In this thesis, the usage of onion-like carbon (OLC) for energy storage applications was researched regarding sustainability, performance and processability. This work targets to increase the scientific understanding regarding the role of OLC in electrodes and to facilitate a large-scale production, which is the foundation for commercial application. Research was devoted to increase the knowledge in the particular field, to yield synergistic approaches and a shared value regarding sustainability and performance. / Im Rahmen dieser Arbeit wurde die Verwendung von Onion-like Carbon (OLC) als Aktivmaterial zur Energiespeicherung untersucht. Die Arbeit zielte darauf ab, das wissenschaftliche Verständnis der Rolle von OLC im Kontext der elektrochemischen Energiespeicherung zu verbessern. Hierfür wurde an den Prozessschritten und Verfahren gearbeitet, um OLC-basierte Elektroden erfolgreich in Superkondensatoren und Pseudokondensatoren zu verwenden. Auch der Einsatz von OLC als Aktivmaterial für Natriumionenbatterien wurde erforscht, wobei sich das Material in dieser Anwendung als Aktivmaterial ungeeignet erwies. Die Bearbeitungen dieser Fragestellungen war darauf ausgerichtet, das Wissen in diesem Bereich zu erweitern, synergetische Ansätze für Problemlösungen zu finden und einen Mehrwert in Bezug auf Nachhaltigkeit, Performance und Prozessierbarkeit zu schaffen.

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The ultimate goal of this research was to gain a more fundamental understanding of the effects of “active"? alloying elements on the performance of low voltage, aluminum, sacrificial anodes. We have developed an overview of elemental trends and a comparison with literature, in support of a larger program on predicting anode behavior. The broader impact of this work was to enhance the ability to control corrosion and reduce the likelihood of hydrogen embrittlement induced by cathodic protection on ships and marine structures. As compared to high voltage anodes, low voltage, aluminum, sacrificial anodes reduce the likelihood of causing hydrogen embrittlement or stress corrosion cracking when used to protect high strength steels. In this study, open circuit potential, potentiostatic, galvanostatic and Tafel tests were performed on eleven high-purity aluminum-based binary and ternary alloys containing Bi, Ga, In and Zn in an effort to understand the individual effects of each element and the interactions between these elements. The microstructures of the as-cast alloys and the corrosion surfaces after testing were characterized using electron microscopy. Current capacities and current capacity efficiencies were calculated from potentiostatic and galvanostatic data. Galvanic coupling data from Druschitz et al was plotted with average values from potentiostatic and galvanostatic tests on Tafel curves for all alloys. [1] Variance of weight loss, average galvanostatic current, and average potentiostatic potential of the Al-0.57 wt% Zn-0.55 wt% Bi alloy was evaluated. Indium and gallium had the most significant effect on corrosion behavior (per wt% added), followed by zinc and bismuth. Bismuth had only a small effect on the weight loss, galvanostatic current and potentiostatic potential. However during potentiostatic testing Al-Bi alloys showed a steady increase in current with time, indicating that larger effects may be seen at longer periods of time. In Al-Zn alloys preferential dissolution of the zinc-rich interdendritic regions was observed. The Al-5.3 wt% Zn alloy showed high current values, but also exhibited high weight loss and more adherent corrosion products. Interdendritic corrosion also occurred with the Al-5.3 Zn-0.011 In alloy. Also, non-uniform dissolution of the remaining primary aluminum dendrites by the formation of small holes was observed, possibly due to indium precipitates. Grain boundary attack and severe intra-granular pitting was observed in Al-In alloys. Small holes were also evident on the surface of pits, similar to those seen on dendrites with the Al-5.3 Zn-0.011 In alloy. The addition of Indium greatly shifted voltages to more negative values (-0.802 to -0.858 VSCE at 9 A/m²) and significantly increased the observed currents (42-83 A/m² at -0.730 VSCE). High potentiostatic current capacities were exhibited by Al-In alloys, Al-0.1 wt% Ga, Al-5.3 wt% Zn-0.011 wt% In, and Al-0.57 wt% Zn-0.55 wt% Bi. However some calculated current capacity values were actually above the theoretical values, possibly due to corrosion products affecting the weight loss measurements. / Master of Science

Le développement des dispositifs microélectroniques a dopé la recherche dans le domaine des microbatteries tout solide rechargeables. Mais actuellement, les performances de ces microbatteries élaborées par des technologies couche mince (2D) sont limitées et le passage à une géométrie 3D adoptant le concept “Li-ion” ou“rocking chair” est incontournable. Cette dernière condition implique de combiner des matériaux de cathode comme LiCoO2, LiMn2O4 or LiFePO4 avec des anodes pouvant réagir de manière réversible avec les ions lithium. Parmi tous les matériaux pouvant servir potentiellement d'anode, les nanotubes de TiO2 révèlent des propriétés intéressantes pour concevoir des microbatteries Li-ion 3D. Facilement réalisable, la nano-architecture auto-organisée a montré des résultats très prometteurs en termes de capacités à des cinétiques relativement modérées. L'utilisation des nanotubes de TiO2 en tant qu'anode conduit à des cellules présentant de faible autodéchargeet élimine le risque de surcharge grâce au haut potentiel de fonctionnement (1.72 V vs. Li+/Li). Dans ce travail de thèse, nous avons étudié la substitution des ions Ti4+ par Sn4+ et Fe2+ dans les nanotubes de TiO2. Bien que la présence d'ions Fe2+ n'ait pas amélioré les performances électrochimiques des nanotubes, nous avons pu mettre en évidence l'effet bénéfique des ions Sn4+. Nous avons aussi pu montré que la fabrication de matériaux composites à base de nanotubes de TiO2 et d'oxyde de métaux de transition électrodéposés se présentant sous forme de particules (NiO et Co3O4 ) augmentait les capacités d'un facteur 4. / The advent of modern microelectronic devices has necessitated the search for high-performance all-solid-state (rechargeable) microbatteries. So far, only lithium-based systems fulfill the voltage and energy density requirements of microbatteries. Presently, there is a need to move from 2D to 3D configurations, and also a necessity to adopt the “Li-ion” or the “rocking-chair” concept in designing these lithium-based (thin-film) microbatteries. This implies the combination of cathode materials such as LiCoO2, LiMn2O4 or LiFePO4 with the wide range of possible anode materials that can react reversibly with lithium. Among all the potential anode materials, TiO2 nanotubes possess a spectacular characteristic for designing 3D Li-ion microbatteries. Besides the self-organized nano-architecture, TiO2 is non-toxic and inexpensive, and the nanotubes have been demonstrated to exhibit very good capacity retention particularly at moderate kinetic rates. The use of TiO2 as anode provides cells with low self-discharge and eliminates the risk of overcharging due to its higher operating voltage (ca. 1.72 V vs. Li+/Li). Moreover, their overall performance can be improved. Hence, TiO2 nanotubes and their derivatives were synthesized and characterized, and their electrochemical behaviour versus lithium was evaluated in lithium test cells. As a first step towards the fabrication of a 3D microbattery based on TiO2 nanotubes, electrodeposition of polymer electrolytes into the synthesized TiO2 nanotubes was also studied; the inter-phase morphology and the electrochemical behaviour of the resulting material were studied.

La thèse s’inscrit dans le cadre d’un projet de recherche visant à élaborer une anode permettant le dégagement d’oxygène en milieu de cryolithe fondue à 960°C et dont l’utilisation supprimerait les émissions de dioxyde de carbone du procédé de production d’aluminium Hall-Héroult. Le type d’anode envisagée est un composite Cermet (CERamique – METal), généralement constitué d’une phase métallique à base de nickel, cuivre et fer et d’une ou plusieurs phase(s) oxyde(s) conductrice(s) du type NixFe3-xO4 et Ni1-xFexO. Deux types de cermet, biphasé et triphasé, ont été étudiés dans le cadre de ce projet. L’objectif principal a été de comprendre les mécanismes de dégradation de telles anodes durant les électrolyses. Les cermets ont été testés sous une densité de courant de 0,80 A/cm² pour différentes durées, puis analysés par microscopie optique et microscopie électronique à balayage couplée à une analyse dispersive en énergie. Les premières électrolyses, effectuées dans un électrolyte synthétique, sans aluminium métallique et sous atmosphère argon ont révélé à la fois une dégradation chimique et électrochimique. L’étude de la dégradation chimique a été réalisée grâce à des immersions dans l’électrolyte sans polarisation. Les résultats ont mis en évidence une dissolution de la phase spinelle, liée à un phénomène de substitution entre les ions Al3+ de l’électrolyte et Fe3+ du spinelle, entrainant la formation d’un aluminate du type NixFe3-x-yAlyO4. Lorsque x = 0 et y proche de 2, la phase spinelle est dissoute alors que lorsque x est proche de 1, la phase spinelle est stabilisée et sa dissolution ralentie. Les électrolyses menées jusqu’à la fin de vie des matériaux ont révélé l'attaque préférentielle de la phase métallique pour former des composés fluorés et oxydes. Grâce aux caractérisations micrographiques et aux calculs thermodynamiques (logiciel FactSage 7.1), un mécanisme de dégradation global des anodes a été proposé. La compréhension des mécanismes de dégradation chimique et électrochimique des matériaux a permis de proposer des voies d'amélioration concernant à la fois le matériau d'anode et la chimie du bain cryolithique. / The thesis is a part of a research project which develop an anode permitting the release of oxygen in molten cryolite medium at 960°C, in order to eliminate carbon dioxide emissions from the aluminium production process called Hall-Héroult process. The type of anode envisaged is a Cermet composite (CERamic - METal), generally consisting of a metallic phase based on nickel, copper and iron and one or more conductor oxide phase(s) such as NixFe3-xO4 and Ni1-xFexO type. Two types of cermet, two-phase and three-phase, have been studied in this project. The main objective was to understand the degradation mechanisms of such anodes during electrolysis. The cermets were tested at a current density of 0.80 A/cm² for different durations and analyzed by optical microscopy and scanning electron microscopy coupled with dispersive energy analysis. The first electrolyses, carried out in a synthetic electrolyte, without metallic aluminum and under argon atmosphere revealed both chemical and electrochemical degradations. Study of chemical degradation was carried out thanks to immersions in the electrolyte without polarization. The results showed a dissolution of the spinel phase, linked to a substitution phenomenon between the Al3+ ions from the electrolyte and Fe3+ from spinel, resulting in the formation of a NixFe3-x-yAlyO4 aluminate type. When x = 0 and y close to 2, the spinel phase is dissolved whereas when x is close to 1, the spinel phase is stabilized and its dissolution slowed down. Electrolyses conducted to the end of life of the materials revealed the preferential attack of the metal phase to form fluorinated compounds and oxides. Thanks to micrographic characterizations and thermodynamic calculations (FactSage 7.1 software), a global degradation mechanism of the anodes has been proposed. The understanding of the chemical and electrochemical degradation mechanisms of the materials made it possible to propose ways of improvement concerning both the anode material and the cryolithic bath chemistry.

A series of cermet powders of composition NixCo(1-x)O-YSZ were synthesized for testing as cermet anode materials for SOFCs. The Co is found by powder XRD to become incorporated into the crystal lattice of the NiO, thus forming a true alloyed material. SEM and EDS results show two types of particles upon sintering to 1380oC: small, amorphous particles of YSZ and large, crystalline particles of nickel. The electrochemical oxidation of hydrogen on a cermet anode composed of Ni0.7Co0.3O-YSZ was investigated using a series of many button cells. Through EIS data, cyclic voltammetry data, the exchange current densities for these button cells were determined. Although a relatively large variation was found (expected to be due to microstructural variation) the average values for both methods of measurement is in good agreement in hydrogen. Following reduction in pure hydrogen, the fuel was changed to a mixture with high concentration of H2S. It was found that a concentration of 10 % H2S/H2 produced a sudden change in anode microstructure and resulted in loss of exchange current density. Lowering the amount of H2S in the initial fuel feed, which allowed for a more gradual microstructural change, allowed the cell to eventually function at concentrations in excess of 10 % H2S/H2. It was determined by OCV values in various concentrations of H2S/H2 that hydrogen is the predominant fuel of choice, even if H2S is available. Following electrochemical testing, slow cooling in a 10 % H2S/H2 mixture following produced metal sulfide spheres, as determined by SEM and EDS. Investigation in hydrocarbon, alcohol and biodiesel fuels was then undertaken to test the fuel variability of the given cermet anode material. Methane containing 10 % H2S was found to have increased exchange current density relative to poisoned hydrogen. Ethane and biodiesel experienced no increase in exchange current density, but a lengthening of the functional lifetime of the cell was observed, indicating reduced carbon poisoning. Methanol is a promising oxygen-containing SOFC fuel since it produced exchange current density values larger than hydrogen, and showed no evidence of coke formation by post-mortem SEM. Since oxygen-containing fuels are known to decompose in the gas phase at typical SOFC operating temperatures, the performance in a mixture of various CO/H2 fuels was then investigated. The Ni0.7Co0.3O-YSZ cermet anode gave higher exchange current density values for low ratio of CO/H2 fuels in the range 20/80 and 30/70 compared to pure H2. This is the first example of a Ni-based anode providing higher performance with a CO/H2 mixed fuel than for a pure H2 fuel. Finally, continuous running of a cell with fuel ratio 25/75 CO/H2 for 7 days produced exchange current density values, which were observed to increase significantly above the values for pure H2 during days 1-4 followed by deterioration below the value for hydrogen on subsequent days.

A series of cermet powders of composition NixCo(1-x)O-YSZ were synthesized for testing as cermet anode materials for SOFCs. The Co is found by powder XRD to become incorporated into the crystal lattice of the NiO, thus forming a true alloyed material. SEM and EDS results show two types of particles upon sintering to 1380oC: small, amorphous particles of YSZ and large, crystalline particles of nickel. The electrochemical oxidation of hydrogen on a cermet anode composed of Ni0.7Co0.3O-YSZ was investigated using a series of many button cells. Through EIS data, cyclic voltammetry data, the exchange current densities for these button cells were determined. Although a relatively large variation was found (expected to be due to microstructural variation) the average values for both methods of measurement is in good agreement in hydrogen. Following reduction in pure hydrogen, the fuel was changed to a mixture with high concentration of H2S. It was found that a concentration of 10 % H2S/H2 produced a sudden change in anode microstructure and resulted in loss of exchange current density. Lowering the amount of H2S in the initial fuel feed, which allowed for a more gradual microstructural change, allowed the cell to eventually function at concentrations in excess of 10 % H2S/H2. It was determined by OCV values in various concentrations of H2S/H2 that hydrogen is the predominant fuel of choice, even if H2S is available. Following electrochemical testing, slow cooling in a 10 % H2S/H2 mixture following produced metal sulfide spheres, as determined by SEM and EDS. Investigation in hydrocarbon, alcohol and biodiesel fuels was then undertaken to test the fuel variability of the given cermet anode material. Methane containing 10 % H2S was found to have increased exchange current density relative to poisoned hydrogen. Ethane and biodiesel experienced no increase in exchange current density, but a lengthening of the functional lifetime of the cell was observed, indicating reduced carbon poisoning. Methanol is a promising oxygen-containing SOFC fuel since it produced exchange current density values larger than hydrogen, and showed no evidence of coke formation by post-mortem SEM. Since oxygen-containing fuels are known to decompose in the gas phase at typical SOFC operating temperatures, the performance in a mixture of various CO/H2 fuels was then investigated. The Ni0.7Co0.3O-YSZ cermet anode gave higher exchange current density values for low ratio of CO/H2 fuels in the range 20/80 and 30/70 compared to pure H2. This is the first example of a Ni-based anode providing higher performance with a CO/H2 mixed fuel than for a pure H2 fuel. Finally, continuous running of a cell with fuel ratio 25/75 CO/H2 for 7 days produced exchange current density values, which were observed to increase significantly above the values for pure H2 during days 1-4 followed by deterioration below the value for hydrogen on subsequent days.

A series of cermet powders of composition NixCo(1-x)O-YSZ were synthesized for testing as cermet anode materials for SOFCs. The Co is found by powder XRD to become incorporated into the crystal lattice of the NiO, thus forming a true alloyed material. SEM and EDS results show two types of particles upon sintering to 1380oC: small, amorphous particles of YSZ and large, crystalline particles of nickel. The electrochemical oxidation of hydrogen on a cermet anode composed of Ni0.7Co0.3O-YSZ was investigated using a series of many button cells. Through EIS data, cyclic voltammetry data, the exchange current densities for these button cells were determined. Although a relatively large variation was found (expected to be due to microstructural variation) the average values for both methods of measurement is in good agreement in hydrogen. Following reduction in pure hydrogen, the fuel was changed to a mixture with high concentration of H2S. It was found that a concentration of 10 % H2S/H2 produced a sudden change in anode microstructure and resulted in loss of exchange current density. Lowering the amount of H2S in the initial fuel feed, which allowed for a more gradual microstructural change, allowed the cell to eventually function at concentrations in excess of 10 % H2S/H2. It was determined by OCV values in various concentrations of H2S/H2 that hydrogen is the predominant fuel of choice, even if H2S is available. Following electrochemical testing, slow cooling in a 10 % H2S/H2 mixture following produced metal sulfide spheres, as determined by SEM and EDS. Investigation in hydrocarbon, alcohol and biodiesel fuels was then undertaken to test the fuel variability of the given cermet anode material. Methane containing 10 % H2S was found to have increased exchange current density relative to poisoned hydrogen. Ethane and biodiesel experienced no increase in exchange current density, but a lengthening of the functional lifetime of the cell was observed, indicating reduced carbon poisoning. Methanol is a promising oxygen-containing SOFC fuel since it produced exchange current density values larger than hydrogen, and showed no evidence of coke formation by post-mortem SEM. Since oxygen-containing fuels are known to decompose in the gas phase at typical SOFC operating temperatures, the performance in a mixture of various CO/H2 fuels was then investigated. The Ni0.7Co0.3O-YSZ cermet anode gave higher exchange current density values for low ratio of CO/H2 fuels in the range 20/80 and 30/70 compared to pure H2. This is the first example of a Ni-based anode providing higher performance with a CO/H2 mixed fuel than for a pure H2 fuel. Finally, continuous running of a cell with fuel ratio 25/75 CO/H2 for 7 days produced exchange current density values, which were observed to increase significantly above the values for pure H2 during days 1-4 followed by deterioration below the value for hydrogen on subsequent days.

Le présent travail souhaite explorer théoriquement et expérimentalement de quelle manière l’augmentation des surfaces d’échange par l’architecturation mésoscopique des interfaces électrode/électrolyte dans une SOFC à anode support pourrait améliorer ses performances. D’abord, une optimisation des caractéristiques microstructurales de l’anode a été effectuée par ajustement de la composition initiale de la barbotine, favorisation de la percolation du réseau de Ni par une microstructure « hiérarchique » et des mesures de perméabilités aux gaz identifiant le choix de l’anode. Ensuite, un modèle électrochimique a montré une augmentation des courants d’échange par rapport à la surface plane dans le cas d’un motif périodique pour une épaisseur d’électrolyte sensiblement plus petite que les dimensions du motif. Ce dernier doit présenter des singularités concaves et convexes de façon à confiner le matériau d’électrode au voisinage de l’interface, ainsi que des caractéristiques géométriques réduisant la surtension de concentration. De telles architectures ont été réalisées, par des techniques de mise en forme des céramiques, sur des anodes auto-supportées (YSZ + Ni) sur lesquelles une couche mince d’électrolyte (YSZ) a été déposée, puis l’ensemble co-fritté. Pour finaliser la cellule, une barrière de diffusion (CGO) et une cathode bicouche (LSCF48 + CGO / LSCF48) ont ensuite été déposées puis frittées. Les premiers résultats électriques et électrochimiques montrent une augmentation de la densité de courant de130 à 300 mA.cm-2 à une tension d’opération de 0,7 V, qui reste plus élevée que ce que prévoyait la modélisation. Les résultats sont discutés ici en termes de géométrie du motif et de son évolution au cours du frittage, ainsi que des surtensions d’activation et de concentration. / The present work aims to explore, theoretically and experimentally, how the increase of exchange surfaces via the mesoscopic scale corrugation of electrode / electrolyte interfaces in an anode-supported SOFC could improve its performance. First, an optimization of the microstructural characteristics of the anode was performed by adjusting the initial composition of the slurry, favoring the percolation of the network of Ni by a "hierarchical" microstructure and gas permeability measurements identifying the choice of the anode. Next, an electrochemical model showed an increase in the exchange currents with respect to the planar surface in the case of a periodic pattern for an electrolyte thickness substantially smaller than the dimensions of the pattern. The latter must have concave and convex singularities so as to confine the electrode material in the vicinity of the interface, as well as geometrical characteristics reducing the concentration overvoltage. Such architectures have been carried out by ceramic shaping techniques on self-supported anodes (YSZ + Ni) on which a thin layer of electrolyte (YSZ) has been deposited, and then the co-sintered along with the anode. To finalize the cell, a diffusion barrier (CGO) and a bi-layered cathode (LSCF48 + CGO / LSCF48) were then deposited and then sintered. The first electrical and electrochemical results show an increase in the current density from 130 to 300 mA.cm-2 at an operating voltage of 0.7V, which is still higher than what was anticipated by modeling, reaching more than the double of the value for flat interfaces. The results are discussed here in terms of geometry of the pattern and its evolution during sintering, as well as activation and concentration overvoltages.

Ces travaux de thèse résultent d’une étude multidisciplinaire dont l’objectif final était d’élaborer une électrode négative à base de zinc pour accumulateur alcalin rechargeable. L’origine de l’étude tient en la découverte surprenante, par la société EASYL, d’un nouveau procédé de synthèse du zincate de calcium (CAZN), matière électrochimiquement active et connue pour ses bonnes caractéristiques de cyclabilité en générateur alcalin rechargeable. L’intérêt de cette découverte réside dans ses caractéristiques avantageuses : la synthèse ultra-rapide se fait en continu, n’utilise aucun système de chauffe ni de solution alcaline et conduit à une granulométrie et une pureté contrôlée du zincate de calcium ; la rendant compatible avec une production industrielle de ce matériau.L’utilisation de CAZN en batterie prismatique de 4 Ah a permis la découverte d’un fonctionnement des électrodes de type cœur-coquille, leur cœur actif étant riche en zinc et leur surface jouant le rôle de couche protectrice ; si la capacité nominale est choisie inférieure à la capacité théorique de la batterie, l’activité à cœur de l’électrode est maintenue sans que sa surface ne soit altérée, ce qui permet d’éviter (ou de ralentir) la formation de dendrite, un effet très bénéfique sur la cyclabilité de l’électrode.Cependant, l’utilisation du zincate de calcium comme seule source de matière active ne semble pas appropriée. En effet, la formation du cœur de zinc conduit à l’apparition d’une couche résistive d’hydroxyde de calcium à sa périphérie, diminuant les performances électrochimiques des électrodes. Aussi surprenant que cela puisse paraitre, il est cependant possible de régénérer une électrode vieillie ayant formé une couche riche en hydroxyde de calcium par un simple repos, soit un arrêt pur et simple de la batterie. La formation de cette couche résistive peut en outre être évitée par l’ajout d’oxyde de zinc sacrificiel au zincate de calcium, additif actif qui s’est avérée efficace tant d’un point de vue morphologique qu’électrochimique.En revanche, la formation contrôlée d’un cœur riche en zinc conduit à la densification du zinc sur lui-même, et diminue la surface de contact matière active/électrolyte et donc les performances électrochimiques. Partant de ce constat, la structure de l’électrode a été intégralement repensée pour permettre la formation, non pas d’un cœur de zinc, mais de plusieurs d’entre eux, par l’emploi de collecteurs de courant multicouches ; cette méthodologie, aussi simple qu’efficace, conduit à d’excellentes performances pratiques et une cyclabilité optimale de la batterie. / The work presented in this document results from a multidisciplinary study, the unique goal of which is to develop a negative electrode for alkaline rechargeable batteries. At the origin of this thesis, is the surprising discovery by EASYL of a new way to synthesize calcium zincate (CAZN), an electrochemically active material known for its good cycling characteristics in alkaline batteries. The advantage of such a discovery resides in its unique characteristics: the ultra-fast synthesis is carried out continuously, uses neither heating system nor alkaline solutions, yields pure and tailored CAZN crystals; it is therefore compatible with an industrial production of this material.Its use in a 4 Ah prismatic batteries allowed to unveil a core-shell operation mechanism, in which the electrode evolves towards an active zinc-core surrounded by a protective shell. So, if the nominal capacity remains below the theoretical one, the core of the electrode can be kept active while the surface is maintained, thus avoiding (or at least slowing down) possible dendrite formation and yielding prolonged cycle life.However, the use of calcium zincate as the only active material source is not appropriate, because the formation of the zinc-core leads to the appearance of a resistive layer of calcium hydroxide at its periphery, which reduces the overall electrochemical performance. As surprising as it may seem, it is possible to regenerate an electrode having formed such a calcium hydroxide-rich layer by a simple rest such as a stop of the battery. Nevertheless, it is preferable to avoid the formation of this resistive layer and to do so, the use of a mixture of sacrificial zinc oxide combined with calcium zincate has proven very effective, both from a morphological and an electrochemical point-of-view.However, the controlled formation of a zinc-rich core leads to zinc densification on itself; this decreases the surface of contact between the active material and the electrolyte, and thus the electrochemical performance. This negative effect has been overcome by drastically rethinking the structure of the electrode, in order to allow the formation of multiple and tailored zinc cores. To that goal, multilayers of current collector were employed, which proved simple and effective to reach high-performance and high cyclability zinc electrodes for alkaline batteries.