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The objective of this study is to optimize the performance of a graphitized carbon xerogel doped with graphene oxide (GXGO) as cathode for sodium dual-ion batteries. Carbon xerogels are synthetic materials produced in large amounts, with well-controlled chemistry, porosity and structure, by a simple and fast microwave process that has been scaled-up. The intercalation of PF6− anions from various NaPF6 salt-based electrolytes in a GXGO-based cathode is investigated by considering the influence of the upper cut-off voltage (UCOV) and of the electrolyte on the electrochemical parameters. The best results were attained in an electrolyte with a 2.0 M NaPF6 concentration in EC : EMC carbonate solvent mixture with added FEC, at a UCOV of 5.0 V. GXGO cathode provides a discharge capacity of 47 mAh g−1 after 2500 cycles with a coulombic efficiency of 97 %. Moreover, it shows great cycling stability and capacity retention of essentially 100 % after the initial cycles.

In recent years, the research on lithium-ion batteries (LIBs) to improve their lifetime, efficiency and energy density has led to the use of silicon-based materials as a promising anode alternative to graphite. Specifically, crystalline silicon (cSi) and silicon carbide (SiC) obtained from deposition or reduction processes (e.g., magnesiothermal reduction) stand out for their electrochemical properties. However, the synthesis routes proposed until now have limitations that make them difficult to afford or operate on a large scale. For this reason, in this work, carbon-silicon (C-Si) hybrid materials synthesized through an efficient route are evaluated as the potential precursor for the obtention of both cSi and SiC species in a single material. The feasibility and influence of the magnesiothermal reduction process were evaluated, and materials with 10 wt.% of reduced Si and 10-26 wt.% of SiC were obtained. Both species play a role in the improvement of the performance of silicon-based materials as anodes in lithium-ion batteries. In comparison with materials obtained by the reduction of silica gels and composites, the reduced C-Si hybrid gels stand out thanks to the homogeneous distribution and stability of the species developed.

A detailed study of the intercalation/de-intercalation mechanisms of PF6− anions in a graphite cathode of sodium dual-ion batteries is carried out by cyclic voltammetry. The influence of the continuous anion intercalation/de-intercalation on the graphite structure is investigated by ex-situ XRD after cycling. It was concluded that the intercalation/de-intercalation occurs through a combination of diffusion-controlled and pseudocapacitive mechanisms. Initially, the contribution of the diffusion-controlled is significant, specifically at the highest voltage and at the lowest scan rates which agrees with the slow kinetic of this mechanism and its usual prevalence in carbon materials with a graphitic structure. However, the continuous anion intercalation/de-intercalation causes some deterioration of the graphite structural order, even from the initial cycles, as it was demonstrated by the evolution of the crystalline parameters, interlayer spacing, d002, and crystallite size, Lc. This deterioration hinders the diffusion-controlled anion intercalation/de-intercalation and, as a consequence, the pseudocapacitive becomes the main mechanism along cycling. Therefore, since graphite is capable of intercalating PF6− anions at high voltages through a capacitive mechanism, with its consequent rapid kinetics, this carbon material is an excellent candidate for using as cathode in high power sodium dual-ion batteries, in which, kinetically fast mechanisms are required.

Silicon-based anodes are widely studied as an alternative to graphite anodes for lithium-ion batteries. Nevertheless, their practical application is mainly limited by the huge volume change that silicon particles undergo due to alloying and de-alloying with lithium ions during discharge/charge processes, which result in cracks and electrode degradation. In the present study, porous silicon-carbon composites are investigated as anode materials for next-generation lithium-ion batteries. These composites are prepared by a cost-effective, easily-scalable method based on a microwave assisted approach for the carbon matrix, followed by dispersion of the silicon in 2-propanol. The electrochemical behavior of the Si/C composites with different proportions of silicon is evaluated in terms of alloying and de-alloying mechanisms of lithium ions, battery reversible capacity, irreversible capacity in the first cycle, retention of capacity along cycling, and cycle efficiency. The composite with 30 wt.% of silicon presents specific discharge capacity as high as 917 mAh g−1 after 200 cycles and excellent stability in the long-term at high current density, which makes it a promising candidate for the lithium-ion battery market.

The intercalation of PF6− anions in graphite from various sodium salt-based electrolytes with organic carbonate mixtures as solvents is investigated. The purpose was to optimize the electrochemical performance of the graphite as cathode in terms of specific capacity, capacity stability, and coulombic efficiency to be coupled in the future with a hard carbon-based anode in a full sodium dual-ion battery. To this end, a detailed study was made of the influence of applied current density, upper cut-off voltage (UCOV), and electrolyte—in terms of both salt concentration and solvent mixture—on the intercalation/de-intercalation of PF6− anions in the graphite cathode. Low (37.2 mA g−1) and high (372.0 mA g−1) currents, UCOVs from 4.8 to 5.2 V, electrolytes with NaPF6 salt concentrations in the range of 0.2–1.2M and EC:DEC, EC:DMC and EC:EMC solvent mixtures were studied. The best graphite cathode performance was attained in 1.2MNaPF6/EC:EMC electrolyte at the highest current density of 372.0 mA g−1 and for the potential range between 2.9 and 5.0 V vs. Na/Na+. In these conditions, a discharge capacity of 79 mAh g−1 after 1000 cycles with a coulombic efficiency of 99 % and a remarkable capacity retention throughout cycling were determined.

The electrochemical intercalation of PF6− anions into graphitic nanomaterials of renewable origin with different degrees of structural order to be subsequently used as cathodes for sodium dual-ion batteries is herein investigated for the first time. Overall, the electrochemical performance of the biogas-derived carbon nanofibers depends on their graphitic structure, specifically on crystallite height which was found to be the determining parameter for the scope of electrochemical intercalation of PF6− anions into these nanomaterials.

Due to their high energy density, lithium-ion batteries with blended silicon-graphite (Si-Gr) anodes and nickel-rich (NMC) cathodes have been regarded as one of the most promising technologies for next-generation consumer electronics and electric vehicles. However, there are still several technical challenges to overcome for successful wide-spread adoption; in particular, deciphering the degradation phenomena remains complex and challenging, as the blended nature of the electrode creates a new paradigm, with the Si/Gr ratio likely changing with aging. Although ex-situ techniques have been used, a set of in-operando tools that enable diagnosis and prognosis on this technology has yet to be developed. Herein, we present a mechanistic investigation that generates a complete degradation mapping coupled with proposed aging features of interest, to attain accurate diagnosis and prognosis. The mechanistic model allows analyzing aging modes that display incubation periods as a potential prelude to thermodynamic plating, and the identification via incremental capacity of unique silicon features that change predictably as it degrades. A comprehensive look-up table summarizing key features is provided to provide support both to scientists and engineers on designing next-generation battery management systems for this technology.

Coal ash char concentrates from four countries (Portugal, Poland, Romania, and South Africa) were prepared, characterised, and graphitized under the scope of the Charphite project (Third ERA-MIN Joint Call (2015) on the Sustainable Supply of Raw Materials in Europe). Coal ash chars may be a secondary raw material to produce synthetic graphite and could be an alternative to natural graphite, which is a commodity with a high supply risk. The char concentrates and the graphitized material derived from the char concentrates were characterised using proximate analysis, X-ray fluorescence, X-ray diffraction (structural), Raman microspectroscopy, solid-state nuclear magnetic resonance, scanning electron microscopy, and petrographic analyses to determine if the graphitization of the char was successful, and which char properties enhanced or hindered graphitization. Char concentrates with a lower proportion of anisotropic particles and a higher proportion of mixed porous particles showed greater degrees of graphitization. It is curious to see that embedded Al2O3 minerals, such as glass and clay, influenced graphitization, as they most likely acted as catalysts for crystal growth in the basal direction. However, the graphitized samples, as a whole, do not compare well against a reference natural graphite sample despite some particles in select char concentrates appearing to be graphitized following graphitization.

Carbon xerogels (CXs) with the same chemical composition and BET surface area but different pore sizes (10–200 nm), which had been easily produced in large amounts via a cost-effective microwave-based process, are investigated as anodes for sodium-ion batteries (SIBs). The role of textural properties of CXs in the process of sodium ions storage was evaluated. The most suitable anode for SIBs was CX-100 with a pore size of 100 nm, the largest micropore volume and the lowest external surface area (Sext), which gives an idea of the most accessible surface of the material, along with relatively high open porosity. Larger pore sizes facilitate electrolyte penetration, thus improving Na+ ions diffusion inside the electrode, while microporosity is crucial in increasing electrode capacity since Na+ ions storage on CXs is mainly due to absorption on the surface and in structural defects (i.e., microporosity). Moreover, lowering Sext leads to a decrease in the Na+ ions used in the formation of the SEI layer and irreversibly absorbed during initial cycles, therefore improving electrode performance. In summary, an optimal combination of textural properties, including pore structure and Sext, should be considered in order to effectively design CXs for SIBs.

Six solid bitumen samples from Paja Formation (Cretaceous of Colombia) were optically, chemically and structurally characterized using bulk chemistry, reflectance indicating surface (RIS), micro-Raman and X-ray diffraction (XRD) parameters. The volatile matter and carbon contents and high random reflectance (Ro%) placed these solid bitumens in the category of cata-impsonites according to Jacob's classification. RIS axes (R, R and R) form almost a sphere, and consequently, the anisotropy (Ram or bireflectance values) of these materials is very weak, comparatively to other carbonaceous materials (coals) of similar degree of evolution. The weak anisotropy character of the solid bitumen is related to the absence of pressure in the system, which did not promote the orientation of the basic structural units (BSUs) in a three-dimensional arrangement. The degree of ordering evaluated by Raman parameters, such as full width at half maximum (FWHM) of the D1 and G bands, and XRD parameters, including d and crystallite sizes Lc and La, showed that the solid bitumens of the Paja Formation have a low structural order equivalent to high-rank coals, specifically anthracites B (3.0% ≤ Ro < 4.0%), although their reflectance values placed them in a higher rank (Ro > 4.0%). The discrepancy between high reflectance and low degree of structural order can explain why some of the equations used to estimate equivalent vitrinite reflectance (Ro eq. Vite) from solid bitumens do not work universally. Taking in consideration several equations available in the literature, Jacob's equation (Jacob, 1989) was the one that fitted the Ro eq. Vite values in the range of 3.0% to 4.0%, which parallels with the degree of structural order obtained for the solid bitumens. Consequently, Jacob's equation can now be extended to solid bitumen in the range of cata-impsonites.

The electrochemical performance of novel nano-silicon/biogas-derived carbon nanofibers composites (nSi/BCNFs) as anodes in lithium-ion batteries was investigated, focusing on composition and galvanostatic cycling conditions. The optimization of these variables contributes to reduce the stress associated with silicon lithiation/delithiation by accommodating/controlling the volume changes, thus preventing anode degradation and therefore improving its performance regarding capacity and stability. Specific capacities up to 520 mAh g−1 with coulombic efficiency > 95% and 94% of capacity retention are achieved for nSi/BCNFs anodes at electric current density of 100/200 mA g−1 and low cutoff voltage of 80 mV. Among the BCNFs, those no-graphitized with fishbone microstructure, which have a great number of active sites to interact with nSi particles, are the best carbon matrices. Specifically, a nSi:BCNFs 1:1 weight ratio in the composite is the optimal, since it allows a compromise between a suitable specific capacity, which is higher than that of graphitic materials currently commercialized for LIBs, and an acceptable capacity retention along cycling. Low cutoff voltage in the 80–100 mV range is the most suitable for the cycling of nSi/BCNFs anodes because it avoids formation of the highest lithiated phase (Li15Si4) and therefore the complete silicon lithiation, which leads to electrode damage

Introduction Silicon appears to be a promising anode material for increasing both the energy density and power of lithium-ion batteries due to, mainly, the high theoretical specific capacity, the relatively low working potential and the abundance in earth crust. However, the lithiation/delithiation of Si causes successive volume changes of this material leading to the fracture of the particles and the consequent poor reversibility and cycling stability of the electrode. Among different strategies which are being developed to avoid the Si-electrode degradation, this work has focused on: (i) the preparation of Si-based composites by adding a matrix (specifically carbon materials) which can help to buffer the volume changes and (ii) the limitation of the lower cut-off voltage (LCOV) which leads to a better control of these changes. Results and discussion Among different carbon matrices studied in this work, free-metal carbon nanofibers obtained from the catalytic decomposition of biogas (BCNFs) result the most suitable ones. Thus, the fishbone microstructure of these carbon nanofilaments, having a great number of active sites to interact with the Si particles, buffer the volume changes associated with the silicon lithiation/delithiation, preventing the electrode degradation. Specifically, an nSi:BCNFs 1:1 weight ratio in the active composite is the optimal. On the other hand, the limitation of the LCOV in the 80-100 mV range avoids the formation of the highest lithiated phase which leads to electrode degradation. Both strategies allow achieving a compromise between the specific capacity, which is greater than that of graphitic materials currently used in LIBs, and acceptable capacity retention along galvanostatic cycling. Thus, electrodes formed by 80 % of the nSi/BCNFs composite, including a 10 % of carbon black (CB), and 20 % of sodium carboxymethyl cellulose (NaCMC) as active material and binder, respectively, has been prepared in this work by a simple, fast and eas

Novel graphitic materials of renewable origin, biogas-derived carbon nanofibers (BCNFs), are investigated as anodes for sodium-ion batteries in a glyme-based electrolyte. These materials show a unique combination of electrochemical properties, including suitable capacity (∼100 mAh g), high rate capability, excellent cycle stability and coulombic efficiency as well as long cycle life (∼6000 cycles up to 7.5 A g) which make them adequate candidates for this application. The sodiation of BCNFs occurs through different combinations of diffusion-controlled intercalation and capacitive intercalation processes. Overall, the quantitative contribution of the capacitive current to the total stored sodium in BCNF electrodes is noteworthy (28-71%), which account for their ultrahigh rate performance, comparable to that of supercapacitors, because of the improvement of the transportability of the Na ions through the graphene layers.

The electrochemical performance as potential anodes for sodium-ion batteries of boron-doped and non-doped graphitic carbon foams is investigated by galvanostic cycling versus Na/Na at different electrical current densities, in glyme-based electrolytes which are known to allow the intercalation of the Na ions into graphite. The influence of materials composition and graphitic degree on battery parameters is firstly determined and further discussed by analyzing the mechanism of the electrochemical storage of Na ions into these materials which was found to occur through different combinations of pseudocapacitive intercalation and diffusion-controlled intercalation processes. In summary, the results of this study have demonstrated that graphitic carbon foams match a very acceptable capacity with excellent cycle stability as well as performance at high electrical current densities (up to ∼ 90 mAh g after 300 cycles at 1.9 A g with coulombic efficiency ∼ 100%) which make them suitable for sodium-ion battery applications. Overall, the increase of the interlayer spacing between the graphene layers and the presence of boron promote the pseudocapacitive intercalation which is responsible for the remarkable rate performance of these materials, whereas the improvement of diffusion-controlled intercalation capacity is mainly related to larger boron content.

[EN] Lithium-ion batteries are the most attractive and feasible alternative for the development of massive electrical energy storage systems to allow the implementation of renewable energy sources as well as the electric vehicle. Nevertheless, it is necessary to identify new eco-friendly electrode materials (active materials, conductive additives and binders) capable of improving the performance of the batteries without increasing the cost. Therefore, the Main Objective of this Thesis is to develop efficient anodes for lithium-ion batteries which increase the energy and power as well as the useful life of these devices, reducing the environmental impact associated with their manufacture, use and subsequent recycling. To achieve this goal, the work is organized in three activities that are related to the Specific Objectives set out. In a first activity, graphitic nanomaterials (graphite nanofibers) were prepared by heat treatment at high temperatures of carbon nanofibers produced in the catalytic decomposition of biogas, a renewable energy source. Graphite nanofibers with a highly-developed three-dimensional structure were used as anode active material for lithium-ion batteries. The electrochemical performance of these nanomaterials is comparable, or even superior at high-density currents, to that of oil-derived micrometric graphite, which is used on a large scale for lithium-ion batteries. The nanometric particle size reduces the diffusion time of the Li+ ions along the intercalation/deintercalation processes, allowing faster charge/discharge rates, thus making these graphite nanofibers potential candidates for anodes of high-power lithium-ion batteries. Afterwards, a series of hydrocolloids, more specifically, natural, safe and biodegradable biopolymers, among them sodium carboxymethyl cellulose, sodium alginate, xanthan gum and guar gum, were employed as an alternative to polyvinylidene difluoride, synthetic fluorinated polymer commonly used as binder in anodes fo

Carbon nanofibers with different microstructure and elemental composition that were produced in the catalytic decomposition of synthetic biogas mixtures, in a rotary-bed reactor using nickel and nickel-cobalt catalysts at 600 °C and 700 °C, were heat treated in the temperature interval 2600–2800 °C to explore their ability to graphitize. The influence of treatment temperature as well as carbon nanofibers composition, particularly metallic species, on the structural and textural properties of the materials prepared is discussed. Graphitic nanomaterials with great development of the three-dimensional structure (d002 ~ 0.3360 nm, Lc ~ 48 nm, La > 100 nm) and low porosity (SBET ~ 20 m2 g− 1) have been achieved. Because of the catalytic effect of silicon in the presence of inherent nickel and cobalt metals, more structurally ordered materials were obtained from the carbon nanofibers by adding silica. Based on the results of this work, the utilization of biogas-derived carbon nanofibers for the production of synthetic nanographite to be used in different applications, such as electrode material in energy storage devices in which both high degree of graphitic order and small surface area are required, appears feasible.

The electrochemical performance as potential anodes for lithium-ion batteries of graphitized biogas-derived carbon nanofibers (BCNFs) is investigated by galvanostatic cycling versus Li/Li+ at different electrical current densities. These graphitic nanomaterials have been prepared by high temperature treatment of carbon nanofibers produced in the catalytic decomposition of biogas. At low current density, they deliver specific capacities comparable to that of oil-derived micrometric graphite, the capacity retention values being mostly in the range 70-80% and cycling efficiency ∼ 100%. A clear tendency of the anode capacity to increase alongside the BCNFs crystal thickness was observed. Besides the degree of graphitic tri-dimensional structural order, the presence of loops between the adjacent edges planes on the graphene layers, the mesopore volume and the active surface area of the graphitized BCNFs were found to influence on battery reversible capacity, capacity retention along cycling and irreversible capacity. Furthermore, provided that the development of the crystalline structure is comparable, the graphitized BCNFs studied show better electrochemical rate performance than micrometric graphite. Therefore, this result can be associated with the nanometric particle size as well as the larger surface area of the BCNFs which, respectively, reduces the diffusion time of the lithium ions for the intercalation/de-intercalation processes, i.e. faster charge-discharge rate, and increases the contact area at the anode active material/electrolyte interface which may improve the Li+ ions access, i.e. charge transfer reaction.

The present invention relates to the production of synthetic graphite fibres of nanometric size using a carbon material from a renewable source, which is obtained together with a hydrogen-rich combustible gas in the process for recovery of biogas by means of catalytic breakdown. Said material, which consists of carbon nanofilaments is gradually transformed into nanofibres with a graphite structure by means of a thermal treatment in an inert atmosphere at temperatures which are no lower than 2400 ºC, in part due to the presence of metal residues that catalyse the process. Said synthesised carbon materials have high value added and many applications, including the use thereof as an anode in ion-lithium batteries, which are essential components of electronic devices such as mobile telephones or portable computers.

La presente invención se refiere a la producción de fibras de grafito sintético de tamaño nanométrico a partir de un material de carbono de origen renovable que se obtiene junto con un gas combustible rico en hidrógeno en el proceso de revalorización de biogás mediante descomposición catalítica. Este material que está constituido por nanofilamentos de carbono se transforma progresivamente en nanofibras con una estructura tipo grafito mediante tratamiento térmico en atmósfera inerte a temperaturas iguales o superiores a 2400ºC debido, en parte, a la presencia de residuos metálicos que catalizan el proceso. Estos materiales de carbono sintetizados poseen un alto valor añadido y numerosas aplicaciones, entre las que se incluyen su uso como ánodo en baterías de ión-litio, componentes fundamentales de dispositivos electrónicos, tales como teléfonos móviles u ordenadores portátiles.

La presente invención se refiere a la producción de fibras de grafito sintético de tamaño nanométrico a partir de un material de carbono de origen renovable que se obtiene junto con un gas combustible rico en hidrógeno en el proceso de revalorización de biogás mediante descomposición catalítica. Este material que está constituido por nanofilamentos de carbono se transforma progresivamente en nanofibras con una estructura tipo grafito mediante tratamiento térmico en atmósfera inerte a temperaturas iguales o superiores a 2400ºC debido, en parte, a la presencia de residuos metálicos que catalizan el proceso. Estos materiales de carbono sintetizados poseen un alto valor añadido y numerosas aplicaciones, entre las que se incluyen su uso como ánodo en baterías de ión-litio, componentes fundamentales de dispositivos electrónicos, tales como teléfonos móviles u ordenadores portátiles.

A series of expanded graphitic materials are prepared from two different precursors: micrometric synthetic graphite and graphitized carbon nanofibers, and tested as anodes for sodium-ion batteries. The materials preparation involves the oxidation of the precursors followed by partial thermal reduction. Overall, the expanded synthetic graphite materials show better electrochemical performance as anode than the expanded graphite nanofibers, providing higher specific capacity, leading to lower capacity losses in the first discharge-charge cycle and exhibiting outstanding cycling stability. Specific capacities of ∼150 mA h g−1 at 37 mA g−1 and ∼110 mA h g−1 at 100 mA g−1 are attained, and up to 50% of the initial capacity at 19 mA g−1 is kept at 372 mA g−1. Unexpectedly, higher capacity losses are measured for the nanostructured electrodes by progressively increasing the current density. These differences are attributed to the lower surface area and porosity of expanded synthetic graphite materials which favors the formation of thinner and more stable SEI, thus reducing the electrode resistance and enhancing the accessibility of Na+ ions to surface oxygen-containing functional groups with the consequent increase of the surface capacity which was found to be the main contribution to the total specific capacity.

In an attempt to find an adequate carbon material to achieve a successful reversible adsorption of Na+ ions, single layer graphene, is experimentally investigated in this work, for the first time, as anode for sodium-ion batteries. To this end, single layer graphene that was grown on copper foil by chemical vapor deposition was subjected to extended galvanostatic cycling and to cyclic voltammetry in the potential range of 0-2.8 V versus Na/Na+. Regardless of the current density and electrolyte formulation used, the amount of Na+ ions adsorbed/desorbed reversibly per surface area (specific reversible cell capacity) was very modest and comparable to that obtained with bare copper electrodes of reference, thus suggesting that the reversible capacity of the single layer graphene electrode is mostly due to the electrochemical response of the copper substrate. These experimental results clearly agree with recent theoretical calculations showing that the adsorption of Na+ ions on the surface of single layer graphene is energetically unfavourable unless that surface includes significant defects density.

The variety of methodologies used to determine the electrical conductivity of carbons makes it very difficult to compare samples and establish reference values. In this study, the electrical conductivity of a wide range of carbons was determined using two different methods: four-point probe and compression. Although the methodologies and the operating conditions are very different, linear correlations between the values measured by these two methods can be established for some of the materials studied. Only materials with a very high conductivity (graphite and carbon black) could not be correlated.

Different carbon materials with high electrical conductivity have been studied as electrocatalyst support for direct alcohol fuel cells (DAFCs). The aim of the work was to establish the influence of the support on the catalyst properties and to improve their efficiency in the fuel cell. Carbon nanofibers (CNFs), carbon nanocoils (CNCs) and ordered mesoporous carbons (gCMK-3) have been used for synthesizing platinum catalysts by the polyol method. Results have been compared with those obtained for a platinum catalyst supported on Vulcan XC-72R, prepared by the same method, and for the commercial Pt/C catalyst from E-TEK. It has been demonstrated that novel carbon supports could help to oxidize CO adsorbed on platinum particles more easily than the commercial carbon support and improve the alcohol oxidation reaction, both in terms of onset potential and current density. The catalyst supported on gCMK-3 carbon resulted to be the most effective in both the methanol and ethanol oxidation, which can be attributed to its ordered structure and high electrical conductivity. © 2013 Elsevier Ltd. All rights reserved.

La presente invención se refiere a un procedimiento para incrementar la conductividad eléctrica de un material de carbono mesoporoso ordenado (CMK-3) obtenido mediante la técnica de nanomoldeo, donde dicho procedimiento comprende tratar térmicamente en atmósfera inerte dicho material de carbono mesoporoso ordenado. Asimismo, es objeto de la invención el material obtenible a partir de dicho procedimiento, un procedimiento para la obtención de un electrocatalizador a partir de dicho material y su uso para la obtención de un ensamblaje membrana-electrodo.

Lithium-ion batteries are versatile, high performance and low cost energy storage systems. These batteries have turned into fundamental components for most of the portable electronic devices. The inherent attractive for lithium-ion batteries is the use of intercalation electrodes which can insert lithium ions in a reversible way inside their structure. Lithium-ion batteries use carbon materials, mainly, synthetic graphite as anode. The Final Objective of this Thesis is to use graphitic materials prepared from different precursors (anthracites, unburned carbon concentrates from coal combustion fly ashes and carbon nanofibers obtained in the catalytic decomposition of methane to produce hydrogen) as anodes in lithium-ion batteries. The graphitic materials were prepared by heating the precursors in the temperature interval 1800-2900 ºC. The materials were then characterized by determining their structural (degree of structural order and orientation of the graphitic domains), electrical (conductivity) and textural (surface area and porosity) properties. Subsequently, the performance of these graphitic materials as anodes in the lithium-ion batteries was evaluated by means the electrochemical parameters (reversible and irreversible capacity, ciclability and efficiency). Moreover, the relation between these parameters and the materials properties was also studied. Finally, a comparative study of electrochemical properties of the graphitic materials prepared in this work and those of synthetic graphites which are currently been employed as anodic materials for commercial lithium-ion batteries was carried out. In terms of reversible capacity, ciclability, irreversible capacity and efficiency of cycle, the battery performance by using as working electrodes the graphitic materials obtained from the unburned carbon concentrates and the carbon nanofibers, and the synthetic graphites of reference are absolutely comparable. Therefore, the application of these graphitic materials, Las baterías de ión-litio son sistemas de almacenamiento de energía de alto rendimiento, bajo coste y versátiles que se utilizan en múltiples aparatos portátiles. El atractivo inherente a una batería de ión-litio es la utilización de electrodos de intercalación que son capaces de insertar de forma reversible iones litio dentro de su estructura. Estas baterías utilizan como ánodos materiales de carbono, generalmente, grafitos sintéticos. El Objetivo Final de esta Tesis Doctoral es utilizar materiales grafíticos preparados a partir de diferentes precursores (antracitas, concentrados de inquemados de cenizas volantes procedentes de la combustión de carbón y nanofibras de carbono generadas en la descomposición catalítica de gas metano para la producción de hidrógeno) como ánodos en baterías de ión-litio. Todos ellos fueron grafitizados en el intervalo de temperaturas 1800-2900 ºC. Los materiales grafíticos preparados fueron caracterizados, determinándose sus propiedades estructurales (grado de orden estructural y de orientación de los microcristales), texturales (área superficial y porosidad) y eléctricas (conductividad), todas ellas relacionadas con su comportamiento como ánodo en las baterías de ión-litio que se evaluó en función de los parámetros electroquímicos de la batería (capacidad reversible e irreversible, ciclabilidad y eficacia). Además, se estudió la relación entre dichos parámetros y las propiedades de los materiales. Finalmente, se llevó a cabo un estudio comparativo de las propiedades electroquímicas de los materiales grafíticos con las correspondientes a grafitos sintéticos que están siendo utilizados como ánodos en baterías de ión-litio comerciales. Las prestaciones de las baterías, en cuanto a capacidad reversible, ciclabilidad, capacidad irreversible y eficacia del ciclado, empleando como electrodos de trabajo materiales grafíticos preparados a partir de los concentrados de inquemados de cenizas volantes y de las nanofibras de carbono, y grafitos sin