NMR Insights into Designing Safe and Efficient Lithium-Ion-Batteries with Solid Electrolyte

Antiferroelectric domain modulation enhancing energy storage performance by phase-field simulations

Increasing the global energy demand as well as the carbon dioxide (CO2) level in the atmosphere caused by burning fossil fuel as the main source of energy motivate the development of green energy technologies. However, the real activity improvement for these technologies is mainly impeded by intermittent nature of renewable energy technologies. One smart approach to overcome this issue is to store energy into the chemical bonds1–6 using inexpensive and efficient energy conversion and storage technologies. In these systems, energy can be converted or stored into chemical bonds as a form of fuels or electricity using renewable energy sources, e.g., solar and wind energy7–9. Despite recent progress, the development of these systems is advanced far more slowly due to the expensive and less efficient materials employed in these technologies. Here, I will present my aim to design, synthesis, and characterization of inexpensive earth-abundant transition metal dichalcogenide class of materials suitable for energy conversion and storage systems. I have tested the performance of this class of catalysts for the carbon dioxide (CO2) reduction reaction, oxygen reduction, oxygen evolution reactions. The results indicate (i) 100 times higher turn over frequency- per atom activity- far exceeding the performance of state-of-the-art catalysts for CO2 reduction reaction, and (ii) a highly efficient bi-functional catalyst for oxygen reduction and evolution reactions in the aprotic media compared to conventional noble metal catalysts used for the same application (e.g., Platinum and Gold). I also tested the performance of molybdenum disulfide nanoflakes (MoS2 NFs) -a versatile member of TMDCs- in lithium-air batteries known as a promising alternative to the conventional lithium-ion batteries. The results indicate that MoS2 NFs in the ionic liquid EMIM-BF4 electrolyte performs remarkably well in the actual air environment with a small discharge/charge potential gap as well as good stability and cyclability up to 550 cycles without any evidence of failure. I will discuss these and other results including the potential of our recent discovery to open a new route towards energy efficient, highly active and cost-effective energy storage and conversion systems to replace fossil fuels.

One of the primary motivations driving battery technology research is the need to develop cleaner and more efficient energy storage systems. The portable electronics industry has developed exponentially, especially over the last couple of decades and therefore the importance of efficient electrochemical energy storage systems cannot be overstated. Li-ion batteries have been the predominant rechargeable energy in use, however, they have their own particular drawbacks viz. flammability of the electrolyte, expensive mining of the Li metal etc. This is where the importance of Na-ion batteries lie. This research focuses on using existing transition metal oxides (TMOs) and tuning their crystal structure as well as morphology for application as anodes in the Na-ion battery systems. The three TMOs used in this thesis are copper (II) oxide (CuO), iron (III) oxide (Fe2O3) and titanium (IV) oxide (TiO2). They are chosen based on their easy availability, affordability and structural flexibility. Aqueous environment has been chosen as it tends to involve simpler and easier fabrication, lower overhead costs and reduce the complexities of glovebox based assembly techniques. Improvement of kinetics and understanding as well as improving structural stability have been the main goals of this dissertation. The analysis is performed by a two-way approach. Multiple morphologies of CuO are used to study the effect of surface area and porosity on kinetics. Similarly, the effect of doping different types of atoms in the hematite (α-Fe2O3) structure is studied in detail and the influence it has on the electrochemical performance. Finally, both the techniques are coupled to study the effects on the TiO2 anode system. It is expected that this dissertation will provide a comprehensive framework for the degradation analysis of simple TMO anodes in aqueous Na-ion battery systems, something which will add significant intellectual merit to the burgeoning field of aqueous rechargeable batteries in general.

Immense progress is required in the field of energy conversion and storage to achieve cost-effective high-performance batteries which could meet future energy demands. It also becomes mandatory to utilize the abundant materials from the earth’s crust, along with safe conversion and storage of electrochemical reactions. In this perspective, aluminium ion batteries (AIBs) could be a viable alternative for the conventional lithium-ion batteries (LIBs). In this mini-review, we focus on the challenges and the latest growth related to the cathode active materials (metal oxides, metal sulfides and other hybrid systems) in AIBs. The development of highly efficient, low cost and safe energy storage systems based on aluminium ion batteries is much explored. Still, commercialization remains a theoretical one, hence this review highlights the significance of the developed materials and their shortcomings that need to be addressed for the commercialization of aluminium ion batteries in the future.

Lithium-sulfur is a redox flow battery with high energy density for applications in safe, reliable, and lasting scaling of energy. However, lithium-based batteries often encounter platting as a problem thanks to poor Li-ions deposition after cycling. Aiming to reduce this impact, a uniform and continuous flow of ions is needed. On this work, novel bio-inspired flow fields in the electrochemical cell were tested to improve ions flowability and lithium platting control, ultimately enhancing battery performance and life. To secure Li-S efficient, low-cost, and secure energy storage capabilities, we chose a configuration with decamethylferrocene and cobaltocene acting as redox mediators, Li metal as anode and sulfur kept in a separate catholyte reservoir. Flow test and battery results insinuated a beneficial influence of bio-inspired designs in flowing electrolyte uniformly with less pressure and pump power in comparison to other conventional designs used in the industry, with an encouraging ability to approach a cheap, safe, and reliable Li-S grid energy storage.

As the world increasingly turns to renewable energy to mitigate the effects of climate change and reduce dependence on fossil fuels, the demand for efficient, safe, and sustainable energy storage solutions is rapidly growing. Electrochemical energy systems, such as batteries, fuel cells, and supercapacitors, are central to this transformation. This research paper explores the fundamental physics underlying electrochemical materials, current advancements in material science, and the necessity for continued research to overcome limitations in performance, cost, and sustainability. Emphasis is laid on the atomic and molecular scale understanding of materials which can drive innovations in energy storage and conversion technologies.

Development of an efficient and sustainable energy storage system by hybridization of compressed air and biogas technologies (BIO-CAES)

A trans-critical carbon dioxide energy storage system with heat pump to recover stored heat of compression

This review focuses on nanostructures-based systems and aims to provide a comprehensive overview of recent advancements in energy storage technologies and modified energy storage materials. The transition towards a sustainable and carbon-free energy system hinges on the progress of efficient and safe energy storage technologies. Supercapacitors have garnered significant interest in diverse energy storage applications due to their rapid charge/discharge rates, high power density, and extended cycle life. Nanostructures have conclusively demonstrated their capability to significantly enhance supercapacitor electrodes' performance. MXene, an innovative category of 2D materials, has emerged as a promising candidate for energy storage applications due to its substantial surface area, exceptional electrical conductivity, and versatile characteristics. Supercapacitors, nanostructures, and MXene are the main topics of the research articles and reviews in this special issue, highlighting recent developments in the design, synthesis, and characterization of advanced energy storage materials and devices. Additionally, this study presents an in-depth investigation of various carbon-based nanomaterials, their synthesis techniques, and their performance in supercapacitors. It also emphasizes the potential of recycling waste materials for developing high-performance nanomaterials for energy storage applications. Finally, this review encourages further research and development of advanced energy storage technologies by giving readers a thorough overview of the current state-of-the-art and future directions in this rapidly expanding sector.

Nasicon-type phosphates as electrode materials for safe and efficient electrochemical energy storage

Energy generation and storage are perhaps two of the most imperative, ongoing, and challenging issues facing the world to date. The rapidly growing global energy demand is placing increasingly greater burdens on the incumbent fossilfuel based infrastructure necessitating the development and mobilization of alternative technologies, particularly those focused on exploiting or scavenging new and clean energy sources alongside the development of highly efficient energy storage devices. Though advanced energy storage concepts and regenerative energy systems have been the focus of considerable attention over the past decade, the advent of the nanoage added traction to field by promising the potential to fabricate, for the first time, a wide range of truly novel devices that will enable this paradigm shift in energy applications. However, breakthroughs are needed to synthesize, engineer, and manufacture, en masse, nanomaterials and microand macrostructures based thereon. Central to this is a new understanding of the atomistic assembly of such materials in order to study energy transduction at nanoscale and to elucidate the underlying chemical and physical mechanism involved in high efficient energy conversion and storage. This special issue—which focuses on the science and engineering of nanomaterials and nanodevices used in all forms of energy harvesting, conversion, storage, and utilization—consists of 13 papers spanning topics detailing the empirical exploitation of nanowires for enhanced supercapacitors to thermoelectric generators, photocatalytic nanoparticles, and small molecule based organic solar cells. L. Chen et al. discuss the use of scanning force microscopy to investigate frictional images of newly cleaved surface domains of single crystal BaTiO 3 under ambipolar biases, providing a new method to determine domain polarization direction, whereas H.-S. Tsai et al. synthesized novel onedimensional SiO 2 /Ta 2 O 5 core-shell nanostructures, proposing a Ta-O diffusion-controlled growth process. P. Hiralal et al. report on the tailored growth of carbon nanostructures for application in high-frequency supercapacitors formed from engineered vertically aligned nanocarbon electrodes which are shown to enhance the porosity and electrolyte permeability within the device, resulting in a novel fabrication route to realise a functionally advanced compact energy storage platform. In a similar approach, H. Xu et al. summarise their work towards the preparation of Co 3 O 4 nanoparticles which facilitate long-lifetime and electrochemically superior supercapacitors by undertaking detailed studies of the electrode metrology. Z. Ma et al. report on energy recovery of coolant heat for internal combustion engines using thermoelectric generation technology. They showed that cooling improved with increased fan speeds and that the Seebeck coefficient was reduced with an increase in temperature difference between the two ends of thermoelectric generator.

Lead-free dielectric ceramics with high energy-storage density and efficiency are ideal energy materials for sustainable development of the enery resource. In this paper, (1–<i>x</i>)K<sub>0.5</sub>Na<sub>0.5</sub>NbO<sub>3</sub>–<i>x</i>Bi(Mg<sub>0.5</sub>Ti<sub>0.5</sub>)O<sub>3</sub> ((1–<i>x</i>)KNN-<i>x</i>BMT, <i>x</i> = 0.05, 0.10, 0.15, 0.20) lead-free relaxor ferroelectric ceramics are prepared by the traditional solid-state method. The effects of BMT on the phase structure, microstructure, dielectric properties and energy storage behavior of KNN based ceramics are studied. With the increase of BMT content, the crystal structures of (1–<i>x</i>)KNN-<i>x</i>BMT ceramics gradually change from orthorhombic to pseudo-cubic phase, and transform into cubic phase finally. The addition of BMT can suppress grain growth of the ceramics, resulting in the average grain size decreasing from 850 to 195 nm when <i>x</i> increases from 0.05 to 0.20. Dielectric properties exhibit that the Curie temperature decreases with BMT content increasing, and dielectric peak at Curie temperature is broadened due to the addition of BMT. In addition, ferroelectric properties demonstrate that the addition of BMT reduces the remnant polarization (<i>P</i><sub>r</sub>) and coercive field (<i>E</i><sub>c</sub>) of the ceramics. The results indicate that (1–<i>x</i>)KNN-<i>x</i>BMT ceramics transform from ferroelectric to relaxor ferroelectric phase. Based on the calculation of hysteresis loop, the best energy storage performance is obtained at <i>x</i> = 0.15, of which the recoverable energy storage density (<i>W</i><sub>rec</sub>) and the energy storage efficiency (<i>η</i>) are 2.25 J·cm<sup>–3</sup> and 84% at its dielectric breakdown strength of 275 kV·cm<sup>–1</sup>. Meanwhile, the ceramic with <i>x</i> = 0.15 exhibits good stability in a frequency range of 1–50 Hz, with an energy density variation of less than 5%, and temperature stability in a range of 25–125 ℃ with change of less than 8%. Moreover, based on direct measurement, the energy storage density (<i>W</i><sub>dis</sub>) of the ceramic with <i>x</i> = 0.15 is 1.54 J·cm<sup>–3</sup>, and the discharge time is only 88 ns. The research shows that (1–<i>x</i>)KNN-<i>x</i>BMT ceramics have a wide application prospect in the field of environmentally friendly capacitors with high energy storage density.

The development of efficient energy conversion and storage technologies is important to meet increasing demand. Solar energy is a valuable renewable and sustainable resource utilized in numerous energy technologies. However, the inherent variability of solar energy necessitates the addition of efficient energy storage components (e.g. batteries, flow cells, etc.) to achieve a continuous supply of electricity. Development of integrated systems that combine solar energy conversion and storage in a single electrochemical device is a promising approach that may potentially improve the efficiency of solar energy utilization. A photoelectrochemical system capable of converting and storing solar energy relies on photo-induced reactions of redox-active species.(1, 2) Polyoxometalates (POMs) are a class of stable anionic metal oxides clusters with multi-electron redox activity.(3) POMs undergo multiple redox transitions by utilizing either electrons or photons and exhibit a color change during certain transitions (photo- and electro chromic).(4) For example, the photo-induced reduction of POM as a photo catalyst has been used in water oxidation and hybrid fuel cell applications.(5, 6) In this work, we developed an integrated photo electrochemical energy storage (IPES) cell with the ability to convert and store solar energy in a single device using POM’s photochromic and redox properties, and explored factors that affect the performance of the IPES cell. Electrode surfaces prepared using conventional solution based methods often contain both electrochemically active ions and inactive counter ions that can hinder electron transfer processes. Previously, we demonstrated that a complete elimination of strongly coordinating counter cations substantially improved the performance of redox-supercapacitors prepared by soft landing of mass-selected POM anions.(7) Ion soft landing enables deposition of uniform layers of electroactive ions with well-defined charge state, composition and kinetic energy onto electrode surfaces, something not possible using other preparation techniques.(8, 9) Herein, we prepared IPES cells with POM anions deposited onto the anode using either ion soft landing or solution based deposition for comparison. The IPES cells consist of (i) Keggin POMs deposited on an indium-tin oxide (ITO) photoanode using either spin casting and or ion soft landing (ii) an ionic liquid membrane that contains ferrocene methanol as a model redox molecule (iii) a glassy carbon cathode. Our preliminary results with the IPES cells irradiated by direct solar light confirmed that the IPES cell generates useful current and potential due to the photo-induced redox conversion of POM at the anode and the counter redox reaction at the cathode. Additionally, in-situ UV-Vis spectroscopy confirmed the photo chromic transition of POM in the IPES cell from a clear to dark blue color upon irradiation. The design of the IPES cell will be presented and its performance under different experimental conditions will be discussed.

Graphene-based supercapacitors (SC) are rising as the most efficient and smart energy storage systems. Nonpareil physiochemical properties of graphene offer immense potential for their use in developing next-generation energy storage and portable devices. Since the rise of graphene, this material has been seen as the best alternative to activated carbon in SC applications. Being a 2D material, its high surface area enables it to store electrostatic charge even after high cycling. Since the first graphene-based SC was fabricated in 2008, this material has been explored beyond the boundaries of pristine graphene. The recent invention paved the way for ultrafast charging devices with excellent efficiency. However, the widespread use of these devices in daily life seems far-fetched, but recent results in graphene-based architectures are fetching these possibilities to life. In the last decade, various revamped and manipulated graphene derivatives have also been investigated and found to have great potential in SC applications. These derivatives have shown tremendous specific capacitance with enhanced cyclability. Graphene derivatives can even exhibit capacitance retention of almost 100% after 20,000 cycles. This book chapter discusses the current state of affairs in various graphene-based SC devices, such as crumpled graphene, graphene-metal oxide composites, graphene-based aerogels, graphene nanoparticle systems, graphene-based fibers, graphene/carbon-based hybrid composites for their potential application in the fabrication of efficient energy devices. This comprehensive study aims to analyze current trends and the opportunities and challenges offered by graphene and its derivatives in the development of nextgeneration SCs.

The lack of efficient energy storage devices is still the major bottleneck for the practical exploit of sustainable and renewable energy sources such as solar, wind or tide. The energy and safety barriers make the state-of-the-art Li-ion batteries not desirable to meet the requirements for large and safe energy storage. As the alternative, multivalent metal-base rechargeable batteries such as Mg, Ca, Zn and Al are more promising as larger and safer energy storage devices due to their advantages in safety, cost and capacity.1-3 For instance, in contrast to lithium, magnesium metal is non-toxic, more air resistant and not suffering from the dangerous dendrite formation. The naturally much more abundance makes magnesium more than 20 times cheaper than lithium in cost. In addition, the divalent characteristic of magnesium ion (Mg/Mg2+) enables magnesium to have nearly doubled volumetric capacity than lithium (3832 mA cm-3 vs 2062 mA cm-3). All these merits have brought significant attention on magnesium as the new generation rechargeable energy storage device. Since the pioneer work by Aurbach group in 2000 with the design of the prototype Mg-Mo6S8 battery using the famous dichloro-complex electrolyte (nBu2Mg + EtAlCl2 in THF),4,5 a lot of efforts have been devoted to the development of high-performance magnesium electrolytes, including the discovery of a few examples with above 3 V (vs Mg/Mg2+) oxidative stabilities.6-10 In contrast to the rapid progress of efficient electrolytes capable of plating/stripping magnesium with wide electrochemical windows, the development of high-performance cathode material is far behind for magnesium storage. Chevral phase Mo6S8 is still the only reliable cathode for Mg-ion batteries to date. However, the relatively low working voltage (< 1.3 V vs Mg) and low theoretical capacity (130 mAh g-1) cannot meet the requirement for high density energy storage. Unfortunately, most of the state-of-the-art metal oxide-based cathode materials were proven unsuccessfully for magnesium storage. In addition to the traditional intercalation type materials, redox-active organic molecule is an alternative solution to provide high voltage high capacity cathodes Mg-ion batteries.11-13 Here, we would like to report our recent progress on the development of a series of redox-active organic molecules as potential high voltage and high capacity cathode materials for efficient magnesium storage. Excellent electrochemical reversibility has been established for the Mg-Organic battery cell by the steady-state cyclic voltammetry measurement. The sustainable cycling performance was further highlighted by the very small amount of capacity loss upon cycling. At a reasonable rate of 0.5C, above 100 mAh g-1 discharge capacity was obtained initially, of which 99% can be retained in at least 100 cycles. The excellent cyclability further highlights the great potential of redox-active organic molecules as high-performance cathode material for Mg-ion batteries. (1) Saha, P.; Datta, M. K.; Velikokhatnyi, O. I.; Manivannan, A.; Alman, D.; Kumta, P. N. Prog Mater Sci 2014, 66, 1. (2) Muldoon, J.; Bucur, C. B.; Gregory, T. Chem Rev 2014, 114, 11683. (3) Yoo, H. D.; Shterenberg, I.; Gofer, Y.; Gershinsky, G.; Pour, N.; Aurbach, D. Energ Environ Sci 2013, 6, 2265. (4) Aurbach, D.; Lu, Z.; Schechter, A.; Gofer, Y.; Gizbar, H.; Turgeman, R.; Cohen, Y.; Moshkovich, M.; Levi, E. Nature 2000, 407, 724. (5) Lipson, A. L.; Pan, B.; Lapidus, S. H.; Liao, C.; Vaughey, J. T.; Ingram, B. J. Chem Mater 2015, 27, 8442. (6) Pan, B.; Zhang, J.; Huang, J.; Vaughey, J. T.; Zhang, L.; Han, S.-D.; Burrell, A. K.; Zhang, Z.; Liao, C. Chem Commun 2015, 51, 6214. (7) Liu, T.; Shao, Y.; Li, G.; Gu, M.; Hu, J.; Xu, S.; Nie, Z.; Chen, X.; Wang, C.; Liu, J. Journal of Materials Chemistry A 2014, 2, 3430. (8) Liao, C.; Guo, B.; Jiang, D.-e.; Custelcean, R.; Mahurin, S. M.; Sun, X.-G.; Dai, S. Journal of Materials Chemistry A 2014, 2, 581. (9) Carter, T. J.; Mohtadi, R.; Arthur, T. S.; Mizuno, F.; Zhang, R. G.; Shirai, S.; Kampf, J. W. Angew Chem Int Edit 2014, 53, 3173. (10) Zhao-Karger, Z.; Zhao, X. Y.; Fuhr, O.; Fichtner, M. Rsc Adv 2013, 3, 16330. (11) Song, Z. P.; Zhou, H. S. Energ Environ Sci 2013, 6, 2280. (12) Haupler, B.; Wild, A.; Schubert, U. S. Adv Energy Mater 2015, 5. (13) Pan, B.; Zhou, D.; Huang, J.; Zhang, L.; Burrell, A. K.; Vaughey, J. T.; Zhang, Z.; Liao, C. J Electrochem Soc 2016, 163, A580.