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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]

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]

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]

With the rapid growth in energy consumption, renewable energy is a promising solution. However, renewable energy (e.g., wind, solar, and tidal) is discontinuous and irregular by nature, which poses new challenges to the new generation of large‐scale energy storage devices. Rechargeable batteries using aqueous electrolyte and multivalent ion charge are considered more suitable candidates compared to lithium‐ion and lead‐acid batteries, owing to their low cost, ease of manufacture, good safety, and environmentally benign characteristics. However, some substantial challenges hinder the development of aqueous rechargeable multivalent ion batteries (AMVIBs), including the narrow stable electrochemical window of water (≈1.23 V), sluggish ion diffusion kinetics, and stability issues of electrode materials. To address these challenges, a range of encouraging strategies has been developed in recent years, in the aspects of electrolyte optimization, material structure engineering and theoretical investigations. To inspire new research directions, this review focuses on the latest advances in cathode materials for aqueous batteries based on the multivalent ions (Zn2+, Mg2+, Ca2+, Al3+), their common challenges, and promising strategies for improvement. In addition, further suggestions for development directions and a comparison of the different AMVIBs are covered. [ABSTRACT FROM AUTHOR]

The next generation of automotive lithium‐ion batteries may employ NMC811 materials; however, defective particles are of significant interest due to their links to performance loss. Here, it is demonstrated that even before operation, on average, one‐third of NMC811 particles experience some form of defect, increasing in severity near the separator interface. It is determined that defective particles can be detected and quantified using low resolution imaging, presenting a significant improvement for material statistics. Fluorescence and diffraction data reveal that the variation of Mn content within the NMC particles may correlate to crystallographic disordering, indicating that the mobility and dissolution of Mn may be a key aspect of degradation during initial cycling. This, however, does not appear to correlate with the severity of particle cracking, which when analyzed at high spatial resolutions, reveals cracking structures similar to lower Ni content NMC, suggesting that the disconnection and separation of neighboring primary particles may be due to electrochemical expansion/contraction, exacerbated by other factors such as grain orientation that are inherent in such polycrystalline materials. These findings can guide research directions toward mitigating degradation at each respective length‐scale: electrode sheets, secondary and primary particles, and individual crystals, ultimately leading to improved automotive ranges and lifetimes. [ABSTRACT FROM AUTHOR]

Several nano-sized mixed molybdenum/vanadium oxide monoclinic solid solutions were synthesised using a continuous hydrothermal flow process and studied with a wide range of physical characterization techniques including X-ray photoelectron spectroscopy, X-ray diffraction, transmission electron microscopy and X-ray absorption spectroscopy. The nanomaterials were tested as anodes for Li-ion batteries in the potential range 0.05–3.00 V vs. Li/Li+. Samples with nominal formulas of Mo 0.5 V 0.5 O 2 and Mo 0.33 V 0.67 O 2 showed excellent performance, especially at high current rates, due to their highly pseudocapacitive charge storage mechanism. At a specific current of 10 A g−1, Mo 0.5 V 0.5 O 2 and Mo 0.33 V 0.67 O 2 showed specific capacities of ca. 200 and 170 mAh g−1, respectively. Mo 0.5 V 0.5 O 2 also showed good cyclability, with a specific capacity of 480 mAh g−1 after 150 cycles at a specific current of 0.5 A g−1. For cyclic voltammetries conducted at high scan rates, pseudocapacitive charge storage contributed more than 90% to the total charge storage for both samples. The scalability of the synthesis technique and excellent electrochemical performance at high power, make these materials promising as negative electrode active materials for Li-ion batteries. [ABSTRACT FROM AUTHOR]

Cost‐effective and environment‐friendly aqueous zinc‐ion batteries (AZIBs) exhibit tremendous potential for application in grid‐scale energy storage systems but are limited by suitable cathode materials. Hydrated vanadium bronzes have gained significant attention for AZIBs and can be produced with a range of different pre‐intercalated ions, allowing their properties to be optimized. However, gaining a detailed understanding of the energy storage mechanisms within these cathode materials remains a great challenge due to their complex crystallographic frameworks, limiting rational design from the perspective of enhanced Zn2+ diffusion over multiple length scales. Herein, a new class of hydrated porous δ‐Ni0.25V2O5.nH2O nanoribbons for use as an AZIB cathode is reported. The cathode delivers reversibility showing 402 mAh g−1 at 0.2 A g−1 and a capacity retention of 98% over 1200 cycles at 5 A g−1. A detailed investigation using experimental and computational approaches reveal that the host "δ" vanadate lattice has favorable Zn2+ diffusion properties, arising from the atomic‐level structure of the well‐defined lattice channels. Furthermore, the microstructure of the as‐prepared cathodes is examined using multi‐length scale X‐ray computed tomography for the first time in AZIBs and the effective diffusion coefficient is obtained by image‐based modeling, illustrating favorable porosity and satisfactory tortuosity. [ABSTRACT FROM AUTHOR]

Abstract In recent years, the ability to examine the processes that cause the catastrophic failure of batteries as a result of thermal runaway has improved substantially. In this work, the effect of thermal runaway on the microstructure of the electrodes of a Na-ion battery is examined using X-ray computed tomography for the first time. The thermal failure induced via accelerating rate calorimetry enabled the examination of failed electrodes, which were subsequently compared with fresh samples. Pre- and post-mortem microstructural analysis shows changes in both electrodes as a result of the thermal runaway process at the micrometre length-scale. It is seen that the cathode shows the largest changes in structure, with the anode remaining morphologically similar post-failure at the sub-micron length-scale. The formation of a highly X-ray attenuating layer, which is proposed to be a metallic product of the thermal runaway reaction, is observed, indicating that the thermal runaway mechanisms which occur in Na-ion batteries may be similar to those reported for Li-ion systems. Graphical abstract Image 1 Highlights • Na-ion electrodes examined after undergoing thermal runaway at two length scales. • Bulk changes in both electrodes observed at micro-scale. • Nano-scale analysis highlights similar anode morphology post failure. • Cathode observed to be fundamentally degraded due to the runaway reaction. • Reduction of cathode and crossover of anode material detailed after thermal failure. [ABSTRACT FROM AUTHOR]

X-ray computed tomography (CT) is an important tool for studying battery electrode microstructures but relies on robust segmentation for validity. Here, several approaches to applying accessible machine-learning segmentation software to segment open-source lithium-ion battery (LIB) electrode tomograms are followed to identify the optimised methodology that minimises variation in active material volume fraction quantification across three users. Iterative, manual training across seven cross-sectional slices (<5%) of a tomogram is identified as an optimal balance between variance and user interaction, where 10–25% of each slice was trained. This approach is applied to lab-based X-ray CT data and compared with data obtained by focused-ion beam/scanning electron microscopy slice-and-view tomography. Variation in active material volume fraction between users is lower for at least one of these two approaches (10% or 25%) when applied to raw LIB cathode tomograms, versus unsupervised techniques such as simple and watershed segmentations. On average, the absolute volume fraction values are closer to that acquired by the correlated technique, most closely matching for high-resolution data. The present analysis provides an optimised approach for using open-source software to apply machine-learning segmentation when quantifying active material volume fractions in cutting-edge LIB electrodes, providing a more robust route to active material quantification. • Machine-learning used to segment X-ray tomograms of lithium-ion battery electrodes. • Focused-ion-beam/scanning electron microscopy used as correlative imaging technique. • Phase fraction variation between users reduced compared with traditional methods. • 10–25% coverage on 5% of tomogram sufficient to reduce variation in phase fraction. [ABSTRACT FROM AUTHOR]

A high performance vanadium-doped LiFePO 4 (LFP) electrode is synthesized using a continuous hydrothermal method at a production rate of 6 kg per day. The supercritical water reagent rapidly generates core/shell nanoparticles with a thin, continuous carbon coating on the surface of LFP, which aids electron transport dynamics across the particle surface. Vanadium dopant concentration has a profound effect on the performance of LFP, where the composition LiFe 0.95 V 0.05 PO 4, achieves a specific discharge capacity which is among the highest in the comparable literature (119 mA h g −1 at a discharge rate of 1500 mA g −1 ). Additionally, a combination of X-ray absorption spectroscopy analysis and hybrid-exchange density functional theory, suggest that vanadium ions replace both phosphorous and iron in the structure, thereby facilitating Li + diffusion due to Li + vacancy generation and changes in the crystal structure. [ABSTRACT FROM AUTHOR]

In situ diagnostic techniques provide a means of understanding the internal workings of fuel cells so that improved designs and operating regimes can be identified. Here, a novel metrology approach is reported that combines current and temperature mapping with water visualisation using neutron radiography. The approach enables a hydro-electro-thermal performance map to be generated that is applied to an air-cooled, open-cathode polymer electrolyte fuel cell. This type of fuel cell exhibits a particularly interesting coupled relationship between water, current and heat, as the air supply has the due role of cooling the stack as well as providing the cathode reactant feed via a single source. It is found that water predominantly accumulates under the cooling channels (thickness of 70-100 μm under the cooling channels and 5-25 μm in the active channels at 0.5 A cm −2 ), in a similar fashion to the lands in a closed-cathode design, but contrary to passive open-cathode systems. The relationship between current, temperature and water accumulation is complex and highly dependent on location within the cell. However, there is a general trend that higher currents and cooling limitations, especially above 0.7 A cm −2 and below 3.9 × 10 −3 m 3 s −1 , leads to temperatures above 60 °C, which dehydrate the membrane (water thickness of 10-25 um) and the cell operates below 0.5 V. [ABSTRACT FROM AUTHOR]

As the drive to improve the cost, performance characteristics and safety of lithium-ion batteries increases with adoption, one area where significant value could be added is that of battery diagnostics. This paper documents an investigation into the use of plasmonic-based optical fibre sensors, inserted internally into 1.4 Ah lithium-ion pouch cells, as a real time and in-situ diagnostic technique. The successful implementation of the fibres inside pouch cells is detailed and promising correlation with battery state is reported, while having negligible impact on cell performance in terms of capacity and columbic efficiency. The testing carried out includes standard cycling and galvanostatic intermittent titration technique (GITT) tests, and the use of a reference electrode to correlate with the anode and cathode readings separately. Further observations are made around the sensor and analyte interaction mechanisms, robustness of sensors and suggested further developments. These finding show that a plasmonic-based optical fibre sensor may have potential as an opto-electrochemical diagnostic technique for lithium-ion batteries, offering an unprecedented view into internal cell phenomena. [ABSTRACT FROM AUTHOR]

The future need to recycle enormous quantities of Li-ion batteries is a consequence of the rapid rise in electric vehicles required to decarbonise the transport sector. Cobalt is a critical element in many Li-ion battery cathode chemistries. Herein, an electrochemical reduction and recovery process of Co from LiCoO 2 is demonstrated that uses a molten salt fluidised cathode technique. For the Li-Co-O-Cl system, specific to the experimental process, a predominance diagram was developed to aid in understanding the reduction pathway. The voltammograms indicate two 2-electron transfer reactions and the reduction of CoO to Co at −2.4 V vs. Ag/Ag+. Chronoamperometry revealed a Faradaic current efficiency estimated between 70-80% for the commercially-obtained LiCoO 2 and upwards of 80% for the spent Li-ion battery. The molten salt electrochemical process route for the recycling of spent Li-ion batteries could prove to be a simple, green and high-throughput route for the efficient recovery of critical materials. [ABSTRACT FROM AUTHOR]

Aqueous electrolyte, cathode materials, multivalent ion batteries, structural engineering Keywords: aqueous electrolyte; cathode materials; multivalent ion batteries; structural engineering EN aqueous electrolyte cathode materials multivalent ion batteries structural engineering 1 1 1 03/27/21 20210324 NES 210324 Aqueous rechargeable multivalent-ion batteries (AMVIBs) are considered suitable candidates for grid-scale energy storage, owing to their low cost, ease of manufacture, safety, and environmentally benign properties. Multivalent Ion Batteries: Cathode Design for Aqueous Rechargeable Multivalent Ion Batteries: Challenges and Opportunities (Adv. Funct. [Extracted from the article]

Zinc-Ion Batteries: Multi-Scale Investigations of -Ni0.25V2O5-nH2O Cathode Materials in Aqueous Zinc-Ion Batteries (Adv. Keywords: 3D tomography; cathode; density functional theory calculation; zinc-ion battery EN 3D tomography cathode density functional theory calculation zinc-ion battery 1 1 1 04/23/20 20200421 NES 200421 In article number 2000058, Guanjie He, Ivan P. Parkin and co-workers report the synthesis of -Ni SB 0.25 sb V SB 2 sb O SB 5 sb materials as aqueous zinc-ion battery cathodes. 3D tomography, cathode, density functional theory calculation, zinc-ion battery. [Extracted from the article]