Electrodes positive materials

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. 

As the cost of LiCo02 is high, other positive electrode materials will eventually take the place of LiCoOz. LiNiOz and... 

LiMn02 are often mentioned as positive electrode materials instead of LiCo02 [87]. LiNiOz is desirable because it offers a larger capacity and lower cost than LiCo02, and it is expected that a LiNiO 2-graphite cell will be commercialized in the near future. 

The interest in ever-higher energy content has caused the development of cells with relatively high voltages to receive much attention in the lithium battery research community in recent years. This has led to the exploration of a number of positive electrode materials that operate at potentials of about 4 V, or even more, positive of the potential of elemental lithium. 

In spite of the extraordinarily high ionic conductivity of silver- and copper-ion conductors, these materials suffer from their low capacity and energy density. In addition, only a few positive electrode materials have been found until now. 

Meunier G, Dormoy R, Levasseur A (1989) New positive-electrode materials for Lithium... 

Martin-Litas 1, Vinatier P, Levasseur A, Dupin JC, Gonbeau D (2001) Promising thin films (WOi 05S2 and WO1.35S2.2) as positive electrode materials in microbatteries. J Power Sources 97-98 545-547... 

The focus of this paper is on the role electronic structure plays in determining the site preference and mobility of 3d transition-metal ions in an oxide and how these factors in turn affect the resistance of metastable 3d transition-metal oxides against transformation. This is a relevant topic to the Li rechargeable battery field because 3d transition-metal oxides are often used as positive electrode materials. 

Initial development of ambient secondary lithium batteries was based on the primary lithium systems described in Chapter 4, consisting of a lithium metal negative, a non-aqueous lithium ion conducting electrolyte and a positive electrode material which could undergo a reversible electrochemical reaction with lithium ions ... 

Suitable positive electrode materials AzBy, such as TiS2 or V6Oi3, generally have rigid lattices with ... 

Some other asymmetric devices have been proposed implying a LTO negative electrode and alternative positive electrode materials as (1) conducting polymers and (2) battery-like material/ activated carbon composites. 

Figure 3.5.6 Discharge curve of LixCoC>2 positive electrode material, with Li metal as negative electrode. Reprinted from [12] with permission, copyright 1980 Elsevier.

Figure 3.5.8 Thermal runaway behavior of the most common positive electrode materials upon heating at 5 K min 1. Source E. Peter Roth, Power Sources Technology Group, Sandia National Laboratories [22], Used with author s permission.

Padhi AK, Nanjundaswamy KS, Goodenough JB. Phospho-olivines as positive-electrode material for rechargable lithium batteries. J Electrochem Soc. 1997 144(4) 1188—94. 

Positive electrode material Average electrode voltage [V vs. Li/Li+] Reversible range [Ax] Theoretical specific capacity [Ah kg ]... 

Much effort has been devoted to the study of manganese oxides as positive electrode materials. Manganese oxides are very promising materials due to their abundance, environmental compatibility, low cost, favorable charge density, relatively high electronic conductivity, and suitable electrode potentials. Different structures of manganese oxides have been investigated and the best known, and the first to be... 

Doped spinel manganese oxides in which Mn + is substituted by other trivalent cations, e.g., AE+, Fe +, Ni +, Co +, or Cr +, have been also investigated they display enhanced structural stability but decreased specific capacity as compared with the undoped LiMn204. These compounds are also classified as high-voltage positive electrode materials because they can operate above 4.5 V vs. Li/Li+ (Table 5) [135]. 

Among the transition metal oxides, mention should also be made of the vanadium oxides, the most studied as positive electrode materials being V2O5, V Oii, and LiV30g, which insert lithium in the potential domain of 3 V vs. Li/Li+. For the vanadium oxides, too, doping and suitable structure have been shown to improve their electrochemical performance, and recently a sol-gel process has yielded high-capacity (500-600 Ah kg ) materials delivering 500 Wh kg at 4 mA cm" [137]. 

Research has also focused on the study of highly reversible negative lithium insertion materials. Transition metal oxides and chalcogenides, such as M0O2, WO2, and TiS2, if combined with a metal oxide positive electrode material yield cells with low OCV values (ca. 1.5-2 V) [111]. 

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