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Ordered mesoporous CuNiCo oxides were prepared via nanocasting with varied Cu/Ni ratio to establish its impact on the electrochemical performance of the catalysts. Physicochemical properties were determined along with the electrocatalytic activities toward oxygen evolution/reduction reactions (OER/ORR). Combining Cu, Ni, and Co allowed creating active and stable bifunctional electrocatalysts. CuNiCo oxide (Cu/Ni≈1 : 4) exhibited the highest current density of 411 mA cm

Coating conducting polymers onto active cathode materials has been proven to mitigate issues at high current densities stemming from the limited conducting abilities of the metal-oxides. In the present study, a carbon coating was applied onto nickel-rich NMC622 via polymerisation of furfuryl alcohol, followed by calcination, for the first time. The formation of a uniform amorphous carbon layer was observed with scanning- and transmission-electron microscopy (SEM and TEM) and X-ray photoelectron spectroscopy (XPS). The stability of the coated active material was confirmed and the electrochemical behaviour as well as the cycling stability was evaluated. The impact of the heat treatment on the electrochemical performance was studied systematically and was shown to improve cycling and high current performance alike. In-depth investigations of polymer coated samples show that the improved performance can be correlated with the calcination temperatures. In particular, a heat treatment at 400 °C leads to enhanced reversibility and capacity retention even after 400 cycles. At 10C, the discharge capacity for carbon coated NMC increases by nearly 50% compared to uncoated samples. This study clearly shows for the first time the synergetic effects of a furfuryl polymer coating and subsequent calcination leading to improved electrochemical performance of nickel-rich NMC622.

Large overpotentials upon discharge and charge of Li-O2 cells have motivated extensive research into heterogeneous solid electrocatalysts or non-carbon electrodes with the aim to improve rate capability, round-trip efficiency and cycle life. These features are equally governed by parasitic reactions, which are now recognized to be caused by the highly reactive singlet oxygen (1O2). However, the link between the presence of electrocatalysts and 1O2 formation in metal-O2 cells is unknown. Here, we show that, compared to pristine carbon black electrodes, a representative selection of electrocatalysts or non-carbon electrodes (noble metal, transition metal compounds) may both slightly reduce or severely increase the 1O2 formation. The individual reaction steps, where the surfaces impact the 1O2 yield are deciphered, showing that 1O2 yield from superoxide disproportionation as well as the decomposition of trace H2O2 are sensitive to catalysts. Transition metal compounds in general are prone to increase 1O2.

In this work, the effect of Cr3+ partial substitution on vanadium site in monoclinic lithium vanadium(III) phosphate (LVP) structure resulting in compounds with general formula: Li3V2- xCr x(PO4)3-C ( x = 0, 0.05, 0.1, 0.15) was studied. A two-step sol-gel combustion method was employed in syntheses. The samples were characterized by X-ray powder diffraction, scanning electron microscopy, coupled plasma optical emission spectroscopy, and flash combustion. The electrochemical performance of the active materials was examined through rate capability tests and cyclic voltammetry. The unsubstituted compound LVPC delivers higher capacity compared to the Cr-containing samples due to chromium inactivity in the potential range 3.0–4.4 V vs. Li/Li+. However, the Cr-substituted materials show better overall capacity retention (97–97.6%) in contrast to Li3V2(PO4)3-C (96%) in long cycling.

Large overpotentials upon discharge and charge of Li-O2 cells have motivated extensive research into heterogeneous solid electrocatalysts or non-carbon electrodes with the aim to improve rate capability, round-trip efficiency, and cycle life. These features are equally governed by parasitic reactions, which are now recognized to be caused by formation of the highly reactive singlet oxygen (1O2). However, the link between the presence of electrocatalysts and 1O2 formation in metal-O2 cells is unknown. Here, we show that, compared to pristine carbon black electrodes, a representative selection of electrocatalysts or non-carbon electrodes (noble metal, transition metal compounds) may both slightly reduce or severely increase the 1O2 formation. The individual reaction steps, where the surfaces impact the 1O2 yield are deciphered, showing that 1O2 yields from superoxide disproportionation as well as the decomposition of traces of H2O2 are sensitive to catalysts. Transition metal compounds in general are prone to increase 1O2. The results highlight the importance of 1O2 in metal-O2 cells and to use a comprehensive set of metrics to judge the impact of catalysts on reversibility.

Batteries based on the magnesium-ion chemistry are considered as promising alternatives to lithium ion technologies due to the di-valent character of the Mg2+ cations, the high theoretical volumetric capacity of magnesium (3833 mA h cm-3 for the Mg-anode), as well as its low toxicity and natural abundance. Furthermore, since magnesium deposition takes place without dendrite formation on the Mg-metal anode surface, the Mg-cell is expected to be considerably safer than comparable cells based on lithium metal.1 Despite these positive attributes, the development of magnesium secondary batteries is hindered by the high charge density and the slow solid-state diffusion of Mg2+ ions into the cathode lattice, which lead to relatively low practical capacities, irreversible capacity losses and poor cyclic stability. In order to improve the slow kinetics of Mg2+ insertion-extraction during the electrochemical reaction, new electrode materials should be developed.2 Since phosphate-based compounds with NASICON and olivine-related structures exhibit open three-dimensional frameworks, structural stability and safety under oxidizing conditions, they are considered as suitable candidate electrode materials for multi-valent ion batteries.3,4 Therefore, in this work the NASICON-structured Mg0.5Ti2(PO4)3 and the novel olivine-related (Mg0.5Ni0.5)3(PO4)2 compounds were synthesised by the solid-state method and investigated as potential electrode materials. Mg0.5Ti2(PO4)3 and (Mg0.5Ni0.5)3(PO4)2 were subjected to a comprehensive physico-chemical characterization (XRD, SEM, BET and DLS techniques) in order to optimize the synthesis conditions, determine the phase purities and assess the particle morphologies. Furthermore, the reaction mechanisms and electrochemical behaviour of the orthophosphate-based materials with monovalent Li+ and divalent Mg2+ ions were investigated using post-mortem analysis (XRD and IR) in order to establish the nature of the charge storage reaction mechanisms (i.e. intercalation or conversion). In addition to the challenges associated with the development of novel electrode materials, it is well known that electrolytes, formed by ionic salts (i.e. Mg(ClO4)2) and aprotic organic solvents (i.e. acetonitrile), form cationic insulating layers on the surface of the Mg metal anode, leading to poor performance of the overall cell. In order to address this problem, two different approaches were adopted during the electrochemical testing. Firstly, sulfone and glyme-based solutions were tested as candidate electrolytes in order to investigate their suitability with the Mg anode by analysing the passivation of the metal surface via infrared spectroscopy measurements. In a second approach, activated carbon (AC) was used as the counter electrode to replace the metallic magnesium when using Mg(ClO4)2 in acetonitrile as the electrolyte, since AC does not participate in parasitic reactions.5 Moreover, due to its high surface area, AC stores charge in a double layer on its external surface. Therefore, the systems formed by coupling AC and a conventional working electrode exhibit hybrid capacitive behaviour. Despite this, the use of AC as a counter electrode allows the investigation of the insertion of Mg2+ cations from the electrolyte into the working electrode. This set up enables the assessment of the electrochemical behaviour of the candidate working material without passivation reactions which could occur at the electrode/electrolyte interface. In particular, promising results are achieved using Mg0.5Ti2(PO4)3 as working electrode material, even though only surface sites were occupied with Mg2+ cations due to the sluggish intercalation kinetics. References 1. H. D. Yoo, I. Shterenberg, Y. Gofer, G. Gershinsky, N. Pour, D. Aurbach, Energy Environ. Sci., 2013, 6, 2265–2279; 2. Z. Ma, D. R. MacFarlane, M. Kar, Batter. Supercaps, 2019, 2, 115–127; 3. P. Canepa, G. Sai Gautam, D. C. Hannah, R. Malik, M. Liu, K. G. Gallagher, K. A. Persson, G. Ceder, Chem. Rev., 2017, 117, 4287–4341; 4. B. Kang, G. Ceder, Nature, 2009, 458, 190; 5. G. Gershinsky, H. D. Yoo, Y. Gofer, D. Aurbach, Langmuir, 2013, 29, 10964–10972.

Lithium Ion Batteries (LIB) find not only wide use in portable devices and consumer electronics, but also attract increasing attention in stationary energy storage and the automotive sector. In this regard, LIBs play a significant role as intermediate energy storage due to their high volumetric and gravimetric energy, high power density, and long cycle life. To achieve the required performance, the interaction of novel anode and cathode materials is of paramount interest. Particularly, the safety of cell operation must be assessed with respect to the formation of volatile and reactive species during cycling which can negatively alter cell components. Gas chromatography mass spectroscopy (GCMS) has proven to be a reliable tool for species detection. Unfortunately, conventional GC systems lack time resolution for in-situ gas analysis regarding fast processes, for example battery failure. Therefore, developing operando testing methods with improved time resolution is key to giving insight into electrolyte alterations during battery operation. Here one of them, a novel multiplex injection method is presented as a monitoring technique for gas species arising from the decomposition of conventional LIB electrolytes. The combination of the multiplexing technique and GCMS allows the analysis of fast decomposition processes by 15 fold increase of time resolution compared to conventional gas chromatography. In addition, FTIR allows online monitoring of selected vibration bands. Commercially produced pouch cells were monitored with respect to evolving gas species during battery operation under overcharge conditions. For the decomposition of LiPF6 / organic carbonate- based electrolytes alkanes, alcohols, ethers, esters, aldehydes and also derivatives that appear in the presence of hydrofluoric acid such as fluorinated alkane species, have been evaluated. The author gratefully acknowledges the FFG (Austrian Research Promotion Agency) for funding this research within project No. 858298.

Cyclopentyl substituted silanetriol can be prepared and isolated. Its condensation yields the corresponding disiloxanetetrol as a primary condensation product. Further condensation leads to the hexameric polyhedral silsesquioxane cage T6. The latter has been mentioned in the literature before however, lacking structural data. All compounds have been characterized with multinuclear NMR spectroscopy and, in addition, the molecular structures have been determined in the case of the disiloxanetetrol and the hexasilsesquioxane via single crystal X-ray diffraction.

A series of organosubstituted mono-, di-, and triselenides has been prepared and structurally characterized. In this series, a novel modification of 1,2,3-triselena-[3]ferrocenophane has been obtai...

Zeolitic imidazolate frameworks (ZIFs) are a subclass of metal-organic frameworks (MOFs) with extended three-dimensional networks of transition metal nodes (bridged by rigid imidazolate linkers), with potential applications in gas storage and separation, sensing and controlled delivery of drug molecules. Here, we investigate the use of

This work was supported by the European Community Seventh Framework Program (FP7/2007-2013) [grant agreement number 608490] (project M4CO2). A.O. would like to acknowledge the SCI for awarding a scholarship for her PhD research. G.M. thanks Institut Universitaire de France for its support. S.S. would like to thank the EPSRC for support EP/M506631/1. S.E.A would like to thank the Royal Society and Wolfson Foundation for a merit award. Polymorphs of Zn(2-nIm)2 (compound 1 ) and Co(2-nIm)2 (compounds 2 and 3 ) (2-nIm = 2-nitroimidazole) have been prepared by two routes: solvothermal synthesis and recrystallisation of ZIF-65(Zn/Co). Compounds 1 and 2 are isostructural, with a tetrahedrally-connected framework topology related to, but different from, that of tridymite (lonsdaleite). Single crystal X-ray diffraction analysis showed that in compound 1 (Pccn, Z = 8; a = 8.462(8) Å, b = 14.549(15) Å, c = 18.799(18) Å, V = 2314(4) Å3) there is rotational disorder for two of the three crystallographically-distinct linker types, which has been investigated computationally and by solid-state NMR spectroscopy. Detailed adsorption studies on a sample of 1 prepared by recrystallisation show 1.1 mmol g-1 uptake of CO2 at 0.1 bar (25 °C) with high affinity for CO2 over CH4 and N2 (adsorption enthalpies of 39.5, 26.0 and 18.5 kJ mol-1, respectively). A cobalt analogue (compound 2 ) with improved water stability (but lower porosity) has also been prepared. Changing the conditions of synthesis and recrystallisation gives rise to a cobalt 2-nitroimidazolate (Co(2-nIm)2, compound 3 ), which has a layered structure (I41/amd, a = 6.025(18) Å, c = 26.95(8) Å, V = 978.3(5) Å3) containing sheets of tetrahedrally-connected Co2+ cations composed of four membered rings, without porosity. Postprint Postprint

The electrolyte/electrode interactions on the anode side of a lithium-ion cell and the formation of the solid electrolyte interphase (SEI) have been investigated intensively in the past and are fairly well understood. Present knowledge about the reactions on the cathode side and the resulting cathode electrolyte interphase (CEI) is less detailed. In this study, the electrolyte/electrode interactions on the surface of the high-voltage cathode material LiNi0.5Mn1.5O4 (LNMO), both bare and FePO4-coated, were investigated. The gases evolving upon first time charging of the system were investigated using a GC/MS combination. The degradation products included THF, dimethyl peroxide, phosphor trifluoride, 1,3-dioxolane and dimethyl difluor silane, formed in the GC’s column as its coating reacts with HF from the experiments. Although these substances and their formation are in themselves interesting, the absence of many degradation products which have been mentioned in the existing literature is of equal interest. Our results clearly indicate that coating a cathode material can have a major influence on the amount and composition of the gaseous decomposition products in the formation phase.

The depletion of fossil fuel reserves as well as climate change motivate the development of new environmentally-friendly technologies for energy generation, storage, and consumption. Robust energy storage devices must be developed to meet the growing demand for portable electronics (i.e. laptops and mobile phones), electric vehicles and energy storage systems. Although lithium-ion batteries have mostly driven the revolution in modern electronics for the last three decades, new chemistries for “next-generation” batteries are currently under research and development. These new technologies are tasked with delivering better performance (capacity and current capability) at low cost while being environmentally friendly. In order to fill the gap between the current state of the art and future energy storage needs, magnesium is considered to be a possible alternative to lithium due to its natural abundancy and low toxicity. Furthermore, due to the divalent nature of the Mg2+ cations, a high theoretical volumetric capacity of 3833 mA h cm-3 can be attained if pure magnesium is used as the anode material.1 Additionally, since magnesium deposition takes place without dendrite formation on the Mg-metal anode surface, the Mg-cell is expected to be considerably safer than comparable cells based on lithium. Despite these positive attributes, the development of magnesium secondary batteries is hindered by the slow solid-state diffusion of Mg2+ ions into the cathode lattice. In this work, this issue is explored by synthesising and characterising two different phosphate-based systems to investigate their suitability as cathode materials for Mg-ion batteries, with phosphates chosen due to their structural stability and safety.2,3 The NASICON and olivine phosphates are known for their high conductivity in lithium-based systems and were selected here as potential hosts for Mg2+intercalation. NASICON compounds are usually reported as cathode or solid electrolyte materials for Li and Na-ion batteries, but there is a lack of reproducible data for Mg ion technologies. Therefore, the NASICON-structured Mg0.5Ti2(PO4)3 compound was selected for synthesis and further electrochemical characterisation. Additionally, the olivine-related (Mg0.5Ni0.5)3(PO4)2 was investigated as a novel cathode active material for the first time. This compound was chosen because of its open crystal structure, which is potentially favourable for magnesium ion diffusion. In parallel, V2O5 was used as a reference cathode active material in order to validate the electrochemical set-up, which is non-trivial for Mg chemistry. Mg0.5Ti2(PO4)3 and (Mg0.5Ni0.5)3(PO4)2 were obtained by the solid-state method and their crystal structures and phase purities were determined by Rietveld analysis of X-ray powder diffraction data. Scanning electron microscopy (SEM) was performed to analyse the particle morphologies, with particle sizes and porosities characterised by dynamic light scattering (DLS) and nitrogen adsorption (BET) techniques, respectively. Both cyclic voltammetry and galvanostatic cycling with potential limitation were carried out in order to investigate the insertion-extraction mechanism of Mg2+ ions. Ex-situ powder X-ray diffraction and SEM confirmed the crystal structures and particle morphologies, respectively, of the cathode active materials after cycling, while X-ray photon electron spectroscopy (XPS) was used to monitor changes in the oxidation state of the transition metal cation. Our results show that cells based on Mg metal anodes utilising Mg(ClO4)2 in acetonitrile as electrolyte suffer from the creation of a passivation layer leading to poor performance. In order to address this problem, activated carbon was used to replace metallic magnesium as the anode material, with the electrolyte acting as the main source for magnesium ions. The use of a carbon-based anode is seen to eliminate the passivation layer problem and improve capacity and cell cyclability. References H. D. Yoo, I. Shterenberg, Y. Gofer, G. Gershinsky, N. Pour, D. Aurbach, Energy Environ. Sci., 2013, 6, 2265–2279; P. Canepa, G. Sai Gautam, D. C. Hannah, R. Malik, M. Liu, K. G. Gallagher, K. A. Persson, G. Ceder, Chem. Rev., 2017,117, 4287–4341; B. Kang, G. Ceder, Nature, 2009,458, 190.

Here we present the results of the rapid screening of novel adsorbents for CO capture. The materials were synthesized as part of the Innovative Gas Separations for Carbon Capture (IGSCC) project, a UK wide consortium which involves the University of Edinburgh in collaboration with the University of St. Andrews, Cardiff University, Imperial College London, the University of Manchester and University College London. For the first time a wide range of materials relevant for carbon capture are investigated with regard to the CO capacity at the same conditions and using the same technique. More than 120 samples, belonging to different classes of adsorbents, were investigated: MOFs, zeolites, PIMs, carbons and silicas. The conditions chosen are the ones of interest for post-combustion applications: 0.1 bar and 35 °C. All the samples were tested using the Zero Length Column (ZLC) method. Relative to other technique, the ZLC presents the advantage of requiring a very small amount of sample (

The crystal structure of the 2:1 adduct of trifluoroacetic acid and its sodium salt has been determined and its bond situation is compared to earlier descriptions based on IR spectroscopy and dissociation pressure measurements.

2D layer structured molybdenum disulfide (MoS2) has been considered as an alternative next generation anode material over graphite, hard carbon and metal alloys, because MoS2 is structurally analogous to graphite (0.335nm) and has the interlayer d-spacing of 0.615nm while exhibiting two or three times the specific capacity of graphite. We will show how electrochemically active molybdenum disulfide (MoS2) with extended interlayer d-spacing was successfully prepared by the solvothermal synthesis method in an ethylene glycol-based mixed solvent at 200oC for 24h under an inert gas atmosphere. Then the prepared MoS2 samples were thermally annealed at various temperatures (300oC, 500oC, 800oC) to remove ethylene glycol from between the MoS2 nanosheets and to tune the d-spacing distance. The main redox reaction is described as Li2S ↔ 2Li+ + S + 2e-, and it suggests that the electrical conductivity of the MoS2 electrode must be enhanced by impregnation with carbonaceous materials to counteract the insulating properties of the sulfur. Therefore, the as-prepared MoS2 powders were surface- modified with nano-carbons (e.g. graphite and graphene) by the substrate-induced coagulation coating process and subsequent annealing at 600oC for 5h under the argon gas environment. The surface-modified carbon-MoS2 composite had a lithium diffusion coefficient (DLi: 1.08x10-6 cm2/s) during charging and discharging as compared to the as-prepared MoS2 (DLi: 4.14x10-7 cm2/s); the cell with the modified MoS2also exhibited higher capacity with a good capacity retention. The carbon-modified MoS2 electrode showed an initial capacity of 1150mAh/g and an average specific capacity of around 900 mAh/g, comparing favorably to the as-prepared MoS2 (700mAh/g). The carbon-MoS2 composite showed a higher capacity with good capacity retention and higher rate capability. The cells were electrochemically characterized by cyclic voltammetry, rate capability measurements, electrochemical impedance spectroscopy, lithium ion diffusion coefficient (DLi) measurement, differential capacity measurements, and in-situ electrochemical XRD measurement. In particular, the volumetric dilatation of the electrode materials during repeated cycles was monitored by in-situ electrochemical dilatometry. It was observed that the dilatations occur during charging /discharging, which corresponds to lithium inter-/deintercalation reactions at redox potentials of reduction at 1.1 V and oxidation at 1.6 V, 2.2V, respectively. The improved electrochemical properties of MoS2 tuned by the enlargement of the d-spacing and by the surface modification make it possible for MoS2to be used as a promising anode material for lithium-ion batteries.

Mixed transition metal oxides are among the most promising cathode materials for lithium ion batteries. The high specific capacity, low cost and thermal stability makes Li(Ni1/3Mn1/3Co1/3)O2, so-called NMC, an excellent material for power tool applications. Therefore, main leading battery manufacturer focus on the combination of these three transition metals to combine the strengths of each of them [1]. The development and design of battery materials require deep understanding of the relations between chemistry, structure and its properties. Nowadays, the commercialized NMC can only reach around 60 % of its theoretical capacity when cycled up to 4.2 V. Higher specific capacities might be reached when the upper voltage limit is raised up to 4.5 V [2], but the lifetime of the cathode then decreases drastically. The deintercalation of more than 0.6 moles of lithium in the charge process of the battery leads to irreversible capacity losses. Lithium nickel manganese cobalt oxides with different transition metal ratios were successfully synthesized via coprecipitation route. The cathode materials were characterized physico- and electrochemically and the composition was confirmed via inductive coupled plasma atomic emission spectroscopy (ICP-AES). Structural changes of non-symmetric NMC compounds at different stages of lithiation were recorded using x-ray diffraction. The resulting patterns were analyzed and the structures refined using the Rietveld method implemented in the GSAS (General Structure Analysis System) package [3]. The same procedure of crystallographic characterization of the NMC structure was carried out for different transition metal ratios cycled up to 4.5 V. The results are presented and comparison between symmetric and non-symmetric lithium nickel manganese cobalt oxides will give better insight into structural changes at higher voltages and the relation to their compositions. Acknowledgement This work was financially supported by the Austrian Federal Ministry for Transport, Innovation and Technology (bmvit) and the Austrian Research Promotion Agency (FFG). [1] N. Yabuuchi, T. Ohzuku, Journal of Power Sources 119-121 (2003): 171-174 [2] Q. Yu, Z. Chen, L. Xing, D. Chen, H. Rong, Q. Liu,W. Li, Electrochimica Acta 176 (2015): 919-925 [3] A. C. Larson, R. B. Von Dreele, Los Alamos National Laboratory Report, No. LAUR-86-748, (1987)

Nickel cations have been introduced into framework sites of the magnesium dioxiterephthalate MOF, CPO-27(Mg), via a procedure involving post-synthetic treatment with an aqueous solution of Ni2+ cations and a weak acid. The final solids have Ni concentrations up to 70 mol% of the total cation content. Selected area EDX analysis, synchrotron X-ray powder diffraction and XPS surface analysis indicate that Ni2+ is distributed throughout the crystals with highest concentration at the external surface. A mechanism involving both crystallisation and predominant isomorphous cation replacement is proposed. The modified solids have much enhanced adsorption capacities following simple thermal evacuation under vacuum than unmodified CPO-27(Mg), particularly for N2 at 77 K, for which uptakes of 17 mmol g−1 are achieved. This is attributed to surface modification that makes the surface more stable to heating under evacuation.

A novel form of mixed-linker ZIF with the RHO topology is one of four zinc-imidazolate frameworks prepared with purine and 2-nitroimidazole. In this structure the linkers order to give a large pore solid with a high pore volume and an unusual symmetry and linker orientation. It possesses extra-framework zinc imidazolate units decorating the internal surface which can be removed to give high porosity.