22 research outputs found
Developing Synchrotron-based Techniques for Characterising Anode/Electrolyte Interface in Li/Na Batteries
No full textWith the increasing demand for lower carbon emissions for the mitigation of global warming, Li/Na battery systems are becoming increasingly ubiquitous in both industries and our daily life. The development of electric vehicles (EV), hybrid electric vehicles (HEV) and mobile devices has put forward the requirements for Li/Na batteries with higher energy density, power density, safer and longer operation time. These factors are significantly affected by the interfacial behaviour at electrolyte/anode interface. Therefore, understanding the interface is very important in improving the performance of Li/Na battery systems. However, the direct characterization and investigation of the anode/electrolyte interface are hard due to the buried and heterogeneous nature of the interface. Owing to the wide energy range, high brightness and flux of the beam provided by synchrotron radiation, an unprecedented opportunity was present to obtain new insights into the material chemistry of the interface. The synchrotron-based techniques were used across the entire thesis, which could provide a deeper understanding of the interfacial behaviour between electrolyte and anode in Li/Na batteries.
In the thesis, the main area of focus will include the application of ex situ and in situ synchrotron radiation-based techniques in the study of the anode/electrolyte interface in Li/Na batteries and the broader design of in situ cells. Based on these studies, the interface behaviour between anodes and different electrolyte systems in Li/Na batteries was investigated, especially the chemical evolution. The developed synchrotron radiation-based techniques and designed specialized in situ cells can be further utilized in understanding other battery systems, not limited to electrode/electrolyte interface but also changes in other components of cell configuration during the operation of batteries.
In Chapter 4, two types of sp2 carbon-based polymer anode were synthesised which show similar chemical structures and different topological structures. The influence of the topological structures on the Li+ storage at the liquid electrolyte/anode interface was investigated by the Near-edge X-ray absorption fine structure (XANES) of C k edge. The potential of such polymer anode was proved by functionating with the -SO3H group, delivering a higher storage capacity. To further boost the energy density of Li-ion batteries by directing using Li metal anode, PEO-based composite polymer electrolytes with the addition of Lithium Bis(trifluoromethanesulphonyl)imide (LiTFSI) and Li6.4La3Zr1.4Ta0.6O12 (LLZTO) fillers were proposed in Chapter 5. The addition of fillers improves the ionic conductivity, electrochemical stability, and contact with Li metal. Combing with the electrochemical tests and in situ X-ray imaging techniques, the role of fillers on the interfacial behaviour between composite polymer electrolytes and Li anode was investigated. In Chapter 6, TiO2 incorporated Na3Zr2Si2PO12 (NZSP-TiO2) solid electrolyte was synthesised to inhibit the metal filament formation during plating at ceramic/metal anode interfaces. The NZSP-TiO2 electrolyte shows an improved density and better cycling stability. An in situ X-ray imaging experiment was designed to investigate the role of TiO2 on the electrochemical behaviour between solid electrolyte and Na metal anode during the cycles
Advances and Challenges in Electrolyte Development for Magnesium-Sulfur Batteries: A Comprehensive Review
No full textMagnesium–sulfur batteries are an emerging technology. With their elevated theoretical energy density, enhanced safety, and cost-efficiency, they have the ability to transform the energy storage market. This review investigates the obstacles and progress made in the field of electrolytes which are especially designed for magnesium–sulfur batteries. The primary focus of the review lies in identifying electrolytes that can facilitate the reversible electroplating and stripping of Mg2+ ions whilst maintaining compatibility with sulfur cathodes and other battery components. The review also addresses the critical issue of managing the shuttle effect on soluble magnesium polysulfide by looking at the innovative engineering methods used at the sulfur cathode’s interface and in the microstructure design, both of which can enhance the reaction kinetics and overall battery efficiency. This review emphasizes the significance of reaction mechanism analysis from the recent studies on magnesium–sulfur batteries. Through analysis of the insights proposed in the latest literature, this review identifies the gaps in the current research and suggests future directions which can enhance the electrochemical performance of Mg-S batteries. Our analysis highlights the importance of innovative electrolyte solutions and provides a deeper understanding of the reaction mechanisms in order to overcome the existing barriers and pave the way for the practical application of Mg-S battery technology
Study on Vertical Propagation of Power Parameters in RC Frame Under Internal Explosion
No full textThe roof slab, as a critical component for partitioning the vertical space within RC frame structures, can effectively mitigate the propagation of shock waves and reduce damage levels in adjacent rooms. This study employed finite element (FE) modeling to investigate the vertical propagation of blast waves and roof ejection velocity in RC frames. The model’s reliability was verified by reconstructing internal explosion tests on RC frames and close-in explosion tests on masonry walls. On this basis, two typical single-room RC frame structures that are vertically adjacent were designed, and numerical simulations of the internal explosion were conducted under four explosive equivalents and four venting coefficients. The propagation of shock waves, load characteristics in the vertically adjacent room, and the dynamic response of roof slabs were examined. The results show that shock waves propagated to the vertically adjacent room decreased by approximately two orders of magnitude for peak overpressure and one order of magnitude for impulse due to the obstruction of shock waves by roof slabs, respectively, compared to the source explosion room. For larger venting coefficients, abundant energy was released through the venting openings, making it difficult to form a quasi-static pressure with a long duration inside the source explosion room. In addition to the shock wave, the explosive ejection of roof slabs in the explosion source room will further exacerbate the damage to the vertically adjacent room. Peak overpressure and impulse propagated to the vertically adjacent room were reduced significantly by the increase in the venting coefficient, resulting in an attenuation of structural damage. Finally, empirical models incorporating the venting coefficient were established to characterize the attenuation coefficients of power parameters, demonstrating the predictive capability for peak overpressure, impulse, and roof ejection velocity in both the explosion source room and the vertically adjacent room
Insight Into Pre‐Intercalation of Layered Vanadium Oxide Cathodes: From Precise Control of the Interspace to Related Electrochemical Performance and Beyond
No full textABSTRACT Pre‐intercalation is the mainstream approach to inhibit the unpredicted structural degradation and the sluggish kinetics of Zn‐ions migrating in vanadium oxide cathode of aqueous zinc‐ion batteries (AZIBs), which has been extensively explored over the past 5 years. The functional principles behind the improvement are widely discussed but have been limited to the enlargement of interspace between VO layers. As the different types of ions could change the properties of vanadium oxides in various ways, the review starts with a comprehensive overview of pre‐intercalated vanadium oxide cathode with different types of molecules and ions, such as metal ions, water molecules, and non‐metallic cations, along with their functional principles and resulting performance. Furthermore, the pre‐intercalated vanadium cathodes reported so far are summarized, comparing their interlayer space, capacity, cycling rate, and capacity retention after long cycling. A discussion of the relationship between the interspace and the performance is provided. The widest interspaces could result in the decay of the cycling stability. Based on the data, the optimal interspace is likely to be around 12 Å, indicating that precise control of the interspace is a useful method. However, more consideration is required regarding the other impacts of pre‐intercalated ions on vanadium oxide. It is hoped that this review can inspire further understanding of pre‐intercalated vanadium oxide cathodes, paving a new pathway to the development of advanced vanadium oxide cathodes with better cycling stability and larger energy density
Bidirectional pH Buffer Effect Facilitates High-Reversible Aqueous Zinc Ion Batteries
No full textAqueous zinc ion batteries (AZIBs) stand out from the crowd of energy storage equipment for their superior energy density, enhanced safety features, and affordability. However, the notorious side reaction in the zinc anode and the dissolution of the cathode materials led to poor cycling stability has hindered their further development. Herein, ammonium salicylate (AS) is a bidirectional electrolyte additive to promote prolonged stable cycles in AZIBs. NH4+ and C6H4OHCOO− collaboratively stabilize the pH at the interface of the electrolyte/electrode and guide the homogeneous deposition of Zn2+ at the zinc anode. The higher adsorption energy of NH4+ compared to H2O on the Zn (002) crystal plane mitigates the side reactions on the anode surface. Moreover, NH4+ is similarly adsorbed on the cathode surface, maintaining the stability of the electrode. C6H4OHCOO− and Zn2+ are co-intercalation/deintercalation during the cycling process, contributing to the higher electrochemical performance of the full cell. As a result, with the presence of AS additive, the Zn//Zn symmetric cells achieved 700 h of highly reversible cycling at 5 mA cm−2. In addition, the assembled NH4V4O10(NVO)//Zn coin and pouch batteries achieved higher capacity and higher cycle lifetime, demonstrating the practicality of the AS electrolyte additive
Robust Biomass-Derived Carbon Frameworks as High-Performance Anodes in Potassium-Ion Batteries
No full textPotassium-ion batteries (PIBs) have become one of the promising candidates for electrochemical energy storage that can provide low-cost and high-performance advantages. The poor cyclability and rate capability of PIBs are due to the intensive structural change of electrode materials during battery operation. Carbon-based materials as anodes have been successfully commercialized in lithium- and sodium-ion batteries but is still struggling in potassium-ion battery field. This work conducts structural engineering strategy to induce anionic defects within the carbon structures to boost the kinetics of PIBs anodes. The carbon framework provides a strong and stable structure to accommodate the volume variation of materials during cycling, and the further phosphorus doping modification is shown to enhance the rate capability. This is found due to the change of the pore size distribution, electronic structures, and hence charge storage mechanism. The optimized electrode in this work shows a high capacity of 175 mAh g^{-1} at a current density of 0.2 A g^{-1} and the enhancement of rate performance as the PIB anode (60% capacity retention with the current density increase of 50 times). This work, therefore provides a rational design for guiding future research on carbon-based anodes for PIBs
On the Penetration of Projectiles into Semi-Infinite Concrete Targets in a Coupled Deforming and Eroding Regime
No full textWith the advancement of high-velocity kinetic energy weapons, the impact velocity encountered by concrete protective structures has evolved from low to high velocity ranges, rendering traditional rigid projectile penetration theories inadequate for accurately describing the physical mechanisms of deformation and erosion coupling during penetration. This study establishes a theoretical analytical framework for penetration dynamics under high-velocity conditions with coupled deformation and erosion effects: the critical velocity threshold distinguishing between rigid projectile penetration and hydrodynamic penetration modes is precisely defined based on the initial impact velocity V0. By integrating empirical mass erosion formulas with cavity expansion theory, a theoretical model encompassing coupled deformation and erosion effects has been developed, incorporating both projectile cross-sectional area evolution and penetration depth prediction. Comparative analysis with published experimental data (small-scale projectiles vertically impacting concrete targets) demonstrates the model’s predictive accuracy, showing maximum errors of 9.5% in critical velocity prediction, 17.89% in projectile cross-sectional area prediction, and 24.4% in penetration depth prediction
Inhibition of zinc dendrite growth by a preferential crystal surface modulation strategy
No full textAqueous zinc-ion batteries (AZIBs) are pivotal in advancing energy storage systems and contributing to global electrification due to their high safety and low cost. However, the development of AZIBs is limited by the several challenges originating from the anode/electrolyte interface such as dendrite growth, hydrogen evolution reactions, and Zn corrosion. Compared to traditional methods which stabilize the interface by constructing artificial/in-situ formed interphases, we propose a novel method to selectively adjust the array of stripes on the Zn surface without altering the chemical composition. Considering that Zn (002) promotes the uniform deposition of Zn while Zn (100) is generally more stable and less reactive, adjusting the ratio of active Zn (002) to Zn (100) can significantly enhance the stability and reversibility of Zn metal. With the AS treatment of 20 minutes, the ratio between Zn (002) to Zn (100) is around 0.93, which exhibits the best electrochemical performance and enables the Zn//Zn symmetric battery to cycle over 2200 hours at 2 mA cm−2 and 1 mAh cm−2. The full cell AS-20//MnO2 had capacity retention of 41.4 % after 600 cycles under a current density of 0.5 A g−1, whereas that of bare Zn//MnO2 was less than 14.5 %
Progress and perspective of interface design in garnet electrolyte-based all-solid-state batteries
No full textInorganic solid-state electrolytes (SSEs) are nonflammable alternatives to the commercial liquid-phase electrolytes. This enables the use of lithium (Li) metal as an anode, providing high-energy density and improved stability by avoiding unwanted liquid-phase chemical reactions. Among the different types of SSEs, the garnet-type electrolytes witness a rapid development and are considered as one of the top candidates to pair with Li metal due to their high ionic conductivity, thermal, and electrochemical stability. However, the large resistances at the interface between garnet-type electrolytes and cathode/anode are the major bottlenecks for delivering desirable electrochemical performances of all-solid-state batteries (SSBs). The electrolyte/anode interface also suffers from metallic dendrite formation, leading to rapid performance degradation. This is a fundamental material challenge due to the poor contact and wettability between garnet-type electrolytes with electrode materials. Here, we summarize and analyze the recent contributions in mitigating such materials challenges at the interface. Strategies used to address these challenges are divided into different categories with regard to their working principles. On one hand, progress has been made in the anode/garnet interface, such as the successful application of Li-alloy anode and different artificial interlayers, significantly improving interfacial performance. On the other hand, the desired cathode/garnet interface is still hard to reach due to the complex chemical and physical structure at the cathode. The common methods used are nanostructured cathode host and sintering additives for increasing the contact area. On the basis of this information, we present our views on the remaining challenges and future research of electrode/garnet interface. This review not only motivates the need for further understanding of the fundamentals, stability, and modifications of the garnet/electrode interfaces but also provides guidelines for the future design of the interface for SSB
Trace Amounts of Multifunctional Electrolyte Additives Enhance Cyclic Stability of High-Rate Aqueous Zinc-Ion Batteries
No full textAqueous zinc ion batteries (AZIBs) are renowned for their exceptional safety and eco-friendliness. However, they face cycling stability and reversibility challenges, particularly under high-rate conditions due to corrosion and harmful side reactions. This work introduces fumaric acid (FA) as a trace amount, suitable high-rate, multifunctional, low-cost, and environmentally friendly electrolyte additive to address these issues. FA additives serve as prioritized anchors to form water-poor Inner Helmholtz Plane on Zn anodes and adsorb chemically on Zn anode surfaces to establish a unique in situ solid-electrolyte interface. The combined mechanisms effectively inhibit dendrite growth and suppress interfacial side reactions, resulting in excellent stability of Zn anodes. Consequently, with just tiny quantities of FA, Zn anodes achieve a high Coulombic efficiency (CE) of 99.55 % and exhibit a remarkable lifespan over 2580 hours at 5 mA cm⁻², 1 mAh cm⁻² in Zn//Zn cells. Even under high-rate conditions (10 mA cm⁻², 1 mAh cm⁻²), it can still run almost for 2020 hours. Additionally, the Zn//V2O5 full cell with FA retains a high specific capacity of 106.95 mAh g⁻¹ after 2000 cycles at 5 A g⁻¹. This work provides a novel additive for the design of electrolytes for high-rate AZIBs.
