A nanoengineered 3D hierarchical ordered porous titanium nitride electrode is applied as an effective and efficient non-carbon electrode to deliver outstanding salt adsorption capacity and record-breaking salt adsorption rate in a capacitive deionization cell.

A device that can derive electrical power from the wastewater treatment process is highly desirable and would help to address both the issues of environmental conservation and energy production. A novel flow-photo catalytic fuel cell (flow-PFC) was designed, using a burr-like Ag-TiO2 coated photoanode, as a promising alternative to microbial fuel cells (MFCs) for extracting electricity during wastewater treatment. The amount of Ag in the photoanode is controlled to provide optimal visible light activity to the cell in the form of plasmon resonance. When fed with real brewery wastewater, the device provides continuous power generation of 1.85 W m(-2) under solar-simulated light, with an average COD removal of 14.8% (532 mg L-1). The flow-PFC provides power densities up to 6 times higher than current MFCs when being fed by wastewater, with comparable if not superior COD removal rates.

Ultramicroporous carbon materials play a critical role in CO2 capture and separation, however facile approaches to design ultramicroporous carbon with controllable amount, ratio and size of pores are still challenging. Herein, a novel strategy to design carbon nanospheres with abundant, uniform, and tunable ultramicroporosity was developed based on an in-situ ionic activation methodology. The adjustable ionexchange capacity derived from oxidative functionalization was found capable of substantially governing the ionic activation and precisely regulating the ultramicroporosity in the resultant product. An ultrahigh ultramicropore content of 95.5% was achieved for the optimally-designed carbon nanospheres, which demonstrated excellent CO2 capture performances with extremely high capacities of 1.58 mmol g(-1) at typical flue gas conditions and 4.30 mmol g(-1) at 25 degrees C and ambient pressure. Beyond that, the CO2 adsorption mechanism in ultramicropore was also investigated through molecular dynamics simulation to guide the pore size optimization. This work provides a novel and facile guideline to engineer carbon materials with abundant and tunable ultramicroporosity towards superior CO2 capture performance, which also delivers great potential in extensive applications such as water purification, catalysis, and energy storage. (C) 2018 Elsevier Ltd. All rights reserved.

Nanonization strategies are effective in preventing silicon anodes from pulverization and reducing the required diffusion lengths of lithium ions inside silicon structure, and thus obtain improved cycling performance over bulky silicon. However, new problems arise with nano silicon, such as reduced tap density, larger specific surface area, and poorly percolating conductive paths in electrodes. These new issues can result in reduced volumetric energy densities, unstable solid electrolyte interphase, increased irreversible capacities and low Coulombic efficiencies. This study introduces an effective strategy in harvesting the benefits of nano silicon, while eliminating the unfavorable phenomena that arise from nanonization. A novel micron-sized secondary cluster with silicon nanoparticles embedded in an amorphous carbon and TiOx matrix is developed. The matrix is conformally formed on the surface of silicon, which not only uniformly casts a protective layer on silicon, but also integrates nano silicon into micron clusters. The secondary cluster exhibits much improved tap density over silicon nanoparticles. The amorphous and defect-rich nature of the TiOx coating not only exhibits enhanced electronic conductivity over its crystalline counterparts, but also provides better elasticity and stress-release capability that can maintain the structural integrity over lithiation/delithiation of silicon. Direct and repetitive contact between silicon and electrolyte is prevented and thus formation of a stable solid electrolyte interphase is facilitated. Half cell batteries made with the composite exhibit an initial capacity of 1410 mA g(-1) at a current density of 100 mA g(-1), and display stable long-term cycling with similar to 88% capacity retention after 200 cycles at 1 A g(-1).

The highly oxidative operating conditions of rechargeable zinc-air batteries causes significant carbon-support corrosion of bifunctional oxygen electrocatalysts. Here, a new strategy for the catalyst support design focusing on oxygen vacancy (OV)-rich, low-bandgap semiconductor is proposed. The OVs promote the electrical conductivity of the oxide support, and at the same time offer a strong metal-support interaction (SMSI), which enables the catalysts to have small metal size, high catalytic activity, and high stability. The strategy is demonstrated by successfully synthesizing ultrafine Co-metal-decorated 3D ordered macroporous titanium oxynitride (3DOM-Co@TiOx Ny ). The 3DOM-Co@TiOx Ny catalyst exhibits comparable activities for oxygen reduction and evolution reactions, but much higher cycling stability than noble metals in alkaline conditions. The zinc-air battery using this catalyst delivers an excellent stability with less than 1% energy efficiency loss over 900 charge-discharge cycles at 20 mA cm-2 . The high stability is attributed to the strong SMSI between Co and 3DOM-TiOx Ny which is verified by density functional theory calculations. This work sheds light on using OV-rich semiconductors as a promising support to design efficient and durable nonprecious electrocatalysts.

In this work, the magnetic Fe3O4-graphene oxide (Fe3O4-GO) nanocomposite is synthesized via a facile one-pot hydrothermal method and used for settling down and removing solid suspended particles in wastewater. Physicochemical characterizations not only confirm the successful in-situ deposition of magnetic Fe3O4 nanoparticles on GO nanosheets, but also disclose the strong interaction between them. The Fe3O4-GO nanocomposite demonstrates an excellent capability of accelerating the settling process in the presence of magnetic field. It can reduce the Kaolinite solid particle concentration by an order of magnitude within 30 minutes, which is one time faster than that in the absence of magnetic field. The solid suspension absorbing behavior on the Fe3O4-GO nanocomposite in the presence of magnetic field is found to fit with Langmuir and Freundlich isotherm models and the pseudo-second-order kinetic model. The calculated adsorption capacity reaches 58.46 mg.mg(-1), and the initial adsorption rate reaches as high as 0.0275 mg.mg(-1) min(-1). The Fe3O4-GO nanocomposite is proved to be an effective, efficient and promising magnetic coagulant for the rapid treatment of solid suspended particles in wastewater and natural water.

In this article, polyurethane/graphene nano-platelet (PU/GnP) composites were fabricated via planetary centrifugal mixer (PCM) and cast on polyethylene terephthalate (PET) and copper substrates. Four different grades of GnP are used to investigate the effect of GnP size on the anti-corrosion performance of the composites. Tafel, Nyquist, and Bode plots are used to quantify and compare the anti-corrosion performance of the composites, and these plots are obtained by electrochemical analysis. In addition to the anti-corrosion performance, mechanical properties and morphologies of the composites are analyzed. Various parameters indicating the anti-corrosion performance illustrate that smaller size of GnP in the composites shows higher anti-corrosion performance on copper substrate. The results show that the smaller size of GnP is not only uniformly dispersed within PU, but also offers a high surface area which helps construct an efficient filler pathway that suppresses the diffusion of a corrosive agent into the polymer matrix. Nevertheless, mechanical properties of the composites are partially improved. Essentially, this study demonstrates that the size of GnP plays a central role in determining the anti-corrosion performance of PU/GnP composites.

In this study, synchrotron X-ray computed tomography has been utilized using two different imaging modes, absorption and Zernike phase contrast, to reconstruct the real three-dimensional (3D) morphology of nanostructured Li4Ti5O12 (LTO) electrodes. The morphology of the high atomic number active material has been obtained using the absorption contrast mode, whereas the percolated solid network composed of active material and carbon-doped polymer binder domain (CBD) has been obtained using the Zernike phase contrast mode. The 3D absorption contrast image revealed that some LTO nano-particles tend to agglomerate and form secondary micro-sized particles with varying degrees of sphericity. The tortuosity of electrode's pore and solid phases were found to have directional dependence, different from Bruggeman's tortuosity commonly used in macro-homogeneous models. The electrode's heterogeneous structure was investigated by developing a numerical model to simulate galvanostatic discharge process using the Zernike phase contrast mode. The inclusion of CBD in the Zernike phase contrast results in an integrated percolated network of active material and CBD that is highly suited for continuum modeling. The simulation results highlight the importance of using the real 3D geometry since the spatial distribution of physical and electrochemical properties have a strong non-uniformity due to microstructural heterogeneities. (C) 2017 The Electrochemical Society. All rights reserved.

An Ag@TiO 2 -TiO 2 flower composite is used as a photoanode in a photoelectrochemical cell. The photoanode shows exceptional performance in the simultaneous photodegradation of organic compounds and photogeneration of electrical power. The TiO 2 flower composite provides a hierarchical morphology that greatly improves the electronic properties of the anode. The addition of small quantities of Ag@TiO 2 immediately improves the short-circuit current of a methanol photocatalytic fuel cell, and the optimal addition of Ag@TiO 2 enhances the maximum power output of the cell under solar simulated light. Compared to commercial TiO 2 material, the Ag@TiO 2 -TiO 2 flower composite improves the short-circuit current of the photocatalytic fuel cell by 97% (1.7 mA cm -2 ) and the maximum power by 131% (0.6 mW cm -2 ) under solar simulated light.

A novel self-supported electrode with long cycling life and high mass loading was developed based on carbon-coated Si nanowires grown in situ on highly conductive and flexible carbon fabric substrates through a nickel-catalyzed one-pot atmospheric pressure chemical vapor deposition. The high-quality carbon coated Si nanowires resulted in high reversible specific capacity (∼3500 mA h g-1 at 100 mA g-1), while the three-dimensional electrode's unique architecture leads to a significantly improved robustness and a high degree of electrode stability. An exceptionally long cyclability with a capacity retention of ∼66% over 500 cycles at 1.0 A g-1 was achieved. The controllable high mass loading enables an electrode with extremely high areal capacity of ∼5.0 mA h cm-2. Such a scalable electrode fabrication technology and the high-performance electrodes hold great promise in future practical applications in high energy density lithium-ion batteries.

This study designs a wearable power generator from a flexible, photocatalytic fuel cell (fPFC) using various biowaste sources (lactic acid, ethanol, methanol, urea, glycerol, and glucose) as fuel. The fPFC uses light irradiation and the decomposition of biowaste to generate electrical power under both flat and bending (r = 3 cm) conditions. When employed as a sweat band, the fPFC generates a maximum power 4.0 mW cm−2 g−1 from human sweat. The wearable fPFC is able to overcome many of the disadvantages of wearable microbial and enzymatic cells while providing comparable if not superior power density.

In this study, polypropylene (PP)/graphene nanoplatelet (GnPs) nanocomposites with very large sized GnPs (similar to 150 mu m) are prepared by melt extrusion followed by injection molding. A number of characteristics including thermal, mechanical, and electrical properties are analyzed. DSC shows that the introduction of GnPs facilitates the crystallization of polymer matrix due to a role of GnPs that serves as seeds for heterogeneous nucleation, and XRD reveals that GnPs have a minor induction effect of beta crystals. Taking advantage of the large size and high aspect ratio of GnPs, a relatively low percolation threshold of similar to 2.99 vol% is obtained with highly increased in-plane and through-plane electrical conductivity. The fitting of experimental data to the percolation theory indicates that GnPs are three dimensionally dispersed within the polymer matrix. The composites exhibit relatively limited mechanical enhancement due to compromising of GnPs by the shear force introduced during the compounding process. Overall, the usage of large sized GnPs is clearly beneficial for obtaining high electrical conductivity with a less amount of filler, but an enhanced dispersion of fillers with controlled morphology is required to achieve great physical and mechanical properties of the PP/GnPs composites. (C) 2017 Elsevier Ltd. All rights reserved.

A simple methodology is developed for the in-situ preparation of flexible, three-dimensional ordered macroporous (3DOM) TiO₂ electrodes with greatly enhanced mass transfer. The 3DOM electrode is fabricated using a polystyrene colloidal crystal templated carbon cloth, and provides significant improvements over conventional nanoparticle electrodes without the use of binder or other additive. When evaluated as an anode in a Li-ion battery, the 3DOM electrode provides outstanding high rate performance. The electrode provides a specific capacity of 174 mAh g-1 at a current density of 2 A g-1, which is 2.6 times greater than that achieved with a nanoparticle electrode (68 mAh g-1). The 3DOM electrode also achieves excellent cycling stability, with a capacity retention of 94.8% (181 mAh g-1) over 1000 cycles at 10C (1.7 A g-1) compared to 93.7% (67 mAh g-1) for the nanoparticle electrode. To the best of our knowledge, the performance of our 3DOM electrode is among the highest of binder-free, flexible TiO₂ electrodes. We believe that this methodology is highly useful and is easily transferable to other materials and applications.

A novel in situ vanadium-modified NiCo2S4 wrapped with graphene sheets was synthesized using a simple solvothermal technique.

Fiber-shaped supercapacitors (FSCs) are a promising candidate as power source or energy storage unit in wearable/stretchable electronics. However, it is still a significant challenge to design FSCs with excellent electrochemical performance while maintaining good flexibility to meet the requirement of wearable/stretchable electronics. Here, a flexible all-solid-state asymmetric FSCs has been rationally designed and successfully prepared with coaxial human hair/Ni/Graphene/MnO2 fiber as positive electrode and coaxial human hair/Ni/Graphene fiber as negative electrode. Importantly, the as-obtained FSCs show extraordinary flexibility and outstanding electrochemical performance with a wide potential window (1.8V), excellent rate capability (up to 20,000mVs−1), fast frequency response (τ0=55ms), high volumetric energy density (1.81mWhcm−3), long cycle stability. With the facile fabrication technology and low-cost raw materials, this strategy not only provides a reference for the construction of high-performance flexible FSCs, but also paves a new way to explore the next-generation portable/wearable energy storage devices.

Li-ion hybrid capacitors (LIHCs) as a novel and promising energy storage unit, consisting of a Li-ion battery type anode and an electrochemical double layer capacitance (EDLC) type cathode, has attracted enormous research attentions. However, it remains a significant challenge to obtain high-performance LIHCs due to most battery-type anodes with the sluggish kinetics of Li-ion storage and low specific capacitance of common capacitor-type cathodes. Thus, it is highly required to design and fabricate novel alternative high-performance battery type anode materials and capacitor-type cathode materials, able to deliver higher energies and power densities in organic electrolyte. In this work, a novel high-performance LIHCs is constructed by combining a Li-ion battery type anode (3D graphene/MoO3 nanocomposite) with a capacitor type cathode (3D graphene/PANI derived carbon material). Such a subtle design endow LIHCs with a wide voltage range of (3.8 V), a high energy density of 128.3 Wh·kg-1, and an ultra-long cycle life up to 3000 cycles with 87% capacity retention.

Novel in situ nickel doped 1-D lithium titanate nanofibers (Li4Ti5−xNixO12, where x = 0, 0.05 and 0.1) have been successfully synthesized using a facile electrospinning process.