batteries has increased during the last 20 years. Applications for traditional and new practical battery systems are increasing, and the market for lithium-ion batteries and nickel-metal hydride batteries has grown remarkably. This chapter deals with consumer-type batteries, which have developed relatively recently. 

Carbon materials which have the closest-packed hexagonal structures are used as the negative electrode for lithium-ion batteries carbon atoms on the (0 0 2) plane are linked by conjugated bonds, and these planes (graphite planes) are layered. The layer interdistance is more than 3.35 A and lithium ions can be intercalated and dein-tercalated. As the potential of carbon materials with intercalated lithium ions is low,... 

There are many kinds of carbon materials, with different crystallinity. Their crystallinity generally develops due to heat-treatment in a gas atmosphere ("soft" carbon). However, there are some kinds of carbon ("hard" carbon) in which it is difficult to develop this cristallinity by the heat-treatment method. Both kinds of carbon materials are used as the negative electrode for lithium-ion batteries. 

Both hard and soft carbons are used as negative electrode materials for lithium-ion batteries. Hard carbon is made by heat-treating organic polymer materials such as phenol resin. The heat-treatment tempera-... 

Polyacene is classified as a material which does not belong to either soft or hard carbons [84], It is also made by heat-treatment of phenol resin. As the heat-treatment temperature is lower than about 1000 °C, polyacene contains hydrogen and oxygen atoms. It has a conjugated plane into which lithium ions are doped. It was reported that the discharge capacity of polyacene is more than 1000 mAhg. However, there are no practical lithium-ion batteries using polyacene. 

Figure 63. Structure of a lithium-ion battery. PTC, positive thermal coefficient device.

As mentioned above, the typical positive electrode material is LiCo02, and there are typically two types of negative electrode materials, such as coke and graphite. The characteristics of lithium-ion batteries constructed using these electrode materials are discussed below. 

Secondary lithium-metal batteries which have a lithium-metal anode are attractive because their energy density is theoretically higher than that of lithium-ion batteries. Lithium-molybdenum disulfide batteries were the world s first secondary cylindrical lithium—metal batteries. However, the batteries were recalled in 1989 because of an overheating defect. Lithium-manganese dioxide batteries are the only secondary cylindrical lithium—metal batteries which are manufactured at present. Lithium-vanadium oxide batteries are being researched and developed. Furthermore, electrolytes, electrolyte additives and lithium surface treatments are being studied to improve safety and recharge-ability. 

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