Energy & Environmental Science (Energ Environ Sci )

Publisher: Royal Society of Chemistry (Great Britain)

Description

The journal recognises the complexity of issues and challenges relating to energy and environmental science and therefore particularly welcomes work of an interdisciplinary nature across both the (bio) chemical and (bio)physical sciences and chemical engineering disciplines.

  • Impact factor
    11.65
  • 5-year impact
    12.46
  • Cited half-life
    1.80
  • Immediacy index
    3.09
  • Eigenfactor
    0.06
  • Article influence
    3.46
  • Website
    Energy & Environmental Science website
  • Other titles
    Energy & environmental science, Energy and environmental science, EES
  • ISSN
    1754-5706
  • OCLC
    232359932
  • Material type
    Document, Periodical, Internet resource
  • Document type
    Internet Resource, Computer File, Journal / Magazine / Newspaper

Publications in this journal

  • Daniel Gamelin, Gerard Carroll, Diane Zhong
    [Show abstract] [Hide abstract]
    ABSTRACT: Interfacing α-Fe2O3 photoanodes with the water-oxidation electrocatalyst Co-Pi is known to enhance their photon-to-current conversion efficiencies by reducing electron-hole recombination near their surfaces, particularly at cathodic potentials, but the mechanism by which Co-Pi modification achieves this enhancement remains poorly understood. Conflicting experimental observations have been recorded with respect to the role of Co-Pi thickness and even the participation of Co-Pi in catalysis, raising important general questions concerning the fundamental properties of catalyst-modified PEC water-oxidation photoanodes for solar energy conversion. Here, we report results from electrochemical, spectroscopic, and microscopic measurements on mesostructured Co-Pi/α-Fe2O3 composite photoanodes that reveal evolving pathways of water oxidation with increasing Co-Pi thickness. These results highlight major fundamental differences between structured and planar Co-Pi/α-Fe2O3 composite photoanodes and help to reconcile previously conflicting mechanistic interpretations.
    Energy & Environmental Science 11/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Room temperature Na-ion secondary battery has been under focus lately due to its feasibility to compete against already well-established Li-ion secondary battery. Although there are many obstacles to overcome before Na-ion battery becomes commercially available, recent research discoveries corroborate that some of the cathode materials for Na-ion battery have indeed indisputable advantages over its Li-ion counterparts. In this publication, a comprehensive review of layered oxides (NaTMO2, TM = Ti, V, Cr, Mn, Fe, Co, Ni, and mixture of 2 or 3 elements) as a viable Na-ion battery cathode is presented. Unary systems are well characterized not only for their electrochemical performance but also for their structural transitions during the cycle. Binary systems are investigated in order to address issues regarding low reversible capacity, capacity retention, operating voltage, and structural stability. In consequence, some materials already have reached energy density of 520 mW h g-1, which is comparable to that of LiFePO4. Furthermore, some ternary system retained more than 72% of its capacity along with over 99.7% Coulombic efficiency for 275 cycles. The goal of this review is to present the development of Na layered oxide materials in the past as well as state of the art today in order to emphasize compatibility and durability of layered oxide as a powerful candidate for Na-ion battery cathode material.
    Energy & Environmental Science 11/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: All photovoltaic solar cells transmit photons with energies below the absorption threshold (bandgap) of the absorber material, which are therefore usually lost for the purpose of solar energy conversion. Upconversion (UC) devices can harvest this unused sub-threshold light behind the solar cell, and create one higher energy photon out of (at least) two transmitted photons. This higher energy photon is radiated back towards the solar cell, thus expanding the utilization of the solar spectrum. Key requirements for UC units are a broad absorption and high UC quantum yield under low-intensity incoherent illumination, as relevant to solar energy conversion devices, as well as long term photostability. Upconversion by triplet-triplet annihilation (TTA) in organic chromophores has proven to fulfil the first two basic requirements, and first proof-of-concept applications in photovoltaic conversion as well as photo(electro)chemical energy storage have been demonstrated. Here we review the basic concept of TTA-UC and its application in the field of solar energy harvesting, and assess the challenges and prospects for its large-scale application, including the long term photostablity of TTA upconversion materials.
    Energy & Environmental Science 11/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Thermal energy was shown to be efficiently converted into electrical power in a thermally regenerative ammonia-based battery (TRAB) using copper-based redox couples [Cu(NH3)42+/Cu and Cu2+/Cu]. Ammonia addition to the anolyte (2 M ammonia in a copper-nitrate electrolyte) of a single TRAB cell produced a maximum power density of 115 ± 1 W m–2 (based on projected area of a single copper mesh electrode), with an energy density of 453 Wh m–3 (normalized to the total electrolyte volume, under maximum power production condition). Adding a second cell doubled both the voltage and maximum power production. Increasing the anolyte ammonia concentration to 3 M further improved power density to 136 ± 3 W m–2. Volatilization of ammonia from the spent anolyte by heating (simulating distillation), and re-addition of this ammonia to the spent catholyte chamber with subsequent operation of this chamber as the anode (to regenerate copper on the other electrode), produced a power density of 60 ± 3 W m–2, with an average energy recovery of ~29% (energy captured versus energy in the starting solutions). Power was restored to 126 ± 5 W m–2 through acid addition to the regenerated catholyte to decrease pH and dissolve Cu(OH)2 precipitates, suggesting that an inexpensive acid or a waste acid could be used to improve performance. These results demonstrated that TRABs using ammonia-based electrolytes and inexpensive copper electrodes can provide a practical method for efficient conversion of low-grade thermal energy into electricity.
    Energy & Environmental Science 11/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Rational design of non-noble metal catalysts with the electrocatalytic activity comparable or even superior to Pt is extremely important for the future fuel cell-based renewable energy device. Herein, we demonstrate a new concept that metal-organic framework (MOF) can be used as a novel precursor to in-situ encapsulate Co@Co3O4@C core@bishell nanoparticles (NPs) into a highly ordered porous carbon matrix (CM) (denoted as Co@Co3O4@C-CM).The central cobalt ions from MOF are used as metal source to produce Co metal cores, which are later transformed into fancy Co@Co3O4 nanostructure via a controlled oxidation. The most notable feature of our Co@Co3O4@C-CM is that the highly ordered CM can provide much better transport pathway than the disordered pure MOF derived nanostructure that can facilitate the mass transport of O2 and electrolyte. As a result, the well-designed Co@Co3O4@C-CM derived from MOF shows almost identical activity but superior stability and methanol tolerance for ORR relatively to the commercial Pt/C in alkaline medium. Our work first reports the novel Co@Co3O4@C nanostructure from MOF and also reveals the important role of the introduction of highly ordered carbon matrix into MOF derived catalyst on enhancing the ORR activity and stability. To the best of our knowledge, Co@Co3O4@C-CM is the most efficient non-noble metal nanocatalyst ever reported for ORR.
    Energy & Environmental Science 11/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Global greenhouse gas (GHG) emission targets can only be met by significantly decarbonising road transport. The only long term way to do this is via the electrification of powertrains combined with the production of low carbon electricity or hydrogen. Current assumptions and models, such as the IEA BLUE Map, demonstrate that this is technically possible, but assume growth in demand for transport services will only double by 2035 and triple by 2050, largely driven by growth in developing economies. However, another transport revolution, automated vehicles, could drive growth in transport services significantly further, which without electrification will have a large negative impact on efforts to curb transport related emissions. In contrast, it is shown in this paper that automated vehicles could significantly improve the economics of electric vehicles, and therefore make the electrification of powertrains more likely, which could help reduce emissions. Despite this uncertainty, little work has been done on understanding how these factors will affect each other, particularly the timing and uptake of automated vehicles and their effect on future transport related GHG emissions and economics, yet the impact on transport policy, infrastructure and society will be profound and should be of interest to policy makers, the automotive and energy industries, and society as a whole.
    Energy & Environmental Science 11/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: We report new p-type FeNb1-xTixSb (0.04≤ x ≤0.24) half-Heusler thermoelectric materials with a maximum zT of 1.1 at 1100K, which is twice higher than the ZrCoSb half-Heusler alloys. The electrical properties are optimized by a tradeoff between band effective mass and mobility via a band engineering approach. High content of Ti up to x=0.2 optimizes the power factor and reduces lattice thermal conductivity. In view of abundantly available elements, good stability and high zT, FeNb1-xTixSb alloys can be great promising for high temperature power generation.
    Energy & Environmental Science 11/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Three dimensional graphene-based composites (3DGCs) have attracted great attention for lithium ion battery applications due to their unique structures and attractive properties. A large number of 3DGCs with novel structures and functions have been developed in the past few years. This review summarizes the current progress of 3DGCs, including their preparation and application in lithium ion batteries, especially from the view point of structurual and interfacial engneering, which have attracted more and more attention for the development of high performance electrode systems.
    Energy & Environmental Science 11/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: The microstructure and photophysics of low-band gap, all-polymer photovoltaic blends are presented. Blends are based on the donor polymer BFS4 (a dithienyl-benzo[1,2-b:4,5-b]dithiophene / 5-fluoro-2,1,3-benzothiadiazole co-polymer) paired with the naphthalene diimide-based acceptor polymer P(NDI2OD-T2). Efficiencies of over 4% are demonstrated, with an open circuit voltage of greater than 0.9 V achieved. Transmission electron microscopy reveals a relatively coarse phase-separated morphology, with elongated domains up to 200 nm in width. Near-edge x-ray absorption fine-structure (NEXAFS) spectroscopy and atomic force microscopy (AFM) measurements reveal that the top surface of BFS4:P(NDI2OD-T2) blends is covered with a pure BFS4 capping layer. Depth profiling measurements confirm this vertical phase separation with a surface-directed spinodal decomposition wave observed. Grazing-incidence wide-angle x-ray scattering (GIWAXS) measurements confirm that BFS4 and P(NDI2OD-T2) are semicrystalline with both polymers retaining their semicrystalline nature when blended. Photoluminescence spectroscopy reveals incomplete photoluminescence quenching with as much as 30% of excitons failing to reach a donor/acceptor interface. Transient absorption spectroscopy measurements also find evidence for rapid geminate recombination.
    Energy & Environmental Science 11/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Organic semiconductor materials have advantages of low cost, light weight, mechanical flexibility and low-temperature solution processability over large areas, enabling the development of personal, portable, and flexible thermal modules. This review article summarizes the recent progress made in the area of organic thermoelectrics (TEs), including organic molecular structures, devices, characterization methods, and approaches to improving the performance. We begin with the discussion of each TE parameter and particularly their correlations in organic TEs. Then the TE applications of molecular organic semiconductors, poly(3,4-ethylenedioxythiophene), polymer nanostructures and molecular junctions are reviewed. Next we turn to highlight the nanocomposites of polymers and carbon nanotubes or nanocrystals, which lead to enhanced TEs. Interestingly, the merge of TEs and photovoltaics offers a new direction towards a great capability of electric energy output. Critical challenges of organic TE materials include stability, sample preparation and measurement techniques, which are also discussed. Finally, the relationship among organic semiconductor structures, hybrid composites, doping states, film morphology and TE performance are revealed, and a viable avenue is envisioned for synergistic optimization of organic TEs.
    Energy & Environmental Science 11/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Alkylation of aromatics with HMF is a new route for the synthesis of biofuels. Alkylation of toluene with HMF has been studied in the presence of large pore (HBeta, USY and Mordenite), delaminated zeolites as well as on mesoporous aluminosilicates. In all cases a mixture of monoalkylated of 5-(o-, m- and p-methyl)benzylfuran-2-carbaldehyde and OBMF coming from self etherification of HMF were obtained. Large pore 3D (USY) and especially 2D (ITQ-2) zeolites are active and selective catalysts for this transformation. The alkylation reaction was extended with good success to other substituted benzenes as well as to a heavy reformate mixture as a source aromatic compounds achieving 91% yield of alkylated products with 93% selectivity. Further hydrodeoxygenation of alkylated compounds in a fixed continuous reactor was performed using Pt/C and Pt/TiO2 as catalysts allowing to obtain a hydrocarbon mixture containing of alkylcyclohexane compounds that can be used as high quality kerosene.
    Energy & Environmental Science 11/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Conductive, amorphous TiO2 coatings deposited by atomic-layer deposition, in combination with a sputter deposited NiCrOx oxygen-evolution catalyst, have been used to protect Si microwire arrays from passivation or corrosion in contact with aqueous electrolytes. Coated np+-Si/TiO2/NiCrOx as well as heterojunction n-Si/TiO2/NiCrOx Si microwire-array photoanodes exhibited stable photoelectrochemical operation in aqueous ferri-/ferro-cyanide solutions. The coatings also allowed for photoanodic water oxidation in 1.0 M KOH(aq) solutions for >2200 h of continuous operation under simulated 1 Sun conditions with 100% Faradaic efficiency for the evolution of O2(g).
    Energy & Environmental Science 11/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: The mechanical properties of organic semiconductors and the mechanical failure mechanisms of devices play critical roles in the yield of modules in roll-to-roll manufacturing and the operational stability of organic solar cells (OSCs) in portable and outdoor applications. This paper begins by reviewing the mechanical properties—principally stiffness and brittleness—of pure films of organic semiconductors. It identifies several determinants of the mechanical properties, including molecular structures, polymorphism, and microstructure and texture. Next, a discussion of the mechanical properties of polymer–fullerene bulk heterojunction blends reveals the strong influence of the size and purity of the fullerenes, the effect of processing additives as plasticizers, and the details of molecular mixing—i.e., the extent of intercalation of fullerene molecules between the side chains of the polymer. Mechanical strain in principle affects the photovoltaic output of devices in several ways, from strain-evolved changes in alignment of chains, degree of crystallinity, and orientation of texture, to debonding, cohesive failure, and cracking, which dominate changes in the high-strain regime. These conclusions highlight the importance of mechanical properties and mechanical effects on the viability of OSCs during manufacture and in operational environments. The review—whose focus is on molecular and microstructural determinants of mechanical properties—concludes by suggesting several potential routes to maximize both mechanical resilience and photovoltaic performance for improving the lifetime of devices in the near term and enabling devices that require extreme deformation (i.e., stretchability and ultra-flexibility) in the future.
    Energy & Environmental Science 11/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: The rapid increase in efficiency of methylammonium lead halide perovskite solar cells necessitates further investigation into the nature of perovskite absorption features and optical properties. Films obtained from the deposition of solutions containing lead halides and the CH3NH3+ organic cation is known to yield the CH3NH3PbI3 perovskite structure upon annealing. In examining the precursor solution used in the processing of CH3NH3PbI3 solar cells, we find that Pb2+ readily forms plumbate complexes in the presence of excess iodide ions and exhibits characteristic absorption bands at 370 (PbI3-) and 425 nm (PbI42-). Through comparative spectral analysis of the absorption features of charge transfer complexes in the solution phase and the final solid-state perovskite films, we are able to fully classify the absorption features in the excited state of CH3NH3PbI3 across the transient absorption spectrum recorded following laser pulse excitation. In particular, we attribute the broad photoinduced absorption to a charge-transfer excited state, and show correlation between the photoinduced absorption and 480 nm bleach signals. These observations lead us to propose a band structure composed of two distinct transitions that is consistent with the various spectral features and kinetic behavior of the CH3NH3PbI3 excited state. Characterization of this unique dual excited state nature provides further insight into the optoelectronic behavior of hybrid lead halide perovskite films and thus aids in elucidating their exceptional photovoltaic properties.
    Energy & Environmental Science 11/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: We report on layered NaTiO2 as a potential anode material for Na-ion batteries. The material is prepared from only earth-abundant elements, delivers 152 mAhg-1 of reversible capacity at C/10 rate, shows excellent cyclability with capacity retention over 98% after 60 cycles, and high rate capability. Furthermore, in situ X-ray diffraction analysis reveals a reversible O3-O’3 phase transition, including an unusual lattice parameter variation coupled to complicated Na vacancy orderings in a series of 2nd order phase transitions.
    Energy & Environmental Science 10/2014;