Electrochemical and In Situ X‐Ray Diffraction Studies of Lithium Intercalation in Li x CoO2

Abstract

containing Zr. This supposition is also borne out by the relatively poor corrosion resistance exhibited by the bulk lithium zirconate specimen.The one nitride included in this test program (A1N + 3% Y203) was equal in corrosion resistance to the best of the oxides. This nitride showed no change in physical appearance and no significant weight loss.The introduction of foreign elements by the capsule material used in these compatibility tests can probably be discounted as a factor affecting results. Metallographic examination of selected capsules after test revealed no evidence of microstructural change or surface attack. Furthermore, comparison of results obtained from steel capsules showed no obvious differences from results of duplicate tests in molybdenum capsules. The method of removing lithium from the test specimens, however, did affect the test results. In cases where specimens had been penetrated by lithium, dissolution of the lithium in water often led to disintegration of the specimen. Removal of the lithium by vacuum distillation was less destructive to the specimens and to any reaction products and therefore facilitated the examination of the less compatible materials. Even in the case of distillation, however, the reaction products can be materially changed by the decrease in lithium activity at the distillation temperature. Thus, the detailed analysis of reaction products is difficult at best, and failure of a specimen to survive water dissolution may in the end be the most definitive test result. Conclusions1. Based on exposure tests in lithium at 400~ beryllia, magnesia, yttria, yttrium aluminum garnet, and aluminum nitride appear to be suitable insulators for service in a Downs cell for lithium electroreduction.2. Aluminum nitride is a particularly promising candidate because of its excellent electrical and thermal properties and good fabricability.3. Yttrium aluminum garnet in single-crystal form is compatible with molten lithium. Performance of polycrystalline YAG is presently being evaluated. The poor performance of alumina suggests that the composition must be closely controlled to avoid any residual alumina in the sintered YAG body.

Structural phase transitions and sodium ordering in Na0.5CoO2: a combined electron diffraction and Raman spectroscopy study

“…Layered deintercalatable alkali metal oxides, such as Li x CoO 2 and Na x CoO 2 , have been a subject of an intense research activity in the past years owing to their potential technological applications as a battery electrodes and thermoelectric materials [1][2][3][4][5][6][7][8][9][10][11]. The notable features of these materials, from both structural and chemical point of views, are that the cation content and crystal structure can vary over a wide range by deintercalation, and that the structural and physical properties are profoundly affected by the cation concentration and cation and vacancy ordering [4][5]11].…”

Tuning charge–discharge induced unit cell breathing in layer-structured cathode materials for lithium-ion batteries

“…They can be viewed as alternatively stacked close-packed Li layers sandwiched between two O-M-O 'slabs' along the c direction 11 . Most of the layer-structured materials have O3-type stacking.…”

Chemomechanics of ionically conductive ceramics for electrical energy conversion and storage

“…Intermediate this layered compound, the shape change is anisotropic, and the partial molar volume of lithium is negative [143]. In all of these cases, the composition-induced stressfree strains are beyond the failure strains of most brittle materials.…”