LiCoO

Figure 52. Discharge characteristics of some lithium-nickel oxides and LiCoO, (current density 0.25 mA cm2).

Figure 1. Charge and discharge curves of an Li/LiCoO, cell at a rate of 0.17 niAcm 2 at 30 °C. The cell was discharged to 2.5V, after a constant-capacity charge at 125 mAhg based on weight of LiCoO,.

LiCoO, + Cy flrstcharging> Li xCo02 + LixCy /discharginB, Li1 x+AxCo02+Ux AxCy... 

Sanyo Yuasa Cylindrical Prismatic LiCoo.3Nio.7O2 LiCo02 Natural graphite Graphite LiPF4/EC+DMC LiBFVpolymer... 

LiCoo.5 Mno.502 LiFeo.5Mno.5O2 LiNio.5Mno.5O2 LiCoo.5Tio.5O2... 

LiCoO, positive electrode Graphite negative electrode... 

CoO, LirCo02,0 Phases obtained by electrochemical delithiation of LiCoO-, 42... 

The high cost and toxicity of cobalt compounds has prompted a search for alternative materials that intercalate lithium ions. Examples of these are LiMn204 [iv], LiCoo.2Nio.8O2. LiNio.5Mni.504 [v], LiNio.5Mno.5O2 [vi], LiFeP04 [vii], Lix VO [viii], and LixMrVOz (M = Ca, Cu) [ix], etc. 

Fig. 1. Schematic illustration for a rechargeable lithium ion battery with LiCoO, cathode, graphite anode and nonaqueous electrolyte.

The obtained curves were similar to those reported in hterature [15]. This indicates that all solid state LiCoO electrode functions as cathode of rechargeable lithium ion battery at relatively high discharge and charge rates. The thickness of... 

Fig. 4.5 Discharge and charge curves of three-dimensionally ordered composite electrode system consisting of Li jjLa jjTiOj and LiCoO ...

The contribution of electric field to lithium transport has been considered by a few authors. Pyun et al argued on the basis of the Armand s model for the intercalation electrode that lithium deintercalation from the LiCoO composite electrode was retarded by the electric field due to the formation of an electron-depleted space charge layer beneath the electrode/electrolyte interface. Nichina et al. estimated the chemical diffusivity of lithium in the LiCo02 film electrode from the current-time relation derived from the Nemst-Planck equation for combined lithium migration and diffusion within the electrode. 

The Li+ ion batteries generally produce an output voltage of approximately 3.5 V with the Li-based cathode materials such as LiCoO, LiMn O, LiFePO, etc. 

The reactions for the charge/discharge processes of Li-ion batteries (Scheme 7.1), if LiCoO and carbon are, respectively, used as cathode and anode, are shown by Equations 7.1-7.3 [11], Obviously, the conductivity in the electrode materials plays a vital role, because the high conductive electrode facilitates the transport of electrons and ions and fully fulfills the capacity of the active materials. However, most of the inorganic materials for either cathode or anodes [2,4],e.g., LiFePO, LiCoO, MnO, SnO, MoOj, and TiO, are limited by their low electronic conductivity. 

Scheme 7.1 Schematic representation of a li-ion battery. Negative electrode (graphite) and positive electrode (LiCoO ) separated by a non-aqueous liquid electrolyte Panel is reproduced with permission [2]. Copyright 2008, Wiley.

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