Abstract With the evolution of energy storage, Thermal Runaway (TR) stands out as the most critical safety concern for Lithium-Ion Batteries (LIBs). This study employs a prismatic lithium battery with a nominal capacity of 40Ah, featuring Li(Ni0.6Co0.2Mn0.2)O2 as the cathode material. The investigation delves into the thermal runaway characteristics of the battery at 25%, 50%, 75%, and 100% State of Charge (SOC) in a nitrogen environment. The findings indicate: 1) an ascending trend in the highest temperatures at various points within the battery as SOC increases, accompanied by a declining trend in normalized gas production and a non-linear relationship between the heat released during TR and the stored electrochemical energy; 2) the highest temperature point within the battery consistently resides at the surface, offering insights for the temperature monitoring of the Battery Thermal Management System (BTMS); 3) a direct correlation between higher SOC and increased material ejection, with a mass loss rate of 25.8% at 100% SOC, a static total gas production of 2.45 mol, and a maximum explosion index of 0.2886 kPa⋅m⋅s⁻¹. storage (TR LithiumIon Lithium Ion LIBs. LIBs . (LIBs) 40Ah Ah LiNi0.6Co0.2Mn0.2O2 LiNi06Co02Mn02O2 LiNiCoMnO Li Ni0.6Co0.2Mn0.2 O2 Ni0 6Co0 2Mn0 2 Ni Co Mn O Li(Ni0.6Co0.2Mn0.2)O 25 25% 50 50% 75 75% 100 (SOC environment indicate 1 increases nonlinear non linear surface BTMS (BTMS) 3 ejection 258 8 25.8 245 45 2.4 mol 02886 0 2886 0.288 kPams¹ kPams kPa m s ¹ kPa⋅m⋅s⁻¹ (LIBs LiNi0 2O2 LiNi LiNi0.6Co0.2Mn0.2O LiNi06Co02Mn02O Ni06Co02Mn02 NiCoMn Ni0.6Co0.2Mn0. 6Co 2Mn 5 7 10 (BTMS 25. 24 4 2. 0288 288 0.28 kPa⋅m⋅s⁻ 2O Ni06Co02Mn0 Ni0.6Co0.2Mn0 028 28 0.2 kPa⋅m⋅s Ni06Co02Mn Ni0.6Co0.2Mn 02 0.

This study examined the potential of electrooxidation techniques for treating Rhodamine B dyestuff from aqueous solutions made from synthetic wastewater. The Rhodamine B dyestuff was electro-oxidized by using five anodes coated with "Ti/IrO2/RuO2" as anode material and five stainless steel cathodes as cathode material. The initial concentration of Rhodamine B, the type of support electrolyte, the current density, and the initial pH of the wastewater were evaluated. KCl, NaCl, NaNO3 and Na2SO4 were used as supporting electrolytes. Colour removal performance was optimum when the initial pH was approximately 5, the current density was 1.78 mA cm-2, and the supporting electrolyte was NaCl at a concentration of 10 mM. Under ideal circumstances, colour removal was shown to be 99.72% effective.

Abstract. Electrochemical oxidation (EO) has been investigated as an alternative treatment technique for the remediation of real textile effluents containing a single dye and a trichromy of Remazol Yellow 3RS (RY 3RS), Remazol Red RR Gran (RR-RR Gran) and Navy Blue CL-R (NB CL-R) dyes, using a parallel plate flow reactor equipped with Ti/Pt or Ti/Pt-Sn-Sb electrocatalytic materials and Ti as cathode. The influence of the anode material and applied current densities on decolourization, organic matter decrease, cell potential and energy consumption during EO was examined. Higher color removal was achieved with Ti/Pt-Sn-Sb in all treated effluents compared to Ti/Pt at all electrolysis times, due to high oxidant production, especially hydroxyl radicals on their surface. Polymer film formation on the anode surface inhibited chemical oxygen demand (COD) removal during the treatment of a single effluent containing RY 3RS and RR-RR Gran dyes with either anode, whereas COD removal efficiencies of 13.93 % and 30.03 %, and 54.74 % and 74.48 % were obtained for Ti/Pt and Ti/Pt-Sn-Sb, respectively, in treating trichromy effluent after 240 min of electrolysis. Lower energy consumption was required by Ti/Pt-Sn-Sb compared to the Ti/Pt anode. In most of the trials studied, EO enhanced dissolved oxygen (DO) and reduced effluent turbidity, making it safe for disposal in the environment.

Resumen. La oxidación electroquímica (EO) se ha investigado como una técnica de tratamiento alternativa para la remediación de efluentes textiles reales que contienen un solo tinte y una tricromía de Remazol Yellow 3RS (RY 3RS), Remazol Red RR Gran (RR-RR Gran) y Navy Blue CL -R (NB CL-R), utilizando un reactor de flujo de placas paralelas equipado con materiales electrocatalíticos Ti/Pt o Ti/Pt-Sn-Sb y Ti como cátodo. Se examinó la influencia del material del ánodo y las densidades de corriente aplicadas sobre la decoloración, la reducción de materia orgánica, el potencial de celda y el consumo de energía durante la EO. Se logró una mayor remoción de color con Ti/Pt-Sn-Sb en todos los efluentes tratados en comparación con Ti/Pt en todos los tiempos de electrólisis, debido a la alta producción de oxidantes, especialmente radicales hidroxilos en su superficie. La formación de una película de polímero en la superficie del ánodo inhibió la eliminación de la demanda química de oxígeno (DQO) durante el tratamiento de un solo efluente que contenía colorantes RY 3RS y RR-RR Gran con cualquiera de los ánodos, mientras que las eficiencias de eliminación de DQO del 13,93 % y 30,03 %, y del 54,74 % y Se obtuvo 74,48 % para Ti/Pt y Ti/Pt-Sn-Sb, respectivamente, en el tratamiento de efluentes de tricromía después de 240 min de electrólisis. El Ti/Pt-Sn-Sb requería un menor consumo de energía en comparación con el ánodo de Ti/Pt. En la mayoría de los ensayos estudiados, el EO mejoró el oxígeno disuelto (OD) y redujo la turbidez del efluente, haciéndolo seguro para su eliminación en el medio ambiente.

The automotive industry is one of the largest industrial segments in the world market. The exhaust system of motor vehicles is responsible for the emission and treatment of toxic gasses released by the engine. In this sense, the application of titanium on an AISI 1020 steel substrate was carried out by plasma deposition using a cathode cage. The aim of this research was to evaluate the application of this material in the exhaust system of motor vehicles. The samples were characterized by scanning electron microscopy (SEM), confocal microscopy (CM), microhardness tests and corrosion resistance tests. The samples exhibited a thin film with higher titanium content and hardness than the uncoated sample. The corrosion potential also increased and the current density was lower than the uncoated sample. The conclusion is that the deposition of thin titanium films on AISI 1020 steel with CCPD has the potential to produce thin films. market engine sense 102 cage SEM, SEM , (SEM) CM, CM (CM) sample 10 (SEM (CM 1

Abstract Investigation of the physical and electrochemical characterization of the sugarcane bagasse-derived activated carbon (SBAC) as a cathode material of lithium-ion capacitor (LIC) was reported in this article. The as-prepared SBAC was tested by BET, SEM, and EDS characterization. SBAC was assembled as cathode material and lithium titanate oxide (LTO) as anode material used to fabricate LIC in a CR2032 coin cell. The results show the as-synthesized SBAC has a microporous architecture with a surface area of 1,906 m2/g. The developed LIC exhibited an energy density of 28.4 Wh/kg and a power density of 1,770 W/kg, and a capacity retention of 75% at 100 cycles. In addition, this LIC has a specific capacitance of 141.8 mF/g. This study indicates that sugarcane bagasse is a prospective carbonaceous material for the cathode of LIC.

ABSTRACT Introduction: The electrical energy storage systems, such as rechargeable Li batteries (BLi) and supercapacitors, are very valuable technologies to meet the needs of the modern automotive sector and photovoltaic systems. The objective of this research is to determine the critical properties of materials for BLi and supercapacitors obtained by the Ionic Conductors (ConIon) research group of IMRE-UH in the last five years. Methods: New strategies for the synthesis and modification of materials were established. The materials were characterized by chemical analysis, HRTEM, SEM, AFM, XPS, FTIR, TG, ATD, DSC, DRX, Raman, 13C NMR, hall effect, voltammetry and chronopotentiometry, among the most important ones. Results and discussion: The graphene oxide obtained resulted in an excellent anodic material with a conductivity of 1.3 S/cm, a reversible specific capacity of 354 mAh/g for BLi and a capacitance of 160-332 F/g for supercapacitors. The new LiB electrolyte (POE)8-LiClO4-LLTO) showed an ionic conductivity value (2.8E-3 S/cm) that is among the highest reported for a solid polymeric electrolyte. The doped oxide LiP0.1Mn1.88O4 turned out to be an excellent cathode material with a higher specific charge storage capacity and electrochemical stability for the manufacture of high-density LiB batteries. Conclusions: These results constitute a higher point of development in the study of advanced functional materials in Cuba to store electrical energy. New and remarkable findings were presented, fundamentally related to the measurement of the critical properties that determine the application of national active materials to rechargeable Li batteries and supercapacitors.

RESUMEN Introducción: Los sistemas almacenadores de energía eléctrica, como las baterías recargables de Li (BLi) y los supercapacitores, son tecnologías vitales para satisfacer necesidades del sector automovilístico moderno y los sistemas fotovoltaicos. El objetivo de esta investigación es determinar las propiedades críticas de materiales para BLi y supercapacitores obtenidos en Cuba por el grupo de conductores iónicos (ConIon) del Instituto de Ciencia y Tecnología de Materiales (IMRE-UH) en los últimos 5 años. Métodos: Se desarrollaron nuevas estrategias de síntesis y modificación de materiales. Los materiales fueron caracterizados mediante HRTEM, SEM, AFM, XPS, FTIR, Análisis químico, TG, ATD, DSC, DRX, Raman, 13C RMN, efecto hall, voltametría y cronopotenciometría, entre las más importantes. Resultados y discusión: El óxido de grafeno obtenido resultó ser un excelente material anódico con una conductividad de 1,3 S/cm, una capacidad específica reversible de 354 mAh/g en BLi y una capacitancia de 160-332 F/g como supercapacitor. El nuevo tipo de electrolito (POE)8-LiClO4-LLTO) para BLi obtenido mostró un valor de conductividad iónica (2,8E-3 S/cm) que está entre los más altos reportados para un electrolito sólito polimérico. El LiP0.1Mn1.88O4 obtenido constituye un material catódico con mayor capacidad específica de almacenamiento de carga y estabilidad electroquímica para la fabricación de baterías LIB de alta densidad. Conclusiones: los resultados obtenidos constituyen un punto superior de desarrollo en el estudio de materiales avanzados en Cuba para almacenar energía eléctrica. Se presentan nuevos y notables hallazgos, fundamentalmente relacionados con la medición de las propiedades críticas que determinan la aplicación de materiales activos nacionales en baterías recargables de Li y supercapacitores.

Abstract This work reports the synthesis, characterization, and catalytic activity of Pt-Ni/CNT with a low platinum load to use as cathode electrocatalyst in PEMFC (proton-exchange membrane fuel cells). The synthesis of nickel particles on the carbon nanotubes surface was carried out by chemical reduction of a Ni(ethylenediamine) complex; after that, the galvanic displacement reaction was performed to platinum deposition onto Ni/CNT. The Pt-Ni/CNT was deposited by spray technique on a gas diffuser layer (GDL) and subsequently subjected to several potential cycles to promote Ni atoms migration. Finally, its catalytic activity was evaluated in a fuel cell.

Resumen En este trabajo, se reporta la síntesis, caracterización y evaluación catalítica del electrocatalizador Pt-Ni/CNT con bajo contenido de platino, empleado como electrocatalizador catódico en una celda de combustible tipo PEMFC (Celda de combustible de membrana de intercambio protónico). La síntesis de las partículas de níquel sobre la superficie de los nanotubos de carbono se llevó a cabo mediante la reducción química del complejo de Ni(etilendiamina) y posteriormente, se depositó platino sobre el material Ni/CNT mediante la reacción de desplazamiento galvánico. Se depositó una película de Pt-Ni/CNT sobre un difusor de gas mediante la técnica de esprayado y posteriormente fue sometido a diversos ciclos de potencial para promover la migración de los átomos de níquel y evaluar su actividad catalítica en una celda de combustible.

LiMn2O4 spinel is a promising cathode material for secondary lithium-ion batteries. Despite showing a high average voltage of lithium intercalation, the material is structurally unstable, undergoing lowering of the crystal symmetry due to Jahn-Teller distortion of the six-fold Mn³+ cations. Although Ni has been proposed as a suitable substitutional dopant to improve the structural stability of LiMn2O4 and enhance the average lithium intercalation voltage, the thermodynamics of the Ni incorporation and its effect on the electrochemical properties of this spinel material are not yet known. In this work, we have employed density functional theory calculations with a Hubbard Hamiltonian (DFT+u) to investigate the thermodynamics of cation mixing in the Li(Mn1_xNi x)2O4 solid solution. Our results suggest LiMn1.5Ni0.5O4 is the most stable composition from room temperature up to at least 1000 K, in agreement with experiments. We also found that the configurational entropy is much lower than the maximum entropy at 1000 K, indicating that higher temperatures are required to reach a fully disordered solid solution. A maximum average lithium intercalation voltage of 4.8 eV was calculated for the LiMn1.5Ni0.5O4 composition, which is very close to the experimental value. The temperature was found to have a negligible effect on the Li intercalation voltage of the most stable composition. The findings reported here support the application of LiMn1.5Ni0.5O4 as a suitable cathode material for lithium-ion batteries, with a highly stable voltage of intercalation under a wide range of temperatures.

Zinc hexacyanoferrate (ZnHCF) is a Prussian Blue analog and can be intercalated by both monovalent and divalent ions. ZnHCF/multi-walled carbon nanotube (MWCNT) film could be used as a cathode for zinc ions battery. Carbon nanotubes improved significantly the electrochemical performance of the electrode. It is described the preparation of ZnHCF/MWCNT films by the interfacial method with cyclohexane/water mixture as solvent. The crystal structure, morphology, and microstructure of the as-prepared products were characterized by X-ray diffraction, scanning electron microscopy, Mossbaüer, Raman spectroscopy, and infrared spectroscopy. Results revealed that the MWCNTs extend the electrochemical properties of the ZnHCF and influence the structure and morphology of the hexacyanoferrate particles. If tested as cathode material for zinc ion batteries, the nanocomposite film exhibits a capacity of 25.81 mA h g-1, which is much higher than those obtained for a ZnHCF single-component film (3.28 mA h g-1). The physical characteristics and properties that allow good reversibility to a high potential difference, achieved with the ZnHCF/MWCNT film, suggest new developments in the manufacture of translucent, flexible and light energy storage devices, which can be used as a lower-cost, safer and environmentally friendly alternative to the currently existing technologies.

Resumen En este trabajo se evaluaron tres tipos de carbones activados como electrodos en la cámara anódica de una celda de combustible microbiana (MFC) de dos cámaras. Se utilizó un cultivo de Shewanella putrefaciens puro debido a sus características gran-negativa. En la cámara catódica se utilizó un electrodo de platino y Nafion® 117 como membrana de intercambio de protones para separar las dos cámaras. Los carbones activados seleccionados presentaron diferentes precursores (cisco de café, carbón comercial, y carbón mineral), con diferentes morfologías y propiedades porosas y superficiales. A partir de las mediciones de voltaje y corriente se encontró que los valores de potencia de la celda variaron entre 0.008 mW y 0.045 mW. El electrodo preparado utilizando carbón activado a partir de cisco de café (Q) presentó el mejor comportamiento electroquímico y valores de potencia más altos; este carbón se obtuvo a partir de la activación de cisco de café con H3PO4 a 450 °C. La morfología macroscópica de este carbón activado permitió una mejor migración del medio de cultivo acuoso hacia los macroporos y posteriormente mesoporos que mejoran la mojabilidad de la superficie. Las microfotografías SEM mostraron una mejor formación de la biopelícula, filamentos más largos de la bacteria y la formación de microlechos en el bio-ánodo Q, que favoreció la interacción con el microorganismo, facilitando su metabolismo y la transferencia extracelular de electrones. Por tal motivo, el carbón activado a partir de cisco de café podría ser considerado como un material prometedor para su implementación como electrodos en celdas de combustible microbiana.

Abstract In this work, three types of activated carbons were evaluated as electrodes in the anode chamber of a two-chamber microbial fuel cell (MFC). The evaluation was applied using a pure Shewanella Putrefaciens culture due to its gram-negative characteristics. In the cathode chamber, a platinum electrode was used, and a Nafion® 117 proton exchange membrane was selected as a separator of both chambers. The activated carbons were obtained from different precursors (coffee husk, commercial coal, and mineral coal), with different microporous and surface properties. From the voltage and current measurements, it was found that the cell power values varied between 0.008 mW and 0.045 mW. The electrode obtained from chemical activation of coffee husk with H3PO4 at 450 °C (Q) showed the best electrochemical behaviour and highest power values. This result may be mainly related to the macroscopic morphology and mesopores that improve the wettability of the surface by the medium thought carbonaceous material. SEM images showed a better biofilm formation, larger filaments of the bacteria, and micro-beds formation over the surface of bio-anode Q, which improved the interaction with the microorganism, its metabolism, and electrons extracellular transfer. Therefore, activated carbon from coffee husk could be considered as a promising material for electrodes of microbial fuel cells.

Resumo Neste trabalho avaliaram-se três tipos de carvões ativados como eletrodos na câmara anódica de uma célula de combustível microbiana (MFC) de duas câmaras. Utilizou-se um cultivo de Shewanella putrefaciens puro devido a suas características gram-negativa. Na câmara catódica utilizou-se um eletrodo de platino e Nafion® 117 como membrana de intercâmbio de prótons para separar as duas câmaras. Os carvões ativados selecionados apresentaram diferentes precursores (cisco de café, carvão comercial, e carvão mineral), com diferentes morfologias e propriedades porosas e superficiais. A partir das medições de voltagem e corrente encontrou-se que os valores de potência da célula variaram entre 0.008 mW e 0.045 mW. O eletrodo preparado utilizando carvão ativado a partir de cisco de café (Q) apresentou o melhor comportamento eletroquímico e valores de potência mais altos; este carvão obteve-se a partir da ativação de cisco de café com H3PO4 a 450 °C. A morfologia macroscópica deste carvão ativado permitiu uma melhor migração do meio de cultivo aquoso em direção aos macroporos e posteriormente mesoporos que melhoram a molhabilidade da superfície. As microfotografias SEM mostraram uma melhor formação da biopelícula, filamentos mais longos da bactéria e a formação de microleitos no bio-ânodo Q, que favoreceu a interação com o micro-organismo, facilitando seu metabolismo e a transferência extracelular de elétrons. Por tal motivo, o carvão ativado a partir de cisco de café poderia ser considerado como um material prometedor para sua implementação como eletrodos em células de combustível microbiana.

Although largely used in mobiles and electric vehicles applications, insertion batteries based on Li-ion technology are high-cost devices. These applications require high-performance energy storage systems with high-energy and high-power densities, which are better attained by Li-ion technology. However, stationary applications such as power plants and uninterruptible power supplies (UPS) mainly require low-cost energy storage devices. In this scenario Na-ion insertion batteries feature as a cheaper option for such applications. Among the several compounds for use as cathode in Na-batteries, a largely studied class of compounds are the sodium-carbonate-phosphates, Na3MCO3PO4 (M = Mn, Fe, Co or Ni), with structure analogue to the mineral sidorenkite. In this work, it was developed a new microwave-assisted hydrothermal method as an ultra-fast way to prepare sodium-carbonate-phosphate compounds. This methodology results in high-quality materials with general formula Na3MCO3PO4 (M = Mn, Fe, Co or Ni) upon only 5 min processing time. Characterization techniques indicate highly ordered materials with sidorenkite-like phase and different morphologies or crystal habits, including plates, rods, and a ‘starfruit’ shape. As a proof-of-application the Mn-based material was evaluated from electrochemical tests for Na+ insertion reactions. The obtained results evidence initial discharge capacity of 107 mA h g-1 with good reversible capacity (65 mA h g-1) after several charge/discharge cycles.

Abstract The cathodic arc discharge is a deposition technique widely used to synthesize hard coatings and thin films. The structure of the plasma generated by the electrical discharge and its interaction with neutral particles was studied using numerical simulations. Typical plasma parameters were characterized considering their spatial and temporal dependence, as well as several cathode materials that are commonly used in these systems. For the evolution of the ion density, it was observed the formation of Knudsen layer, and also a dependence of pressure gradients in the global behavior. With respect to the kinetic energy, it was found a deceleration of ions, which is represented by a shock front produced in the plasma−neutrals interaction. On the other hand, the energy releasing was generated due to the heat transference between electrons and ions. The plasma potential follows a behavior, which is similar to that of the ion density, and it is caused by the dynamics of charged particles which is directly affected by the concentration of neutrals and ions. In general, the physical quantities are directly affected by electrical and thermal conductivity of the cathode material. Our results can be applied to understand the plasma phenomena produced in a cathodic arc discharge.

Resumen Películas delgadas de bisulfuro de tungsteno dopado con titanio fueron depositadas usando la técnica de magnetron co- sputtering DC sobre sustratos de acero inoxidable AISI 304 y Silicio. Para producir los recubrimientos, la densidad de potencia del cátodo de titanio fue variada entre 0 y 1.25 W/cm2. Los resultados de espectroscopia de energía dispersiva muestran un incremento en el porcentaje de Ti a expensas de W, además muestra una disminución en el porcentaje de azufre. Con las medidas de espectroscopía Raman se identificaron las bandas al enlace W-S para WS2 sin dopar. Cuando el material es dopado, los cambios en la estructura cristalina producen la separación de las principales bandas del enlace W-S. Usando la prueba de rayado dinámico, la adhesión de los recubrimientos fue estudiada, mostrando que la carga critica (Lc) incrementa con el porcentaje de Ti; además, la falla pasa de adhesiva a cohesiva con el incremento de Ti. Finalmente, la resistencia a la corrosión fue evaluada usando la técnica espectroscopia de impedancia electroquímica (EIS), y es observado que a altas cantidades de Ti, se mejora la resistencia a la corrosión debido a que el Ti facilita la densificación y genera una capa protectora.

Abstract Titanium-doped tungsten disulfide thin films (WS2-Ti) were deposited using a DC magnetron co-sputtering on AISI 304 stainless steel and silicon substrates. Different Ti cathode power densities between 0 and 1.25 W/cm2 were used for coating deposition. Energy-dispersive spectroscopy evidenced an increase in Ti percentage at the expense of W, as well as a sulfur deficiency. Raman spectroscopy was used to identify bands corresponding to W-S for undoped WS2. As the material was doped, changes in crystalline structure caused W-S main bands to separate. Scratch adhesion testing showed that Ti percentage increased along with the critical load (Lc). Furthermore, adhesive failure type changed from plastic to elastic. Finally, corrosion resistance analysis using electrochemical impedance spectroscopy (EIS) showed that, at high Ti concentrations, corrosion resistance was enhanced as Ti facilitates coating densification and generates a protective layer.

RESUMEN Los óxidos de manganeso con estructura tipo espinela (LiMn 2 O 4) han sido utilizados con éxito como materiales de cátodo para las baterías de ion-litio. Para mejorar la capacidad e incrementar el potencial de descarga de la batería, comúnmente se han adicionado metales de transición a la espinela, como dopantes o sustituyentes del manganeso. Esto puede conferirle también estabilidad a la estructura del material de cátodo. En este trabajo se evaluó la obtención y el desempeño de las espinelas de LiMn 2 O 4 (LMO) y LiNi 0.5 Mn 1.5 O 4 (LNMO) obtenidas por procesos de síntesis en estado sólido y sol-gel se estudiaron. Los materiales sinterizados de (LMO) y (LMNO) se caracterizaron por espectroscopia Raman y difracción de rayos X (DRX) para evidenciar la formación de la estructura tipo espinela. Fue corroborado que mediante ambos métodos de síntesis se puede producir una estructura de espinela adecuada. El análisis SEM mostró en general que la espinela adquiere una forma octahedral. El tamaño de partícula cambia de acuerdo al método de síntesis empleado, obteniendo un menor tamaño de partícula en la síntesis por sol-gel. La caracterización electroquímica demuestra que la síntesis por estado sólido genera componentes con mayor pureza y cristalinidad, los cuales generan una mayor capacidad de intercalación de iones litio. La adición de níquel a la espinela incrementa el potencial de descarga del cátodo en 0.5V.

ABSTRACT Spinel-structured lithium manganese oxide (LiMn 2 O 4) has been successfully used as a cathode material for various lithium batteries. To improve the capacity and increase the discharge potential of the battery, transition metals are commonly added to the spinel as dopants or as a substitute for manganese. This can also confer stability on the structure of the cathode material. In this work, the production and performance of spinel LiMn 2 O 4 (LMO) and LiNi 0.5 Mn 1.5 O 4 (LNMO) by solid-state and sol-gel synthesis methods were studied. Synthetized (LMO) and (LNMO) materials were characterized by Raman spectroscopy and X-ray diffraction (XRD) to verify the formation of a spinel-like structure. It was corroborated that both synthesis methods can produce an adequate spinel structure. SEM analyses showed that in general, spinel take an octahedral form. The particle size changes according to the synthesis method used. Lower particle sizes were obtained by sol-gel. The electrochemical characterization demonstrates that solid-state synthesis generates compounds with greater purity and crystallinity, which induces a greater capacity of lithium ion intercalation. The addition of nickel to the spinel increases the discharge potential of the cathode by 0.5V.

Resumen Las técnicas asistidas por plasma han sido ampliamente utilizadas para la deposición de películas delgadas y recubrimientos metalúrgicos de alta calidad. La descarga luminiscente producida en la región entre electrodos y cámara de un arco catódico fue modelada. El comportamiento del plasma fue caracterizado para diferentes materiales del cátodo comúnmente utilizados en descarga de arco catódico. Se encontró que la temperatura electrónica, densidad y potencial eléctrico decrecen como función de la distancia desde la región de puntos catódicos. Sin embargo, la energía cinética del ion tiende a incrementar debido a la aceleración de los iones provenientes de la región central del arco. Nuestros resultados muestran que el arco catódico no es directamente afectado por el potencial del plasma de la descarga luminiscente y que el material del cátodo tiene una influencia importante en el comportamiento del plasma, principalmente debido a la conductividad eléctrica y térmica de cada material.

Abstract Plasma-assisted techniques have been widely used for deposition of high quality thin films and metallurgical coatings. The glow plasma produced in the region between the electrodes and the chamber wall of a cathodic arc was modeled. The plasma behavior was characterized for different cathode materials that are commonly used in a cathodic arc deposition. The electron temperature, density, and electric potential were found to decrease as function of the distance from the spot region. However, the ion kinetic energy tends to increase due to the acceleration of the ions coming from the bulk region. Our results show that the cathodic arc is not directly affected by the plasma potential of the glow plasma and that the cathode material has an important influence on the plasma behavior, mainly because of the electrical and thermal conductivity of each material.