Lithium-ion solid conductors

Table 1. Conductivities, activation enthalpies, and other aspects of fast lithium-ion solid conductors...

Quite a large variety of interesting fast lithium-ion solid conductors is now known, as compiled in Fig. 9 and Table 1. In the case of sodium- and potassium-ion conductors only the / / / " -alumina fam-... 

Quite a large variety of interesting fast lithium-ion solid conductors is now known, as compiled in Figure 19.9 and Table 19.1. In the case of sodium-and potassium-ion conductors only the /l/)3"-alumina family, and for sodium the NASICON structure, were considered for practical application, due to the high ionic conductivities of these materials which are unmatched by any other sodium- or potassium-ion conductor. However, for 73/73"-alumina, NASICON and structurally related ionic conductors, the ionic conductivities and activation enthalpies are... 

The third aspect, the stability range of solid electrolytes, is of special concern for alkaline-ion conductors since only a few compounds show thermodynamic stability with, e.g., elemental lithium. Designing solid electrolytes by considering thermodynamic stability did lead to very interesting compounds and the discovery of promising new solid electrolytes such as the lithium nitride halides [27]. However, since solid-state reactions may proceed very slowly at low temperature, metasta-... 

In practice, for a ternary system, the decomposition voltage of the solid electrolyte may be readily measured with the help of a galvanic cell which makes use of the solid electrolyte under investigation and the adjacent equilibrium phase in the phase diagram as an electrode. A convenient technique is the formation of these phases electrochemically by decomposition of the electrolyte. The sample is polarized between a reversible electrode and an inert electrode such as Pt or Mo in the case of a lithium ion conductor, in the same direction as in polarization experiments. The... 

At this time the only commercially available all-solid-state cell is the lithium battery containing Lil as the electrolyte. Many types of solid lithium ion conductors including inorganic crystalline and glassy materials as well as polymer electrolytes have been proposed as separators in lithium batteries. These are described in the previous chapters. A suitable solid electrolyte for lithium batteries should have the properties... 

A second type of solid ionic conductors based around polyether compounds such as polyethylene oxide) (PEO) has been discovered and characterized. The polyethers can complex and stabilize lithium ions in organic media. They also dissolve salts such as L1CIO4 to produce conducting solid solutions. The use of these materials in rechargeable lithium-batteries has been proposed. 

Two types of solid ionic conductors are of special interest—those in which metallic cations such as lithium ions can be transported across the polymer membrane, and others in which protons can move from one side of the membrane to the other. The first... 

Appreciable ionic conductivity is found in open framework or layered materials containing mobile cations (see Ionic Conductors). Several phosphates have been found to be good ionic conductors and are described above NASICON (Section 5.2.1), a-zirconium phosphates (Section 5.3.1), HUP (Section 5.3.3), and phosphate glasses (Section 5.4). Current interest in lithium ion-conducting electrolytes for battery apphcations has led to many lithium-containing phosphate glasses and crystalline solids such as NASICON type titanium phosphate being studied. ... 

The solid state synthesis process has also been used to study many other variations of doped lithium titanium phosphate solid ionic conductors. The ionic conductivities and compositions of the most promising lithium-ion ceramic electrolytes are shown in Table 26.2. 

Irvine, J. and West, A., Crystalline lithium ion conductors, in High Conductivity Solid Ionic Conductors, T. Takahashi, Ed., World Scientific, Singapore, 1989. 

Lithium ion conductors are very much desired in commercial applications because of the relatively high open circuit voltages (up to 4 V) that can be achieved in electrochemical devices employing lithium-based anodes with high chemical activities (or chemical potentials). Many of the polycrystalline lithium-based solid electrolytes, that have been studied to date have ionic resistivities at 300°C in the range between 20 and 200 fl cm. While thin-film applications for these materials are possible, the biggest drawback associated with lithium ion conductors is their chemical and electrochemical instability over time at temperatures of interest in environments very high in lithium chemical activity. 

Zhang, Y.C., Kaneko. M., Uchida, K.. Mizusaki, J. and Tagawa, H. (2001) Solid electrolyte CO2 sensors with lithium-ion conductor and Li transition metal complex oxide as solid reference electrode./. Electrochem. Soc., 148 (8). H81-4. 

Solid Ionic Conductors. Membranes that provide a medium for the transport of lithium ions or protons... 

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