Lithium positive electrode 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. 

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. 

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

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 ... 

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

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]. 

Padhi, A.K., Nanjundaswamy, K.S., and Goodenough, J.B., Phospho-olivines as positive-electrode materials for rechargeable lithium batteries, J. Electrochem. Soc., 144, 1188, 1997. 

As far as the positive electrode material is concerned, promising alternatives appear to be the mixed lithium vanadates of general formula LiCoyNi(i.y)V04 [3,4]. These compounds adopt an inverse spinel structure, where Li ions reside in octahedral sites, Ni and Co ions... 

The carbazole polymer poly(iV-vinylcarbazole) functions as a positive electrode material for a secondary lithium battery <85CC553>, and as a memory photoreceptor <91M1 204-0l>. The related poly[3-(3-bromocarbazol-9-yl)propyl]methylsiloxane (18) forms novel electrochromic films <89CC196>. Carbazole anions have b n used to initiate the polymerization of acrylates and methacrylates <95CC275>. The novel polymeric pyrrolocarbazole (19) displays physical properties similar to those of polyanilines. 

Lithium insertion and extraction into/from the positive electrode material must occur at a higher potential and the same reactions on the negative electrode material must occur at the maximum negative potential. The difference between the lithium insertion and extraction potentials for the same material must be... 

In all primary lithium cells, the negative electrode is made of metallic lithium. Thus, different types of lithium cells differ in the positive electrode material and in the type of electrolyte. A variety of oxidant materials was offered as the active material of the positive electrode. These included different oxides, sulfides, selenides, oxysulfides, oxychlorides, and some other substances perfluorinated carbon and sulfur. However, only a small number of electrochemical systems in the cells actually reached the industrial production stage. The electrochemical systems of the cells produced industrially are given in Table 11.1. This Table also presents the values of open circuit voltage (OCV) of these cells and the theoretical values of their energy density. 

While the development of primary cells with a lithium anode has been crowned by relatively fast success and such cells have filled their secure rank as power sources for portable devices for public and special purposes, the history of development of lithium rechargeable batteries was full of drama. Generally, the chemistry of secondary batteries in aprotic electrolytes is very close to the chemistry of primary ones. The same processes occur under discharge in both types of batteries anodic dissolution of lithium on the negative electrode and cathodic lithium insertion into the crystalline lattice of the positive electrode material. Electrode processes must occur in the reverse direction under charge of the secondary battery with a negative electrode of metallic lithium. Already at the end of the 1970s, positive electrode materials were found, on which cathodic insertion and anodic extraction of lithium occur practically reversibly. Examples of such compounds are titanium and molybdenum disulfides. 

As not all conventional positive electrode materials are designed for the charging at relatively high positive potentials, these materials pose certain problems regarding operational safety of lithium ion batteries. That is why much attention has been lately... 

Yuan, A. B., M. Zhou, X. L. Wang, Z. H. Sun, and Y. Q. Wang. 2008. Synthesis and characterization of nanostructured manganese dioxide used as positive electrode material for electrochemical capacitor with lithium hydroxide electrolyte. Chinese Journal of Chemistry 26 65-69. 

A Review of Positive Electrode Materials for Lithium-Ion Batteries... 

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