Abstract: The lithium storage properties of graphene nanosheet (GNS) materials as high capacity anode materials for rechargeable lithium secondary batteries (LIB) were investigated. Graphite is a practical anode material used for LIB, because of its capability for reversible lithium ion intercalation in the layered crystals, and the structural similarities of GNS to graphite may provide another type of intercalation anode compound. While the accommodation of lithium in these layered compounds is influenced by the layer spacing between the graphene nanosheets, control of the intergraphene sheet distance through interacting molecules such as carbon nanotubes (CNT) or fullerenes (C60) might be crucial for enhancement of the storage capacity. The specific capacity of GNS was found to be 540 mAh/g, which is much larger than that of graphite, and this was increased up to 730 mAh/g and 784 mAh/g, respectively, by the incorporation of macromolecules of CNT and C60 to the GNS.

Abstract: Carbon-coated Fe3O4 nanospindles are synthesized by partial reduction of monodispersed hematite nanospindles with carbon coatings, and investigated with scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and electrochemical experiments. The Fe3O4C nanospindles show high reversible capacity (∼745 mA h g−1 at C/5 and ∼600 mA h g−1 at C/2), high coulombic efficiency in the first cycle, as well as significantly enhanced cycling performance and high rate capability compared with bare hematite spindles and commercial magnetite particles. The improvements can be attributed to the uniform and continuous carbon coating layers, which have several functions, including: i) maintaining the integrity of particles, ii) increasing the electronic conductivity of electrodes leading to the formation of uniform and thin solid electrolyte interphase (SEI) films on the surface, and iii) stabilizing the as-formed SEI films. The results give clear evidence of the utility of carbon coatings to improve the electrochemical performance of nanostructured transition metal oxides as superior anode materials for lithium-ion batteries.

Abstract: The present invention, in one aspect, relates to a solar cell In one embodiment, the solar cell includes an anode, a p-type semiconductor layer formed on the anode, and an active organic layer formed on the p-type semiconductor layer, where the active organic layer has an electron-donating organic material and an electron-accepting organic material

Abstract: Lithium batteries, as a main power source or back-up power source for mobile communication devices, portable electronic devices and the like, have attracted much attention in the scientific and industrial fields due to their high electromotive force andhigh energy density. Tomeet the demand for batteries having higher energy density and improved cycle characteristics, in recent years, a great deal of attempt has been made to develop new electrode materials or design new structures of electrode materials. For anode materials, among them, some elementary substances such as silicon (Si), germanium (Ge), or tin (Sn) provide promising alternative to conventional carbonaceous anode active materials, because they are capable of alloying with more lithium and thus leading to the extreme high initial capacity density. For example, metallic tin has recently been widely concerned as one of the promising anode materials for lithium batteries due to the following reasons. Firstly, its theoretical specific capacity (Li4.4Sn, 992mAhg ) ismuchhigher than that of conventional graphite (LiC6, 372 mA h g ). Secondly, the tin anode has higher operating voltage than graphite, so it is less reactive and the safety of batteries during rapid charge/discharge cycle could be improved. Furthermore, a significant advantage of metallic tin over graphite is that it does not encounter solvent intercalationwhich causes irreversible charge losses at all. Unfortunately, the biggest challenge for employing metallic tin as applicable active anode materials is that it is suffering from huge volume variation during Liþ insertion/extraction cycle, which leads to pulverization of the electrode and very rapid capacity decay. Without appropriate structure design, the tin electrode typically fails after only a few discharge/charge cycles. It is therefore very desirable to design a new tinbased materials mainly composed of metallic tin with high specific capacity as well as good cycle performance. Some metal/oxides and carbon nanocomposites have been reported with high capacity and capacity retention when used as anodematerials, because the carbon shell has itself good electronic conductivity and prevents the aggregation of active materials, and especially thin carbon shell has good elasticity to effectively accommodate the strain of volume change during Liþ insertion/extraction. Very recently, tin-encapsulated spherical hollow carbon was synthesized by the pyrolysis of tin-containing organic precursors have exhibited higher capacity and better cycle performance than unencapsulated mixture materials, in which the content of tin active substance was only 24 wt%. Nanostructured tin dispersed in a carbonmatrix and carbon-encapsulated hollow tin nanopartides were also reported as superior anode materials. These studies showed that both coating tin nanomaterials with carbon layer and dispersing tin nanoparticles in carbon matrix are effective to improve their electrochemical properties in lithium ion batteries. It is obvious that thehigher content of and smaller size of tin, as well as the thinner carbon coating will greatly contribute to the further enhancement of material performance since the lithium storage density in tin ismuch higher than that in carbon. Meanwhile, this tin-based anode material has to be designed to own enough void volume to compensate the volume expansion during Liþ insertion, which is important to improve its cycle performance. In the presentwork,we therefore designed anewapproach to synthesize tin nanoparticles encapsulated elastic hollow carbon spheres (TNHCs) with uniform size, in which multiple tin nanoparticles with a diameter of less than 100 nm were encapsulated inone thin hollow carbon spherewith a thickness of only about 20 nm, thus leading to both the content of Sn up to over 70% by weight and the void volume in carbon shell as high as about 70–80%by volume. This void volume and the elasticity of thin carbon spherical shell efficiently accommodate the volume change of tin nanoparticles due to theLi-Sn alloying-dealloying reactions, and thus prevent the pulverization of electrode. As a result, this type of tin-based nanocomposites have very high specific capacity of >800 mA h g 1 in the initial 10 cycles, and >550mAh g 1 after the 100th cycle, as well as excellent cycling [*] Prof. L.-J. Wan, W.-M. Zhang, Dr. J.-S. Hu, Prof. Y.-G. Guo, S.-F. Zheng, L.-S. Zhong, Prof. W.-G. Song Beijing National Laboratory for Molecular Sciences Institute of Chemistry Chinese Academy of Sciences (CAS) Beijing 100080 (P.R. China) E-mail: wanlijun@iccas.ac.cn

Abstract: Rechargeable lithium-ion batteries are essential to portable electronic devices. Owing to the rapid development of such equipment there is an increasing demand for lithium-ion batteries with high energy density and long cycle life. For high energy density, the electrode materials in the lithium-ion batteries must possess high specific storage capacity and coulombic efficiency. Graphite and LiCoO2 are normally used and have high coulombic efficiencies (typically >90%) but rather low capacities (372 and 145 mAhg, respectively).[1–5] Various anode materials with improved storage capacity and thermal stability have been proposed for lithium-ion batteries in the last decade. Among these, silicon has attracted great interest as a candidate to replace commercial graphite materials owing to its numerous appealing features: it has the highest theoretical capacity (Li4.4Sio4200 mAhg) of all known materials, and is abundant, inexpensive, and safer than graphite (it shows a slightly higher voltage plateau than that of graphite as shown in Figure S1, and lithiated silicon is more stable in typical electrolytes than lithiated graphite[6]).

Abstract: Ge nanowire electrodes fabricated by using vapor−liquid−solid growth on metallic current collector substrates were found to have good performance during cycling with Li. An initial discharge capacity of 1141 mA·h/g was found to be stable over 20 cycles at the C/20 rate. High power rates were also observed up to 2C with Coulombic efficiency > 99%. Structural characterization revealed that the Ge nanowires remain intact and connected to the current collector after cycling. Nanowires connected directly to the current collector have facile strain relaxation and material durability, short Li diffusion distances, and good electronic conduction. Thus, Ge nanowire anodes are promising candidates for the development of high-energy-density lithium batteries.

Abstract: Silicon has been investigated for use as a next-generation, high-capacity anode material as its theoretical lithium capacity of approximately 4140 mAhg 1 (ca. Li4.4Si) is eleven times higher than the capacity of graphite (ca. 372 mAhg ), which is currently used as an anode material. In spite of the high capacity of silicon, severe particle pulverization can be triggered by a large volume change (> 300%) during lithium alloying (to form LixSi) and de-alloying (to reform Si), which results in electrically disconnected smaller particles. These disconnected particles cause a rapid decrease in cycling stability. Intense studies have focused on reducing this volume change by using composites with an inactive carbon phase to prevent the aggregation of particle growth and to act as electrically connecting media between anode particles and the current collector when the particle is pulverized. However, these methods lead to a decrease in the charge capacity to less than 1500 mAhg 1 after dozens of cycles. On the other hand, control of the volume change by control of the morphology of the Si has very rarely been reported. Chan et al. have reported Si nanowires that showed a reversible capacity of approximately 2900 mAhg 1 at a rate of 0.05 C, which were grown on a metallic current collector. However, the capacity retention at a 2 C rate was less than 50% of the initial capacity. Ma et al. reported a first-charge capacity of 3952 mAhg 1 for nestlike Si particles, but the capacity retention of the particles was 36% between 1.6 V and 0.02 V at a rate of 0.5 C after 50 cycles. Recently, Liu and co-workers demonstrated that 3Dmetal foam structures of Cu and Sn fabricated by using an electrochemical deposition process exhibited not only fast transport of lithium ions through the electrolyte and the electrode, but also rapid electrochemical reactions, which resulted in a high performance anode with a superior rate capability. For instance, a Cu6Sn5 alloy showed a 45% capacity retention at a 20 C cycling rate, but, because of a very thick pore wall (> 100 mm), capacity fade was pronounced after 40 cycles. To date, there have been no reports of the synthesis of 3D porous Si particles, with the exception of those from the magnesiothermic reduction method. Using this method, threedimensional silica microassemblies were formed into microporous silicon replicas in a sealed steel ampoule at 650 8C by the following reaction: 2Mg + SiO2 (s)!2MgO (s) + Si (s). Herein, we report a versatile synthetic method for the formation of 3D porous bulk Si particles by the thermal annealing and etching of physical composites obtained from butyl-capped Si gels and SiO2 nanoparticles at 900 8C under an Ar atmosphere. Complete etching of the SiO2 from the SiO2/carbon-coated Si (c-Si) composite results in the retention of the remaining c-Si as a highly porous but interconnected structure, thus preserving the starting morphology. A thin pore-wall size of approximately 40 nm can accommodate large strains without pulverization, even after 100 cycles, and a maintained charge capacity of greater than 2800 mAhg 1 at a rate of 1 C (= 2000 mAhg ). SEM images of the SiO2/c-Si composites etched in HF (1m) for 2 h show that the Si particles retained their threedimensional morphology and show that the Si particles have many voids, like an “octopus foot” (Figure 1a–d). Because

Abstract: Hydrogen gas can be produced by electrohydrogenesis in microbial electrolysis cells (MECs) at greater yields than fermentation and at greater energy efficiencies than water electrolysis. It has been assumed that a membrane is needed in an MEC to avoid hydrogen losses due to bacterial consumption of the product gas. However, high cathodic hydrogen recoveries (78 ± 1% to 96 ± 1%) were achieved in an MEC despite the absence of a membrane between the electrodes (applied voltages of 0.3 < Eap < 0.8 V; 7.5 mS/cm solution conductivity). Through the use of a membrane-less system, a graphite fiber brush anode, and close electrode spacing, hydrogen production rates reached a maximum of 3.12 ± 0.02 m3 H2/m3 reactor per day (292 ± 1 A/m3) at an applied voltage of Eap = 0.8 V. This production rate is more than double that obtained in previous MEC studies. The energy efficiency relative to the electrical input decreased with applied voltage from 406 ± 6% (Eap = 0.3 V) to 194 ± 2% (Eap = 0.8 V). Overall energy efficienc...

Abstract: Identifying the limiting factors in a microbial fuel cell (MFC) system requires qualifying the contribution of each component of an MFC to internal resistance. In this study, a new method was developed to calculate the internal resistance distribution of an MFC. Experiments were conducted to identify the limiting factors in single-chamber MFCs by varying the anode surface areas, cathode surface areas, and phosphate buffer concentrations. For the MFCs with equally sized electrodes (7 cm2) and 200 mM phosphate buffer, the anode contributed just 5.4% of the internal resistance, while the cathode and the electrolyte each contributed 47.3%, indicating that the anode was not the limiting factor in power generation. The limitation of the cathode was further revealed by the 780% higher area-specific resistance (284.4 Ω cm2) than the 32.3 Ω cm2 of the anode. The electrolyte limitation was also evidenced by the greatly increased contribution of electrolyte in internal resistance from 47.3 to 78.2% when the concentr...

Abstract: Summary It has been previously noted that mixed communities typically produce more power in microbial fuel cells than pure cultures. If true, this has important implications for the design of microbial fuel cells and for studying the process of electron transfer on anode biofilms. To further evaluate this, Geobacter sulfurreducens was grown with acetate as fuel in a continuous flow ‘ministack’ system in which the carbon cloth anode and cathode were positioned in close proximity, and the cation-selective membrane surface area was maximized in order to overcome some of the electrochemical limitations that were inherent in fuel cells previously employed for the study of pure cultures. Reducing the size of the anode in order to eliminate cathode limitation resulted in maximum current and power densities per m 2

Abstract: valuesoriginatefromthelossofchargecarriersthroughleakagepathsincluding pinholes in the films and the recombination andtrapping of the carriers during their transit through the cell,leading to a decrease in device performance.Modification of electrodes has been commonly employed toimprove the contact between the active organic layer andelectrodes. At the indium tin oxide (ITO) anode side, a thinbuffer layer of a conductive polymer, poly(3,4-ethylene-dioxylene thiophene):poly(styrene sulfonic acid) (PED-OT:PSS), is often used to increase the work-function of ITOfor effective hole collection.

Abstract: The impedance of anode-supported single cells [Ni/8 yttria-stabilized zirconia (YSZ) anode; La 0.58 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ cathode; 8YSZ electrolyte; area 1 cm 2 ] was characterized in a broad measuring range of temperature and air/fuel gas composition. The data has been analyzed by calculating the distribution function of relaxation times (DRTs). DRT computations enabled us to separate five different loss mechanisms occurring inside the cathode and anode without the need of an equivalent circuit. Two processes exhibit a systematic dependency on changes in the oxygen partial pressure of the cathode gas and thus can be attributed to diffusional and electrochemical losses on the cathode side. The remaining three processes are very sensitive to changes in the fuel gas but are not affected by variations of the cathode gas. These resistances are classified as a gas diffusion polarization within the anode-substrate and as an electro-oxidation reaction at the triple-phase boundary, respectively.

Abstract: Mesoporous Si@carbon core-shell nanowires with a diameter of approximately 6.5 nm were prepared for a lithium battery anode material using a SBA-15 template. As-synthesized nanowires demonstrated excellent first charge capacity of 3163 mA h/g with a Coulombic efficiency of 86% at a rate of 0.2 C (600 mA/g) between 1.5 and 0 V in coin-type half-cells. Moreover, the capacity retention after 80 cycles was 87% and the rate capability at 2 C (6000 mA/g) was 78% the capacity at 0.2 C.

Abstract: Anode-respiring bacteria (ARB) in a biofilm anode carry out an oxidation half-reaction of organic matter, producing an electrical current from renewable biomass, including wastes. At the same time, ARB produce protons, usually one proton for every electron. Our study shows how current density generated by an acclimated ARB biofilm was limited by proton transport out of the biofilm. We determined that, at high current densities, protons were mainly transported out of the biofilm by protonating the conjugate base of the buffer system; the maximum current generation was directly related to the transport of the buffer, mainly by diffusion, into and out of the biofilm. With non-limiting acetate concentrations, the current density increased with higher buffer concentrations, going from 2.21 +/- 0.02 A m(-2) with 12.5-mM phosphate buffer medium to 9.3 +/- 0.4 A m(-2) using a 100-mM phosphate buffer at a constant anode potential of E(anode) = -0.35 V versus Ag/AgCl. Increasing the concentration of sodium chloride in the medium (0-100 mM) increased current density by only 15%, indicating that ion migration was not as important as diffusion of phosphate inside the biofilm. The current density also varied strongly with medium pH as a result of the buffer speciation: The current density was 10.0 +/- 0.8 A m(-2) at pH 8, and the pH giving one-half the maximum rate was 6.5. A j-V curve analysis using 100 mM phosphate buffer showed a maximum current density of 11.5 +/- 0.9 A m(-2) and half-saturation potential of -0.414 V versus Ag/AgCl, a value that deviated only slightly from the standard acetate potential, resulting in small anode-potential losses. We discuss the implications of the proton-transport limitation in the field of microbial fuel cells and microbial electrolytic cells.

Abstract: This work is focused on the comparative analysis of electrochemical and transport properties in the major families of cathode and anode compositions for intermediate-temperature solid oxide fuel cells (SOFCs) and materials science-related factors affecting electrode performance. The first part presents a brief overview of the electrochemical and chemical reactions in SOFCs, specific rate-determining steps of the electrode processes, solid oxide electrolyte ceramics, and effects of partial oxygen ionic and electronic conductivities in the SOFC components. The aspects associated with materials compatibility, thermal expansion, stability, and electrocatalytic behavior are also briefly discussed. Primary attention is centered on the experimental data and approaches reported during the last 10–15 years, reflecting the main challenges in the field of materials development for the ceramic fuel cells.

Abstract: Large-area, wafer-scale silicon nanowire arrays prepared by metal-induced chemical etching are shown as promising scalable anode materials for rechargeable lithium battery. In addition to being low cost, large area, and easy to prepare, the electroless-etched silicon nanowires (SiNWs) have good conductivity and nanometer-scale rough surfaces; both features facilitate charge transport and insertion/extraction of Li ions. The electroless-etched SiNWs anode showed larger charge capacity and longer cycling stability than the conventional planar-polished Si wafer.

Abstract: The binder's influence on the cycling stability of high-energy anodes for lithium-ion batteries is demonstrated. Varying the binder's nature strongly influences the composite electrode's performance on deep charging/discharging. If sodium-carboxymethylcellulose is used as binding agent, then a chemical bond between binder and silicon particles can be detected (attenuated total reflection-Fourier transform infrared spectroscopy). Consequently, a reaction mechanism that describes a condensation reaction between the binder and the silicon particles is verbalized. It is shown that, not necessarily the binder's physical flexibility, but its chemical interaction with the active masses is the major claim leading to long-lasting reversible lithium uptake/release.

Abstract: Proton exchange membranes (PEMs) are one of the most important components in microbial fuel cells (MFCs), since PEMs physically separate the anode and cathode compartments while allowing protons to transport to the cathode in order to sustain an electrical current. The Nafion 117 membrane used in this study is generally regarded as having excellent proton conductivity, though many problems for its application in MFCs remain. We investigated problems associated with Nafion including: oxygen leakage from cathode to anode, substrate loss, cation transport and accumulation rather than protons, and biofouling. It was found that Nafion was quite permeable to oxygen. The oxygen mass transfer coefficient (KO) and the oxygen diffusion coefficient (DO) for Nafion was estimated as KO = 2.80 × 10−4 cm/s and DO = 5.35 × 10−6 cm2/s, respectively when a 50 mM phosphate buffer was used as the catholyte. The MFC with distilled water instead of phosphate buffer showed similar values (KO = 2.77 × 10−4 cm/s, DO = 5.27 × 10−6...

Abstract: A unique nanostructured polyaniline (PANI)/mesoporous TiO(2) composite was synthesized and explored as an anode in Escherichia coli microbial fuel cells (MFCs). The results of X-ray diffraction, morphology, and nitrogen adsorption-desorption studies demonstrate a networked nanostructure with uniform nanopore distribution and high specific surface area of the composite. The composite MFC anode was fabricated and its catalytic behavior investigated. Optimization of the anode shows that the composite with 30 wt % PANI gives the best bio- and electrocatalytic performance. A possible mechanism to explain the excellent performance is proposed. In comparison to previously reported work with E. coli MFCs, the composite anode delivers 2-fold higher power density (1495 mW/m(2)). Thus, it has great potential to be used as the anode for a high-power MFC and may also provide a new universal approach for improving different types of MFCs.

Abstract: The anode potential in microbial fuel cells controls both the theoretical energy gain for the microorganisms as the output of electrical energy. We operated three reactors fed with acetate continuously at a poised anode potential of 0 (R0), -200 (R(-200)) and -400 (R(-400)) mV versus Ag/AgCl and investigated the resulting bacterial activity. The anode potential had no influence on the start-up time of the three reactors. During a 31-day period, R(-200) produced 15% more charge compared to R0 and R(-400). In addition, R(-200) had the highest maximal power density (up to 199 W m(-3) total anode compartment during polarization) but the three reactors evolved to the same power density at the end of the experimental period. During polarization, only the current of R(-400) levelled off at an anode potential of -300 mV versus Ag/AgCl. The maximum respiration rate of the bacteria during batch tests was also considerably lower for R(-400). The specific biomass activity however, was the highest for R(-400) (6.93 g chemical oxygen demand g(-1) biomass-volatile suspended solids (VSS) d(-1) on day 14). This lowered during the course of the experiment due to an increase of the biomass concentration to an average level of 578+/-106 mg biomass-VSS L(-1) graphite granules for the three reactors. This research indicated that an optimal anode potential of -200 mV versus Ag/AgCl exists, regulating the activity and growth of bacteria to sustain an enhanced current and power generation.

Abstract: Disclosed are an organic electroluminescent device (organic EL device) which is improved in luminous efficiency, fully secured of driving stability, and of simple constitution and a compound useful for the fabrication of said organic EL device. The compound for the organic EL device has an indolocarbazole structure or a structure similar thereto in the molecule wherein an aromatic group is bonded to the nitrogen atom in the indolocarbazole. The organic EL device has a light-emitting layer disposed between an anode and a cathode piled one upon another on a substrate and said light-emitting layer comprises a phosphorescent dopant and the aforementioned compound for an organic electroluminescent device as a host material.

Abstract: Layered double hydroxide (LDH) nano- and microstructures with controllable size and morphology have been fabricated on “bivalent metal” substrates such as zinc and copper by a one-step, room-temperature process, in which metal substrates act as both reactants and supports. By manipulating the concentration of NH3 · H2O, the thickness and lateral size of the LDH materials can be tuned from several tens of nanometers to several hundreds of nanometers and from several hundreds of nanometers to several micrometers, respectively. This method is general and may be readily extended to any other alkali-resisted substrate coated with Zn and Cu. As an example, Zn-covered stainless steel foil has been shown to be effective for the growth of a ZnAl LDH film. After calcinating the as-grown LDH at high temperature (650 °C) in argon gas, a ZnO/ZnAl2O4 porous nanosheet film is obtained, which is then directly used for the first time as the anode material for Li-ion batteries with the operating voltage window of 0.05–2.5 V (vs. Li). The result demonstrates that ZnO/ZnAl2O4 has higher discharge and charge capacities and considerably better cycling stability compared to pure ZnO (Li insertion/extraction rate: 200 or 500 mA g−1). The improved electrochemical performance can be ascribed to the buffering effect of the inactive matrix ZnAl2O4 by relieving the stress caused by the volume change during charge–discharge cycling. This work represents a successful example for the development of promising ZnO-based anode materials for Li-ion batteries.