Introduction The Royal Society of Chemistry Faraday Discussions are a series of meetings focusing on rapidly developing areas of physical chemistry. Contrary to typical conferences, Faraday Discussions rely on the active participation of speakers and audience alike. Topics for each session are based on new research papers submitted specifically for the meeting. Audience participation is...
Introduction The third UK Energy Storage Conference (UKES2016) was held at the Edgbaston campus of the University of Birmingham, UK, from midday on Wednesday 30th November to midday on Friday 2nd December 2016. The aim of the conference, organised by the Energy Storage Research Network on behalf of the UK Research Council funded Energy SuperStore Hub and chaired by Professor Nigel Brandon...
Lithium Sulfur: Mechanism, Modelling and Materials (Li-SM3) was organised by Oxis Energy Ltd, UK, Imperial College London, UK, and the Joint Center for Energy Storage Research (JCESR), USA. It was held at the Institution of Engineering and Technology (IET), Savoy Place, London from 26th–27th April 2017. More than 150 researchers from around the world attended this event, 44 of them...
Rechargeable metal-oxygen cells could exceed the stored energy of today’s most advanced lithium-ion cells. However challenges exist that must be overcome to bring this technology into practical application. These challenges include, among others, the recharge and cyclability efficiency, materials development and improvements in fundamental understanding of the electrochemistry and chemistry inside the cell. The common challenges for the anode, including corrosion, passivation and dendrite formation and those for the air cathode and the electrolyte are summarised in this review for cells based on magnesium, calcium, aluminium, silicon, zinc and iron.
Historically, Johnson Matthey has had a long association with electrochemistry, and perhaps this was inevitable because of the importance of the platinum group metals (pgm) to Johnson Matthey’s early development. Platinum, in particular, has been incredibly useful in the field, because of its exceptional electrocatalytic activity and impressive inertness in most environments. Famously,...
Introduction “Electrochemistry: Volume 14” is a collated book of five papers edited by Craig Banks (Manchester Metropolitan University, UK) and Steven McIntosh (Lehigh University, Bethlehem PA, USA), both of whom are well established in the field with research interests covering the topics in the book. The book is one of a series which aims to collate and summarise the key topics receiving...
Chemically regenerative redox cathode (CRRC) polymer electrolyte fuel cells (PEFCs) are attracting more interest as a platinum-free PEFC technology. These fuel cells utilise a liquid catalyst or catholyte, to perform the indirect reduction of oxygen, eliminating the major degradation mechanisms that plague PEFC durability. A key component of a CRRC PEFC system is the catholyte. This article reports a thorough study of the effect of catholyte concentration and temperature on CRRC PEFC system performance for H7PV4Mo8O40 and Na4H3PV4Mo8O40, two promising polyoxometalate (POM)-based catholytes. The results suggest 80°C and a catholyte concentration of 0.3 M provide the optimum performance for both H7PV4Mo8O40 and Na4H3PV4Mo8O40 (for ambient pressure operation).
To date, the world has been making a massive shift away from fossil fuels towards cleaner energy sources. For the past decade, polymer electrolyte membrane fuel cells (PEMFCs) powered by hydrogen have attracted much attention as a promising candidate for eco-friendly vehicles, i.e. fuel cell electric vehicles (FCEVs), owing to their high power density, high efficiency and zero emission features. Since the world’s first mass production of Tucson ix35 FCEV by Hyundai in 2013, global automotive original equipment manufacturers (OEMs) have focused on commercialising FCEVs. In 2018, Hyundai also unveiled the second generation of the mass-produced FCEV (i.e. Nexo) with improved performances and durability compared with its predecessor. Since then, the global market for PEMFCs for a variety of FCEV applications has been growing very rapidly in terms of both passenger vehicles and medium- and heavy-duty vehicles such as buses and trucks, which require much higher durability than passenger vehicles, i.e. 5000 h for passenger vehicles vs. 25,000 h for heavy-duty vehicles. In addition, PEMFCs are also in demand for other applications including fuel cell electric trains, trams, forklifts, power generators and vessels. We herein present recent advances in how hydrogen and PEMFCs will power the future in a wide range of applications and address key challenges to be resolved in the future.
Electrochemistry studies on the derivatives of graphene have been in the forefront of chemical research in recent years. The large specific surface area, high electrical conductivity, fast electron transfer rate and excellent biocompatibility to biomolecules constitute a few of the underlying reasons for the extensive application of graphene derivatives in modern electrochemistry and related technologies. Much interest in graphene derivatives has been driven by the ease of intentional functionalisation of the carbon backbone of graphene with dopants, such as nitrogen. Doping enhances the electrical conductivity and biocompatibility of nitrogen-doped graphene (NGr) nanomaterials and aids in their potential applications in electrochemical sensing and spectroelectrochemical devices. Despite the application of NGr in electrochemical sensing devices, the major challenge for reproducible industrial application still lies in the use of surfactants and binders and the limited knowledge on the correlation between the N-configurations and the electrocatalytic performance of these NGr-based electrodes. Therefore, the purpose of this short review article is to highlight some recent progress on the application of NGr derivatives for electrochemical detection of biomarkers such as uric acid and dopamine. The paper will also illustrate design parameters for new surfactant-free two-dimensional (2D) N-doped graphene based electrochemical sensors with variable N-functionalities for the detection of dopamine and uric acid.
“Electrolytes for Lithium and Lithium-Ion Batteries”, published in 2014 by Springer, is Volume 58 in the Modern Aspects of Electrochemistry series. The volume is edited by T. Richard Jow, Kang Xu, Oleg Borodin and Makoto Ue. In the preface the Editors set out their purpose in compiling this volume, which was to provide a comprehensive overview of electrolytes for lithium-ion batteries. It covers electrolyte research and development in the last ten years and may be used as a foundation for future work and directions. The volume succeeds in covering the multifaceted area of electrolytes in a logical and highly comprehensive manner.
Chapter topics include lithium salts, advances in solvents, additives and ionic liquids, then progressing to understanding of the cathode and anode interphases, reviewing various characterisation approaches, a discussion of modelling approaches and finally future technologies such as lithium air batteries.
“Nanomaterials for Lithium-Ion Batteries: Fundamentals and Applications” is edited by Rachid Yazami and is published by Pan Stanford Publishing Pte Ltd. The book covers the latest developments in new materials for lithium-ion batteries including examples of novel alloys, oxides and conversion materials for use as anodes and phosphates, high voltage spinels and layered oxides for use as cathodes. Composite structures incorporating reduced graphene oxide are considered along with thin films and nanowires. Emphasis is also placed on combining electrochemical test data with materials characterisation and detailed explanation of the mechanisms occurring.
It may surprise some readers to see an edition of this journal dedicated largely to lithium-ion batteries, but this is a technology that Johnson Matthey considers a major new business area for the company. Johnson Matthey has been involved in research and development (R&D) in the battery materials space for several years and launched its commercial business operations in the sector in...
Angel Cuesta is a Senior Lecturer at the University of Aberdeen, UK. His research is of interest in the field of materials for electrochemical applications and focuses on combining classical electrochemical techniques, in situ vibrational and optical spectroscopy and in situ scanning probe microscopy to obtain as detailed a description as possible, at the molecular level, of the...
To combat the global problem of carbon dioxide emissions, hydrogen is the desired energy vector for the transition to environmentally benign fuel cell power. Water electrolysis (WE) is the major technology for sustainable hydrogen production. Despite the use of renewable solar and wind power as sources of electricity, one of the main barriers for the widespread implementation of WE is the scarcity and high cost of platinum group metals (pgms) that are used to catalyse the cathodic hydrogen evolution reaction (HER) and the anodic oxygen evolution reaction (OER). Hence, the critical pgm-based catalysts must be replaced with more sustainable alternatives for WE technologies to become commercially viable. This critical review describes the state-of-the-art pgm-free materials used in the WE application, with a major focus on phosphides and borides. Several emerging classes of HER and OER catalysts are reviewed and detailed structure–property correlations are comprehensively summarised. The influence of the crystallographic and electronic structures, morphology and bulk and surface chemistry of the catalysts on the activity towards OER and HER is discussed.
Following the development of commercial secondary lithium-ion batteries (LIBs), this article illustrates the progress of therein-utilised anode materials from the first successful commercialisation to recent research activities. First, early scientific achievements and industrial developments in the field of LIBs, which enabled the remarkable evolution within the last 20 years of this class of batteries, are reviewed. Afterwards, the characteristics of state-of-the-art commercially available anode materials are highlighted with a particular focus on their lithium storage mechanism. Finally, a new class of anode active materials exhibiting a different storage mechanism, namely combined conversion and alloying, is described, which might successfully address the challenges and issues LIB anodes are currently facing.
Developing novel hydrogen evolution reaction (HER) catalysts with high activity, high stability and low cost is of great importance for the applications of hydrogen energy. In this work, iridium-nickel thin films were electrodeposited on a copper foam as electrocatalyst for HER, and electrodeposition mechanism of iridium-nickel film was studied. The morphology and chemical composition of thin films were determined by scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS), respectively. The electrocatalytic performances of the films were estimated by linear sweep voltammograms (LSV), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The results show that iridium-nickel thin films were attached to the substrate of porous structure and hollow topography. The deposition of nickel was preferable in the electrolyte without the addition of additives, and the iridium-nickel thin film was alloyed, resulting in a high deposition rate for Ir42Ni58 thin film, and subsequently an increase of iridium content in the thin films of Ir80Ni20 and Ir88Ni12. Iridium-nickel thin films with Tafel slopes of 40–49 mV dec–1 exhibited highly efficient electrocatalytic activity for HER. The electrocatalytic activity of iridium-nickel thin films showed a loading dependence. As the solution temperature increased from 20°C to 60°C, the hydrogen evolution performance of iridium-nickel thin films improved. The apparent activation energy value of Ir88Ni12 film was 7.1 kJ mol–1. Long-term hydrogen evolution tests exhibited excellent electrocatalytic stability in alkaline solution.
Palladium based membranes are widely used for supplying ultra-high purity hydrogen to a polymer electrolyte fuel cell (PEFC) installed on small vehicles and various electronic devices. Compared to pressure swing adsorption (PSA), the use of palladium based membrane is more economical for small size (small capacity) applications. The transportation of hydrogen through a palladium based membrane is governed by Sieverts’ Law and quantified with Fick’s First Law. Since the 20th century, the fabrication of high-performance palladium based membrane for enhanced hydrogen recovery performance has become practical. However, along with the improvement in hydrogen recovery performance, concentration polarisation becomes unavoidable because hydrogen permeation flux starts to affect hydrogen concentration at the membrane surface. Various parametric studies have investigated the effects of membrane thickness, hydrogen molar fraction and total upstream and downstream pressures on concentration polarisation level. The influence of membrane temperature, permeability, type and number of species in the hydrogen mixture, diffusivity of the hydrogen mixture, system configurations and flow patterns are also reported and comprehensively reviewed in this paper. Part II will complete the presentation.
Recently lithium-ion batteries have started to be used in a number of automotive passenger car applications. This paper will review these applications and compare the requirements of the applications with the capabilities of the lithium-ion chemistries that are actually being used. The gaps between these requirements and capabilities will be highlighted and future developments that may be able to fill these gaps will be discussed. It is concluded that while improvements to the lithium-ion cell chemistry will help reduce the weight of battery packs for electric vehicle applications the largest weight gains will come from the pack design.
This article completes the presentation of various techniques reducing concentration polarisation in palladium based membranes for supplying ultra-high purity hydrogen to a polymer electrolyte fuel cell (PEFC), such as the implementation of baffles and the use of microchannel configuration. The present paper also reviews and reports the current methods for estimating hydrogen permeation flux under concentration polarisation influence, which will be a useful guide for academics and industrial practitioners.
Portable electronic devices, electric vehicles and stationary energy storage applications, which encourage carbon-neutral energy alternatives, are driving demand for batteries that have concurrently higher energy densities, faster charging rates, safer operation and lower prices. These demands can no longer be met by incrementally improving existing technologies but require the discovery of new materials with exceptional properties. Experimental materials discovery is both expensive and time consuming: before the efficacy of a new battery material can be assessed, its synthesis and stability must be well-understood. Computational materials modelling can expedite this process by predicting novel materials, both in stand-alone theoretical calculations and in tandem with experiments. In this review, we describe a materials discovery framework based on density functional theory (DFT) to predict the properties of electrode and solid-electrolyte materials and validate these predictions experimentally. First, we discuss crystal structure prediction using the ab initio random structure searching (AIRSS) method. Next, we describe how DFT results allow us to predict which phases form during electrode cycling, as well as the electrode voltage profile and maximum theoretical capacity. We go on to explain how DFT can be used to simulate experimentally measurable properties such as nuclear magnetic resonance (NMR) spectra and ionic conductivities. We illustrate the described workflow with multiple experimentally validated examples: materials for lithium-ion and sodium-ion anodes and lithium-ion solid electrolytes. These examples highlight the power of combining computation with experiment to advance battery materials research.
