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A polymerization strategy to integrate conjugated structures with rich redox-active units for lithium ion batteries has been rapidly adopted to realize highly efficient polymer cathodes, because polymerization can solve the poor conductivity issue as well as solubility problem, existing in small organic molecules. However, the structural–property correlation of such polymers has not been systematically investigated, and the great impact of the conjugated structures on the overall performance has not been clearly revealed. In this work, we design and synthesize three novel pyrene-4,5,9,10-tetraone (PTO)-based polymers containing different thiophene derivatives as linking units, poly(2,7-thiophene pyrene-4,5,9,10-tetraone) (P(PTO-T1)), poly(2,7-(2,2′-bithiophene)pyrene-4,5,9,10-tetraone) (P(PTO-T2)) and poly(2,7-(thieno[3,2-b]thiophene)pyrene-4,5,9,10-tetraone) (P(PTO-TT)), to tune their electronic structures for high-performance lithium-ion batteries (LIBs). All these three materials deliver high specific capacity and long-cycle stability, which benefits from the high activity of the PTO units, the good conductivity of conjugated frameworks, and the insoluble properties of the polymers. Moreover, polymers with different thiophene moieties show distinct electrochemical performances, among which P(PTO-TT) exhibits the best rate capability (a reversible capacity of 129 mA h g−1 at a high current density of 2 A g−1 and a high capacity retention of 94% after 1200 cycles). Electrochemical and theoretical analyses reveal that an optimized electronic structure of P(PTO-TT) determined by using the thieno[3,2-b]thiophene (TT) linking units is crucial to realize the excellent battery performance. Our work unveils the structure–property correlation of PTO-based polymers as cathode materials, which provides inspiration for rational design of polymer cathodes for high-performance LIBs. [ABSTRACT FROM AUTHOR]

Lithium–air batteries (LABs) have attracted tremendous attention since the proposal of the LAB concept in 1996 because LABs have a super high theoretical/practical specific energy and an infinite supply of redox-active materials, and are environment-friendly. However, due to the lack of critical electrode materials and a thorough understanding of the chemistry of LABs, the development of LABs entered a germination period before 2010, when LABs research mainly focused on the development of air cathodes and carbonate-based electrolytes. In the growing period, i.e., from 2010 to the present, the investigation focused more on systematic electrode design, fabrication, and modification, as well as the comprehensive selection of electrolyte components. Nevertheless, over the past 25 years, the development of LABs has been full of retrospective steps and breakthroughs. In this review, the evolution of LABs is illustrated along with the constantly emerging design, fabrication, modification, and optimization strategies. At the end, perspectives and strategies are put forward for the development of future LABs and even other metal–air batteries. [ABSTRACT FROM AUTHOR]

Interfacial engineering is an appealing strategy to construct heterogeneous nanostructures and tunes the morphology of metal–organic frameworks (MOFs) and MXenes for hybrid supercapacitors. Herein, a temperature-controlled annealing process is introduced to fabricate Ni-MOFs/V2CTx–MXene (Tx denotes the surface groups, –O, –OH, and –F) composites on Ni foam (NF) (namely MOF/MXene/NF) and subsequently build the heterogeneous structure of a hierarchically-porous nanorod composite without a change in the crystalline structure. Experimental characterizations and theoretical calculations reveal that Ni–O–V bridging bonds are constructed at the Ni-MOF and V2CTx interfaces, which could be used to establish a favorable electronic structure in promoting conductivity and reactivity. The optimized MOF/MXene/NF electrode obtained at 300 °C (i.e., MOF/MXene/NF-300) delivers an ultrahigh specific capacity of 1103.9 C g−1 at 1 A g−1. The as-assembled hybrid supercapacitor, composed of MOF/MXene/NF-300 as the cathode and activated carbon/NF as the anode, delivers a high energy density of 46.3 W h kg−1 at a power density of 746.8 W kg−1 and an outstanding cycling stability of ca. 118.1% capacity retention after 15 000 cycles. Such an achievement stems from the strong chemical bonds at the interface and unique porous morphology. This work suggests a new avenue for designing and preparing robust and high-performance electrode materials for hybrid supercapacitors. [ABSTRACT FROM AUTHOR]

Hydrogen (H2) has been extensively considered as a clean and renewable energy carrier and the most promising alternative to conventional fossil fuels for future energy supplies due to its ultrahigh energy density and zero pollution. Selective "on–off" switches for on-demand liquid-phase H2 evolution are crucial and challenging for efficient utilization and production of H2. At present, the on-demand liquid-phase H2 evolutions are mainly controlled by five types of switches, namely catalyst-transfer switch, phase-transfer switch, pH-adjusting switch, temperature-adjusting switch, and light-adjusting switch. In this minireview, an overview of these "on–off" approaches with a particular emphasis on the recent advances in mechanism exploration and applications has been presented. Finally, we provide the future research directions and perspectives for overcoming the challenges in the commercialization of a promising approach. [ABSTRACT FROM AUTHOR]

Organic cathode materials (OCMs), synthesized from abundant and renewable resources, could be the most promising cathode materials for next-generation high capacity lithium-ion batteries (LIBs) due to their inherent advantages of high specific capacity, low cost, and excellent safety. According to theoretical calculations, imide and thioimide could be two classes of high-capacity OCMs for LIBs since these OCMs could undergo H-transfer processes to generate reaction sites for lithium ion storage and facilitate the ultra-high storage capacity of cathode materials. In this work, we adopt cyanuric acid (CA) and trithiocyanuric acid (TTCA) as the imide and thioimide for cathode materials of LIBs. Based on the 6-electron storage mechanism, CA and TTCA have remarkable theoretical specific capacities of 1246 and 908 mA h g−1, and experimentally deliver capacities of 464.6 and 820.6 mA h g−1, respectively, at a current density of 500 mA g−1 at room temperature. A H-transfer reaction mechanism was proposed and supported by ex situ Raman and XPS studies, electrochemical characterization, and NMR measurements. This work suggests that the H-transfer mechanism could be a promising pathway for the design and development of OCMs for high-capacity cathodes in high energy density LIBs. [ABSTRACT FROM AUTHOR]

Pseudocapacitive energy storage via Li+ storage at the surface/interface of the electrode is promising for achieving both high energy density and high power density in lithium-ion batteries (LIBs). Thus, we created holey graphene (HG) via an etching method, and then in situ grew atomically thin mesoporous NiCo2O4 nanosheets on the HG surface, resulting in a NiCo2O4–HG heterostructure. Since both NiCo2O4 and HG possess atomic thickness and porous structures, the as-prepared nanocomposite enables efficient electrolyte diffusion and mass transfer, providing abundant accessible surface atoms for enhanced redox pseudocapacitance. Moreover, the strong coupling effect between NiCo2O4 and graphene produces an ultra-large interfacial area and enhanced electrical conductivity, and subsequently promotes the intercalation pseudocapacitance. Consequently, the NiCo2O4@HG exhibits a high specific capacity of 1103.4 mA h g−1 at 0.2C, ∼88.9% contribution from pseudocapacitance at 1 mV s−1, excellent rate capability, and ultra-long life up to 450 cycles with 931.2 mA h g−1 retention, significantly outperforming previously reported electrodes. This work suggests that the maximum exposure and utilization of the surface/interfacial active sites is vital for the construction of high-performance pseudocapacitive energy storage devices. [ABSTRACT FROM AUTHOR]

To obtain high energy density, it is crucial to fabricate high-loading electrodes, which is severely hindered by their mechanical degeneration. Furthermore, a general strategy with low cost, eco-friendliness, and facile operability is urgently required for wide application. Herein, a novel 3D network binder with an efficient damper is proposed via thermal condensation of polyacrylic acid and xanthan gum (c-PAA-XG), in which the covalent crosslinking provides robust mechanical strength to withstand the mechanical degeneration. Meanwhile, due to abundant dynamic intermolecular hydrogen bonds and molecular chain weaving, the double-helix-structure XG can partly deform and self-assemble and act as a high-efficiency damper to protect the network binder from fracture when large impulse occurs under high loading. Consequently, a wide range of ultrahigh-loading electrodes can be successfully achieved through simply applying this c-PAA-XG binder with traditional doctor blade coating technology on planar current collector. In particular, for the nano/micro-Si/C anode with a high loading of 18.3 mg cm−2, an ultrahigh reversible areal capacity of 27.7 mA h cm−2 can be delivered. Reaction kinetics investigations suggest that the charge–discharge process of the Si/C electrode is dominated by a capacitive-controlled behavior, resulting in fast storage/release of Li+ in high-loading electrodes. Furthermore, the c-PAA-XG binder has the advantages of low cost, eco-friendliness, and water-solubility, resulting in a sustainable electrode fabrication. [ABSTRACT FROM AUTHOR]

The loading of noble-metal cocatalysts on photocatalysts can significantly increase the energy conversion efficiency from light to hydrogen (H2). However, the high cost of noble metals limits their practical application. Therefore, it is of great significance to explore alternative catalysts based on noble-metal-free materials. Herein, FeNi intermetallic compound nanoparticles wrapped with N-doped graphitized carbon (FeNi@NGC) are prepared by a facile pyrolysis approach. The FeNi@NGC is used as a novel cocatalyst of host photocatalysts, such as g-C3N4, to boost their photogenerated charge separation. In an aqueous solution containing triethanolamine and under visible-light irradiation, the optimized FeNi@NGC/g-C3N4 (FNC15) composite photocatalyst exhibits significantly increased PC activity with a H2 production rate of 2.696 mmol g−1 h−1, which is over 283 times that of primary g-C3N4 and even higher than that of 1.0 wt% Pt/g-C3N4. Furthermore, the FNC15 showed excellent stability and reusability. The apparent quantum yield (AQY) of the FNC15 composite photocatalyst reaches 24.78% and 7.28% at 400 nm and 420 nm, respectively. Notably, the FNC15 can promote photocatalytic overall water splitting with an H2 evolution rate of about 0.167 mmol g−1 h−1. Experimental analysis and DFT calculations are performed to investigate the mechanism of excellent PC H2 evolution. It appears that the FeNi@NGC loading on the surface of host photocatalysts can (i) boost the charge carrier separation and transfer because of the secondary charge transfer in the FeNi intermetallic compound and (ii) ameliorate the kinetics of H2 evolution on the surface of the photocatalyst and achieve obviously enhanced H2 generation. This work provides a new strategy for preparing efficient noble-metal-free cocatalysts for boosting photocatalytic H2 evolution. [ABSTRACT FROM AUTHOR]

Sodium ion batteries (SIBs) and lithium–sulfur (Li–S) batteries are considered as the most promising next-generation energy storage devices to displace the widely used lithium ion batteries due to their inherent advantages. Here, polypyrrole-encapsulated amorphous Bi2S3 hollow spheres are prepared by the sulfuration of Bi–glycol spheres with a polypyrrole (PPy) coating. Benefiting from the unique hollow structure (Kirkendall effect) and the excellent conductivity and flexibility of the PPy coating, this material can be applied in both SIBs and Li–S batteries. For SIBs, the unconductive amorphous Bi2S3 is electrochemically reduced to conductive metallic Bi, leading to a Bi–PPy core–shell structure. The resulting Bi acts as the main active material while the PPy coating accommodates the volume variation of Bi during sodiation/desodiation. For Li–S batteries, the outer double layer structure effectively prevents the dissolution and “shuttle effect” of polysulfides by physically containing and chemically adsorbing polysulfides, and tolerates the volume expansion of sulfur. Meanwhile, the residual polyvinyl pyrrolidone in the preparation process is chemically bonded with sulfur and exhibits the electrochemical properties, and results in additional discharging/charging capacity. Thus, this multifunctional electrode shows excellent rate capability and cycling life in SIBs and Li–S batteries. This work provides new insight into the design of multifunctional electrodes. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) has drawn intense research interest over the past decade, contributing to remarkable progress in its relevant applications. The chemical production of GO, however, is challenged by destructive and slowly propagating oxidation, especially for large flake graphite. Herein, we report a simple but effective method to produce well-oxidized and less defective GO by chemically oxidizing commercially available expandable graphite at room temperature (25 °C). Compared to natural graphite with similar flake sizes, expandable graphite afforded faster complete oxidation under the same oxidizing conditions. In addition, chemical oxidation at room temperature, relative to that at higher temperatures (35 and 45 °C), resulted in a reduced defect concentration in GO. Furthermore, the GO derived from the oxidation of expandable graphite at room temperature exhibited superior electrical conductivity after mild thermal treatment at 150 °C. Considering the energy-saving in both GO synthesis and reduction, the low temperature GO conversion process can be easily integrated into many other electroconductive applications. As a proof of concept, we achieved a good LiFePO4 (without carbon-coating) cathode formulation with our GO, which contributed as a 2D binder (before annealing), and obtained a conductive cathode with improved capacity and high rate performance after mild thermal annealing at 150 °C. [ABSTRACT FROM AUTHOR]

Metal organic polymers (MOPs), including metal coordination polymers (CPs, one-dimensional), metal–organic frameworks (MOFs, two-/three-dimensional), Prussian blue (PB) and Prussian blue analogues (PBAs), have recently emerged as promising electrochemically active materials for energy storage and conversion systems. Due to the tunability of their composition and the structural versatility, diverse electrochemical behaviors for multi-electron reactions, fast-ion diffusion, and small volume change of electrodes could be achieved upon charging and discharging. Because of these superiorities, MOPs are considered as effective substitutes for future advanced energy storage systems. Here, we summarize the recent progress in pristine MOPs as electrode candidates for rechargeable lithium and sodium ion batteries. The working mechanisms and strategies for enhancing the electrochemical performance in related advanced electrochemical energy storage (EES) applications are also highlighted in this review. [ABSTRACT FROM AUTHOR]

In this work, phase boundary engineered cerium oxide–cerium nitride (CeO2/CeN) is synthesized and used as a high performance photocatalyst for photo-thermocatalytic degradation of organic pollutants in wastewater. A CeO2/CeN composite is obtained through simply annealing CeO2 nanowires under an ammonia atmosphere. Both theoretical and experimental analyses are used to study the interfacial interaction between CeO2 and CeN crystallites. Benefiting from the interface engineering, the as-prepared CeO2/CeN composite exhibits higher photo-thermocatalytic performance than pristine CeO2 for the removal of organic pollutants. Electron spin resonance (ESR) spectroscopy and liquid chromatography tandem mass spectrometry analysis of intermediates and products are used to further confirm the synergetic effect and degradation mechanism of the photo-thermocatalysis reactions. The results of this work suggest that the synergetic effect of the photo-thermal reaction can be considered as one of the most efficient strategies for environmental pollution remediation. [ABSTRACT FROM AUTHOR]

Constructing high-areal-capacity anodes with high loading for Li-ion batteries is still an enormous challenge, due to the drastic volume change of large-capacity anode materials during cycling. The conventional PVDF binder system fails to withstand the degradation of high-loading electrodes. Therefore, advanced binders are urgently required. Herein, for the first time, the guar gum (GG) biopolymer has been exploited as a robust binder for micro-sized ZnCo2O4 (ZCO) anode materials. Because of its robust mechanical properties and strong interactions with ZCO, the cycling stability of the ZCO anode has been significantly improved with a capacity of 412 mA h g−1 after 600 cycles at 1200 mA g−1. More importantly, the ZCO can act as a “crosslinking agent” to in situ form a robust network with GG, which efficiently maintains the electrode structure stability. Hence, a ZCO anode with an ultrahigh loading of 6.73 mg cm−2 can be achieved and deliver a high areal capacity of 5.6 mA h cm−2. Simultaneously, benefiting from the high tap density of micro-ZCO, the ZCO anode gives a high volumetric capacity of 1179 mA h cm−3. This study will make a significant contribution to accelerating the progress of designing high-areal-capacity anodes. [ABSTRACT FROM AUTHOR]

Binders play a crucial role in improving the electrochemical performance of batteries. The major challenges associated with the sulfur cathode in lithium-sulfur (Li–S) batteries are up to 76% volume change during cycling from sulfur (S) to lithium sulfide (Li2S) and the shuttle effect of polysulfide anions, resulting in poor cycling performance. Herein, we design a network binder through the crosslinking effect of sodium alginate (SA) and Cu2+ ions (named the SA–Cu binder), in which Cu2+ ions work not only as an ionic crosslinking agent for a robust network structure, but also as a chemical binding agent for polysulfide anions. The robust network binder buffers large volume variations during cycling, while electropositive Cu2+ ions immobilize polysulfide anions through strong chemical binding. The resulting sulfur electrode delivers a capacity of 925 mA h g−1 after 100 cycles at 0.2C, which is much higher than those of sulfur electrodes with only SA and PVDF binders. Due to the robust mechanical properties of the SA–Cu binder, a high-loading and crack-free sulfur electrode, i.e., a sulfur loading up to 8.05 mg cm−2, is also achieved and delivers a high areal capacity up to 9.5 mA h cm−2. This study paves a new way to immobilize polysulfide anions using the dual functions of Cu2+ ions as both the ionic crosslinking and chemical binding agents, which could open up a new direction for advanced binders for Li–S batteries in the near future. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) nanomaterials are extraordinarily attractive for use in energy storage devices because of their unique electronic and mechanical properties. However, the synthesis of ultrathin 2D nanomaterials is still a great challenge. In this paper, a top-down strategy using a high-pressure hydrogen surface treatment and controlled etching to reduce the thickness of iron(iii) oxide (Fe2O3) nanoplates is proposed. As a result, the ultrathin Fe2O3 hexagonal nanoflakes with a thickness of approximately 4 nm are successfully synthesized. When employed as an anode material in rechargeable lithium-ion batteries, it delivers a super-high reversible capacity of approximately 1043 mA h g−1 after 100 cycles at a current density of 0.1 A g−1 and approximately 578 mA h g−1 after 500 cycles at a current density of 5.0 A g−1. It is also the best performing Fe2O3 electrode among the reported Fe2O3 anodes in the literature. Such excellent cycling performances can be attributed to the ultrathin structure which is able to enhance the mass transport of the lithium ion, short electron transport length as well as tolerance of large volume changes. This work provides a guidance to the synthesis of ultra-thin 2D oxide nanomaterials for energy storage. [ABSTRACT FROM AUTHOR]

Conventional electrode manufacturing processes for lithium ion batteries involve the use of toxic organic solvents (such as N-methyl-2-pyrrolidone, NMP). A low cost and green preparation process for high performance electrodes for sodium ion batteries (SIBs) is important to address simultaneously the environmental and health risks of production processes and the shortage of lithium metal. Herein, gum arabic (GA), which is a non-toxic biodegradable biopolymer, is used as a water soluble binder to design a water-based electrode preparation process to fabricate α-Fe2O3 electrodes (i.e., α-Fe2O3@GA electrode). The α-Fe2O3@GA electrode demonstrates better mechanical properties and binding capability than that of the α-Fe2O3 electrode with poly(vinylidene fluoride) (PVDF) as the binder (α-Fe2O3@PVDF electrode). Due to these merits, a higher rate and cycling performance of the α-Fe2O3@GA electrode are achieved compared with the α-Fe2O3@PVDF electrode when both electrodes are used for SIBs' application. The α-Fe2O3@GA electrode demonstrates high initial discharge and charge capacities of 2437 and 1102 mA h g−1 at the current density of 0.2 A g−1. The α-Fe2O3@GA electrode maintains a high reversible discharge capacity of 492 mA h g−1 at the current density of 5 A g−1 after 500 cycles with a fading rate of 0.08% per cycle after the first cycle, which indicates a superior cycling performance. The outstanding performance of the resultant SIBs suggests that the green fabrication process of the α-Fe2O3@GA electrode would play a critical role in the future battery industry. [ABSTRACT FROM AUTHOR]

Conductive confinement of sulfur and polysulfides via carbonaceous blocking layers can simultaneously address the issues of low conductivity, volume expansion of sulfur during the charge/discharge process and the polysulfide shuttling effect in lithium–sulfur (Li–S) batteries. Herein, a conductive and porous nitrogen and phosphorus dual doped graphene (p-NP-G) blocking layer is prepared via a thermal annealing and subsequent hydrothermal reaction route. The doping levels of N and P in p-NP-G as measured by X-ray photoelectron spectroscopy are ca. 4.38% and ca. 1.93%, respectively. The dual doped blocking layer exhibits higher conductivity than N or P single doped blocking layers. More importantly, density functional theory (DFT) calculations demonstrate that P atoms and –P–O groups in the p-NP-G layer offer stronger adsorption of polysulfides than the N species. The electrochemical evaluation results illustrate that the p-NP-G blocking layer can deliver superior initial capacity (1158.3 mA h g−1 at a current density of 1C), excellent rate capability (633.7 mA h g−1 at 2C), and satisfactory cycling stability (ca. 0.09% capacity decay per cycle), which are better than those of the N or P single doped graphene. This work suggests that this synergetic combination of conductive and adsorptive confinement strategies induced by the multi-heteroatom doping scheme is a promising approach for developing high performance Li–S batteries. [ABSTRACT FROM AUTHOR]

A low cost, up-scalable and one-pot wet-mechanochemical approach is designed for fabricating TiO2–SnO2@graphene nanocomposites where TiO2 and SnO2 solid solution nanoparticles are evenly anchored on graphene sheets. As an anode material of lithium ion batteries (LIBs), the as-prepared nanocomposites deliver a superior rate performance of 388 mA h g−1 at 1.5 A g−1 and an outstanding reversible cycling stability (617 mA h g−1 at 0.4 A g−1 after 750 cycles, 92.2% capacity retention), due to the synergistic effects contributed from individual components, i.e., high specific capacity of SnO2, excellent conductivity of 3D porous graphene networks, good rate capability and structural stability of TiO2 structures. [ABSTRACT FROM AUTHOR]

Natural bamboo, as a sustainable precursor, is used to prepare porous bamboo carbon fibers (BCFs) that are subsequently interwoven into a BCF membrane (BCFM) as a captor interlayer for the lithium polysulfide intermediates between the sulfur cathode and the separator in Li–S batteries. On one hand, the interwoven BCFs offer efficient conductive networks. On the other hand, the pores of the BCFM facilitate fast mass transport of the electrolyte and Li ions and accommodate severe volume changes of the sulfur cathode during charge/discharge processes. Furthermore abundant macro/microporous structures of BCFs provide substantial adsorption capability to remarkably suppress the formation of the Li2S2/Li2S layer on the cathode and extend the lifetime of the electrode by successfully confining sulfur within the carbon networks. Consequently, Li–S batteries with the BCFM deliver excellent electrochemical performances with a high coulombic efficiency (ca. 98%), low capacity fade at only 0.11% per cycle, and long-term cyclability over 300 cycles at a high charge/discharge rate of 1 C. This green, low cost BCFM can provide an attractive alternative for large-scale commercialization of Li–S batteries. [ABSTRACT FROM AUTHOR]

The high capacity Si (4200 mA h g−1, Li4.4Si) commonly undergoes cracking and delamination due to drastic volume change (∼300%) during lithiation/delithiation processes in lithium ion batteries (LIBs). In this work, abundant and sustainable natural polymer gum arabic (GA) and low cost polyacrylic acid (PAA) are used to fabricate Si anodes with resilient, crack-blocking properties. The esterification reaction between GA and PAA establishes a flexible network resulting in reinforced mechanical strength and enhanced coherent strength. Meanwhile, the water vapour resulting from the esterification reaction generates micron-sized pores which relieves the stress and blocks the formation and propagation of cracks. As a result of the crack-blocking effect, the resultant Si anodes present a superior volumetric capacity of 2890 A h L−1. In addition, charge–discharge cycling for more than 1000 cycles is achieved with the Li insertion capacity limited to 1000 mA h g−1 at a 1 C rate. [ABSTRACT FROM AUTHOR]

Directional synthesis of SnO2@graphene nanocomposites via a one-step, low-cost, and up-scalable wet- mechanochemical method is achieved using graphene oxide and SnCl2 as precursors. The graphene oxides are reduced to graphene while the SnCl2 is oxidized to SnO2 nanoparticles that are in situ anchored onto the graphene sheets evenly and densely, resulting in uniform SnO2@graphene nanocomposites. The prepared nanocomposites possess excellent electrochemical performance and outstanding cycling in Li-ion batteries. [ABSTRACT FROM AUTHOR]

Here we report a green production process polymer binder, Eastman AQ™ 55S (EAQ) polymer, which has plentiful active hydroxyl groups on its surface that is different from the chemically inert PVDF binder for lithium ion batteries (LIBs). The water soluble EAQ binder tuned the performance of the oxidized graphite with carboxyl group for the maximum effect. [ABSTRACT FROM AUTHOR]

A simple photoelectrochemical method is developed to measure the intrinsic electron transport resistance (R0) of TiO2photoanodes. R0is considered as the sum of electron transport resistance at the TiO2/FTO interface and among TiO2nanoparticulates during electron transport process, which is independent of the manner of electron injection, its physical and chemical environments. Because TiO2photoanodes are the common electron transport pathways for dye-sensitized solar cells (DSSCs) process and the photoelectrocatalytic oxidation process, R0can be also considered as a quantitative measure of the electron transport resistance of the photoanodes in the DSSC process. The proposed method will provide a simple and rapid alternative to quantitatively evaluate the quality of the TiO2photoanodes for DSSCs using R0values. A series of TiO2/FTO photoanodes with different electron transport resistance were fabricated using conventional screen-printing technique, surface modifications using titanium organic sol and TiCl4aqueous solution. R0values of the photoanodes were characterized and subsequently used to correlate with the important performance parameters of the corresponding DSSCs. The preliminary results suggest that these surface modifications do not significantly affect the surface area, film thickness, dye loading and optical properties of the TiO2film, but significantly decrease the R0values. Furthermore, the DSSCs photoanodes with lower R0values due to the organic sol or TiCl4modification bestow better photovoltaic performance than the corresponding non-modified photoanodes. Therefore, it can be concluded that the performance improvements were mainly attributed to the decrease of the R0values, which validates the proposed electrochemical evaluation method. [ABSTRACT FROM AUTHOR]

Anatase TiO2microspheres with exposed mirror-like plane {001} facets were successfully synthesized viaa facile hydrothermal process. The photoanode composed of TiO2microsphere top layer shows an improved DSSCs efficiency owing to the superior light scattering effect of microspheres and excellent light reflecting ability of the mirror-like plane {001} facets. [ABSTRACT FROM AUTHOR]

Anatase TiO(2) microspheres with exposed mirror-like plane {001} facets were successfully synthesized via a facile hydrothermal process. The photoanode composed of TiO(2) microsphere top layer shows an improved DSSCs efficiency owing to the superior light scattering effect of microspheres and excellent light reflecting ability of the mirror-like plane {001} facets.

A simple photoelectrochemical method is developed to measure the intrinsic electron transport resistance (R(0)) of TiO(2) photoanodes. R(0) is considered as the sum of electron transport resistance at the TiO(2)/FTO interface and among TiO(2) nanoparticulates during electron transport process, which is independent of the manner of electron injection, its physical and chemical environments. Because TiO(2) photoanodes are the common electron transport pathways for dye-sensitized solar cells (DSSCs) process and the photoelectrocatalytic oxidation process, R(0) can be also considered as a quantitative measure of the electron transport resistance of the photoanodes in the DSSC process. The proposed method will provide a simple and rapid alternative to quantitatively evaluate the quality of the TiO(2) photoanodes for DSSCs using R(0) values. A series of TiO(2)/FTO photoanodes with different electron transport resistance were fabricated using conventional screen-printing technique, surface modifications using titanium organic sol and TiCl(4) aqueous solution. R(0) values of the photoanodes were characterized and subsequently used to correlate with the important performance parameters of the corresponding DSSCs. The preliminary results suggest that these surface modifications do not significantly affect the surface area, film thickness, dye loading and optical properties of the TiO(2) film, but significantly decrease the R(0) values. Furthermore, the DSSCs photoanodes with lower R(0) values due to the organic sol or TiCl(4) modification bestow better photovoltaic performance than the corresponding non-modified photoanodes. Therefore, it can be concluded that the performance improvements were mainly attributed to the decrease of the R(0) values, which validates the proposed electrochemical evaluation method.

A new approach to overcome chloride interferences in the photoelectrochemical determination of chemical oxygen demand (PeCOD) was developed. This approach was based on the kinetic characteristics of photocatalytic oxidation reactions of chloride in the presence and absence of organics. The effectiveness of the proposed approach was evaluated using the newly developed PeCOD system with a wide range of possible scenarios. It was found that the chloride interference was insignificant when a sample meets the two critical criteria, i.e., chloride concentration