Carbon Aerogel Based Thin Electrodes for Zero-Gap all Vanadium Redox Flow Batteries – Quantifying the Factors Leading to Optimum Performance

Funder: Shell Global Solutions International B.V.Abstract: Direct growth of resorcinol−formaldehyde carbon aerogels (CAGs) on carbon paper electrodes was achieved using a new approach. Materials with variations in density, mesoporosity and microporosity were prepared. Microstructural properties of the resultant thin electrodes are shown to directly influence performance in zero‐gap redox flow battery (RFB). BET analysis shows a total surface area between 643 to 931 m2 g−1. Deposition of only ≈15 wt.% CAG on the carbon electrode leads to a 320‐fold increase in electrochemical surface area. Analysis of the results saw a strong positive correlation of RFB performance with surface area. The best performing electrodes had a good balance between microporous and external surface area, and on the macroscopic scale had sufficiently large pores to allow efficient electrolyte permeation. The poorest performing electrodes which had the highest surface area, also had poor macroscopic porosity leading to large mass transport and solution resistance losses. The best performing electrodes were tested in a zero‐gap setup using polarization curves, showing a 25 % increase in power density at 100 mA cm−2 and a peak power density of 706 mW cm−2 at 1 V using thin electrodes

2021 roadmap on lithium sulfur batteries

Batteries that extend performance beyond the intrinsic limits of Li-ion batteries are among the most important developments required to continue the revolution promised by electrochemical devices. Of these next-generation batteries, lithium sulfur (Li–S) chemistry is among the most commercially mature, with cells offering a substantial increase in gravimetric energy density, reduced costs and improved safety prospects. However, there remain outstanding issues to advance the commercial prospects of the technology and benefit from the economies of scale felt by Li-ion cells, including improving both the rate performance and longevity of cells. To address these challenges, the Faraday Institution, the UK's independent institute for electrochemical energy storage science and technology, launched the Lithium Sulfur Technology Accelerator (LiSTAR) programme in October 2019. This Roadmap, authored by researchers and partners of the LiSTAR programme, is intended to highlight the outstanding issues that must be addressed and provide an insight into the pathways towards solving them adopted by the LiSTAR consortium. In compiling this Roadmap we hope to aid the development of the wider Li–S research community, providing a guide for academia, industry, government and funding agencies in this important and rapidly developing research space

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]

2021 roadmap on lithium sulfur batteries

Abstract: Batteries that extend performance beyond the intrinsic limits of Li-ion batteries are among the most important developments required to continue the revolution promised by electrochemical devices. Of these next-generation batteries, lithium sulfur (Li–S) chemistry is among the most commercially mature, with cells offering a substantial increase in gravimetric energy density, reduced costs and improved safety prospects. However, there remain outstanding issues to advance the commercial prospects of the technology and benefit from the economies of scale felt by Li-ion cells, including improving both the rate performance and longevity of cells. To address these challenges, the Faraday Institution, the UK’s independent institute for electrochemical energy storage science and technology, launched the Lithium Sulfur Technology Accelerator (LiSTAR) programme in October 2019. This Roadmap, authored by researchers and partners of the LiSTAR programme, is intended to highlight the outstanding issues that must be addressed and provide an insight into the pathways towards solving them adopted by the LiSTAR consortium. In compiling this Roadmap we hope to aid the development of the wider Li–S research community, providing a guide for academia, industry, government and funding agencies in this important and rapidly developing research space

High energy density hydrogen/vanadium hybrid redox flow battery utilizing HCl as a supporting electrolyte for large scale energy storage applications

A high energy density Hydrogen/Vanadium (6 M HCl) system is demonstrated with increased vanadium concentration (2.5 M vs. 1 M), and standard cell potential (1.167 vs. 1.000 V) and high theoretical storage capacity (65 Wh L−1) compared to previous vanadium systems. The system is enabled through the development and use of HER/HOR catalysts with improved chemical stability towards the halogen-containing electrolyte within which the usual catalyst (Pt/C) is shown to quickly degrade during potential hold experiments. The implementation of an Ir/C catalyst at the negative side enables a system with high achievable energy density of 45 W h L−1 at 75 mA cm−2 associated with 67% electrolyte utilization. Based on such a promising performance, the system here presented could be a suitable solution for medium and large-scale energy storage with lower cost and volume footprint than existing batteries, particularly all-vanadium RFBs

Supported transition metal phosphides: Activity survey for HER, ORR, OER and corrosion resistance in acid and alkaline electrolytes

Carbon supported MxPy (M = Ni, Co, W, Cr and Mo) were prepared via pyrolysis using a very simple and scalable method utilizing non-toxic metal and phosphorous precursors. The electrochemical hydrogen evolution (HER), oxygen reduction (ORR), and oxygen evolution (OER) reactions and corrosion resistance under both acid and alkaline conditions were examined for all these catalysts and compared to the benchmark catalysts Pt/C (HER/ORR) and IrO2(OER). The highest activities were found in alkaline solutions for Co2P for HER and ORR and Ni2P for OER. Good activity for these was also found in acid for some of these reactions, although the catalysts suffered from susceptibility to corrosion. Co2P was further studied in an alkaline environment as it shows high catalytic activity towards the oxygen reduction reaction (ORR) without significant hysteresis. The onset potential (at 0.5 mA cm-2) obtained was 0.8 V and a Tafel slope value of 38 mV dec-1 with a maximum kinetic mass activity of 2870 A gCo-1 at 0.7 V (RHE). Utilising high resolution transmission electron microscopy (HRTEM) it is possible to observe high-surface area needle-like single crystal cobalt oxide structures on the surfaces of the Co2P particles at the beginning of the ORR. Hence the high rates of initial corrosion of the Co2P identified appear to be associated with the dissolution and precipitation of Cobalt oxide on the particle surface. The as-synthesised Co2P/C also shows good performance in an 8-hour stability test for the Oxygen Evolution Reaction (OER), carried out at 1.6 V vs. RHE in alkaline conditions, with negligible drop in current density over time. Interestingly, in an acidic environment the catalyst is very active towards 2-electron- oxygen reduction leading to H2O2 with high selectivity (85%). It is intriguing that the pH dependence on this catalyst towards the ORR is similar to that seen for gold

Mechanical and environmental assessment of the use of fly ash with alkaline activation as an alternative to total replacement of cement in the manufacture of prefabricated tablets

The present investigation is focused on the implementation of alkaline activated fly ash as a total replacement of Portland cement in the manufacture of prefabricated tablets. The experimental program included the physico-chemical characterization of raw materials, finding the optimum alkaline activator/fly ash ratio and mechanical tests of compressive strength and rupture modulus. Additionally, a comparison of the carbon footprint of a batch of prefabricated tablets made from Portland cement mortar and fly ash was also performed. The activation of the fly ash was carried out by means of the combination of alkaline activators composed of NaOH and Na2SiO3. The results obtained showed that fly ash mortars have good mechanical properties and environmental viability in terms of carbon footprint. The fly ash can be used in the industry of prefabricated tablets as an option of lower environmental impact with optimal resistance to compression and rupture modulus

Especies de flora y fauna de la dehesa salmantina: Abundancia relativa, intervención humana y regulación

[ESP]Se elalora un catálogo de especies de flora y fauna de la dehesa salmantina (bienes fácilmente perceptibles)bajo el denominador común de producción sociel y se cualifica cada especie según su abundancia relativa y las consecuencias de las prácticas culturales( intervención humana). Dicha producción no es considerada de forma directa en los circuitos comerciales derivados de la gestión antrópica de la dehesa, pero se trata de elementos integrados en el paisaje, que únicamente pueden disfrutarse allí donde se hallan localizados. La revalorización de estos sistemas de uso múltiple, a través de considerar la totalidad de sus utilidades comerciales v ambientales. llevara a considerarlos como una unidad ambiental y, tal vez nás importante desde el punto de vista cicntifico, a analizar su estado de eficiencia en función de Ia demanda de la calidad recreativa. En la situación actual, las limitaciones del mercado para alcanzir remuneraciones adecuadas derivadas de los recursos comerciales de la dehesa, podrán superarse con intervención pública orientada a prácticas agronómicas capitalizadoras del medio, natural, como complemento de la intervención sohre hienes comerciales[ENG]A flora and fauna specics index of lhr dehcs;i. in Salamanca province (easily detectable goods) was made on the basis of soci:il production and each species was qu;ilified according to its relative abundance and the consrquences of the traditional methods. Such a pn,duction is not con5idered directly in the business circuits derived from the anthropocentric m:~nagt.ment of the =deliesa~b,u t it is about elements integrated in the landsc;ipe and it is possible to enjoy then only wherever they are located. The revaluation of these lnultinle use systems. bv means of cr,nsi- &ring their whole busincss and environmental profits, will 1c;ld to thcir consideration as an environmental unit and also to analyse the eficiency sit~lation according to amenity qirality demand. At present, market restrictions to achieve suitable remuneration from the business resources of the ~dehesa-c, ould be overcame by means of the public intervention in agronomic practices which capitalize the natural environmcnt, as a complement of thc public intervention to business goods.Proyecto de la UE 8001-CT-0028 y Facultad de Veterinaría de la Universidad de Extremadura.Peer reviewe