In this chapter, we will restrict our attention to the ferrites and a few other closely related materials. The great interest in ferrites stems from their unique combination of a spontaneous magnetization and a high electrical resistivity. The observed magnetization results from the difference in the magnetizations of two non-equivalent sub-lattices of the magnetic ions in the crystal structure. Materials of this type should strictly be designated as “ferrimagnetic” and in some respects are more closely related to anti-ferromagnetic substances than they are to ferromagnetics in which the magnetization results from the parallel alignment of all the magnetic moments present. We shall not adhere to this special nomenclature except to emphasize effects, which are due to the existence of the sub-lattices.

Ferromagnetic materials

Metal Oxides and Oxysalts as Anode Materials for Li Ion Batteries

This Review is focused on ion-transport mechanisms and fundamental properties of solid-state electrolytes to be used in electrochemical energy-storage systems. Properties of the migrating species significantly affecting diffusion, including the valency and ionic radius, are discussed. The natures of the ligand and metal composing the skeleton of the host framework are analyzed and shown to have large impacts on the performance of solid-state electrolytes. A comprehensive identification of the candidate migrating species and structures is carried out. Not only the bulk properties of the conductors are explored, but the concept of tuning the conductivity through interfacial effects—specifically controlling grain boundaries and strain at the interfaces—is introduced. High-frequency dielectric constants and frequencies of low-energy optical phonons are shown as examples of properties that correlate with activation energy across many classes of ionic conductors. Experimental studies and theoretical results are...

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Inorganic Solid-State Electrolytes for Lithium Batteries: Mechanisms and Properties Governing Ion Conduction

Manganese oxides for lithium batteries

Batteries are electrochemical devices that store electrical energy in the form of chemical energy. Among known batteries, Li ion batteries (LiBs) provide the highest gravimetric and volumetric energy densities, making them ideal candidates for use in portable electronics and plug-in hybrid and electric vehicles. Conventional LiBs use an organic polymer electrolyte, which exhibits several safety issues including leakage, poor chemical stability and flammability. The use of a solid-state (ceramic) electrolyte to produce all-solid-state LiBs can overcome all of the above issues. Also, solid-state Li batteries can operate at high voltage, thus, producing high power density. Various types of solid Li-ion electrolytes have been reported; this review is focused on the most promising solid Li-ion electrolytes based on garnet-type metal oxides. The first studied Li-stuffed garnet-type compounds are Li5La3M2O12 (M = Nb, Ta), which show a Li-ion conductivity of ∼10−6 at 25 °C. La and M sites can be substituted by various metal ions leading to Li-rich garnet-type electrolytes, such as Li6ALa2M2O12, (A = Mg, Ca, Sr, Ba, Sr0.5Ba0.5) and Li7La3C2O12 (C = Zr, Sn). Among the known Li-stuffed garnets, Li6.4La3Zr1.4Ta0.6O12 exhibits the highest bulk Li-ion conductivity of 10−3 S cm−1 at 25 °C with an activation energy of 0.35 eV, which is an order of magnitude lower than that of the currently used polymer, but is chemically stable at higher temperatures and voltages compared to polymer electrolytes. Here, we discuss the chemical composition–structure–ionic conductivity relationship of the Li-stuffed garnet-type oxides, as well as the Li ion conduction mechanism.

Garnet-type solid-state fast Li ion conductors for Li batteries: critical review

Synthesis and structure analysis of tetragonal Li7La3Zr2O12 with the garnet-related type structure

Preparation of the hydrides Mg2FeH6 and Mg2CoH5 by mechanical alloying followed by sintering

Preparation and crystal structure refinement of Li4Mn5O12 by the rietveld method

Crystal structures of novel La–Mg–Ni hydrogen absorbing alloys

In situ X-ray and neutron powder diffraction were carried out for the La 4 MgNi 19 alloy sample, which was obtained by annealing under controlled Mg-vapor pressure and temperature The sample contained five phases: Ce 5 Co 19 -type La 4 MgNi 19 , Pr 5 Co 19 -type La 4 MgNi 19 , Gd 2 Co 7 -type La 3 MgNi 14 , Ce 2 Ni 7 -type La 3 MgNi 14 , and CaCu 5 -type LaNi 5  Those mass fractions were 51%, 19%, 16%, 4%, and 10%, respectively The crystal structures for the samples before and after hydrogenation were refined by the Rietveld method The full hydride of the main phase La 4 MgNi 19 D x had a rhombohedral structure (space group: R3m) with a = 053990(3) nm, c = 52458(3) nm Lattice expansions Aa/a and Ac/c in hydrogenation were 73% and 88%, and volume expansion ΔV/V was 253% The hydrogen content D/M obtained from the refinement was 091(5), and hydrogen was evenly located in both the MgZn 2 -type cell and the CaCu 5 -type cell

Hiroshi Hayakawa

Papers

Synthesis and structure analysis of tetragonal Li7La3Zr2O12 with the garnet-related type structure

Preparation of the hydrides Mg2FeH6 and Mg2CoH5 by mechanical alloying followed by sintering

Preparation and crystal structure refinement of Li4Mn5O12 by the rietveld method

Crystal structures of novel La–Mg–Ni hydrogen absorbing alloys

Structural Study of La4MgNi19 Hydride by In Situ X-ray and Neutron Powder Diffraction