Review of UK microgeneration. Part 1 : policy and behavioural aspects

A critical review of the literature relating to government policy and behavioural aspects relevant to the uptake and application of microgeneration in the UK is presented. Given the current policy context aspiring to zero-carbon new homes by 2016 and a variety of minimum standards and financial policy instruments supporting microgeneration in existing dwellings, it appears that this class of technologies could make a significant contribution to UK energy supply and low-carbon buildings in the future. Indeed, achievement of a reduction in greenhouse gas emissions by 80% (the UK government's 2050 target) for the residential sector may entail substantial deployment of microgeneration. Realisation of the large potential market for microgeneration relies on a variety of inter-related factors such as microeconomics, behavioural aspects, the structure of supporting policy instruments and well-informed technology development. This article explores these issues in terms of current and proposed policy instruments in the UK. Behavioural aspects associated with both initial uptake of the technology and after purchase are also considered

High speed 4D neutron computed tomography for quantifying water dynamics in polymer electrolyte fuel cells

In recent years, low temperature polymer electrolyte fuel cells have become an increasingly important pillar in a zero carbon strategy for curbing climate change, with their potential to power multiscale stationary and mobile applications. The performance improvement is a particular focus of research and engineering roadmaps, with water management being one of the major areas of interest for development. Appropriate characterisation tools for mapping the evolution, motion and removal of water are of high importance to tackle shortcomings. This article demonstrates the development of a 4D high speed neutron imaging technique, which enables a quantitative analysis of the local water evolution. 4D visualisation allows the time resolved studies of droplet formation in the flow fields and water quantification in various cell parts. Performance parameters for water management are identified that offer a method of cell classification, which will, in turn, support computer modelling and the engineering of next generation flow field design

Roadmap on Li-ion battery manufacturing research

Growth in the Li-ion battery market continues to accelerate, driven primarily by the increasing need for economic energy storage for electric vehicles. Electrode manufacture by slurry casting is the first main step in cell production but much of the manufacturing optimisation is based on trial and error, know-how and individual expertise. Advancing manufacturing science that underpins Li-ion battery electrode production is critical to adding to the electrode manufacturing value chain. Overcoming the current barriers in electrode manufacturing requires advances in materials, manufacturing technology, in-line process metrology and data analytics, and can enable improvements in cell performance, quality, safety and process sustainability. In this roadmap we explore the research opportunities to improve each stage of the electrode manufacturing process, from materials synthesis through to electrode calendering. We highlight the role of new process technology, such as dry processing, and advanced electrode design supported through electrode level, physics-based modelling. Progress in data driven models of electrode manufacturing processes is also considered. We conclude there is a growing need for innovations in process metrology to aid fundamental understanding and to enable feedback control, an opportunity for electrode design to reduce trial and error, and an urgent imperative to improve the sustainability of manufacture

Roadmap on Li-ion battery manufacturing research

Growth in the Li-ion battery market continues to accelerate, driven by increasing need for economic energy storage in the electric vehicle market. Electrode manufacture is the first main step in production and in an industry dominated by slurry casting, much of the manufacturing process is based on trial and error, know-how and individual expertise. Advancing manufacturing science that underpins Li-ion battery electrode production is critical to adding value to the electrode manufacturing value chain. Overcome the current barriers in the electrode manufacturing requires advances in material innovation, manufacturing technology, in-line process metrology and data analytics to improve cell performance, quality, safety and process sustainability. In this roadmap we present where fundamental research can impact advances in each stage of the electrode manufacturing process from materials synthesis to electrode calendering. We also highlight the role of new process technology such as dry processing and advanced electrode design supported through electrode level, physics-based modelling. To compliment this, the progresses in data driven models of full manufacturing processes is reviewed. For all the processes we describe, there is a growing need process metrology, not only to aid fundamental understanding but also to enable true feedback control of the manufacturing process. It is our hope this roadmap will contribute to this rapidly growing space and provide guidance and inspiration to academia and industry

Challenges and opportunities for characterisation of high-temperature polymer electrolyte membrane fuel cells: a review

High-temperature (120–200 °C) polymer electrolyte membrane fuel cells (HT-PEMFCs) are promising energy conversion devices that offer multiple advantages over the established low-temperature (LT) PEMFC technology, namely: faster reaction kinetics, improved impurity tolerance, simpler water and thermal management, and increased potential to utilise waste heat. Whilst HT- and LT-PEMFCs share several components, important differences in the membrane materials, transport mechanisms and operating conditions provide new challenges and considerations for characterisation. This review focuses on phosphoric acid-doped HT-PEMFCs and provides a detailed discussion of the similarities and differences compared to LT-PEMFCs, as well as state-of-the-art performance and materials. Commonly used characterisation techniques including electrochemical, imaging, and spectroscopic methods are reviewed with a focus on use in HT-PEMFCs, how experimentation or analyses differ from LT-PEMFCs, and new opportunities for research using these techniques. Particular consideration is given to the presence of phosphoric acid and the absence of liquid water. The importance of accelerated stress tests for effective characterisation and durability estimation for HT-PEMFCs is discussed, and existing protocols are comprehensively reviewed focusing on acid loss, catalyst layer degradation, and start-up/shutdown cycling. The lack of standardisation of these testing protocols in HT-PEMFC research is highlighted as is the need to develop such standards

Multiscale tomographic analysis of the thermal failure of Na-Ion batteries

In recent years, the ability to examine the processes that cause the catastrophic failure of batteries as a result of thermal runaway has improved substantially. In this work, the effect of thermal runaway on the microstructure of the electrodes of a Na-ion battery is examined using X-ray computed tomography for the first time. The thermal failure induced via accelerating rate calorimetry enabled the examination of failed electrodes, which were subsequently compared with fresh samples. Pre- and post-mortem microstructural analysis shows changes in both electrodes as a result of the thermal runaway process at the micrometre length-scale. It is seen that the cathode shows the largest changes in structure, with the anode remaining morphologically similar post-failure at the sub-micron length-scale. The formation of a highly X-ray attenuating layer, which is proposed to be a metallic product of the thermal runaway reaction, is observed, indicating that the thermal runaway mechanisms which occur in Na-ion batteries may be similar to those reported for Li-ion systems

ZIF-8-derived hollow carbon for efficient adsorption of antibiotics

The harmful nature of high concentrations of antibiotics to humans and animals requires the urgent development of novel materials and techniques for their absorption. In this work, CTAB (Cetyltrimethyl Ammonium Bromide)-assisted synthesis of ZIF-8 (zeolitic imidazolate framework)-derived hollow carbon (ZHC) was designed, prepared, and used as a high-performance adsorbent, and further evaluated by Langmuir and Freundlich isothermal adsorption experiments, dynamic analysis, as well as theoretical calculation. The maximum capacities of ZHC for adsorbing tetracycline (TC), norfloxacin (NFO), and levofloxacin (OFO) are 267.3, 125.6, and 227.8 mg g−1, respectively, which delivers superior adsorptive performance when compared to widely studied inorganic adsorbates. The design concept of ZIF-8-derived hollow carbon material provides guidance and insights for the efficient adsorbent of environmental antibiotics

Core–shell TiO2@C ultralong nanotubes with enhanced adsorption of antibiotics

As materials capable of adsorbing antibiotics continue to be developed, composite adsorbents have been shown to offer advantages over mono-material adsorbents. In this work, ultralong titanium dioxide@carbon nanotubes were prepared by a simple hydrothermal treatment, followed by carbonization. The composite material is able to adsorb three different categories of antibiotics, including tetracycline (TC), ofloxacin (OFO) and norfloxacin (NFO). The adsorption results show that the adsorption properties of composite materials have been greatly improved compared with single inorganic adsorbent materials, for which the adsorption capacities are 240 mg g−1 (TC), 232 mg g−1 (OFO), and 190 mg g−1 (NFO), respectively. The adsorption mechanism is consistent with a Langmuir pseudo-first-order kinetic model

A nature inspired solution for water management in flow fields for electrochemical devices

A systematic, nature inspired chemical engineering approach is employed to solve the issue of flooding in electrochemical devices. The mechanism of passive water transport utilized by lizards living in arid environments is leveraged to design flow fields with a microchannel structure on their surface, through which capillary pressure rapidly removes the water generated in the electrochemical device. This water management strategy is implemented in proton exchange membrane fuel cells PEMFCs with a lung inspired flow field, which ensures uniform distribution of reactants across the catalyst layer. Jointly, this nature inspired approach results in flood free, stable operation at 100 RH and a amp; 8764;60 increase in current amp; 8764;1.9 A cm amp; 8722;2 and peak power density amp; 8764;650 mW cm amp; 8722;2 compared to current PEMFCs with a flood prone, serpentine flow field amp; 8764;0.8 A cm amp; 8722;2 and 280 mW cm amp; 8722;2, respectively . This significant advance allows for PEMFC operation at fully humidified condition

Two-dimensional model of low-pressure PEM electrolyser: Two-phase flow regime, electrochemical modelling and experimental validation

International audienceBased on proton conduction of polymeric electrolyte membrane (PEM) technology, the PolymerElectrolyte Membrane Water Electrolyser (PEMWE) offers an interesting solution forefficient hydrogen production. During the electrolysis of water in PEMWE, water is split intooxygen, protons and electrons at the anode and a water-gas two-phase flow results. The aimof this study is to investigate the link between the two-phase flow at the anode side and cellperformance under low-pressure conditions. We have developed a two-dimensional stationaryPEMWE model that takes into account electrochemical reaction, heat transfer, masstransfer (bubble flow) and charge balance through theMembrane Electrodes Assembly (MEA).In order to take into account the changing electrical behaviour, our model combines twoscales of descriptions: at microscale within anodic active layer and MEA scale. The watermanagement at both scales is strongly linked to the Not Coalesced Bubble regime (NCBregime) or the Coalesced Bubble regime (CB regime). Therefore, water content close to activesurface areas depends on two-phase flow regimes. Our simulation results demonstrate thatthe coalesced phenomenon is associated with improvement of mass transfer, a decrease inohmic resistance and an enhancement of the PEMWE efficiency. At low and medium currentdensity values, themodel has been validated using two separate experiment electrolysis cells