Carbon Anode Materials Research Articles

A tin(ii) sulfide–carbon anode material based on combined conversion and alloying reactions for sodium-ion batteries

SnS–C nanocomposite can deliver a high capacity (568 mA h g−1) for Na storage based on the conversion and alloying reaction.

The Effect of Ball Milling on the Electrochemical Behavior of Silicon Composite Electrode

Silicon material possesses the highest theoretic capacity (4200mAh/g, ten times of the capacity of commercialized carbon anode materials) of all known anode materials for lithium ion batteries and thus receives lots of attention to date. Silicon-containing composite electrode for lithium ion batteries was prepared by high-energy ball milling process. The microstructure and morphology of silicon electrode was investigated in detail. The effect of the structure transformation of the electrode by ball milling on the electrochemical behavior was systematically analyzed. Electrode precursors after a mediate ball milling time of 45min is beneficial to get a better cycling performance, due to the well distributed and less destroy of Carboxyl Methyl Cellulose (CMC). Weak lithium insertion into CMC occurs unavoidably in the charging-discharging process of the composite electrodes, which should be the main reason for the sudden disability of electrode. The electrochemical properties can get a dramatic enhancement within voltage window of 0.02-1.5V. Excellent cyclability with high capacity retention above 1800mAh/g after 40 cycles could be gained by controlling the ball-milling time and the voltage windows. It might be a feasible way to obtain satisfactory cyclability for high capacity anode materials.

Synthesis and characterisation of sponge-like carbon anode materials for lithium ion batteries

Micro-sized carbon material with a unique sponge-like morphology has been fabricated by hydrothermal method coordinating etching process. When evaluate its electrochemical properties in lithium ion batteries, the sponge-like carbon structure exhibits very high specific capacity (around 1175mAhg−1 after 140th cycle tested at the charge/discharge current density of 200mAg−1) and wonderful cyclability (about 117% retention is available when cycled back from very high current density of 800mAg−1) during the galvanostatic cycling, indicating it may be a promising candidate as anode material for Li-ion batteries.

Post Oxygen Treatment Characteristics of Coke as an Anode Material for Li-Ion Batteries

The effect of a oxygen treatment on the electrochemical characteristics of a soft carbon anode material for Li-ion batteries was investigated. After a coke carbonization process at 1000 degrees C in an argon atmosphere, the samples were treated under a flow of oxygen gas to obtain a mild oxidation effect. After this oxygen treatment, the coke samples exhibited an improved initial coulombic efficiency and cycle performance as compared to the carbonized sample. High-resolution transmission electron microscopy revealed that the carbonized cokes consisted of disordered and nanosized graphene layers and the surface of the modified carbon was significantly changed after the treatment. The chemical state of the cokes was analyzed using X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The enhanced electrochemical properties of the surface modified cokes could be attributed to the mild oxidation effect induced by the oxygen treatment. The mild oxidation process could have led to the elimination of surface imperfections and the reinforcement of a solid electrolyte interphase film, which resulted in the improved electrochemical characteristics.

Electricity production with living plants on a green roof: environmental performance of the plant‐microbial fuel cell

AbstractSeveral renewable and (claimed) sustainable energy sources have been introduced into the market during the last century in an attempt to battle pollution from fossil fuels. Especially biomass energy technologies have been under debate for their sustainability. A new biomass energy technology was introduced in 2008: the plant‐microbial fuel cell (P‐MFC). In this system, electricity can be generated with living plants and thus bioelectricity and biomass production can be combined on the same surface. A green roof producing electricity with a P‐MFC could be an interesting combination. P‐MFC technology is nearing implementation in the market and therefore we assessed the environmental performance of the system with an early stage life cycle assessment (LCA). The environmental performance of the P‐MFC is currently worse than that of conventional electricity production technologies. This is mainly due to the limited power output of the P‐MFC and the materials presently used in the P‐MFC. Granular activated carbon (anode material), gold wires (current collectors), and Teflon‐coated copper wires (connecting anode and cathode) have the largest impact on environmental performance. Use of these materials needs to be reduced or avoided and alternatives need to be sought. Increasing power output and deriving co‐products from the P‐MFC will increase environmental performance of the P‐MFC. At this stage it is too early to compare the P‐MFC with other (renewable) energy technologies since the P‐MFC is still under development. © 2013 Society of Chemical Industry and John Wiley & Sons, Ltd

Preparation of High Performance Silicon/Carbon Anode Materials for Lithium Ion Battery by High Energy Ball Milling

Silicon/carbon anode materials of different proportions for lithium ion battery were prepared by high energy ball milling. The composites were characterized using X-ray diffraction (XRD), and scanning electron microscope (SEM). The electrochemical performance of the composites was tested by means of galvanostatic testing system. The results indicated that the initial reversible capacity reached to 2162 mAh•g-1, which was much larger than the theoretical capacity of carbon negative materials at the ratio of 6:4 (Si: C). The capacity maintained to 1042 mAh•g-1 after 50 cycles. High capacity and good cycle property of the Si/C composites revealed that they were potential to take the place of the traditional carbon anode materials.

Nano-MgO Templated Mesoporous Carbon as Anode Material for Li-Ion Batteries

The mesoporous carbon material is prepared by using phenolic resin and MgO nanoparticles as precursor and template, respecitively. The microstructure of the carbon is characterized by N2 adsorption/desorption, Hg porosimetry and field-emission scanning electron microscopy(SEM). The electrochemical performances of the carbon as anode material for lithium ion batteries are evaluated by galvanostatic charge/discharge and cyclic voltammetry tests. It is shown that the BET surface area of the mesoporous carbon material can reach 1024 m2/g. Its pore size distributes between 20 and 50nm. The mesoporous carbon possesses high first discharge capacity and good cycling performance. It is believed that it is an effective method to use nano-MgO particle as template to prepare mesoporous carbon anode materials for lithium ion batteries.

Carbon Nanomaterials with Different Dimensions for Anode of Li-Ion Batteries

In this article, the structure and morphology of the carbon anode materials with different dimensions have been characterized through SEM and TEM. The performances of electrochemical intercalation and deintercalation of lithium-ions have been studied. The results show that graphene as the two dimensional nanomaterials possess more advantages of microstructure and better Li-ions intercalation performances than carbon nanotubes (CNTs) and graphite. The superior abilities of Li-ions intercalation and deintercalation are attributed to increasing lithium storage space, decreasing Li diffusion distance, and higher specific surface area for Li-ions.

High-rate charging performance using high-capacity carbon nanofilms coated on alumina nanoparticles for lithium ion battery anode

Carbon nanofilms of less than 20nm in thickness were prepared on alumina nanoparticles by pyrolysis of a citric acid precursor to test high-rate charging anode material in lithium ion battery. The electrochemical reaction mechanism of the anode was investigated by changing the voltage from 1.5V to 0.01V with a counter Li metal electrode. The specific capacity of ∼20nm thick carbon nanofilm was 2180mAhg−1, much larger than those of conventional carbon anode materials. The high capacity of carbon nanofilm was attributed to adsorption of Li ion multi-layers on carbon nanofilm surfaces and adsorption on defects, functional groups or micropores of amorphous carbon, in addition to Li intercalation in hard carbons. Very short diffusion path length from ∼20nm ultrathin film (∼20nm) with high specific capacitance was mainly responsible for achieving high-rate charging performance while maintaining reasonable charging capacity compared to soft carbon. The fabricated anode with ∼20nm thick carbon film on alumina nanoparticles improved the specific charging capacity by 9.4% at 1C rate and 8.3% at 10C rate compared to conventional soft carbon.

An activated microporous carbon prepared from phenol-melamine-formaldehyde resin for lithium ion battery anode

Microporous carbon anode materials were prepared from phenol-melamine-formaldehyde resin by ZnCl2 and KOH activation. The physicochemical properties of the obtained carbon materials were characterized by scanning electron microscope, X-ray diffraction, Brunauer–Emmett–Teller, and elemental analysis. The electrochemical properties of the microporous carbon as anode materials in lithium ion secondary batteries were evaluated. At a current density of 100mAg−1, the carbon without activation shows a first discharge capacity of 515mAhg−1. After activation, the capacity improved obviously. The first discharge capacity of the carbon prepared by ZnCl2 and KOH activation was 1010 and 2085mAhg−1, respectively. The reversible capacity of the carbon prepared by KOH activation was still as high as 717mAhg−1 after 20 cycles, which was much better than that activated by ZnCl2. These results demonstrated that it may be a promising candidate as an anode material for lithium ion secondary batteries.

Preparation of Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> as Anode Material by Solution Method

Lithium titanate was synthesized by liquid method and lithium hydroxide was used as raw materials. During the synthesis process, the value of n(Li)/n(Ti), the calcination temperature and calcination time were investigated. The experiment results show that when the molar ratio of Li/Ti is 0.85 and the lithium titanate was heat-treated at 750 °C for 8 h, we could get the target product which showed the best electrochemical performances. it was considered to be an excellent electrode materials for lithium-ion battery, and an ideal alternative to carbon anode materials.

A novel activated nitrogen-containing carbon anode material for lithium secondary batteries

A novel activated nitrogen-containing carbon anode material has been prepared by carbonization and activation of phenol-melamine-formaldehyde resin which is synthesized by the condensation polymerization method. The physicochemical properties of the carbon were characterized by scanning electron microscope, X-ray diffraction, Raman spectra, Brunauer–Emmett–Teller, elemental analysis and X-ray photoelectron spectroscopy measurement. Lithium storage performances have been analyzed by galvanostatic charge/discharge and cycle performance. The carbonization sample shows a first discharge capacity of 515 mAh g −1. After activation, the first discharge capacity is up to 917 mAh g −1, the reversible capacity is still as high as 251 mAh g − 1 after 20 cycles. It may be a promising candidate as anode material for lithium secondary batteries.

Fracture and physical properties of carbon anodes for the aluminum reduction cell

An experimental study with total 504 specimens has been carried out to investigate the fracture and physical properties of the carbon anode materials. The specimens were sampled from anodes produced with machined stub holes. From normal-and Weibull analysis the fracture toughness and the tensile strength showed a clear temperature dependency and orthotropic behavior. It has been found that both the fracture toughness and tensile strength increases with the temperature and are larger for the specimens directed in the horizontal direction than in the vertical direction. The variation in the tensile strength within an anode decreased with the temperature but the variation in the fracture strain increased. The tensile strain appears to be only dependent on the temperature and insensitive to the routine anode properties of the anode material. A multivariate linear regression analyses of the fracture toughness and tensile strength has been conducted and a typical correlation of R 2 = 0.5 ( R is the Coefficient of Determination) to the measured routine anode properties was found. The thermal expansion coefficient is also larger in the vertical anode direction which makes the crack initiation more sensitive to temperatures. The orthotropic studies also showed that the air permeability has a tendency to be larger in the horizontal direction in the upper part of the anode which can induce unnecessary burning from the anode sides. The influence of the processing parameters in the paste plant and baking furnace has not been presented in this paper.

A hierarchical porous carbon material for high power, lithium ion batteries

We synthesize a carbon anode material with unique nanostructure for high power lithium ion batteries. The carbon material is composed of numerous clusters of carbon nanobeads, and shows a macro-meso-micro hierarchical porous structure. This unique nanostructure appears to facilitate the rapid transfer of lithium ions and a very large ion adsorption. It exhibits a reversible capacity of 407.4 mAh g −1 and its rate performance is drastically improved in comparison with that of the commercial graphite. The unique structure enables the anode to combine the advantages of both lithium ion batteries and electrochemical double layer capacitors, resulting in the good electrochemical performance.

Nano-CaCO3 templated mesoporous carbon as anode material for Li-ion batteries

Mesoporous hard carbon is obtained by pyrolyzing a mixture of sucrose and nanoscaled calcium carbonate (CaCO3) particles. The microstructure of the carbon is characterized by N2 adsorption/desorption, Hg porosimetry, field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and Raman spectroscopy. The electrochemical performances of the carbon as an anode material for lithium ion batteries are evaluated by galvanostatic charge/discharge and cyclic voltammetry tests. It is shown that this mesoporous carbon possesses high capacity, good cycling performance and rate capability, indicating the promising application of nano-CaCO3 particle as template in massive fabrication of mesoporous carbon anode materials for lithium ion batteries.

Consideration of carbon structure effect on thermal stability of carbon anode for Li ion rechargeable batteries

Thermal stability of carbon structure anode materials for Li-ion rechargeable batteries is studied with the consideration to carbon physical property and structure. Differential scanning calorimeter (DSC) thermal test shows that the thermal decomposition of fully delithiated carbon anode materials at an elevated temperature to about 230 °C generate weak exothermic heat and the heat amount is in the linear relation to their carbon specific surface area. Meanwhile, the fully lithiated carbon anode materials generates much stronger exothermic heat in the same temperature range and the heat amount is largely differed with their carbon structure. X-ray diffraction (XRD) and DSC tests reveal that intercalated lithium inside the carbon structure is involved in thermal reactions with aqueous liquid electrolyte and the evolved specific heat per lithium mol is largely differed with the carbon structure.

Room-temperature sodium-ion batteries: Improving the rate capability of carbon anode materials by templating strategies

Current kinetic limitations of carbon anode materials in sodium-ion batteries can be effectively tackled by using tailor-made carbon materials with hierarchical porosity prepared via the nanocasting route. Capacities exceeding 100 mA h g−1 at C/5 are found while exhibiting excellent rate capability and reasonable cycle life.

KINETIC TRANSFORMATION OF SPINEL TYPE LiMnLiMn<sub>2</sub>O<sub>4</sub> INTO TUNNEL TYPE MnO<sub>2</sub>

Lithiated phase LiMn2O4 is a potential cathode material for high-energy batteries because it can be used in conjunction with suitable carbon anode materials to produce so-called lithium ion cells. The kinetic transformation of LiMn2O4 into manganese dioxide (MnO2) in sulphuric acid has been studied. It is assumed that the conversion of LiMn2O4 into R-MnO2 is a first order autocatalytic reaction. The transformation actually proceeds through the spinel l-MnO2 as an intermediate species which is then converted into gamma phase of manganese dioxide. In this reaction LiMn2O4 whose structure spinel type, which is packing between tetrahedral coordination and octahedral coordination, is converted to form octahedral tunnel structure of manganese dioxide, which is probably regarded as a reconstructive octahedral-coordination transformation. Therefore, it is a desire to investigate the transformation of manganese oxides in solid state chemistry by analysing XRD powder patterns. Due to the reactions involving solids, concentrations of reactant and product are approached with the expression of peak areas. Keywords: high-energy battery, lithium ion cells, kinetic transformation

Development of efficient carbon anode material for a high-power and long-life lithium ion battery

The Li ion battery with high power and long life is required for the hybrid electronic vehicle. A new carbon anode material called “ICOKE” has been prepared by the graphitization of coke at ca. 2000 °C and is shown to have excellent pulse charge/discharge characteristics and long cycle performance. The charge/discharge reaction mechanism of ICOKE was investigated in detail based on the result of cyclic voltammetry and X-ray diffraction profile change of ICOKE before and after charging. As a result, it was found that Li-intercalation reaction to ICOKE proceeds without forming higher stage compounds and the 1st and the 2nd stage compounds are directly formed.

Carbon anode material formed from template molecules occluded in a magnesium-substituted aluminophosphate

A new doped carbon material has been prepared from a magnesium-substituted aluminophosphate with occluded organic molecules. The carbon material is mainly composed of microcrystalline graphite and amorphous carbon, and a certain amount of H, N and Al also exist in the material. This carbon material is useful as anode material for lithium secondary batteries. After 15 cycling tests, the carbon material retains a reinsertion capacity of 384mAhg−1 at a current density of 10mAg−1. Even at a high current density of 100mAg−1, the reversible capacity of the carbon material is 185mAhg−1 after 20 cycling tests.