Carbon Cloth Anode Research Articles

Nitrogen-enriched pseudographitic anode derived from silk cocoon with tunable flexibility for microbial fuel cells

Microbial fuel cells (MFCs), promising for converting biomass energy into electricity, have attracted much research enthusiasm. However, high performance anode materials for MFC, particularly with tunable flexibility for diverse cell configurations, are still limited. In this study, through a simple one-step carbonization of a versatile protein precursor, silk cocoon, both freestanding and flexible bioanode materials, with enriched nitrogen contents and hierarchical pores, can be easily fabricated. Importantly, the carbonized silk cocoon, as a freestanding MFC anode, and flexible carbon fiber, as a flexible MFC anode, exhibit high performance in electricity generation, yielding about 2.5-fold and 3.1-fold maximum gravimetric power density than that of MFCs with carbon cloth anode, respectively. We attribute the improved anode performance of these flexibility tunable carbon materials to their good biocompatibility, reduced electron transfer resistance and high capacitance. This study will not only offer great opportunities for the fabrication of high-performance MFC anode with varied designs and 3-dimensional architectures, but also shed light on the future development of MFC and proper utilization of the abundant “green” natural resources.

Enhanced power production of microbial fuel cells by reducing the oxygen and nitrogen functional groups of carbon cloth anode

The physicochemical properties of anode material are important for the electron transfer of anode bacteria and electricity generation of microbial fuel cells (MFCs). In this work, carbon cloth anode was pretreated with isopropanol, hydrogen peroxide (H2O2) and sodium hypochlorite (NaOCl) in order to reduce the anode functional groups. The influence of functional groups on the electrochemical properties of carbon cloth anode and power generation of MFCs was investigated. The anode pretreatments removed the surface sizing layer of carbon cloth and substantially reduced the contents of C‐O and pyridinic/pyrrolic N groups on the anode. Electrochemical impedance spectroscopy and cyclic voltammetry analyses of the biofilm‐matured anodes revealed an enhanced electrochemical electron transfer property because of the anode pretreatments. As compared with the untreated control (612 ± 6 mW m−2), the maximum power density of an acetate‐fed single‐chamber MFC was increased by 26% (773 ± 5 mW m−2) with the isopropanol treated anode. Additional treatment with H2O2 and NaOCl further increased the maximum power output to 844 ± 5 mW m−2 and 831 ± 4 mWm−2. A nearly inverse liner relationship was observed between the contents of C‐O and pyridinic/pyrrolic N groups on anodes and the anodic exchange current density and the power output of MFCs, indicating an adverse effect of these functional groups on the electricity production of anodes. Results from this study will further our understanding on the microbial interaction with carbon‐based electrodes and provide an important guidance for the modification of anode materials for MFCs in future studies. Copyright © 2016 John Wiley & Sons, Ltd.

Electro-Fenton for control and removal of micropollutants - process optimization and energy efficiency.

The removal of micropollutants is an important environmental and health issue. Electro-Fenton offers an electrochemical advanced treatment that is particularly effective for the breakdown of aromatic contaminants. Due to the wide variety of chemicals, it is preferable to analyze model contaminants, such as phenol, when optimizing and assessing the efficacy of a novel treatment process. In this study, we therefore made use of innovative types of electrode material and optimized operating parameters (current density and aeration rate) for the removal of phenol by electro-Fenton, with a view to maximize the energy efficiency of the process. By determining the best current density (1.25 mA cm-2), frequency of aeration (continuous) and by using a boron-doped diamond (BDD) anode, it was possible to achieve over 98.5% phenol (1 mM) removal within 1.5 h. BDD further outcompeted platinum as anode material in terms of mineralization rate and yield, and displayed low energy consumption of 0.08 kWh (g-TOC)-1, about one order of magnitude lower than other advanced oxidation processes, such as UV/TiO2 and UV/O3. Furthermore, a carbon cloth anode proved even more cost-effective than BDD if the end goal is the removal of phenol by electro-Fenton instead of complete mineralization.

All-flexible lithium ion battery based on thermally-etched porous carbon cloth anode and cathode

Flexible electrode material with high mechanical strength and excellent electrical stability is still a great challenge for the fabrication of highly flexible energy storage devices. Commercial carbon cloth has been long reported as flexible substrate for many electrode materials due to their high mechanical strength and flexibility. However, their application directly as electrode material for flexible lithium ion batteries is yet to be reported. In this paper, commercial carbon cloth was thermally etched and used directly as electrode material in the half-cell and all-flexible full lithium ion batteries. Upon the mass weight and the large diameter of the carbon fiber, the as-prepared free-standing N-doped Porous carbon cloth delivered an initial capacity of 1.75mAh/cm2 (190mAh/g) and capacity up to 1.65mAh/cm2 (168mAh/g) after long electrochemical cycles in the half-cell. The all-flexible device exhibits a high working potential of 3.4V, remarkable lithium storage performance and excellent flexibility. It also achieves a maximum volumetric energy density of 43Wh/cm3 at 0.125mA/cm2 and power density 800W/cm3 at 5.0mA/cm2. The excellent performance can be attributed to N-doped porous surfaces, which provide large surface area for more lithium storage.

Enhanced performance of microbial fuel cells by using MnO2/Halloysite nanotubes to modify carbon cloth anodes

The modification of anode materials is important to enhance the power generation of MFCs (microbial fuel cells). A novel and cost-effective modified anode that is fabricated by dispersing manganese dioxide (MnO2) and HNTs (Halloysite nanotubes) on carbon cloth to improve the MFCs' power production was reported. The results show that the MnO2/HNT anodes acquire more bacteria and provide greater kinetic activity and power density compared to the unmodified anode. Among all modified anodes, 75 wt% MnO2/HNT exhibits the highest electrochemical performance. The maximum power density is 767.3 mWm−2, which 21.6 higher than the unmodified anode (631 mW/m2). Besides, CE (Coulombic efficiency) was improved 20.7, indicating that more chemical energy transformed to electricity. XRD (X-Ray powder diffraction) and FTIR (Fourier transform infrared spectroscopy) are used to characterize the structure and functional groups of the anode. CV (cyclic voltammetry) scans and SEM (scanning electron microscope) images demonstrate that the measured power density is associated with the attachment of bacteria, the microorganism morphology differed between the modified and the original anode. These findings demonstrate that MnO2/HNT nanocomposites can alter the characteristics of carbon cloth anodes to effectively modify the anode for practical MFC applications.

In-situ modified carbon cloth with polyaniline/graphene as anode to enhance performance of microbial fuel cell

The microbial fuel cell (MFC) technology has potential in recovering bioelectricity from different types of waste. However, the low power density, closely associated with anode performance, limits its practical application. In this study, polyaniline (PANI) together with graphene was chosen to in-situ modify oxidized carbon cloth (CC) by the aid of secondary bond forces (such as π–π stacking, hydrogen bonds and electrostatic forces). The MFC reactor with PANI/graphene modified CC (PANI+G+CC) anode achieved the highest voltage with 573 ± 37 mV, and produced a peak power density of 884 ± 96 mW/m2, which was 1.3 and 1.9 times of those with the CC control. Based on cyclic voltammetry (CV) scanning and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) spectra, it was speculated that the weakly acidic microenvironment derived from bio-anode delayed or impeded the deprotonation of PANI and made PANI hold a certain level of conductivity for electron transfer. This study provided a simple and environment-friendly modifying method to enable the prepared PANI+G+CC anode to dramatically promote the performance of MFC.

Disposable self-support paper-based multi-anode microbial fuel cell (PMMFC) integrated with power management system (PMS) as the real time “shock” biosensor for wastewater

A paper-based multi-anode microbial fuel cell (PMMFC) integrated with power management system (PMS) was developed as a disposable self-support real-time “shock” biosensor for wastewater. PMMFCs were examined at three types of shocks (chromium, hypochlorite and acetate) in a batch-mode chamber, and exhibited various responses to shock types and concentrations. The power output of PMMFC sensor was four times as the carbon cloth (CC)-based MFCs, indicating the advantage of paper-based anode for bacterial adhesion. The power output was more sensitive than the voltage output under shocks, and thus preventing the false signals. The simulation of power harvest using PMS indicated that PMMFC could accomplish more frequent data transmission than single-anode MFCs (PSMFC) and CC anode MFCs (CCMMFC), making the self-support wastewater monitor and data transmission possible. Compared with traditional MFC sensors, PMMFCs integrated with PMS exhibit the distinct advantages of tight paper-packed structure, short acclimation period, high power output, and high sensitivity to a wide range of shocks, posing a great potential as “disposable self-support shock sensor” for real time in situ monitoring of wastewater quality.

Operation and Performance of Large-Scale MFCs for Treating Brewery Waste

Each year, Americans consume over 6.3 billion gallons of beer. As a result, over 50 billion gallons of brewery wastewater is created annually. Wastewater pre-treatment is an important investment for craft breweries as the biological oxygen demand (BOD) and the total suspended solids (TSS) from the waste stream leaving the brewery have to be significantly reduced before it enters the municipal system. Therefore, the treatment of brewery wastewater is an enormous and expensive part of the environmentally conscious brewing business. Brewery wastewater is characterized with high amounts of sugar, starch, and proteins, which makes it perfect candidate for Microbial Fuel Cell (MFC) application. MFCs have been proven as a promising technology for sustainable wastewater treatment and also as a way for direct recovery of electric energy [1]. In this study, two 10 liter MFCs were used to treat brewery waste collected from Stone Brewery, Escondido, CA. The MFCs had tubular design with a nanofiltration membrane separator, submerged oxygen reducing cathode and carbon cloth anode (Fig. 1). The two reactors were connected in series and operated under continuous flow. The objective of the study was to evaluate the long-term treatment capacity of the MFCs and optimize the operational parameters for maximum volumetric treatment rates and energy recovery. Three main parameters were used to evaluate the MFCs performance. These were chemical oxygen demand (COD) removal, the magnitude of the generated current density and the columbic efficiency (CE) of the COD transformation into electricity. The MFCs had an anode volume of 10L and anode surface area of 65 m2. The first MFC in the series (MFC #1) was first had an inflow of diluted buffered brewery wastewater effluent. MFC #2 was operated with the outflow of MFC #1. The MFCs was continuously running for 250 days when various flow rates of 1ml/min, 2ml/min, 3ml/min and 5ml/min were explored during the study. Over the period of 250 days and loading rates between 1ml/min to 5 ml/min, MFC #1 demonstrated an average COD removal rate of 51.6 ± 19.4%, current density of 2.77 ± 0.99 A/m3 and CE of 8 ± 7%. MFC #2 had an average COD removal of 50.9 ± 20.5%, current density of 2.0 ± 0.6 A/m3 and CE of 14 ± 11% (Fig. 2). Thus the whole system showed an average COD removal of 74.7 ± 19.2%, COD treatment rate of 0.56 ± 0.37 kg-COD/anode-m3-day, CE of 9 ± 6%, and current density of 2.4± 0.6 A/m3. This study demonstrated that MFCs could be useful devices for long-term continuous treatment of brewery wastewater. The system tested is modular, scalable and constructed from cost-effective materials. Future work will include additional large-scale pilot testing and further design and operational optimization to accomplish higher volumetric treatment rates.

Enhanced electrical power generation using flame-oxidized stainless steel anode in microbial fuel cells and the anodic community structure

BackgroundCarbon-based materials are commonly used as anodes in microbial fuel cells (MFCs), whereas metal and metal-oxide-based materials are not used frequently because of low electrical output. Stainless steel is a low-cost material with high conductivity and physical strength. In this study, we investigated the power generation using flame-oxidized (FO) stainless steel anodes (SSAs) in single-chambered air-cathode MFCs. The FO-SSA performance was compared to the performance of untreated SSA and carbon cloth anode (CCA), a common carbonaceous electrode. The difference in the anodic community structures was analyzed using high-throughput sequencing of the V4 region in 16S rRNA gene.ResultsFlame oxidation of SSA produced raised node-like sites, predominantly consisting of hematite (Fe2O3), on the surface, as determined by X-ray diffraction spectroscopy. The flame oxidation enhanced the maximum power density (1063 mW/m2) in MFCs, which was 184 and 24 % higher than those for untreated SSA and CCA, respectively. The FO-SSA exhibited 8.75 and 2.71 times higher current production than SSA and CCA, respectively, under potentiostatic testing conditions. Bacteria from the genus Geobacter were detected at a remarkably higher frequency in the biofilm formed on the FO-SSA (8.8–9.2 %) than in the biofilms formed on the SSA and CCA (0.7–1.4 %). Bacterial species closely related to Geobacter metallireducens (>99 % identity in the gene sequence) were predominant (93–96 %) among the genus Geobacter in the FO-SSA biofilm, whereas bacteria with a 100 % identity to G. anodireducens were abundant (>55 %) in the SSA and CCA biofilms.ConclusionsThis is the first demonstration of power generation using an FO-SSA in MFCs. Flame oxidation of the SSA enhances electricity production in MFCs, which is higher than that with the common carbonaceous electrode, CCA. The FO-SSA is not only inexpensive but also can be prepared using a simple method. To our knowledge, this study reveals, for the first time, that the predominant Geobacter species in the biofilm depends on the anode material. The high performance of the FO-SSA could result from the particularly high population of bacteria closely related to G. metallireducens in the biofilm.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-016-0480-7) contains supplementary material, which is available to authorized users.

MnO2/Polypyrrole/MnO2 multi-walled-nanotube-modified anode for high-performance microbial fuel cells

Hierarchical multi-walled MnO2/polypyrrole/MnO2 nanotubes (NT-MPMs) were synthesized by a hydrothermal method and were decorated on a carbon cloth anode to promote microbial fuel cell (MFC) power production. Compared with bare carbon cloth (CK) anodes, the maximum power density of the MFC with an NT-MPM-decorated anode reaches 32.7±3W/cm3, which is approximately 1.3 times higher than that of the CK, and it exhibits excellent durability. The voltage outputs of the NT-MPM anode MFC decreased by 9.2% after being subjected to more than 90 full discharging–charging cycles. In additionbanode, which facilitated biofilm growth and promoted extracellular electron transfer between the bacteria and the electrode. Electrochemical impedance spectroscopy (EIS) measurements reveal that NT-MPM anodes lead to a low charge transfer resistance and provide unique active centers that host the bacteria for more efficient electrocatalysis. This study introduces a promising method for the fabrication of high-performance anodes from simple, inexpensive materials.

Architectural design of hierarchically meso–macroporous carbon for microbial fuel cell anodes

The HN-C exhibited a high power density (1034 mW m−2), which was much higher than the macroporous carbon anode MFC (811 mW m−2) and mesoporous carbon anode MFC (678 mW m−2) and was 2.2-folds that of carbon cloth anode MFC (467 mW m−2).

Examining sludge production in bioelectrochemical systems treating domestic wastewater

Sludge production in microbial bioelectrochemical systems (BES) was assessed in conjunction with anaerobic and aerobic control reactors. Effluent after primary settling tank (EAPS) and depleted EAPS spiked with acetate were treated. The reactors were loaded with total suspended solids (TSS) and chemical oxygen demand (COD) at average loading rates of 22mgTSSd−1L−1 and 86mgCODd−1L−1, respectively. Carbon cloth anode equipped BES reactors delivered the highest performance. They achieved on average a COD removal of 80%, a Coulomb efficiency of 77% for EAPS, a maximum current density of 39μAcm−3/175μAcm−2 for EAPS and a TSS removal of 59%, yielding a sludge production of only 80mg TSS per g ΔCOD. This study provides further evidence that BES can improve the economics of wastewater treatment via lower sludge production as well as providing a framework for understanding sludge production in BES.

Bifunctional Manganese Ferrite/Polyaniline Hybrid as Electrode Material for Enhanced Energy Recovery in Microbial Fuel Cell.

Microbial fuel cells (MFCs) are emerging as a sustainable technology for waste to energy conversion where electrode materials play a vital role on its performance. Platinum (Pt) is the most common material used as cathode catalyst in the MFCs. However, the high cost and low earth abundance associated with Pt prompt the researcher to explore inexpensive catalysts. The present study demonstrates a noble metal-free MFC using a manganese ferrite (MnFe2O4)/polyaniline (PANI)-based electrode material. The MnFe2O4 nanoparticles (NPs) and MnFe2O4 NPs/PANI hybrid composite not only exhibited superior oxygen reduction reaction (ORR) activity for the air cathode but also enhanced anode half-cell potential upon modifying carbon cloth anode in the single-chambered MFC. This is attributed to the improved extracellular electron transfer of exoelectrogens due to Fe(3+) in MnFe2O4 and its capacitive nature. The present work demonstrates for the first time the dual property of MnFe2O4 NPs/PANI, i.e., as cathode catalyst and an anode modifier, thereby promising cost-effective MFCs for practical applications.

Evaluation of organic matter removal and electricity generation by using integrated microbial fuel cells for wastewater treatment

A floating all-in-one type of microbial fuel cell (Fa-MFC) that allows simple operation and installation in existing wastewater reservoirs for decomposition of organic matter was designed. A prototype cell was constructed by fixing a tubular floater to an assembly composed of a proton-exchange membrane and an air-cathode. To compare anode materials, carbon-cloth anodes or carbon-brush anodes were included in the assembly. The fabricated assemblies were floated in 1-L beakers filled with acetate medium. Both reactors removed acetate at a rate of 133–181 mg/L/d. The Fa-MFC quipped with brush anodes generated a 1.7-fold higher maximum power density (197 mW/m2-cathode area) than did that with cloth anodes (119 mW/m2-cathode area). To evaluate the performance of the Fa-MFCs on more realistic substrates, artificial wastewater, containing peptone and meat extract, was placed in a 2-L beaker, and the Fa-MFC with brush anodes was floated in the beaker. The Fa-MFC removed the chemical oxygen demand of the wastewater at a rate of 465–1029 mg/L/d, and generated a maximum power density of 152 mW/m2-cathode area. When the Fa-MFC was fed with actual livestock wastewater, the biological oxygen demand of the wastewater was removed at a rate of 45–119 mg/L/d, with electricity generation of 95 mW/m2-cathode area. Bacteria related to Geobacter sulfurreducens were predominantly detected in the anode biofilm, as deduced from the analysis of the 16S rRNA gene sequence.

Conducting Polymers As Electrode Modifiers for the Enhanced Microbial Fuel Cell Performance

The low power density of a microbial fuel cell (MFC) compared to other fuel cells has been a problem for this technology to be implanted in the real world despite the fact that it has many merits as an alternative energy source such as environmental sustainability and carbon neutrality. The main reason lies in the slow electron transfer (ET) kinetics at the anode and the cathode. Electrons produced from the oxidation of organic matters by the bacterial biofilm on the anode are transferred to the cathode where oxygen reduction reaction (ORR) takes place. Thus fast ET at both electrodes is very important to increase current density that leads to enhanced power density. Here we show how polyaniline (PANI) and polypyrrole (Ppy) can be utilized as electrode modifiers to greatly improve MFC performance.First, we have used PANI and Ppy to modify anodes. When Ppy was applied to the anode in a mediator-type MFC using Proteus vulgaris as a biocatalyst, a large enhancement in power density was observed. A dramatic power enhancement was resulted from the electrodeposited Ppy onto the reticulated vitreous carbon (RVC) electrode. Our obtained maximum power density of 1.2 mW cm−3 is the highest value among the reported ones for the similar system. From impedance measurements, enhancement was attributed to the decrease in charge transfer resistance. More practical MFCs are single chamber and mediatorless type MFCs with a biofilm formed from activated sludge. We prepared polyaniline/carbon black (PANI/C) composite and applied it to carbon cloth anode. It shortened start-up period and significantly enhanced power density from 764 mW m-2 to 1277 mW m-2. Enhances performance was also attributed to fast electron transfer to the anode through PANI. The anode surface was characterized by employing various surface characterization techniques such as scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The power output depended upon the amount of PANI/C, showing a highest value at 0.2 mg cm-2. Coulombic efficiency was more than 30% at 4.3 A m-2.Second, PANI was also utilized as an ORR catalyst for an MFC cathode. We used polyaniline nanofibers (PANInf) synthesized by interfacial polymerization and prepared PANInf/Carbon black composite for the cathode. Higher electrocatalytic activity for the oxygen reduction compared to pristine PANInf was resulted, thus leading to a large power density enhancement 185 mW m−2 for the pristine PANInf to 496 mW m−2 for the composite material. Although the power density was still lower than when conventional Pt catalyst was used (604.3 mW m−2), a facile bulk synthesis and cheaper price would make PANInf/C an alternative to Pt when a large scale application comes to an issue.PANI was also used as a support to incorporate compounds that have high catalytic activity toward oxygen reduction. Iron phthalocyanine (FePc) has been known as effective oxygen reduction catalyst. FePc was incorporated into Polyaniline/carbon black (PANI/C) composite. Thus prepared (PANI/C/FePc) was used as a catalyst for the ORR in an air–cathode microbial fuel cell (MFC). The electrocatalytic activity of the PANI/C/FePc toward the ORR was compared with carbon-supported FePc. The ORR overpotential was decreased and current density was greatly increased, indicating that polyaniline plays a key role in ORR reactions. This PANI/FePc/C composite was also well adopted as a cathode material in MFCs. The maximum power density of 630.5 mW m−2 with the PANI/C/FePc cathode was higher than that of 336.6 mW m−2 with the C/FePc cathode because of enhanced ORR activity. We compared monetary aspect per power for these materials. It turned out that the power per cost of the PANI/C/FePc cathode is 7.5 times greater than that of the Pt cathode. Thus, the PANI/C/FePc can be a potential alternative to Pt in MFCs.We found PANInf could be a useful material for modifying the interior of the three-dimensional anode. Reticulated vitreous carbon (RVC) is an ideal material in that it has many interconnected pores inside so that substrate can freely flow through the pores. The PANInf layer was easily formed on the interior surface of the RVC on which a stable and robust bacterial biofilm was formed, giving higher power density.In conclusion, conducting polymers have been proven very promising materials for the MFC power enhancement. Electron transfer barrier at the anode and cathode can be lowered when conducting polymers are used. Modification of these polymers with foreign species can further increase power density.

Facile Fabrication of Graphene-Containing Foam as a High-Performance Anode for Microbial Fuel Cells.

Facile fabrication of novel three-dimensional anode materials to increase the bacterial loading capacity and improve substrate transport in microbial fuel cells (MFCs) is of great interest and importance. Herein, a novel graphene-containing foam (GCF) was fabricated easily by freeze-drying and pyrolysis of a graphene oxide-agarose gel. Owing to the involvement of graphene and stainless-steel mesh in the GCF, the GCF shows high electrical conductivity, enabling the GCF to be a conductive electrode for MFC applications. With the aid of agarose, the GCF electrode possesses a supermacroporous structure with pore sizes ranging from 100-200 μm and a high surface area, which greatly increase the bacterial loading capacity. Cell viability measurements indicate that the GCF possesses excellent biocompatibility. The MFC, equipped with a 0.4 mm-thick GCF anode, shows a maximum area power density of 786 mW m(-2) , which is 4.1 times that of a MFC equipped with a commercial carbon cloth anode. The simple fabrication route in combination with the outstanding electrochemical performance of the GCF indicates a promising anode for MFC applications.

Enhancement of power production with tartaric acid doped polyaniline nanowire network modified anode in microbial fuel cells

The feasibility to use tartaric acid doped PANI for MFC anode modification was determined. Uniform PANI nanowires doped with tartaric acid were synthesized and formed mesoporous networks on the carbon cloth surface. By using this tartaric acid doped PANI modified carbon cloth (PANI-TA) as the anode, the voltage output (435±15mV) and power output (490±12mW/m2) of MFC were enhanced by 1.6 times and 4.1 times compared to that of MFC with plain carbon cloth anode, respectively. Strikingly, the performance of PANI-TA MFC was superior to that of the MFCs with inorganic acids doped PNAI modified anode. These results substantiated that tartaric acid is a promising PANI dopant for MFC anode modification, and provided new opportunity for MFC performance improvement.

A Novel Exfoliation Strategy to Significantly Boost the Energy Storage Capability of Commercial Carbon Cloth.

A facile and efficient electrochemical oxidation method to directly activated carbon cloth as an excellent electrode material for supercapacitors is reported. Flexible asymmetric supercapacitor devices based on activated carbon cloth anodes reach a remarkable energy density and excellent long-term durability.

High‐Performance and Ultra‐Stable Lithium‐Ion Batteries Based on MOF‐Derived ZnO@ZnO Quantum Dots/C Core–Shell Nanorod Arrays on a Carbon Cloth Anode

MOF-derived ZnO@ZnO Quantum Dots/C core-shell nanorod arrays grown on flexible carbon cloth are successfully fabricated as a binder-free anode for Li-ion storage. In combination with the advantages from the ZnO/C core-shell architecture and the 3D nanorod arrays, this material satisfies both efficient ion and fast electron transport, and thus shows superior rate capability and excellent cycling stability.

Electricity Generation from Microbial Fuel Cell with Polypyrrole-Coated Carbon Nanofiber Composite.

Polyacrylonitrile (PAN) nanofibers, with and without embedded carbon nanotubes (CNTs) were fabricated by the electrospinning process. Polypyrrole (PPy) was coated on the activated PAN/CNT nanofiber by in-situ chemical polymerization in order to improve the electrochemical performance. The electrocatalytic behaviors of the PPy-PAN/CNT composite anode were investigated by means of cyclic voltammetry to evaluate as the anode for microbial fuel cells (MFCs) application. In comparison with unmodified carbon cloth (CC) anodes, PPy-PAN/CNT nanofiber composite showed the improvement of the maximum power density by 40%. The PPy-PAN/CNT nanofiber composite electrode therefore offers good prospects for application in MFCs.