Improved Safety Characteristics Research Articles

Glyoxylic‐Acetal‐Based Gel‐Polymer Electrolytes for Lithium‐Ion Batteries

AbstractThis work focuses on the combination of two strategies to improve the safety of lithium‐ion batteries: The use of a glyoxylic‐acetal, 1,1,2,2‐tetraethoxyethane, in the solvent blend to reduce the flammability of the liquid electrolyte and further its confinement inside of a methacrylate‐based polymer matrix, to prevent electrolyte leakage from the battery cells. Physicochemical characterizations of this novel gel‐polymer electrolyte (GPE) confirm its improved thermal properties and suitable ionic conductivity, as well as electrochemical stability window. Tests in LFP and hard carbon half‐cells vs. lithium metal show that the combination of glyoxylic‐acetal‐based electrolyte and the methacrylate‐based polymer matrix can promote lithium‐ion intercalation and deintercalation with stable capacity values. The application in lithium‐ion battery full cells furthermore shows that the GPE can promote a similar performance compared to the respective liquid electrolyte and can therefore make possible the realization of energy storage devices with improved safety characteristics.

Ion Trap LC/MS reveals the generation of reactive intermediates in acalabrutinib metabolism: phase I metabolic profiling and bioactivation pathways elucidation.

Acalabrutinib (CALQUENCE; ACB) is a Bruton tyrosine kinase inhibitor (BTKI) used to treat mantle cell lymphoma, small lymphocytic lymphoma (SLL), and chronic lymphocytic leukemia (CLL). On 21 November 2019, ACB was approved by the U.S. FDA for the use as a single therapy for the treatment of CLL/SLL. In silico studies were first done to propose vulnerable sites of metabolism and reactivity pathways by StarDrop software and Xenosite online software; respectively. ACB metabolites and stable adducts were characterized in vitro from rat liver microsomes (RLMs) using Ion Trap LC/MS. Generation of reactive intermediates (RIs) in the in vitro metabolism of ACB was investigated using glutathione, potassium cyanide, and methoxylamine as trapping nucleophiles for the RIs including iminopyridinone, iminium, and aldehyde, respectively, to form stable adducts that can be identified and characterized by Ion Trap LC/MS. Five phase I metabolites, seven 6-iminopyridin-3(6H)-one and five aldehyde RIs of ACB were identified. Based on literature reviews, the generation of RIs of ACB, and the subsequent drug-induced organ toxicity (DIOT) reactions may provide an explanation of ACB ADRs. Additional drug discovery investigations can be performed to facilitate the creation of novel medications with improved safety characteristics.

Robust Self‐Standing Single‐Ion Polymer Electrolytes Enabling High‐Safety Magnesium Batteries at Elevated Temperature

AbstractRechargeable magnesium batteries (RMBs) have great potential in the field of high‐temperature specialized batteries owing to the superior thermostability and lower propensity for dendrite formation of Mg metal anodes. And the development of Mg2+‐conducting electrolytes that can operate stably under elevated temperature conditions (>100 °C) is the key to high‐temperature RMBs. Here, a robust self‐standing single‐ion polymer electrolyte (SSPE) enabling high‐safety RMBs working at elevated temperature is presented. This SSPE exhibits an expanded electrochemical stability window of 4.8 V (vs Mg2+/Mg), a remarkable Mg2+‐ion transference number of 0.79, and a highly reversible Mg plating/stripping performance. This rationally designed SSPE enables home‐made Mo6S8//Mg batteries with superior high‐temperature (up to 150 °C) performance and significantly improved safety characteristics under abuse conditions. This design concept for a robust SSPE provides a promising path to high‐safety specialized RMBs operating at the elevated temperature, which also offers a new path for the development of functionalized electrolytes.

HMX surface modification with polymers via sc-CO2 antisolvent process: A way to safe and easy-to-handle energetic materials

The continuous need for energetic materials with increased performance and improved safety characteristics stimulates synthetic efforts as well as physical modification of existing compounds. The present study reports the fabrication of 1,3,5,7-tetranitro-1,3,5,7-tetrazoctane (HMX)-based composites with common commercial polymers, polymethyl acrylate (PMA), acrylonitrile butadiene styrene rubber (ABS), ethyl cellulose (EC), polylactide (PLA), and polyethylene terephthalate glycol (PETG). To precipitate the polymer on the HMX particles, the supercritical CO2-based anti-solvent method was employed. Surface state studies with various modes of scanning probe microscopy show that the polymers at less than 3 wt% content do not form a continuous layer but precipitate as globular islands. Nevertheless, the coating effectively absorbs the mechanical stress, resulting in a much lower sensitivity to impact and a considerable improvement of the HMX friction sensitivity. Specifically, for HMX@3PMA composite the impact and friction sensitivities are 54 J and 240 N, as compared to 7 J and 150 N for neat HMX. Additionally, the beneficial improvement of flowability is observed for the fabricated composites, and evidenced by small-scale flow cup studies. Importantly, the suggested procedure affords the safe and easy-to-handle energetic material powder containing only 1–3 wt% of the polymer additive.

A Study of 3,5‐Dinitro‐1‐(2,4,6‐trinitrophenyl)‐1H‐pyrazol‐4‐amine (PicADNP) as a New High Energy Density Booster Explosive

AbstractTwo improved, fast, feasible, scalable, and economic synthetic protocols for the laboratory scale manufacturing of 3,5‐dinitro‐1‐(2,4,6‐trinitrophenyl)‐1H‐pyrazol‐4‐amine (PicADNP) are described. The previous set of analytical data from an earlier publication could be verified and complemented by additional measurements. The material was fully characterized by multinuclear NMR, spectroscopic methods, elemental analysis, DSC and DTA, as well as X‐ray diffraction. The crystal structure was elucidated and Hirshfeld surface analysis, as well as 2D fingerprint plot analysis for the assessment of sensitivities towards external stimuli was applied. The sensitivity towards shock, friction and electrostatic discharge was also determined experimentally. The performance of the title compound was calculated by applying the EXPLO5 computer code and the theoretical results were compared with the results of SSRT and booster testing experiments. The title compound combines good energetic properties with improved safety characteristics and could find its way into application as a new booster explosive to replace the state‐of‐the‐art material PETN. The optimizations of the synthetic protocol comprise a greener solvent system, shorter reaction times, higher yields for the pure material and a nontoxic byproduct to make the manufacturing process more attractive and better suitable for a subsequent scale up to the technical and industrial scale.

Tracking the Influence of Thermal Expansion and Oxygen Vacancies on the Thermal Stability of Ni-Rich Layered Cathode Materials.

The ever‐growing demand for high‐energy lithium‐ion batteries in portable electronics and electric vehicles has triggered intensive research efforts over the past decade. An efficient strategy to boost the energy and power density of lithium‐ion batteries is to increase the Ni content in the cathode materials. However, a higher Ni content in the cathode materials gives rise to safety issues. Herein, thermal expansion and oxygen vacancies are proposed as new critical factors that affect the thermal stability of charged Ni‐rich cathode materials based on a systematic synchrotron‐based X‐ray study of Li0.33Ni0.5+ xCo0.2Mn0.3‐ xO2 (x = 0, 0.1, 0.2) cathode materials during a heating process. Charged cathode materials with higher Ni contents show larger thermal expansion, which accelerates transition metal migration to the Li layers. Oxygen vacancies are formed and accumulate mainly around Ni ions until the layered‐to‐spinel phase transition begins. The oxygen vacancies also facilitate transition metal migration to the Li layers. Thermal expansion and the presence of oxygen vacancies decrease the energy barrier for cation migration and facilitate the phase transitions in charged cathode materials during the heating process. These results provide valuable guidance for developing new cathode materials with improved safety characteristics.

The Therapeutic Potential of Nanobodies.

Today, bio-medical efforts are entering the subcellular level, which is witnessed with the fast-developing fields of nanomedicine, nanodiagnostics and nanotherapy in conjunction with the implementation of nanoparticles for disease prevention, diagnosis, therapy and follow-up. Nanoparticles or nanocontainers offer advantages including high sensitivity, lower toxicity and improved safety—characteristics that are especially valued in the oncology field. Cancer cells develop and proliferate in complex microenvironments leading to heterogeneous diseases, often with a fatal outcome for the patient. Although antibody-based therapy is widely used in the clinical care of patients with solid tumours, its efficiency definitely needs improvement. Limitations of antibodies result mainly from their big size and poor penetration in solid tissues. Nanobodies are a novel and unique class of antigen-binding fragments, derived from naturally occurring heavy-chain-only antibodies present in the serum of camelids. Their superior properties such as small size, high stability, strong antigen-binding affinity, water solubility and natural origin make them suitable for development into next-generation biodrugs. Less than 30 years after the discovery of functional heavy-chain-only antibodies, the nanobody derivatives are already extensively used by the biotechnology research community. Moreover, a number of nanobodies are under clinical investigation for a wide spectrum of human diseases including inflammation, breast cancer, brain tumours, lung diseases and infectious diseases. Recently, caplacizumab, a bivalent nanobody, received approval from the European Medicines Agency (EMA) and the US Food and Drug Administration (FDA) for treatment of patients with thrombotic thrombocytopenic purpura.

Enhanced Electrochemical Performance of LiNi0.8Co0.1Mn0.1O2 Cathode with an Ionic Liquid-Based Electrolyte

An ionic liquid-based electrolyte consisted of N-methyl-N-propylpyrrolidine bis(trifluoromethanesulfonyl)imide (Pyr13TFSI), sulfolane (SL) and ethyl methyl carbonate (EMC) as co-solvent, lithium difluoro(oxalate)borate (LiDFOB) as Li salt for cathode material LiNi0.8Co0.1Mn0.1O2 (NCM811) is investigated in this study. The electrolyte with ionic liquid (IL) has improved safety characteristics and a wide electrochemical window that can reach 4.8V (vs. Li/Li+). The Li/NCM811 half-cells with the electrolyte display outstanding electrochemical performance, achieving a discharge capacity and capacity retention of 166.1 mAh g−1 and 97.6% after 100 cycles between 3.0 and 4.3V at 25°C. This excellent electrochemical performance is due to a thin and compact cathode electrolyte interphase (CEI) film formed on the surface of the LiNi0.8Co0.1Mn0.1O2 electrode derived from the electrolyte with IL and reduction of lithium dendrite formation. The film inhibits the volume change of the material during the charge-discharge cycles and maintains the structural integrity of the cathode material, which enhances electrochemical performance of the Li/NCM811 half-cells.

A Holistic Approach in the Development of a High Energy Density, Long Cycle Life and Safe Li-S Battery

Rechargeable lithium-sulfur (Li-S) batteries are widely considered the most promising “Beyond Li-ion” candidates, notably for their high theoretical energy density. The low and moderate atomic weight of Li and S, respectively, translates to a battery chemistry pairing that is lightweight. Since each S atom can ultimately host two lithium ions (Li+), compared with 0.5–0.7 Li+ per host atom in Li-ion batteries [1], the Li-S battery chemistry offers a much higher Li storage capacity potential. Assuming a complete redox couple reaction, S8 + 16Li+ + 16e- ↔ 8Li2S, the S cathode can have a high theoretical specific capacity of 1672 mAh/g with an average discharge voltage of ~2.1V (vs. Li/Li+), which leads to a theoretical specific energy of ~2500 Wh/kg based on the active material weight of a Li-S cell [2]. Other compelling attributes of Li-S batteries include high S natural abundance, low cost of S materials and safety characteristics owing to an intrinsic tolerance to overcharge [3]. In addition, the primary constituents of Li-S batteries are non-toxic and environmentally friendly [4]. However, currently no commercial Li-S battery exists due to some significant technical challenges that have thus far prevented the realization of the tremendous energy density and performance potentials of Li-S batteries. These technical challenges include: low practical specific energy or energy density yield, significant capacity loss with cycling, high self-discharge rates, low Coulombic efficiency and safety concerns due to the use of Li metal anode [5]. We will present our efforts in the development of a high energy density, long cycle life, safe and economically scalable Li-S battery technology via a holistic approach to nanoengineer/functionalize cell components including active components (i.e., S cathode, Li metal anode) and inactive components (e.g., separator, electrolyte), to address the Li-S battery cycle life degradation challenges and safety concerns. We will show that our comprehensive approaches render much improved discharge specific capacity/energy, Coulombic efficiency and cycle life of the resultant Li-S cells. Our experimental evidence suggests (i) much reduced polysulfide dissolution and (ii) much improved safety characteristics of the cycled Li-S cells constructed from the nanoengineered/functionalized cell components. Our study demonstrates that the holistic approach of nanoengineering/functionalizing the active and inactive cell components represent a very promising strategy to develop a high energy density, long cycle life, safe and economically scalable Li-S battery technology. References Bullis, “Revisiting Lithium-Sulfur Batteries” MIT Review, May 22, 2009.Arumugam Manthiram, Yongzhu Fu, and Yu-Sheng Su, Acc. Chem. Res., 46 (5), pp 1125–1134 (2013)James R. Akridge, “Lithium Sulfur Rechargeable Battery Safety”, Battery Power Products & Technology, October 2001.Yongguang Zhang, Yan Zhao, Kyung Eun Sun and P. Chen, The Open Materials Science Journal, 5, 215-221 (2011).Monica Marinescu, Laura O’Neill, Teng Zhang, Sylwia Walus, Timothy E. Wilson, and Gregory J. Offer, J. Electrochem. Soc, 165 (1) A6107-A6118 (2018).

The Scale‐up and Commercialization of Nonaqueous Na‐Ion Battery Technologies

AbstractThis report provides an overview of development activities that enable the scale‐up and thereby a pathway toward the commercialization of sodium‐ion battery technologies for the energy storage market. The electrochemical performance of active materials and full cell performance of batteries developed by two startup companies, Novasis Energies, Inc. and Faradion Limited, are discussed in detail. Both companies offer low‐cost sodium‐ion battery chemistries with uniquely developed active materials that afford high rate capability and cycling stability. Their technologies are highly scalable due to the implementation of abundant and predominantly nontoxic elements and the ability to utilize common battery fabrication and manufacturing equipment. Both companies utilize active materials that are cost competitive compared to low‐cost lithium‐ion battery materials while exhibiting very similar specific capacity. In addition, improved safety characteristics with respect to operation and transportation distinguish the described sodium‐ion batteries from their incumbent lithium‐ion counterparts. The featured technology is particularly attractive for large‐scale energy storage applications.

Concentration-Dependent Dimerization of Anthraquinone Disulfonic Acid and Its Impact on Charge Storage Capabilities

Redox flow batteries (RFBs) offer several advantages over enclosed batteries in grid-scale applications such as decoupled power rating (reactor size) and energy capacity (tank size), high active-to-inactive materials ratio (especially at long durations), and improved safety characteristics.1 Recent literature has focused on emerging aqueous organic RFBs (AORFB) which employ abundant redox active organic species dissolved in an inexpensive water-based electrolyte. While many new organic redox couples have been proposed, to date, quinones have achieved the greatest success with 9,10-Anthraquinone-2,7-disulfonic acid (AQDS) being the most promising and widely reported derivative. AQDS is considered a benchmark compound for AORFBs2–5 due to its good charge retention (days), low crossover rates (through Nafion), high solubility (>1 M), and low redox potential (~0.2 V vs RHE). Some studies report idealized electrochemical behavior of AQDS at low concentrations (1 mM),6 however, at higher concentrations AQDS deviates from ideal behavior and undergoes dimerization, contributing to changes in energy density, solubility, and redox potential. In this work, we examine the nuances of AQDS in aqueous solution utilizing cyclic voltammetry (CV), bulk electrolysis (BE), chemical titration, and nuclear magnetic resonance (NMR) spectroscopy. Depending on the AQDS concentration, electrolyte choice, and time scale (electrolytic vs. voltammetric), the electrochemical behavior can vary and follow different mechanistic pathways. To elucidate the reaction mechanism, we synthesize various derivatives of AQDS and examine their electrochemistry through CV and BE, as well as their chemical structures by NMR. Further, we correlate the dimer structure of AQDS in solution with the observed electrochemistry to explain the variations in accessible capacity and to provide guidelines for maximizing storage performance. The complex, solution-phase interactions of AQDS suggest that other organic compounds may display similar (or more convoluted) phenomena. The suite of chemical and electrochemical studies developed in this study are general and can be applied to other organic candidates for RFBs to understand known issues with energy density, solubility, and stability. Acknowledgments We thank the Joint Center for Energy Storage Research for financial support. This research was conducted with Government support under and awarded by DoD, Air Force Office of Scientific Research, National Defense Science and Engineering Graduate (NDSEG) Fellowship, 32 CFR 168a. References (1) Su, L.; Kowalski, J. A.; Carroll, K. J.; Brushett, F. R. Recent Developments and Trends in Redox Flow Batteries. In Rechargeable Batteries; Zhang, Z., Zhang, S. S., Eds.; Green Energy and Technology; Springer International Publishing, 2015; pp 673–712.(2) Huskinson, B.; Marshak, M. P.; Suh, C.; Er, S.; Gerhardt, M. R.; Galvin, C. J.; Chen, X.; Aspuru-Guzik, A.; Gordon, R. G.; Aziz, M. J. A Metal-Free Organic-Inorganic Aqueous Flow Battery. Nature 2014, 505 (7482), 195–198.(3) Yang, B.; Hoober-Burkhardt, L.; Wang, F.; Prakash, G. S.; Narayanan, S. R. An Inexpensive Aqueous Flow Battery for Large-Scale Electrical Energy Storage Based on Water-Soluble Organic Redox Couples. J. Electrochem. Soc. 2014, 161 (9), A1371–A1380.(4) Lin, K.; Chen, Q.; Gerhardt, M. R.; Tong, L.; Kim, S. B.; Eisenach, L.; Valle, A. W.; Hardee, D.; Gordon, R. G.; Aziz, M. J.; Marshak, M. P. Alkaline Quinone Flow Battery. Science 2015, 349 (6255), 1529–1532.(5) Yang, B.; Hoober-Burkhardt, L.; Krishnamoorthy, S.; Murali, A.; Prakash, G. K. S.; Narayanan, S. R. High-Performance Aqueous Organic Flow Battery with Quinone-Based Redox Couples at Both Electrodes. J. Electrochem. Soc. 2016, 163 (7), A1442–A1449.(6) Batchelor-McAuley, C.; Li, Q.; Dapin, S. M.; Compton, R. G. Voltammetric Characterization of DNA Intercalators across the Full pH Range: Anthraquinone-2,6-Disulfonate and Anthraquinone-2-Sulfonate. J. Phys. Chem. B 2010, 114 (11), 4094–4100.

Surface Structure, Morphology, and Stability of Li(Ni1/3Mn1/3Co1/3)O2 Cathode Material

Layered Li(Ni1–x–yMnxCoy)O2 (NMC) oxides are promising cathode materials capable of addressing some of the challenges associated with next-generation energy storage devices. In particular, improved energy densities, longer cycle-life, and improved safety characteristics with respect to current technologies are needed. However, sufficient knowledge on the atomic-scale processes governing these metrics in working cells is still lacking. Herein, density functional theory (DFT) is employed to predict the stability of several low-index surfaces of Li(Ni1/3Mn1/3Co1/3)O2 (NMC111) as a function of Li and O chemical potentials. Predicted particle shapes are compared with those of single crystal NMCs synthesized under different conditions. The most stable surfaces for stoichiometric NMC111 are predicted to be the nonpolar (104), the polar (012) and (001), and the reconstructed, polar (110) surfaces. Results indicate that intermediate spin Co3+ ions lower the (104) surface energy. Furthermore, it was found that remo...

Iron oxide/aluminum/graphene energetic nanocomposites synthesized by atomic layer deposition: Enhanced energy release and reduced electrostatic ignition hazard

Nanocomposites consisting of iron oxide (Fe2O3) and nano-sized aluminum (Al), possessing outstanding exothermic redox reaction characteristics, are highly promising nanothermite materials. However, the reactant diffusion inhibited in the solid state system makes the fast and complete energy release very challenging. In this work, Al nanoparticles anchored on graphene oxide (GO/Al) was initially prepared by a solution assembly approach. Fe2O3 was deposited on GO/Al substrates by atomic layer deposition (ALD). Simultaneously thermal reduction of GO occurs, resulting in rGO/Al@Fe2O3 energetic composites. Differential scanning calorimetry (DSC) analysis reveals that rGO/Al@Fe2O3 composite containing 4.8wt% of rGO exhibits a 50% increase of the energy release compared to the Al@Fe2O3 nanothermite synthesized by ALD, and an increase of about 130% compared to a random mixture of rGO/Al/Fe2O3 nanoparticles. The enhanced energy release of rGO/Al@Fe2O3 is attributed to the improved spatial distribution as well as the increased interfacial intimacy between the oxidizer and the fuel. Moreover, the rGO/Al@Fe2O3 composite with an rGO content of 9.6wt% exhibits significantly reduced electrostatic discharge sensitivity. These findings may inspire potential pathways for engineering energetic nanocomposites with enhanced energy release and improved safety characteristics.

Development of Cathode Materials of Lithium-Ion Secondary Batteries for High Energy and Safety

As a consequence of shortage of fossil fuels, development of electrified vehicles (EVs) has further raised the performance requirements of rechargeable battery system. The research and development efforts in meeting these challenges have focused on identifying and designing new cathode materials with capacity higher than 200 mAh g −1 and improved safety characteristics. In order to improve the thermal and structural stability of the Ni-rich layered cathode materials, cathodes enriched in Mn at the outer layer were proposed to suppress the undesired Ni 4+ reduction because Mn 4+ is naturally stable (MnO2 is a stable compound) and does not participate in the redox reaction during the charge and discharge cycle. Recently, we developed a high-energy cathode material with not only full concentration gradient materials but also two-sloped full concentration gradient materials, in which the Ni concentration decreases and the Mn concentration increases toward the particle surface. These cathode materials are synthesized via a specially designed batch-type reactor. The cathode delivers high discharge capacity with excellent capacity retention. The cathode materials exhibits the best cycling stability, rate capability, and thermal stability compared to conventional cathode (CC) and Li[Ni0.8Co0.15Al0.05]O2 (NCA). While the chemical partitioning of the composition generated the observed high capacity and thermal stability, the unique microstructure of the FCG secondary particle provided excellent cycle stability and rate capability.

Novel High Energy Density Sodium Layered Oxide Cathode Materials - from Material to Cells

Lithium ion batteries have now been commercially available for the past twenty-five years. There has been a steady improvement in lithium ion battery technology throughout this period and lithium ion batteries are widely considered as the technology of choice to meet the energy demands of the future. However, there is growing research and commercial interest in other metal-ion battery technologies that could also meet certain areas of future energy demand. Sodium-ion technology has commanded an increasing research and commercial interest over recent years due to the high abundance and uniform distribution of sodium across the world, and the reported potential commercial advantages of lower cost, greater sustainability and improved safety characteristics of sodium ion batteries compared with their lithium-ion counterparts. Sharp Laboratories of Europe Ltd have been developing a new sodium ion cell chemistry based upon a tin-containing nickel based layered oxide cathode and a hard carbon anode. Here we report on the challenges faced during the development of a new sodium-ion technology in moving from a new electrode material, through from half cell results to small full cell development and then larger scale full cell development. We discuss the optimisation of the material choice, electrolyte, electrode parameters and formation process on the gravimetric and volumetric cell energy density along with the lifetime and rate behaviour of the cells.

High Energy Density Na-Ion Battery Technology

High energy density sodium-ion (Na-ion) batteries are now close to successful commercialization. These energy storage devices offer some significant advantages over their lithium-ion counterparts, such as lower material costs, improved safety characteristics and superior transportation properties [1,2]. In this study we demonstrate the electrochemical performance characteristics of full Na-ion cells constructed using a proprietary layered oxide cathode NaaNi(1-x-y-z)MnxMgyTizO2 and a hard carbon anode material [3]. Figure 1 depicts the voltage profile for a typical Faradion Na-ion cell. The cathode material delivers a reversible specific capacity of over 146 mAh/g and the cell generates an average discharge cell voltage of around 3.2 V. The projected specific energy for this battery system is 140-150 Wh/kg. The cell cycles with low polarization and with excellent columbic and (round-trip) energy efficiency. Figure 2 denotes a typical cycle life plot (100 % DOD) for a representative Na-ion cell. Following 170 cycles the discharge capacity fade is less than 1%. Simple linear extrapolation indicates that this cell should cycle 1000 cycles while maintaining well over 90% of its original discharge capacity. To demonstrate the commercial viability of Na-ion batteries, Faradion has scaled-up this cell chemistry to the 3 Ah (9 Wh) prismatic pouch cell level. These cells were fabricated using traditional Li-ion manufacturing methods. Multiple prototype cells have been incorporated successfully into E-Bike (>400 Wh) and E-Scooter (>750 Wh) demonstrator packs [4,5]. Further performance and safety characteristics of the Na-ion cells will be provided during the presentation.

A Novel P2-Type Layered Cathode Material for Sodium-Ion Batteries

Since 1990 lithium-ion (Li-ion) batteries have been commercially available and currently remain as the technology of choice for applications where high energy densities are required. Sodium-ion (Na-ion) technology is similar in many ways to Li-ion technology, but is still in its initial stage. Current research trends are mostly based on Na-ion based technology due to several commercial advantages, including lower cost, greater sustainability and improved safety characteristics.1, 2 Among different types of cathode materials available, layered oxides such as NaxMO2 (M = transition metal) have shown great promise in terms of both cost and performance.3,4 According to Delmas et al, these layered oxides are classified into different structures, the most common of which are O3, P2 and P3.5 In these descriptions, the O and P refer to an octahedral (O), or prismatic (P), coordination of the Na-ions, and the number refers to the number of layers in the unit cell. P2-type Na-Ni-Mn-O has been considered as a suitable cathode material for the modern day requirement of high power and energy applications due to their low cost, easy synthesis and high theoretical capacity of greater than 250 mAhg-1. However this material has the serious problem of capacity fading due to structural instability. Cationic substitution and surface coating was an efficient strategy to enhance the electrochemical performance by improving the structural stability and preventing Mn3+ dissolution into electrolyte at higher voltages. In this work a novel P2-type Na0.5Ni0.33Cu0.07Mn0.67O2 was synthesized using the single step conventional solid state method and studied as cathode material for sodium ion batteries. The presence of Cu in the lattice structure enhanced the capacity retention to 83% after 100 cycles along with smooth voltage plateau in the high voltage region as shown in Figure 1. Surface coating with MgO increased the specific capacity of the material in the extended voltage window of 2.0 – 4.5V. The MgO coated material shows a smooth voltage plateau without any phase gliding in the higher voltage as in Figure 2. The capacity retention after 70 cycles is found to be 77.6% with enhanced performance. Hence the MgO coated Na0.5Ni0.26Cu0.07Mn0.67O2is studied as a novel cathode for room temperature Na-ion batteries.

Nanostructured Garnet-Type Solid Electrolytes for Lithium Batteries: Electrospinning Synthesis of Li7La3Zr2O12 Nanowires and Particle Size-Dependent Phase Transformation

Lithium lanthanum zirconate (LLZO) is a promising ceramic solid electrolyte for all-solid-state lithium batteries with improved safety characteristics. However, the different phases of LLZO differ in lithium ionic conductivity by several orders of magnitude, with extrinsic dopants often required to stabilize the high conductivity cubic phase. Here we show that cubic LLZO can be stabilized at room temperature in nanostructured particles without the use of extrinsic dopants. LLZO nanowires were synthesized using electrospinning and formed cubic phase materials after only 3 h calcination at 700 °C. Bulk LLZO with tetragonal structure was transformed to the cubic phase using particle size reduction via ball milling. Heating conditions that promoted particle coalescence and grain growth induced a transformation from the cubic to tetragonal phases in both types of nanostructured LLZO. Detailed structural characterizations with XRD and TEM were performed to understand the LLZO formation processes and phase transformations. This work demonstrates another strategy, namely the use of nanostructuring, as an alternative to extrinsic doping for obtaining cubic phase LLZO.

Back Cover: Electrolyte Mixtures Based on Ethylene Carbonate and Dimethyl Sulfone for Li‐Ion Batteries with Improved Safety Characteristics (ChemSusChem 11/2015)

Back Cover: Electrolyte Mixtures Based on Ethylene Carbonate and Dimethyl Sulfone for Li‐Ion Batteries with Improved Safety Characteristics (ChemSusChem 11/2015)

Electrolyte Mixtures Based on Ethylene Carbonate and Dimethyl Sulfone for Li-Ion Batteries with Improved Safety Characteristics.

In this study, novel electrolyte mixtures for Li-ion cells are presented with highly improved safety features. The electrolyte formulations are composed of ethylene carbonate/dimethyl sulfone (80:20 wt/wt) as the solvent mixture and LiBF4 , lithium bis(trifluoromethanesulfonyl)azanide, and lithium bis(oxalato)borate as the conducting salts. Initially, the electrolytes are characterized with regard to their physical properties, their lithium transport properties, and their electrochemical stability. The key advantages of the electrolytes are high flash points of >140 °C, which enhance significantly the intrinsic safety of Li-ion cells containing these electrolytes. This has been quantified by measurements in an accelerating rate calorimeter. By using the newly developed electrolytes, which are liquid down to T=-10 °C, it is possible to achieve C-rates of up to 1.5 C with >80 % of the initial specific capacity. During 100 cycles in cell tests (graphite||LiNi1/3 Co1/3 Mn1/3 O2 ), it is proven that the retention of the specific capacity is >98 % of the third discharge cycle with dependence on the conducting salt. The best electrolyte mixture yields a capacity retention of >96 % after 200 cycles in coin cells.