Cathode Electronic Structure Impact on Lithium and Sodium Batteries Parameters

The author of this work basing on her own investigations of AxMO2 cathode materials (A = Li, Na; M = 3d) has demonstrated that the electronic structure of these materials plays an important role in the electrochemical intercalation process. The proposed electronic model of intercalation is universal and has outstanding significance with regard to tailoring the properties of electrode materials to the most efficient application in Li-ion and Na-ion batteries. The paper reveals correlation between electronic structure, transport, and electrochemical properties of layered LixCoO2, LixNi1−y−zCoyMnzO2 and NaxCoO2 cathode material and explains of apparently different character of the discharge/charge curve in LixCoO2 (monotonous curve) and NaxCoO2 systems (step-like curve). Comprehensive experimental studies of physicochemical properties of LixNi1−y−zCoyMnzO2 cathode material (XRD, electrical conductivity, and thermoelectric power) are supported by electronic structure calculations performed using the Korringa-Kohn-Rostoker method with the coherent potential approximation (KKR-CPA) to account for chemical disorder. It is found that even small oxygen defects (~1%) may significantly modify DOS characteristics via formation of extra broad peaks inside the former gap leading to its substantial reduction

Solid Oxide Fuel Cells-Materials and Prospects

本文依据固体氧化物燃料电池(SOFC)于运作条件下的基本性能,诸如化学稳定性、电迁移、催化和热机械性能等评述SOFC组成部分(电极材料和电解质)的基本性质.示明由氧偏离化学计量比引起的电极材料结构缺陷与其电子性质及催化活性之间的相互关系,提出单室燃料电池概念.The paper summarizes and discusses the basic properties of solid oxide fuel cell(SOFC) components(electrode materials and electrolyte) from the point of view of their essential functional parameters suck as chemicalstability,transport,catalytic and thermomechanical properties under operational conditions in a SOFC.An interrela-tion between the defect structure of these materials related to oxygen nonstoichiometry and their electronic propertiesand catalytic activity was shown.Single-chamber fuel cell concept was also presented.作者联系地址：AGH科技大学 材料科学与陶瓷学院al.Mickiewicza 30,30-059 Krakow,波兰,AGH科技大学,材料科学与陶瓷学院al.Mickiewicza 30,30-059 Krakow,波兰,Author's Address: Faculty of Materials Science and Ceramics,AGHUniversity of Science and Technologyal.Mickiewicza 30,30-059 Krakow,Polan

Corrélation entre les propriétés électroniques et électrochimiques du bronze NaxCoO2 (P2). Modèle électronique du processus d'intercalation

Thèse de Doctorat, spécialité : SciencesIn recent years, numerous studies have been carried out on the study of non-stoichiometric materials capable of reversibly intercalating alkali ions in their skeleton without significant modification of the latter. The two-dimensional materials containing layers MX2 (M: transition element, X = 0, S, Se) were certainly The most studied (1,2,3)...Ces dernières années de nombreux travaux ont porté sur l'étude de matériaux non- stœchiométriques susceptibles d'intercaler réversiblement dans leur squelette des ions alcalins sans modification importante de celui - ci. Les matériaux bïdiroensionnels contenant des couches MX2 (M : élément de transition, X = 0 , S, Se) ont été certainementles plus étudiés (l ,2,3). Les éléments de transition ont un environnement octaédrique ou prismatique triangulaire . Les positions interstitielles situées entre deux feuillets consécutifs MX2 s ont occupées par les ions alcalins intercalés . Ce type de structure est très favorable à l'existence d'une conduction mixte (ionique et électronique) indispensable au processus d'intercalation. Certains de ces matériaux sont susceptibles d'avoir des applications en tant qu 'électrode positive de générateurs électrochimiques fonctionnant selon la chaîne A/A+/AxMX2..