The 3D printing of a polymeric electrochemical cell body and its characterisation

An undivided flow cell was designed and constructed using additive manufacturing technology and its mass transport characteristics were evaluated using the reduction of ferricyanide, hexacyanoferrate (III) ions at a nickel surface. The dimensionless mass transfer correlation Sh = aRebScdLee was obtained using the convective-diffusion limiting current observed in linear sweep voltammetry; this correlation compared closely with that reported in the literature from traditionally machined plane parallel rectangular flow channel reactors. The ability of 3D printer technology, aided by computational graphics, to rapidly and conveniently design, manufacture and re-design the geometrical characteristics of the flow cell ishighlighted

Energy monitoring as a practice: Investigating use of the iMeasure online energy feedback tool

Energy feedback is a prominent feature of policy initiatives aimed at reducing domestic energy consumption. However little research has been conducted on the phenomenon of energy monitoring itself, with most studies looking at whether, and how, feedback impacts on energy conservation. This paper aims to address that gap from a practice theory perspective. In particular we: set out the difference between energy feedback and energy monitoring; define the practice of energy monitoring; and investigate the rationale and qualitative experiences of those performing energy monitoring. An online energy feedback tool (‘iMeasure’) was the basis of the case study. A netnographic analysis of online discussion about the tool informed complementary in-depth interviews with ten current/former iMeasure users. We found energy monitoring to be a distinct practice that focuses on measuring and identifying energy use trends and requires specific know-how to perform. However, its connections to other household practices were weak and, for those who did perform monitoring, there was no guarantee that this practice would reorganise other practices to induce household energy saving. In fact, monitoring often followed decisions to make energy-related changes, rather than prompting them. We conclude that policy expectations need to be reframed in terms of how energy monitoring tools are used

Electrochemically treated TiO₂ for enhanced performance in aqueous Al-ion batteries

The potential for low cost, environmentally friendly and high rate energy storage has led to the study of anatase-TiO2 as an electrode material in aqueous Al3+ electrolytes. This paper describes the improved performance from an electrochemically treated composite TiO2 electrode for use in aqueous Al-ion batteries. After application of the cathodic electrochemical treatment in 1 mol/dm3 KOH, Mott-Schottky analysis showed the treated electrode as having an increased electron density and an altered open circuit potential, which remained stable throughout cycling. The cathodic treatment also resulted in a change in colour of TiO2. Treated-TiO2 demonstrated improved capacity, coulombic efficiency and stability when galvanostatically cycled in 1 mol·dm-3AlCl3/1 mol·dm-3 KCl. A treated-TiO2 electrode produced a capacity of 15.3 mA·h·g-1 with 99.95% coulombic efficiency at the high specific current of 10 A/g. Additionally, X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy were employed to elucidate the origin of this improved performance.</p

Advances in prevention of thermal runaway in lithium-ion batteries

The prevention of thermal runaway (TR) in lithium‐ion batteries is vital as the technology is pushed to its limit of power and energy delivery in applications such as electric vehicles. TR and the resulting fire and explosion have been responsible for several high‐profile accidents and product recalls over the past decade. Herein, the causes of TR are described and novel preventative methods are examined, approaching the problem from different angles by altering the internal structure of the battery to undergo thermal shutdown or developing the battery and thermal management systems so that they can detect and prevent TR. Ultimately, a variety of different technologies is needed to address the emerging market of highly specialized lithium‐ion batteries. Key innovations discussed include positive temperature coefficient (PTC) materials, self‐healing polymer electrolytes, and hybrid liquid–solid‐state electrolytes. Mist cooling achieves a highly uniform temperature inside the battery pack without the need for pumps to circulate a coolant. The development of battery management systems (BMSs) which model the internal temperature of the cell from real‐time data and prevent the cell reaching a critical temperature is an essential area for further research

A review of the iron–air secondary battery for energy storage

Recent interest in the iron–air flow battery, known since the 1970s, has been driven by incentives to develop low-cost, environmentally friendly and robust rechargeable batteries. With a predicted open-circuit potential of 1.28?V, specific charge capacity of &lt;300?A?h?kg?1 and reported efficiencies of 96, 40 and 35?% for charge, voltage and energy, respectively, the iron–air system could be well suited for a range of applications, including automotive. A number of challenges still need to be resolved, including: efficient and moderate-cost bifunctional oxygen electrodes, low-cost iron electrodes able to decrease corrosion and hydrogen evolution, new cell designs using additive manufacturing technologies and mathematical models to improve battery performance. This Mini review considers the thermodynamics and kinetics aspects of the iron–air battery, the operational variables and cell components, thereby highlighting current challenges and assessing recent developments

Current distribution in a rectangular flow channel manufactured by 3D-printing

The characterization and improvement of a rectangular channel electrolyte flow compartment used in an iron-air flow battery was carried out by using an arrangement of copper electrodes to measure the current density distribution employing the limiting current technique. The present work addresses the hydrodynamics and mass transport distribution in the compartment and their improvement by an improved electrolyte compartment that results in a more uniform current distribution. The current distribution was evaluated as the ratio between the local and the averaged limiting current densities during the reduction of copper ions over a range of mean linear flow velocity across the electrode surface (2-30 cm s-1). The initial compartment, showed larger differences between the minimum and maximum currents than the electrolyte compartment that resulted as part of the design process and showed a higher pressure drop at a given mean linear flow velocity

The ex-pat effect: presence of recent Western immigrants is associated with changes in age at first birth and birth rate in a Maya population from rural Guatemala

<p><b>Background:</b> Economic transitions expose indigenous populations to a variety of ecological and cultural challenges, especially regarding diet and stress. These kinds of challenges are predicted by evolutionary ecological theory to have fitness consequences (differential reproduction) and, indeed, are often associated with changes in fertility dynamics. It is currently unclear whether international immigration might impact the nature of such an economic transition or its consequences for fertility.</p> <p><b>Aim:</b> To examine measures of fertility, diet and stress in two economically transitioning Maya villages in Guatemala that have been differentially exposed to immigration by Westerners.</p> <p><b>Subjects and methods:</b> This study compared Maya women’s ages at first birth and birth rates between villages and investigated whether these fertility indicators changed through time. It also explored whether the villages differed in relation to diet and/or a proxy of stress.</p> <p><b>Results:</b> It was found that, in the village directly impacted by immigration, first births occurred earlier, but birth rate was slower. In both villages, over the sampled time window, age at first birth increased, while birth rate decreased. The villages do not differ significantly in dietary indicators, but the immigration-affected village scored higher on the stress proxy.</p> <p><b>Conclusion:</b> Immigration can affect fertility in host communities. This relationship between immigration and fertility dynamics may be partly attributable to stress, but this possibility should be evaluated prospectively in future research.</p

Dataset for Current distribution in a rectangular flow channel manufactured by 3D-printing

The characterization and improvement of a rectangular channel electrolyte flow compartment used in an iron-air flow battery was carried out by using an arrangement of copper electrodes to measure the current density distribution employing the limiting current technique. The present work addresses the hydrodynamics and mass transport distribution in the compartment and their improvement by an improved electrolyte compartment that results in a more uniform current distribution. The current distribution was evaluated as the ratio between the local and the averaged limiting current densities during the reduction of copper ions over a range of mean linear flow velocity across the electrode surface (2-30 cm s-1). The initial compartment, showed larger differences between the minimum and maximum currents than the electrolyte compartment that resulted as part of the design process and showed a higher pressure drop at a given mean linear flow velocity. This data supports the publication: Figueredo Rodriguez, Horacio, Mckerracher, Rachel, Ponce De Leon Albarran, Carlos and Walsh, Frank (2016) Current distribution in a rectangular flow channel manufactured by 3D-printing. AIChE Journal , 1-35. (doi:10.1002/aic.15454).</span

Effect of 1-octanethiol as an electrolyte additive on the performance of the iron-air battery electrodes

4 figuresIt has recently been established that 1-octanethiol in the electrolyte can allow iron electrodes to be discharged at higher rates. However, the effect of thiol additives on the air electrode has not yet been studied. The effect of solvated thiols on the surface positive electrode reaction is of prime importance if these are to be used in an iron-air battery. This work shows that the air-electrode catalyst is poisoned by the presence of octanethiol, with the oxygen reduction overpotential at the air electrode increasing with time of exposure to the solution and increased 1-octanethiol concentration in the range 0–0.1 mol dm−3. Post-mortem XPS analyses were performed over the used air electrodes suggesting the adsorption of sulphur species over the catalyst surface, reducing its performance. Therefore, although sulphur-based additives may be suitable for nickel-iron batteries, they are not recommended for iron-air batteries except in concentrations well below 10 × 10−3 mol dm−3.This work was enabled by an EU grant FP7 (NECOBAUT grant agreement no. 314159). H.A.F-R. acknowledges financial support from CONACYT, Mexico. CNR-ITAE authors acknowledge funding from the “Accordo di Programma CNR-MiSE, Gruppo tematico Sistema Elettrico Nazionale – Progetto: Sistemi elettrochimici per l’accumulo di energia”. C.A. thanks the Short-Term Mobility project of CNR and for her Juan de la Cierva contract (FJCI-2015-25560). The authors also acknowledge financial support given by Aragon Government to the Fuel Conversion Group (T06_17R).Peer reviewe

Iron electrodes based on sulfur-modified iron oxides with enhanced stability for iron-air batteries

7 figures.-- Supporting information available.Iron–air systems are a very promising technology with the potential to become one of the cheapest and safest energy storage solutions of the future. However, iron anodes still face some challenges like passivation, resulting in loss of capacity, due to the formation of nonconductive species during cycling as well as the hydrogen evolution reaction, a parasitic reaction interfering with the charging of the electrode. In the present work these two issues are addressed: Sulfur-modified mesoporous iron oxides are obtained and used as hot-pressed negative electrodes for alkaline iron–air batteries. Iron electrodes present average capacity values between 400 and 500 mA h g Fe–1 for ∼100 h of operation, the S-modified iron oxides being the most stable ones. An exponential deactivation model fitting the discharge capacity of the different electrodes compared to the number of cycles was proposed. According to the model, the best of the electrodes loses less than 0.5% of its capacity per cycle. Furthermore, doubling the charge and discharge rates allows increasing both the discharge capacity and the Coulumbic efficiency, though at the expense of stability. This manuscript proves that the proper distribution of sulfur on the surface of the iron oxide is fundamental to suppress the HER and passivation, enhancing the stability of the electrode. These properties were further corroborated in long test-runs which comprised more than 400 h of charging and discharging.The authors acknowledge the financial support from the Aragón Government to the Fuel Conversion Group (Grant T06-20R). C.A. also acknowledges MICINN for her Juan de la Cierva Contract IJCI-2017-32354. N.V. acknowledges the Aragón Government for his predoctoral contract and Ibercaja and Erasmus programs for the funding of his research stay in the University of Southampton in July 2018.Peer reviewe