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Abstract The energy consumed during the desalination process in a flow-electrode capacitive deionization (FCDI) is recovered by a two-chamber device, where the adsorbed electrodes are discharged with constant current. When single constant discharge current is applied, the maximum energy of 36.3 J can be obtained with 0.50 mA/cm2 discharge current density. Much more energy is recovered by applying successive discharge currents. With additional conductive agent carbon nanotubes in the suspend carbon electrodes, the ratio was further enhanced by 60%. Increased salt concentration of the electrolyte could decrease the energy consumption and improve the energy recovery. The energy recovery ratio was promoted to 9.4% when the salt concentration of the electrolyte increased to 9.60 g L−1. Highlights • Two-chamber device to recover the energy from FCDI. • Successive discharging currents benefit the energy recovery. • Additional CNT improved energy recovery ratio by 60%. • Increased salt concentration of electrode improved energy recovery performance. [ABSTRACT FROM AUTHOR]

A novel anode is fabricated by electrodepositing manganese dioxide (MnO 2 ) on carbon felt to promote MFC's power production. Compared to the bare carbon felt anode, when the electrodeposition time increases to 60 min, the anode capacitance improves 46 times. The maximum power density of the MFC with the MnO 2 -coated anode reaches 3580 ± 130 mW m −2 , 24.7% higher than that with the bare carbon felt anode (2870 mW m −2 ). MnO 2 is believed to facilitate extracellular electron transfer and accordingly improve the power output. Three anode substrate circulation modes, i.e., flow-through, side-flow, and no-flow, are applied. Electrochemical impedance spectroscopy (EIS) tests reveal that flow-through mode decreases the anode mass transfer resistance by 41.4% compared to the no-flow mode and contributes to the MFC's power production improvement. [ABSTRACT FROM AUTHOR]

Silicon and lithium metal are promising anode materials toward high energy densities Li (ion) batteries. However, silicon and lithium generally have dramatic volume change during lithiation/delithiation cycles. With the repeated expansion/shrinkage, the internal stress fluctuations and electrode pulverization can cause high interfacial resistance and the failure of electrodes. Herein, a novel strategy is proposed to engineer the current collector by using a polydopamine-assisted electroless metallization process to prepare an elastic deformable current collector covered with a high electrical conductivity Cu nano-network surface. The deformable current collectors can not only stabilize the interfacial stress as an artificial-spring, but also improve the electrical conductivity of anodes without any binders and conductive agents. Featured with outstanding deformable structure, the well-designed current collector achieves a low surface resistance of 0.06 Ω/sq and excellent electrochemical performance when applied in the commercial Si anode batteries, solid-state batteries, and ionic liquid electrolyte batteries at room-temperature. • A highly elastic and low resistance deformable current collector. • The deformable current collector achieves a low surface resistance of 0.06 Ω/sq. • Stabilized the interface stress of anodes as an artificial-spring. • Improve the electrical conductivity of anodes without binders and conductive agents. • Achieved >400 stable cycling performance when applied in a commercial Si anode. [ABSTRACT FROM AUTHOR]

Advancing the application of bioelectrochemical systems necessitates the comprehensive understanding of electron transfer process in electrode-associated biofilm. While in situ electrical measurement by using the split electrode can illustrate the electron conduction in biofilm, the accuracy and interpretation of the obtained data is still in debate. Here, conductance of Geobacter sulfurreducens biofilm is measured by using the split electrode as substrate concentration is changed. Biofilm conductance decreases with the current production as the consumption of substrate. In addition, the measured conductance increases with the area of drain electrode (13.8 ± 1.8 μS for 0.5 cm2 and 29.4 ± 4.2 μS for 1 cm2). These results suggest the measured conductance of biofilm is influenced by microbial metabolism. This effect will diminish when the measurement is performed by using electrochemical impedance spectroscopy or under non-turnover condition. Our results provide the insight on the electrochemical origin of biofilm conductance determined by the in situ electrical measurement. • Biofilm conductance decreased with current production as consumption of substrate. • Biofilm conductance increased with the area of drain electrode. • The measurement of biofilm conductance was influenced by microbial metabolism. • Biofilm conductance significantly decreased under non-turnover condition. [ABSTRACT FROM AUTHOR]

Although transition metal oxides anodes have attracted lots of attention, there are still many problems to be resolved. Complicated fabrication process, high cost and poor electrochemical performances are the most important ones, together hindering transition metal oxides anodes for practical use. Herein, we provide a new approach to fabricate a binder-free and conductive-additive-free TiO 2 /WO 3 -W integrative anode material through the nanosecond laser ablation and dip-coating technology, which simplifies the entire anode preparation process with no need for a conventional tape-casting procedure. Using this method, great time cost, machine cost and labor cost related to mixing and tape-casting process can be saved on the basis of good electrochemical performances. The prepared TiO 2 /WO 3 -W integrative anode realizes a first Coulombic efficiency of 75.6% and attains to a stable capacity within the first five cycles. It can still maintain a capacity of 600 mAh g −1 in the range of 0.01–3 V vs. Li + /Li at a current rate of 0.2 C after 500 cycles. This work offers a new way to achieve a fast fabrication of the integrative anode for lithium ion battery, which is universal for other transition metals (such as Fe, Cu, Ni, Co, Mo, W etc.). [ABSTRACT FROM AUTHOR]

Microbial desalination cells are considered a low-energy-consumption, clean technology to simultaneously purify wastewater and desalinate saline water by utilizing the in situ energy source contained in wastewater. To enhance desalination performance and achieve an optimal membrane stack configuration, an enlarged stacked microbial desalination cell (SMDC) has been developed and tested with 6–14 desalination cells. The cross-membrane area of the enlarged SMDC is 100 cm 2 . The anode and cathode volumes are both 200 mL. To reduce internal resistance, the width of desalination cells is kept as <0.5 mm. The optimal configuration with 10 desalination cells achieves the highest total desalination rate (TDR) of 423 mg/h and the highest charge transfer efficiency (CTE) of 836% when treating the 20 g/L NaCl solution. During this process, the junction potential across membranes increases from 0 to 374 mV, and occupies up to 74% of the total potential loss inside the SMDC. This shows that the SMDC used in this work achieves the highest TDR and CTE among the reported studies, and the junction potential should be effectively controlled to achieve the desired desalination performance in future practical applications. [ABSTRACT FROM AUTHOR]

Abstract High-efficiency cathode catalysts are essential for microbial fuel cell development since they are one of the key components in chemical energy conversion in organic compounds into electricity. Here, novel Fe Mn bimetallic nanocatalysts are designed and hydrothermally synthesized for microbial fuel cells. Fe:Mn (atom%) = 1:4, 1:2, 1:1, and α-MnO 2 are applied in air-cathodes with Pt/C and activated carbon catalysts as benchmarks, and Fe Mn catalysts can enhance the performance. When Fe:Mn = 1:2, the FeMn 2 achieves a maximum power density of 1940 ± 31 mW m−2 in microbial fuel cells and a current density of 19.4 A m−2 at −0.056 V in abiotic electrochemical tests, 24% and 37% higher than Pt/C respectively. Material characteristics are systematically analyzed since they are directly related to the catalytic performance. The high catalytic activity of FeMn 2 proves to result from a combination of the weak Mn O bonds, large quantity of defects, large specific surface area and high Mn(III):Mn(IV) ratio, according to the proposed possible mechanisms of Fe Mn catalysts to enhance the output. This work not only puts forwards an easy-to-accomplish method to design and prepare bimetallic nanocatalysts, but also provides a potential alternative to Pt/C in microbial fuel cells for sustainable energy generation. Graphical abstract Image 1 Highlights • Fe Mn nanocatalysts were designed and prepared for MFC via hydrothermal method. • FeMn 2 air-cathode exhibited the highest MFC maximum power density of 1940 mW m−2. • The synergism of Fe3+ and α-MnO 2 lattice has been demonstrated. • The best performance of FeMn 2 was illustrated by proposed catalytic mechanisms. • The FeMn 2 outperformed commercial Pt/C and could be a potential alternative. [ABSTRACT FROM AUTHOR]

A structure with ion migration channels and continuous conductive network is crucial for the rate performance of activated carbon. In this work, a phenolic resin and ammonium alginate composite derived carbon is prepared by sol-gel method, carbonization and KOH activation. Compared with pure phenolic resin derived carbon, adding ammonium alginate in carbon preparation process can form interconnected coral-like carbon structure with higher specific surface area and meso-macro pores volume. These advantages of carbon make it provide sufficient access for ions diffusion and continuous skeleton for electron transport. In addition, the morphology of carbon materials can be adjusted by ammonium alginate. A two-electrode system coupled with 6 M KOH as electrolyte is assembled to test the electrochemical properties of these carbon materials. High specific capacitances of 282.8 F g−1 and 232.1 F g−1 at 0.5 A g−1 and 100 A g−1 are obtained, respectively, with a high capacitance retention of 82%. Moreover, high energy density of 9.82 Wh kg−1 at 115 W kg−1 and conspicuous cycling stability with a capacitance retention of 95% after 20,000 cycles are showed for the symmetrical supercapacitor. This work provides reference for preparation of the 3D interconnected hierarchical porous carbon for high performance supercapacitor. [Display omitted] • Coral-like 3D interconnected morphology carbons were prepared. • Ammonium alginate as additive can improve the morphology of carbon. • The Coral-like 3D carbons showed high specific capacitance and cycling stability. • The improved electron/ion transport enhanced the rate performance of supercapacitor. [ABSTRACT FROM AUTHOR]

Recovery of nutrient resources from the wastewater is now an inevitable strategy to maintain the supply of both nutrient and water for our huge population. While the intensive energy consumption in conventional nutrient recovery technologies still remained as the bottleneck towards the sustainable nutrient recycle. This study proposed an enlarged microbial nutrient recovery cell (EMNRC) which was powered by the energy contained in wastewater and achieved multi-cycle nutrient recovery incorporated with in situ wastewater treatment. With the optimal recovery solution of 3 g/L NaCl and the optimal volume ratio of wastewater to recovery solution of 10:1, >89% of phosphorus and >62% of ammonium nitrogen were recovered into struvite. An extremely low water input ratio of <1% was required to obtain the recovered fertilizer and the purified water. It was proved the EMNRC system was a promising technology which could utilize the chemical energy contained in wastewater itself and energy-neutrally recover nutrient during the continuous wastewater purification process. [ABSTRACT FROM AUTHOR]

Revealing the pathways of electron transport within electrochemically active biofilms (EABs) is of great importance. Here, mixed-culture EABs are grown on three interdigitated microelectrode arrays (IDAs) with different gap widths of 10 μm, 20 μm and 50 μm and their conductances are determined. The maximum conductive current increases with the decrease of the gap width and charge transfer resistance obtained for the biofilm attaching on the electrode is 3–11 fold less than that for biofilm bridging gaps, suggesting high conductance of biofilm closer to the electrode surface. Results from Raman analysis show high abundance of multi-heme cytochromes in biofilm bridging 10 μm gap, leading to small resistance of biofilm growing on the IDA with 10 μm gap. In addition, the maximum conductive current of biofilm bridging gaps at the potential of −0.40 V vs. Ag/AgCl suggests that electron transfer in biofilm growing on IDAs is redox driven. All these results indicate the spatial heterogeneity of electron transport processes acting within biofilm. Biofilm conductance decreased with the increase of gap's width. Small resistance was found for biofilm adjacent to the electrode surface. Biofilm conductance was depended the abundance of multi-heme cytochrome. The process of electron transfer with EABs was spatial heterogeneous. Panpan Liu: Conducting a research and investigation process, writing the initial draft [ABSTRACT FROM AUTHOR]