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Lithium–sulfur batteries (LSBs) with high theoretical capacity are regarded as the most promising candidates for next‐generation energy storage systems. However, the low conductivity, high volume change, and shuttle effect need to be addressed before the commercialization of LSBs. Organosulfur with covalent CS bonds can solve these problems when applied as different components of LSBs. Recent advances of application of organosulfur as cathodes, electrolytes, interlayers, and binders in LSBs are reviewed. Finally, the prospects for organosulfur are proposed from both the perspectives of mechanism understanding and practical applications. [ABSTRACT FROM AUTHOR]

The tortuosity of a structure plays a vital role in the transport of mass and charge in electrochemical devices. Concentration polarisation losses at high current densities are caused by mass transport limitations and are thus a function of microstructural characteristics. As tortuosity is notoriously difficult to ascertain, a wide and diverse range of methods have been developed to extract the tortuosity of a structure. These methods differ significantly in terms of calculation approach and data preparation techniques. Here, a review of tortuosity calculation procedures applied in the field of electrochemical devices is presented to better understand the resulting values presented in the literature. Visible differences between calculation methods are observed, especially when using porosity–tortuosity relationships and when comparing geometric and flux-based tortuosity calculation approaches. [ABSTRACT FROM AUTHOR]

Abstract: Homogenously doped and mixed yttria stabilized zirconia, YSZ (with 3 and 10mol% Y2O3 known as 3YSZ and 10YSZ) and NiO/10YSZ co-precipitates (nominally corresponding to 7, 12, 24, 30, 35 and 45vol.% Ni metal), were synthesized using a continuous hydrothermal flow synthesis (CHFS) system which uses a stream of superheated water at 450°C and 24.1MPa as a reaction medium to cause rapid precipitation of metal oxide nanoparticle co-precipitates from a mixed metal salt solution. All products were obtained directly from the outlet of the CHFS reactor as a slurry, which was then cleaned and freeze-dried prior to further processing. The highly crystalline nano-powdered products were characterized using a range of analytical methods, including: powder X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), Raman spectroscopy and BET surface area measurements. Spherical primary particles of 10YSZ and 3YSZ were observed under the TEM and found to be 5.0±0.8nm (range 3.2–6.3nm) and 6.2±1.4nm (range 3.3–8.4nm) in size, with measured BET surface areas of 160.6 and 241.7m2 g− 1, respectively. Sintering of the nano-powder co-precipitates was performed via spark plasma sintering (SPS) at 1100°C for 1min, leading to densities of ca. 98% for 10YSZ and ca. 96% for Ni/10YSZ cermets (all NiO was converted into Ni due to the reducing atmosphere of the SPS). The 24% Ni/10YSZ cermet was subjected to focused ion beam tomography, which allowed the 3D arrangement of the conducting Ni metallic network of the dense cermet to be elucidated, and showed that a complete 3D network of Ni existed throughout the dense cermet disk. Electrical conductivity tests showed that the samples exhibited higher than expected electrical conductivity (for such low metal content), e.g., the 24vol.% Ni-containing sample achieved an electrical conductivity of ∼200Scm− 1 at the fuel cell operating temperature, which corresponds to an effective conductivity of ∼117Scm− 1 if a porosity of 30% were to be introduced. [Copyright &y& Elsevier]

Abstract: An electrochemical quartz crystal microbalance study of platinum phthalocyanine thin films in aqueous media is presented. It has been shown that these films exhibit significant mass changes upon electrochemical cycling. These mass changes have been shown to be controlled by the ingress and egress of solvated anions during oxidation and reduction of the film, respectively. The mass changes within the film are shown to tend to steady state after a prolonged period of cycling. Chrono-amperometric studies have additionally shown that the movement of cations also has a role in the electrochemistry and mass transport within these films, but generally these events occur on a shorter timescale than those involving the solvated anions, and are hidden during most potential cycling studies. [Copyright &y& Elsevier]

Stripping voltammetry analysis using a hemispheroidal mercury microelectrode has been previously assessed theoretically as a possible candidate ‘primary method’ for amount of substance measurement. It was shown that the measurement methodology can be described completely by a set of measurement equations when a novel quantification process is employed to measure the steady-state diffusion-limited deposition current over an optimum sampling time, instead of employing an analyte stripping step. The corollary is that, for solutions of known composition, the method may be used for highly accurate determination of diffusion coefficients. This investigation uses experimental data from steady-state diffusion-limited current measurements with sampling periods optimised using Allan deviation techniques, together with a full uncertainty analysis to estimate feasibility and likely accuracy of this method. [ABSTRACT FROM AUTHOR]

With the increasing focus on decarbonisation of the transport sector, it is imperative to consider routes to electrify vehicles beyond those achievable using lithium-ion battery technology. These include heavy goods vehicles and aerospace applications that require propulsion systems that can provide gravimetric energy densities, which are more likely to be delivered by fuel cell systems. While the discussion of light-duty vehicles is abundant in the literature, heavy goods vehicles are under-represented. This paper presents an overview of the electrochemical degradation of a proton exchange membrane fuel cell integrated into a simulated Class 8 heavy goods range-extender fuel cell hybrid electric vehicle operating in urban driving conditions. Electrochemical degradation data such as polarisation curves, cyclic voltammetry values, linear sweep voltammetry values, and electrochemical impedance spectroscopy values were collected and analysed to understand the expected degradation modes in this application. In this application, the proton exchange membrane fuel cell stack power was designed to remain constant to fulfil the mission requirements, with dynamic and peak power demands managed by lithium-ion batteries, which were incorporated into the hybridised powertrain. A single fuel cell or battery cell can either be operated at maximum or nominal power demand, allowing four operational scenarios: maximum fuel cell maximum battery, maximum fuel cell nominal battery, nominal fuel cell maximum battery, and nominal fuel cell nominal battery. Operating scenarios with maximum fuel cell operating power experienced more severe degradation after endurance testing than nominal operating power. A comparison of electrochemical degradation between these operating scenarios was analysed and discussed. By exploring the degradation effects in proton exchange membrane fuel cells, this paper offers insights that will be useful in improving the long-term performance and durability of proton exchange membrane fuel cells in heavy-duty vehicle applications and the design of hybridised powertrains. [ABSTRACT FROM AUTHOR]

Crystals growing via nonclassical crystallisation pathways often lose the shape factor and the mechanisms involved are often anomalous. This makes it difficult to predict the crystal growth kinetics using the conventional crystal growth kinetic models. A new pseudo second order growth kinetic expression to predict the anomalous growth behaviour of curcumin crystals is introduced. This model also allows several important parameters relevant to the kinetics of the crystal growth, such as mass crystallised with respect to time, overall crystal growth kinetic constant, the maximum number of active sites involved in the crystal growth process and the initial crystal growth rate, to be obtained. According to the pseudo second order kinetics, the activation energy for the nonclassical crystal growth of curcumin was found to be ∼69 kJ mol−1, which seems to agree with the activation energy for the classical crystal growth of organic compounds reported in the literature. The total number of active sites involved in the crystal growth process was found to be ∼1022 per gram of the seeds. [ABSTRACT FROM AUTHOR]

Although proton exchange membranes (PEMs) are widely deployed in an array of commercial applications, limitations linked to their proton conductivity, water retention, and gas permeability still limit ultimate device performance. While ex situ studies have shown additives can enhance membrane stability and mass transport, to date few have demonstrated that these performance enhancements are maintained when tested in commercially relevant electrochemical technologies, such as fuel cells or electrolyzers. Herein, a new multifunctional additive, 2D poly(triazine imide) (PTI), is demonstrated for composite PEMs, which is shown to boost proton conductivity by 37% under optimal high relative humidity (RH) conditions and 67% at low RHs. PTI also enables major improvements (over 55%) in both current and power densities in industrially relevant PEM fuel cells (PEMFCs). Most importantly, in situ and ex situ characterization suggests that the enhanced performance is due to polymer aggregate‐PTI clusters that form with increasing 2D character and improved long‐range connectivity, while acid‐base interactions with pyridinic nitrogen facilitate the critical proton hopping mechanism at all RHs. Hence, this work offers both a new membrane concept with proven benefits for important electrochemical technologies, as well as design principles for future optimization of proton transport and water management within PEMs. [ABSTRACT FROM AUTHOR]

For zinc‐ion batteries (ZIBs), the non‐uniform Zn plating/stripping results in a high polarization and low Coulombic efficiency (CE), hindering the large‐scale application of ZIBs. Here, inspired by biomass seaweed plants, an anionic polyelectrolyte alginate acid (SA) was used to initiate the in situ formation of the high‐performance solid electrolyte interphase (SEI) layer on the Zn anode. Attribute to the anionic groups of −COO−, the affinity of Zn2+ ions to alginate acid induces a well‐aligned accelerating channel for uniform plating. This SEI regulates the desolvation structure of Zn2+ and facilitates the formation of compact Zn (002) crystal planes. Even under high depth of discharge conditions (DOD), the SA‐coated Zn anode still maintains a stable Zn stripping/plating behavior with a low potential difference (0.114 V). According to the classical nucleation theory, the nucleation energy for SA‐coated Zn is 97 % less than that of bare Zn, resulting in a faster nucleation rate. The Zn||Cu cell assembled with the SA‐coated electrode exhibits an outstanding average CE of 99.8 % over 1,400 cycles. The design is successfully demonstrated in pouch cells, where the SA‐coated Zn exhibits capacity retention of 96.9 % compared to 59.1 % for bare Zn anode, even under the high cathode mass loading (>10 mg/cm2). [ABSTRACT FROM AUTHOR]

For zinc‐ion batteries (ZIBs), the non‐uniform Zn plating/stripping results in a high polarization and low Coulombic efficiency (CE), hindering the large‐scale application of ZIBs. Here, inspired by biomass seaweed plants, an anionic polyelectrolyte alginate acid (SA) was used to initiate the in situ formation of the high‐performance solid electrolyte interphase (SEI) layer on the Zn anode. Attribute to the anionic groups of −COO−, the affinity of Zn2+ ions to alginate acid induces a well‐aligned accelerating channel for uniform plating. This SEI regulates the desolvation structure of Zn2+ and facilitates the formation of compact Zn (002) crystal planes. Even under high depth of discharge conditions (DOD), the SA‐coated Zn anode still maintains a stable Zn stripping/plating behavior with a low potential difference (0.114 V). According to the classical nucleation theory, the nucleation energy for SA‐coated Zn is 97 % less than that of bare Zn, resulting in a faster nucleation rate. The Zn||Cu cell assembled with the SA‐coated electrode exhibits an outstanding average CE of 99.8 % over 1,400 cycles. The design is successfully demonstrated in pouch cells, where the SA‐coated Zn exhibits capacity retention of 96.9 % compared to 59.1 % for bare Zn anode, even under the high cathode mass loading (>10 mg/cm2). [ABSTRACT FROM AUTHOR]

Automotive drive cycles have existed since the 1960s. They started as requirements as being solely used for emissions testing. During the past decade, they became popular with scientists and researchers in the testing of electrochemical vehicles and power devices. They help simulate realistic driving scenarios anywhere from system to component-level design. This paper aims to discuss the complete history of these drive cycles and their validity when used in an electrochemical propulsion scenario, namely with the use of proton exchange membrane fuel cells (PEMFC) and lithium-ion batteries. The differences between two categories of drive cycles, modal and transient, were compared; and further discussion was provided on why electrochemical vehicles need to be designed and engineered with transient drive cycles instead of modal. Road-going passenger vehicles are the main focus of this piece. Similarities and differences between aviation and marine drive cycles are briefly mentioned and compared and contrasted with road cycles. The construction of drive cycles and how they can be transformed into a 'power cycle' for electrochemical device sizing purposes for electrochemical vehicles are outlined; in addition, how one can use power cycles to size electrochemical vehicles of various vehicle architectures are suggested, with detailed explanations and comparisons of these architectures. A concern with using conventional drive cycles for electrochemical vehicles is that these types of vehicles behave differently compared to combustion-powered vehicles, due to the use of electrical motors rather than internal combustion engines, causing different vehicle behaviours and dynamics. The challenges, concerns, and validity of utilising 'general use' drive cycles for electrochemical purposes are discussed and critiqued. [ABSTRACT FROM AUTHOR]

Crystallisation from solution is an important process in pharmaceutical industries and is commonly used to purify active pharmaceutical ingredients. Crystallisation involves phase change and the mechanisms involved are random which makes the process stochastic. This creates a variation in the time required to reach a fixed percentage of yield from batch to batch. It is essential to regulate the batch crystallisation process and make it more predictable for industrial applications for the ease of process chain scheduling of upstream and downstream unit operations. In this work, we propose a new technique called dotted crystallisation, where carbon dots are used to dictate and regulate events associated with nucleation and crystallisation processes. Following the rules of two-step nucleation theory, the carbon dots intentionally added to a supersaturated solution of curcumin anchors the crystallising compound to form prenucleation clusters that evolve into stable nuclei. Using curcumin as a model compound, we showed that the nucleation of this compound in isopropanol can be regulated, and the nucleation rate can be improved via addition of small quantities of carbon dots to the supersaturated solution. Our results confirmed that the nucleation rate of curcumin by dotted crystallisation was roughly four times higher than the nucleation rate by conventional cooling crystallisation and produced smaller sized crystals with a narrow size distribution. [ABSTRACT FROM AUTHOR]

Fuel cell based micro-combined heat and power (CHP) units used for domestic applications can provide significant cost and environmental benefits for end users and contribute to the UK’s 2050 emissions target by reducing primary energy consumption in dwellings. Lately there has been increased interest in the development of systematic methods for the design of such systems and their smoother integration with domestic building services. Several models in the literature, whether they use a simulation or an optimisation approach, ignore the dwelling side of the system and optimise the efficiency or delivered power of the unit. However the design of the building services is linked to the choice of heating plant and its characteristics. Adding the dwelling’s energy demand and temperature constraints in a model can produce more general results that can optimise the whole system, not only the micro-CHP unit. The fuel cell has various heat streams that can be harvested to satisfy heat demand in a dwelling and the design can vary depending on the proportion of heat needed from each heat stream to serve the energy demand. A mixed integer non-linear programming model (MINLP) that can handle multiple heat sources and demands is presented in this paper. The methodology utilises a process systems engineering approach. The model can provide a design that integrates the temperature and water flow constraints of a dwelling’s heating system with the heat streams within the fuel cell processes while optimising total CO 2 emissions. The model is demonstrated through different case studies that attempt to capture the variability of the housing stock. The predicted CO 2 emissions reduction compared to a conventionally designed building vary from 27% to 30% and the optimum capacity of the fuel cell ranges between 1.9 kW and 3.6 kW. This research represents a significant step towards an integrated fuel cell micro-CHP and dwelling design. [ABSTRACT FROM AUTHOR]

During the growth of crystals in impure solution, impurities can pin the flow of the elementary steps and decrease the growth rate or even arrest the crystal growth. In this work, for the first time, we showed that curcumin crystals can grow in impure solution that contains two structurally similar impurities, following a non-classical crystallisation pathway that deviates from the pinning mechanism. We showed that, in a highly impure solution that contains 20 wt% of impurities, a high supersaturation can initiate the crystal growth via sympathetic nucleation that involves the formation of new growth surfaces on the seed crystals. These new surfaces formed on the seed crystals at the expense of higher supersaturation act like active growth surfaces and dictate the entire crystal growth kinetics especially at lower supersaturations. We showed that, if we can artificially create new surfaces that look like giant macrosteps at the micron scale on the crystal surface, then these macrosteps can not only speed-up the crystallisation rate but also control the rate of transfer of impurities into the bulk crystals. [ABSTRACT FROM AUTHOR]

Demand for low carbon energy storage has highlighted the importance of imaging techniques for the characterization of electrode microstructures to determine key parameters associated with battery manufacture, operation, degradation, and failure both for next generation lithium and other novel battery systems. Here, recent progress and literature highlights from magnetic resonance, neutron, X‐ray, focused ion beam, scanning and transmission electron microscopy are summarized. Two major trends are identified: First, the use of multi‐modal microscopy in a correlative fashion, providing contrast modes spanning length‐ and time‐scales, and second, the application of machine learning to guide data collection and analysis, recognizing the role of these tools in evaluating large data streams from increasingly sophisticated imaging experiments. [ABSTRACT FROM AUTHOR]

Reduced graphene‐oxide (RGO)‐based electrodes in supercapacitors deliver high energy/power capacities compared to typical nanoporous carbon materials. However, extensive critical analysis of literature reveals enormous discrepancies (up to 250 F g−1) in the reported capacitance (variation of 100–350 F g−1) of RGO materials synthesized under seemingly similar methods, inhibiting an understanding of capacitance variation. Here, the key factors that control the capacitance performance of RGO electrodes are demonstrated by analyzing and optimizing various types of commonly applied electrode fabrication methods. Beyond usual data acquisition parameters and oxidation/reduction properties of RGO, a substantial difference of more than 100% in capacitance values (with change from 190 ± 20 to 340 ± 10 F g−1) is found depending on the electrode preparation method. For this demonstration, ≈40 RGO‐based electrodes are fabricated from numerous distinctly different RGO materials via typically applied methods of solution (aqueous and organic) casting and compressed powders. The influence of data acquisition conditions and capacitance estimation practices are also discussed. Furthermore, by optimizing electrode processing method, a direct surface area governed capacitance relationship for RGO structures is revealed. [ABSTRACT FROM AUTHOR]

The electrochemical synthesis of hydrogen peroxide (H2O2) via a two‐electron (2 e−) oxygen reduction reaction (ORR) process provides a promising alternative to replace the energy‐intensive anthraquinone process. Herein, we develop a facile template‐protected strategy to synthesize a highly active quinone‐rich porous carbon catalyst for H2O2 electrochemical production. The optimized PCC900 material exhibits remarkable activity and selectivity, of which the onset potential reaches 0.83 V vs. reversible hydrogen electrode in 0.1 M KOH and the H2O2 selectivity is over 95 % in a wide potential range. Comprehensive synchrotron‐based near‐edge X‐ray absorption fine structure (NEXAFS) spectroscopy combined with electrocatalytic characterizations reveals the positive correlation between quinone content and 2 e− ORR performance. The effectiveness of chair‐form quinone groups as the most efficient active sites is highlighted by the molecule‐mimic strategy and theoretical analysis. [ABSTRACT FROM AUTHOR]

Electrocatalytic oxygen reduction reaction (ORR) has been intensively studied for environmentally benign applications. However, insufficient understanding of ORR 2 e−‐pathway mechanism at the atomic level inhibits rational design of catalysts with both high activity and selectivity, causing concerns including catalyst degradation due to Fenton reaction or poor efficiency of H2O2 electrosynthesis. Herein we show that the generally accepted ORR electrocatalyst design based on a Sabatier volcano plot argument optimises activity but is unable to account for the 2 e−‐pathway selectivity. Through electrochemical and operando spectroscopic studies on a series of CoNx/carbon nanotube hybrids, a construction‐driven approach based on an extended "dynamic active site saturation" model that aims to create the maximum number of 2 e− ORR sites by directing the secondary ORR electron transfer towards the 2 e− intermediate is proven to be attainable by manipulating O2 hydrogenation kinetics. [ABSTRACT FROM AUTHOR]

The electrochemical synthesis of hydrogen peroxide (H2O2) via a two‐electron (2 e−) oxygen reduction reaction (ORR) process provides a promising alternative to replace the energy‐intensive anthraquinone process. Herein, we develop a facile template‐protected strategy to synthesize a highly active quinone‐rich porous carbon catalyst for H2O2 electrochemical production. The optimized PCC900 material exhibits remarkable activity and selectivity, of which the onset potential reaches 0.83 V vs. reversible hydrogen electrode in 0.1 M KOH and the H2O2 selectivity is over 95 % in a wide potential range. Comprehensive synchrotron‐based near‐edge X‐ray absorption fine structure (NEXAFS) spectroscopy combined with electrocatalytic characterizations reveals the positive correlation between quinone content and 2 e− ORR performance. The effectiveness of chair‐form quinone groups as the most efficient active sites is highlighted by the molecule‐mimic strategy and theoretical analysis. [ABSTRACT FROM AUTHOR]

Electrocatalytic oxygen reduction reaction (ORR) has been intensively studied for environmentally benign applications. However, insufficient understanding of ORR 2 e−‐pathway mechanism at the atomic level inhibits rational design of catalysts with both high activity and selectivity, causing concerns including catalyst degradation due to Fenton reaction or poor efficiency of H2O2 electrosynthesis. Herein we show that the generally accepted ORR electrocatalyst design based on a Sabatier volcano plot argument optimises activity but is unable to account for the 2 e−‐pathway selectivity. Through electrochemical and operando spectroscopic studies on a series of CoNx/carbon nanotube hybrids, a construction‐driven approach based on an extended "dynamic active site saturation" model that aims to create the maximum number of 2 e− ORR sites by directing the secondary ORR electron transfer towards the 2 e− intermediate is proven to be attainable by manipulating O2 hydrogenation kinetics. [ABSTRACT FROM AUTHOR]

Quartz Crystal Microbalance (QCM) sensors are actively being implemented in various fields due to their compatibility with different operating conditions in gaseous/liquid mediums for a wide range of measurements. This trend has been matched by the parallel advancement in tailored electronic interfacing systems for QCM sensors. That is, selecting the appropriate electronic circuit is vital for accurate sensor measurements. Many techniques were developed over time to cover the expanding measurement requirements (e.g., accommodating highly-damping environments). This paper presents a comprehensive review of the various existing QCM electronic interfacing systems. Namely, impedance-based analysis, oscillators (conventional and lock-in based techniques), exponential decay methods and the emerging phase-mass based characterization. The aforementioned methods are discussed in detail and qualitatively compared in terms of their performance for various applications. In addition, some theoretical improvements and recommendations are introduced for adequate systems implementation. Finally, specific design considerations of high-temperature microbalance systems (e.g., GaPO4 crystals (GCM) and Langasite crystals (LCM)) are introduced, while assessing their overall system performance, stability and quality compared to conventional low-temperature applications. [ABSTRACT FROM AUTHOR]

Routine electrolyte additives are not effective enough for uniform zinc (Zn) deposition, because they are hard to proactively guide atomic‐level Zn deposition. Here, based on underpotential deposition (UPD), we propose an "escort effect" of electrolyte additives for uniform Zn deposition at the atomic level. With nickel ion (Ni2+) additives, we found that metallic Ni deposits preferentially and triggers the UPD of Zn on Ni. This facilitates firm nucleation and uniform growth of Zn while suppressing side reactions. Besides, Ni dissolves back into the electrolyte after Zn stripping with no influence on interfacial charge transfer resistance. Consequently, the optimized cell operates for over 900 h at 1 mA cm−2 (more than 4 times longer than the blank one). Moreover, the universality of "escort effect" is identified by using Cr3+ and Co2+ additives. This work would inspire a wide range of atomic‐level principles by controlling interfacial electrochemistry for various metal batteries. [ABSTRACT FROM AUTHOR]

Routine electrolyte additives are not effective enough for uniform zinc (Zn) deposition, because they are hard to proactively guide atomic‐level Zn deposition. Here, based on underpotential deposition (UPD), we propose an "escort effect" of electrolyte additives for uniform Zn deposition at the atomic level. With nickel ion (Ni2+) additives, we found that metallic Ni deposits preferentially and triggers the UPD of Zn on Ni. This facilitates firm nucleation and uniform growth of Zn while suppressing side reactions. Besides, Ni dissolves back into the electrolyte after Zn stripping with no influence on interfacial charge transfer resistance. Consequently, the optimized cell operates for over 900 h at 1 mA cm−2 (more than 4 times longer than the blank one). Moreover, the universality of "escort effect" is identified by using Cr3+ and Co2+ additives. This work would inspire a wide range of atomic‐level principles by controlling interfacial electrochemistry for various metal batteries. [ABSTRACT FROM AUTHOR]

Rechargeable aqueous zinc‐iodine batteries (ZIBs) are considered a promising newly‐developing energy‐storage system, but the corrosion and dendritic growth occurring on the anode seriously hinder their future application. Here, the corrosion mechanism of polyiodide is revealed in detail, showing that it can spontaneously react with zinc and cause rapid battery failure. To address this issue, a sulfonate‐rich ion‐exchange layer (SC‐PSS) is purposely constructed to modulate the transport and reaction chemistry of polyiodide and Zn2+ at the zinc/electrolyte interface. The resulting ZIBs can work properly over 6000 cycles with high‐capacity retention (90.2%) and reversibility (99.89%). Theoretical calculations and experimental characterization reveal that the SC‐PPS layer blocks polyiodide permeation through electrostatic repulsion, while facilitating desolvation of Zn(H2O)62+ and restricting undesirable 2D diffusion of Zn2+ by chemisorption. [ABSTRACT FROM AUTHOR]

A stable cathode–electrolyte interface (CEI) is crucial for aqueous zinc‐ion batteries (AZIBs), but it is less investigated. Commercial binder poly(vinylidene fluoride) (PVDF) is widely used without scrutinizing its suitability and cathode‐electrolyte interface (CEI) in AZIBs. A water‐soluble binder is developed that facilitated the in situ formation of a CEI protecting layer tuning the interfacial morphology. By combining a polysaccharide sodium alginate (SA) with a hydrophobic polytetrafluoroethylene (PTFE), the surface morphology, and charge storage kinetics can be confined from diffusion‐dominated to capacitance‐controlled processes. The underpinning mechanism investigates experimentally in both kinetic and thermodynamic perspectives demonstrate that the COO− from SA acts as an anionic polyelectrolyte facilitating the adsorption of Zn2+; meanwhile fluoride atoms on PTFE backbone provide hydrophobicity to break desolvation penalty. The hybrid binder is beneficial in providing a higher areal flux of Zn2+ at the CEI, where the Zn‐Birnessite MnO2 battery with the hybrid binder exhibits an average specific capacity 45.6% higher than that with conventional PVDF binders; moreover, a reduced interface activation energy attained fosters a superior rate capability and a capacity retention of 99.1% in 1000 cycles. The hybrid binder also reduces the cost compared to the PVDF/NMP, which is a universal strategy to modify interface morphology. [ABSTRACT FROM AUTHOR]

In the present study, a commercial 18650 Li-ion cylindrical cell is investigated with non-destructive 3D X-ray microscopy across a range of length scales, beginning with a survey of the entire cell and non-destructively enlarging a smaller section. Active materials are extracted from a disassembled cell and imaging performed using a combination of sub-micron X-ray microscopy and 2D scanning-electron microscopy, which point toward the need for multi-scale analysis in order to accurately characterize the cell. Furthermore, a small section is physically isolated for 3D nano-scale X-ray microscopy, which provides a measurement of porosity and enables the effective diffusivity and 3-dimensional tortuosities to be calculated via computer simulation. Finally, the 3D X-ray microscopy data is loaded into a correlative microscopy environment, where a representative sub-surface region is identified and, subsequently, analyzed using electron microscopy and energy-dispersive X-ray spectroscopy. The results of this study elucidate the microstructural characteristics and potential degradation mechanisms of a commercial NCA battery and, further, establish a technique for extracting the Bruggeman exponent for a real-world microstructure using correlative microscopy. [ABSTRACT FROM AUTHOR]

Tremella-like NiO@Co 3 O 4 @MnO 2 particles of core-double-shelled structure were synthesized by a three-step hydrothermal route and thermal treatment. The hierarchical layered porous structure of the particles has a BET surface area of 179.2 m 2 g −1 . Galvanostatic cycling in 6.0 M KOH aqueous solution produced capacitance over an ideal cathode potential cycling range. At a high current density of 2 A g −1 , NiO@Co 3 O 4 @MnO 2 has a high specific capacitance of 792.5 F g −1 with > 90% capacity retention over 1000 cycles, and a high rate capability of 68.9% of its initial capacitance was also maintained over a 0.2–4 A g −1 current density increase. We conclude that NiO@Co 3 O 4 @MnO 2 offers a promising high rate, high specific capacitance cathode material for alkaline supercapacitors, which owes both to its porous architecture and its synergistic mixed oxide core-shell-shell composition. [ABSTRACT FROM AUTHOR]

In moving towards a more sustainable society, hydrogen fueled polymer electrolyte membrane (PEM) fuel cell technology is seen as a great opportunity to reduce the environmental impact of the transport sector. However, decision makers have the challenge of understanding the real environmental consequences of producing fuel cell vehicles (FCVs) compared to alternative green cars, such as battery electric vehicles (BEVs). and more conventional internal combustion engine vehicles (ICEVs). In this work, we presented a comprehensive life cycle assessment (LCA) of a FCV focused on its manufacturing phase and compared with the production of a BEV and an ICEV. For the manufacturing phase, the FCV inventories started from the catalyst layer to the glider, including the hydrogen tank. A sensitivity analysis on some of the key components of the fuel cell stack and the FC system (such as balance-of-plant and hydrogen tank) was carried out to account for different assumptions on materials and inventory models. The production process of the fuel cell vehicle showed a higher environmental impact compared to the production of the other two vehicles power sources. This is mainly due to the hydrogen tank and the fuel cell stack. However, by combining the results of the sensitivity analysis for each component - a best-case scenario showed that there is the potential for a 25% reduction in the climate change impact category for the FCV compared to a baseline FCV scenario. Reducing the environmental impact associated with the manufacture of fuel cell vehicles represents an important challenge. The entire life cycle has also been considered and the manufacturing, use and disposal of FCV, electric vehicle and conventional diesel vehicle were compared. Overall, the ICEV showed the highest GWP and this was mainly due to the use phase and the fossil carbon emissions associated to the use of diesel. [ABSTRACT FROM AUTHOR]

[Display omitted] • Providing a highly active and stable PdPt catalysts with unique porous structure. • Designing correlative methodology including ADT, IL-imaging, in situ XAFS, MP-AES and DFT calculations. • Tracing dynamic structural evolution of PdPt alloy during electrochemical degradation in both theory and experiment. • Establishing an accurate structure-performance relationship of PdPt catalysts under ORR reaction conditions. Proton exchange membrane fuel cells require oxygen reduction catalysts with high activity and stability. Pt based alloy materials are most widely applied ORR catalyst due to its high intrinsic activity, but usually suffer from rapid deactivation as a result of particle agglomeration, detachment, Ostwald ripening and/or Pt dissolution. Here we investigate the degradation of the PdPt alloys via in situ X-ray absorption fine structure, Δ μ analysis, identical location-electron microscopy and DFT calculations. We conclude that the origin of high activity and stability of the PdPt catalyst stems from the oxidation resistance of metallic Pt, forming mainly surface adsorbed O species at high potentials. Two stage degradation process are observed, showing an evolution of dynamic surface dependent ORR performance along with the deactivation process. The careful design of Pt alloy structure leads to controlled surface oxygen behaviours. This opens a new way to increase the lifespan of fuel cells and improve the Pt utilization efficiency. [ABSTRACT FROM AUTHOR]

Layered manganese oxides adopting pre‐accommodated cations have drawn tremendous interest for the application as cathodes in aqueous zinc‐ion batteries (AZIBs) owing to their open 2D channels for fast ion‐diffusion and mild phase transition upon topochemical (de)intercalation processes. However, it is inevitable to see these "pillar" cations leaching from the hosts owing to the loose interaction with negatively charged Helmholtz planes within the hosts and shearing/bulking effects in 2D structures upon guest species (de)intercalation, which implies a limited modulation to prevent them from rapid performance decay. Herein, a new class of layered manganese oxides, Mg0.9Mn3O7·2.7H2O, is proposed for the first time, aims to achieve a robust cathode for high‐performance AZIBs. The cathode can deliver a high capacity of 312 mAh g−1 at 0.2 A g−1 and exceptional cycling stability with 92% capacity retention after 5 000 cycles at 5 A g−1. The comprehensive characterizations elucidate its peculiar motif of pined Mg‐□Mn‐Mg dumbbell configuration along with interstratified hydrogen bond responsible for less Mn migration/dissolution and quasi‐zero‐strain characters. The revealed new structure‐function insights can open up an avenue toward the rational design of superstructural cathodes for reversible AZIBs. [ABSTRACT FROM AUTHOR]

There is a growing need for lithium-ion batteries that possess increased energy storage capabilities, with a simultaneous requirement for fast charging and improved rate performance. Thick electrodes provide proportionately more active material and thus better storage capabilities, while having the unavoidable characteristic of an increased diffusion length that adversely affects the high rate performance of an electrode. Here, the workflow of advanced X-ray nano-computed tomography (CT) imaging, morphological image processing techniques, and a coupled electrochemical model is established. This tool facilitates the digital alteration of realistic electrode microstructures in a rational manner and permits studies such as the one presented in this work where an extensive parametric study is carried out and assesses the influence of thickness, porosity and discharge rate on electrode performance under the theme of heterogeneity, a key advantage of image-based analysis. In broad terms, the model shows high levels of heterogeneity in lithium, lithium-ion, and current density distributions across the electrode that gives rise to the significant and inextricable link between thickness, porosity and discharge rate. The modelling methodology presented in this work provides a foundation for the design of novel thick battery electrodes, and an example of such a design is presented here. [Display omitted] • X-ray image-based model of thick battery electrode microstructures. • Image processing techniques allow analysis and design of realistic microstructures. • Parametric study illustrates limitations arising from porosity and thickness. • Detailed insight of electrode heterogeneities due to sluggish species transport. [ABSTRACT FROM AUTHOR]

Ultra-thin layered sodium titanate nano-sheets were synthesised using a continuous hydrothermal flow process and the as-prepared materials were investigated as an anode material for lithium-ion batteries. In comparison to previous studies on similar materials, the layered titanates herein showed high electrochemical activity at lower potentials. Cyclic voltammetry measurements in the potential range of 0.05–2.1 V vs . Li/Li + , revealed that charge storage occurred from both lithium-ion intercalation as well as pseudocapacitive surface chemical processes. During electrochemical cycling tests, a high specific current of 0.5 A g −1 was applied and the cells achieved a stable specific capacity of ca . 120 mAh g −1 for over 1200 cycles. Even at an applied current of 10 A g −1 , the electrode material delivered a stable specific capacity of 38 mAh g −1 , which suggests that this material may be suitable for high power applications. [ABSTRACT FROM AUTHOR]

The next generation of proton exchange membrane fuel cells (PEMFCs) require a substantial reduction or elimination of Pt-based electrocatalyst from the cathode, where O 2 reduction takes place. The most promising alternative to Pt is atomic Fe embedded in N-doped C (Fe–N–C). Successful incorporation of Fe–N–C in PEMFCs relies on a thorough understanding of the catalyst layer properties, both ex situ and in situ , with tailored electrode interface engineering. To help resolve this conundrum, we provide a quantitative protocol on the optimisation of I/C for Fe–N–Cs. It is demonstrated that a high pore volume (3.33 cm3 g−1 FeNC) Fe–N–C catalyst requires a sufficiently high ionomer to catalyst mass ratio (I/C, 2.8≤I/C ≤ 4.2) for optimum PEMFC activity under H 2 /O 2. Emerging electrochemical techniques (distribution of relaxation times and Fourier transformed alternating current voltammetry) were used to deconvolute for the first time the trade-off between proton and electron resistance and accessible FeN x active site density with increasing ionomer loading. These findings highlight the significant impact of tuning the I/C ratio based on the catalyst layer properties and feature the power of evolving electrochemical tools for optimising performance in PEMFCs and other electrochemical devices. [Display omitted] • In situ FTacV quantified Fe–N–C electrochemical active site density in fuel cell. • Fe–N–C active site density and current density correlated with ionomer loading. • DRT quantified resistance to proton transport and oxygen diffusion in fuel cell. • Fe–N–C to ionomer ratio optimised based on quantitative protocol. [ABSTRACT FROM AUTHOR]

A recycled solvent-based green synthesis strategy for 2D/3D zeolitic imidazolate frameworks (ZIFs) has been developed to produce functional nanoporous carbons (NPCs) with tuneable morphology, graphitization, N-doping and high porosity via direct pyrolysis. These tailored NPCs show superior supercapacitance performance over typical NPC derived from MOFs and chemical activation/template-directed methods. [Display omitted] • Two important aspects of green synthesis and improved supercapacitance are reported. • A green synthesis route for ZIF-8 via recycling mother liquors (RMLs) is developed. • Rod-/sheet-/polyhedral-like 2D/3D microstructures are produced with RMLs. • 2D/3D NPCs deliver excellent capacitance values and device-level performance. Carbonized metal–organic frameworks (MOFs)-based nanoporous carbon materials (NPCs) offer attractive activities in electrochemical energy conversion and storage (EECS) applications; however, there is the need for scalable MOFs production under reduced energy/environmental impact. This study reports a green synthesis route for model zeolitic imidazolate framework (ZIF-8) materials via recycling methanol-based mother liquors (ZIF-RML x) under room temperature stirring and their carbonized materials (CZC-RML x) for high-performance supercapacitors. Series of ZIF-RML x samples produced in four recycles offer rod-/sheet-/polyhedral-like 2D/3D microstructures with tuneable internal and external framework and morphological features. Accordingly, CZC-RML x , obtained by direct pyrolysis, with high microporosity and surface area of 1500 m2 g−1 deliver excellent capacitance values of 200–340 F g−1, compared to typical MOFs-derived or chemically activated/templated NPCs, produced via extended chemical processing. Structure-relevant and comparative performance analysis reveal insights for improved charge storage and carbonization-dependent graphitization, nitrogen-doping and microporosity-controlled capacitance characteristics in the CZC-RML x over typical NPCs in literature. The device-level performance with a long-term durability over 21,000 cycles is demonstrated. The practical potential of CZC-RML x is further evaluated by fabricating solid-state cells and their parallel and series circuit combinations result in overall capacitance and voltage boost to 450 F g−1 and 2.4 V, respectively. [ABSTRACT FROM AUTHOR]

Sodium super‐ionic conductor (NASICON)‐structured phosphates are emerging as rising stars as cathodes for sodium‐ion batteries. However, they usually suffer from a relatively low capacity due to the limited activated redox couples and low intrinsic electronic conductivity. Herein, a reduced graphene oxide supported NASICON Na3Cr0.5V1.5(PO4)3 cathode (VC/C‐G) is designed, which displays ultrafast (up to 50 C) and ultrastable (1 000 cycles at 20 C) Na+ storage properties. The VC/C‐G can reach a high energy density of ≈470 W h kg−1 at 0.2 C with a specific capacity of 176 mAh g−1 (equivalent to the theoretical value); this corresponds to a three‐electron transfer reaction based on fully activated V5+/V4+, V4+/V3+, V3+/V2+ couples. In situ X‐ray diffraction (XRD) results disclose a combination of solid‐solution reaction and biphasic reaction mechanisms upon cycling. Density functional theory calculations reveal a narrow forbidden‐band gap of 1.41 eV and a low Na+ diffusion energy barrier of 0.194 eV. Furthermore, VC/C‐G shows excellent fast‐charging performance by only taking ≈11 min to reach 80% state of charge. The work provides a widely applicable strategy for realizing multi‐electron cathode design for high‐performance SIBs. [ABSTRACT FROM AUTHOR]

Hybrid fuel cell battery electric vehicles require complex energy management systems (EMS) in order to operate effectively. Poor EMS can result in a hybrid system that has low efficiency and a high rate of degradation of the fuel cell and battery pack. Many different types of EMS have been reported in the literature, such as equivalent consumption minimisation strategy and fuzzy logic controllers, which typically focus on a single objective optimisations, such as minimisation of H 2 usage. Different vehicle and system specifications make the comparison of EMSs difficult and can often lead to misleading claims about system performance. This paper aims to compare different EMSs, against a range of performance metrics such as charge sustaining ability and fuel cell degradation, using a common modelling framework developed in MATLAB/Simulink - the Electric Vehicle Simulation tool-Kit (EV-SimKit). A novel fuzzy logic controller is also presented which mutates the output membership function depending on fuel cell degradation to prolong fuel cell lifetime – the Mutative Fuzzy Logic Controller (MFLC). It was found that while certain EMSs may perform well at reducing H 2 consumption, this may have a significant impact on fuel cell degradation, dramatically reducing the fuel cell lifetime. How the behaviour of common EMS results in fuel cell degradation is also explored. Finally, by mutating the fuzzy logic membership functions, the MFLC was predicted to extend fuel cell lifetime by up to 32.8%. [Display omitted] • Comparison of energy management systems for hybrid fuel cell/battery vehicles. • Mutative Fuzzy Logic Controller prolongs fuel cell lifetime. • Reducing H2 consumption can degrade performance. [ABSTRACT FROM AUTHOR]

The remaining useful lifetime (RUL) of proton exchange membrane fuel cell (PEMFC) has been influenced by the heterogeneous distribution. In this presented paper, a novel method considering the internal heterogeneity is proposed and investigated to manage the proton exchange membrane fuel cell (PEMFC) operation thus prolonging the remaining useful lifetime. This method including the mathematic steps of quantification, normalization, and coordinate transformation, converts the conventional power-current density curve into a novel power-heterogeneity curve. The electro-thermal mapping device is applied to measure the physical-field heterogeneity of a single cell during the polarization curve tests under different temperature conditions. This method is validated by the results in the current region of 750–860 mA cm−2 of the polarization curves under temperature conditions of 50 °C and 60 °C. The novel method shows the effectiveness to make the fuel cell operate at a lower heterogeneity extent meanwhile a similar performance. • The heterogeneity degree of current density distribution is quantified by an index. • The increases of temperature and current intensify the heterogeneity extent. • A novel method in consideration of heterogeneity extent is proposed and studied. • This method consists of quantification, normalization and transformation. • The effectiveness of this method is evaluated by the experimental results. [ABSTRACT FROM AUTHOR]

Fuel cells offer many benefits for residential micro-cogeneration because of their high electrical efficiency, low emissions, and low heat-to-power ratio. However, the current design of fuel cell micro combined heat and power (CHP) systems for dwellings can be improved by better matching of the heat generated by the plant with the dwelling’s load profile and heat emitters. This paper explores the design options in building services using fuel cell micro-CHP and aims to bring the two research fields together in order to design superior integrated systems. Therefore a review of current literature on the field is performed and current available options for heat recovery from fuel cells, including the grades of heat available from different fuel cell process units are discussed. This is discussed in relation to the heat demand in a dwelling and the required temperature of the most suitable heat emitters for building services design. The paper motivates a methodology that considers all possible interconnections of plant in the design of fuel cell micro-CHP in dwellings and provides an example of how multi-objective optimisation can be used to identify promising system designs. [ABSTRACT FROM AUTHOR]

The current work reports an unprecedented multifunctional material with optical activity and a modified magnetic response by a unique combination of doping with P and Fe into the spinel LiMn 2 O 4. Through inductively coupled plasma – optical emission spectroscopy, X-ray absorption near-edge spectroscopy, X-ray diffraction and scanning transmission electron microscopy, the chemical composition, oxidation state and the crystalline structure are determined. Solid-state UV-Vis spectroscopy, magnetic susceptibility and electronic conductivity reveal the critical importance of the interaction between iron and phosphorus when simultaneously doping the crystalline structure of LiMn 2 O 4. The presence of Fe and P considerably increases charge carrier concentration as a mechanism for enhancing electronic conductivity. Fe and P doping also creates Fe-Fe spin interactions that allow double electron optical excitations. This opens a pathway to create multifunctional materials for light-assisted charging lithium-ion batteries. P doping also induces the formation of magnetic clusters arising from the Fe-O-Fe, Fe-O-Mn and Mn-O-Mn spin exchange interactions. The magnetic response of the materials is strongly influenced by the relative amount of Fe in octahedral or tetrahedral sites of the spinel structure. Such ferrimagnetic behaviour has not been reported before LiMn 2 O 4 doped with Fe or P separately. The potential applicability of this newly identified magnetic feature was demonstrated by a significant capacity gain when a lithium-ion cell is exposed to a static external magnetic field. • Simultaneous P and Fe doping of the LiMn 2 O 4 spinel develops new ferro/ferrimagnetic properties in this material. • Phosphorous stabilizes iron-iron magnetic interactions, unseen in previous Fe doped LiMn 2 O 4. • Iron-iron magnetic interaction gives rise to double optical electron excitation and ferro/ferrimagnetic features. • Under magnetic field, ferromagnetic P and Fe doped LiMn 2 O 4 delivers higher capacity gains than other generic LIB materials. • Enhanced capacity gains occur due to an increased magnetohydrodynamic effect on the surface of the particles. [ABSTRACT FROM AUTHOR]

Electrochemical clean energy conversion and the production of sustainable chemicals are critical in the journey to realizing a truly sustainable society. To progress electrochemical storage and conversion devices to commercialization, improving the electrocatalyst performance and cost are of utmost importance. Research into dual‐metal atom catalysts (DACs) is rising in prominence due to the advantages of these sites over single‐metal atom catalysts (SACs), such as breaking scaling relationships for the adsorption energy of reaction intermediates and synergistic effects. This review provides an examination of the fundamental theoretical principles and experimental electrochemical performance of DACs in idealized half cells, as well as fuel cells, before proceeding to analyze the methods used for producing and identifying DACs. Current challenges and potential future research directions of DACs are also discussed. [ABSTRACT FROM AUTHOR]

Lithium‐ion battery manufacturing chain is extremely complex with many controllable parameters especially for the drying process. These processes affect the porous structure and properties of these electrode films and influence the final cell performance properties. However, there is limited available drying information and the dynamics are poorly understood due to the limitation of the existing metrology. There is an emerging need to develop new methodologies to understand the drying dynamics to achieve improved quality control of the electrode coatings. A comprehensive summary of the parameters and variables relevant to the wet electrode film drying process is presented, and its consequences/effects on the finished electrode/final cell properties are mapped. The development of the drying mechanism is critically discussed according to existing modeling studies. Then, the existing and potential metrology techniques, either in situ or ex situ in the drying process are reviewed. This work is intended to develop new perspectives on the application of advanced techniques to enable a more predictive approach to identify optimum lithium‐ion battery manufacturing conditions, with a focus upon the critical drying process. [ABSTRACT FROM AUTHOR]

Atomically dispersed transition metal‐nitrogen‐carbon catalysts are emerging as low‐cost electrocatalysts for the oxygen reduction reaction in fuel cells. However, a cost‐effective and scalable synthesis strategy for these catalysts is still required, as well as a greater understanding of their mechanisms. Herein, iron, nitrogen co‐doped carbon spheres (Fe@NCS) have been prepared via hydrothermal carbonization and high‐temperature post carbonization. It is determined that FeN4 is the main form of iron existing in the obtained Fe@NCS. Two different precursors containing Fe2+ and Fe3+ are compared. Both chemical and structural differences have been observed in catalysts starting from Fe2+ and Fe3+ precursors. Fe2+@NCS‐A (starting with Fe2+ precursor) shows better catalytic activity for the oxygen reduction reaction. This catalyst is studied in an anion exchange membrane fuel cell. The high open‐circuit voltage demonstrates the potential approach for developing high‐performance, low‐cost fuel cell catalysts. [ABSTRACT FROM AUTHOR]

Durable and efficient hydrogen evolution reaction (HER) electrocatalysts that can satisfy industrial requirements need to be developed. Platinum (Pt)‐based catalysts represent the benchmark performance but are less studied for HER under high current densities in neutral electrolytes due to their high cost, poor stability, and extra water dissociation step. Here a facile and low‐temperature synthesis for constructing "blackberry‐shaped" Pt nanocrystals on copper (Cu) foams with low loading as self‐standing electrodes for HER in neutral media is proposed. Optimized hydrogen adsorption free energy and robust interaction induced by charge density exchange between Pt and Cu ensure the efficient and robust HER, especially under high current densities, which are demonstrated from both experimental and theoretical approaches. The electrode exhibits small overpotentials of 35 and 438 mV to reach current densities of ‐10 and ‐1000 mA cm−2, respectively. Meanwhile the electrode illustrates outstanding stability during chronoamperometry measurement under high current densities (‐100 to ‐400 mA cm−2) and 1000 cycles linear sweep voltammetry tests reaching ‐1000 mA cm−2. This study provides new design strategies for self‐standing electrocatalysts by fabricating robust metal–metal interactions between active materials and current collectors, thus facilitating the stable function of electrodes for HER under technologically relevant high current densities. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents the first part of a complete ex-situ characterisation of a wide range of commercial Gas Diffusion Layers (GDLs) used in low temperature and high temperature Proton Exchange Membrane (PEM) fuel cells. Physical and electrical characteristics of the GDLs are reported. The results show that the substrate structure has a significant effect on the mechanical and electrical properties of the GDL. Moreover, the Micro Porous Layer (MPL) structure determines the roughness of the surface, and affects the permeability and porosity of the GDL. It was found that the substrate treatment with PTFE affects the GDL characteristics; PTFE loading increases the GDLs hydrophobicity and permeability, however, decreases its overall porosity and resistivity. Adding a MPL to the substrate, results in a decrease in porosity and permeability and an increase in resistivity. The contact resistance of the GDL and the bipolar plate increases when the GDL thickness and PTFE loading are increased. This technical paper shows a close relationship between GDL materials and their physical characteristics and highlights the importance of optimising GDLs for fuel cell applications. [Copyright &y& Elsevier]

Abstract: We describe a simple nanoprecursor route for direct solid-state combinatorial synthesis and discovery of heterometallic materials compositions which are normally difficult to make in a single step. Using a combinatorial robot (incorporating a continuous hydrothermal reactor), co-precipitated nanoprecursors containing different amounts of La, Ni and Fe oxides were made. These samples were divided into two identical cloned libraries, which were heat-treated to bring about solid-state transformations at either 1348K or 1573K for 12h. In each case, experimental conditions were designed to form the corresponding La4Ni3−xFexO10 phases (x=0.0–3.0) directly without comminution. Such materials are difficult to make without multiple heating and grinding steps. The heat-treated samples from each library were embedded into a wellplate and analysed by powder X-ray diffraction methods in order to elucidate trends in phase behaviour. Several hitherto unknown phase-pure Ruddlesden Popper type La4Ni3−xFexO10 compositions were identified and their DC electrical conductivities measured. [Copyright &y& Elsevier]

Abstract: A novel two-step standard addition calibration procedure for stripping voltammetry, whereby the analytes under investigation act as internal standards for each other, is described. In this way, the benefits of an internal standard for improving precision are obtained, without the requirement to add internal standard solutions. Only the standard solutions used to perform quantification are required. The proposed methodology has been tested against the traditional standard addition method with no internal standardisation, for the measurement of Zn, Cd, Pb and Cu in synthetic and real ambient air sample digests. The new procedure is shown to improve substantially precision and accuracy compared to traditional standard addition without internal standardisation. [Copyright &y& Elsevier]

Although lithium, and other alkali ion, batteries are widely utilized and studied, many of the chemical and mechanical processes that underpin the materials within, and drive their degradation/failure, are not fully understood. Hence, to enhance the understanding of these processes various ex situ, in situ and operando characterization methods are being explored. Recently, electrochemical atomic force microscopy (EC‐AFM), and related techniques, have emerged as crucial platforms for the versatile characterization of battery material surfaces. They have revealed insights into the morphological, mechanical, chemical, and physical properties of battery materials when they evolve under electrochemical control. This critical review will appraise the progress made in the understanding batteries using EC‐AFM, covering both traditional and new electrode–electrolyte material junctions. This progress will be juxtaposed against the ability, or inability, of the system adopted to embody a truly representative battery environment. By contrasting key EC‐AFM literature with conclusions drawn from alternative characterization tools, the unique power of EC‐AFM to elucidate processes at battery interfaces is highlighted. Simultaneously opportunities for complementing EC‐AFM data with a range of spectroscopic, microscopic, and diffraction techniques to overcome its limitations are described, thus facilitating improved battery performance. [ABSTRACT FROM AUTHOR]

Polymer electrolyte fuel cells (PEFCs) are a promising replacement for the fossil fuel–dependent automotive and energy sectors. They have become increasingly commercialized in the last decade; however, significant limitations on durability and performance limit their commercial uptake. Catalyst layer (CL) design is commonly reported to impact device power density and durability; although, a consensus is rarely reached due to differences in testing conditions, experimental design, and types of data reported. This is further exacerbated by aspects of CL design such as catalyst support, proton conduction, catalyst, fabrication, and morphology, being significantly interdependent; hence, a wider appreciation is required in order to optimize performance, improve durability, and reduce costs. Here, the cutting‐edge research within the field of PEFCs is reviewed, investigating the effect of different manufacturing techniques, electrolyte distribution, support materials, surface chemistries, and total porosity on power density and durability. These are critically appraised from an applied perspective to inform the most relevant and promising pathways to make and test commercially viable cells. This holistic view of the competing aspects of CL design and preparation will facilitate the development of optimized CLs, especially the incorporation of novel catalyst support materials. [ABSTRACT FROM AUTHOR]

Supercapacitors are increasingly used in short‐distance electric transportation due to their long lifetime (≈15 years) and fast charging capability (>10 A g−1). To improve their market penetration, while minimizing onboard weight and maximizing space‐efficiency, materials costs must be reduced (<10 $ kg−1) and the volumetric energy‐density increased (>8 Wh L−1). Carbon nanofibers display good gravimetric capacitance, yet their marketability is hindered by their low density (0.05–0.1 g cm−3). Here, the authors increase the packing density of low‐cost, free‐standing carbon nanofiber mats (from 0.1 to 0.6 g cm−3) through uniaxial compression. X‐ray computed tomography reveals that densification occurs by reducing the inter‐fiber pore size (from 1–5 µm to 0.2–0.5 µm), which are not involved in double‐layer capacitance. The improved packing density is directly proportional to the volumetric performances of the device, which reaches a volumetric capacitance of 130 F cm−3 and energy density of 6 Wh L−1 at 0.1 A g−1 using a loading of 3 mg cm−2. The results outperform most commercial and lab‐scale porous carbons synthesized from bioresources (50–100 F cm−3, 1–3 Wh L−1 using 10 mg cm−2) and contribute to the scalable design of sustainable electrodes with minimal 'dead volume' for efficient supercapacitors. [ABSTRACT FROM AUTHOR]

Polypyrrole (PPy) has high electrochemical activity and low cost, so it has great application prospects in wearable supercapacitors. Herein, we have successfully prepared polypyrrole/reduced graphene oxide (PPy/rGO) nanocomposite cotton fabric (NCF) by chemical polymerization, which exhibits splendid electrochemical performance compared with the individual. The addition of rGO can block the deformation of PPy caused by the expansion and contraction. The as-prepared PPy-0.5/rGO NCF electrode exhibits the brilliant specific capacitance (9300 mF cm−2 at 1 mA cm−2) and the capacitance retention with 94.47% after 10 000 cycles. At the same time, the superior capacitance stability under different bending conditions and reuse capability have been achieved. All-solid-state supercapacitor has high energy density of 167 μWh cm−2 with a power density of 1.20 mW cm−2. Therefore, the PPy-0.5/rGO NCF electrode has a broad application prospect in high-performance flexible supercapacitor fabric electrode. [ABSTRACT FROM AUTHOR]