Irreversible Phase Research Articles

An in-Operando XRD Study of TiO2 Based Anode Materials for Secondary Li Ion Batteries Application

In recent years, lithium-ion batteries (LIB) have emerged as one of the most representative rechargeable energy-storage systems. Among the various anode materials used, titanium dioxide stands out for its excellent stability, superior safety, and high cycling performance. Moreover, its remarkable stability in high-capacity charge–discharge cycles is useful for developing fast-charging batteries. Therefore, this material has attracted significant attention from researchers. In this study, we investigate aluminum-doped and carbon-coated non-stoichiometric titanium dioxide for in operando X-ray diffraction (XRD) analysis using synchrotron radiation to explore the behavior of lithium ions intercalating into and deintercalating from the titanium dioxide lattice and draw insights from the variations in the characteristic lattice diffraction peaks.In Al-TiOx part, the lithium-ion intercalation and deintercalation behaviors within the mixed-phase titanium dioxide used herein (anatase and rutile). During discharge, a new reversible intermediate phase, LiTiO2, as well as a partially irreversible intermediate phase, Li0.55TiO2, are generated in the anatase phase. This is the first reported experimental observation of the coexistence of these three phases. The irreversible reaction kinetics of these phases contribute to capacity decay. In the rutile phase, the diffraction peaks exhibit a trend of broadening and narrowing during charge–discharge, resembling an hourglass-like structure. This phenomenon implies non-uniform stress within the material due to lithium-ion diffusion through a relatively faster channel. By using in situ XRD, we propose an interaction mechanism between lithium ions and the lattice of mixed-phase (anatase, rutile) titanium dioxide. In C@TiOx part, the rutile TiO2 undergoes a non-uniform strain at a rate of 0.5 C, causing the peak to broaden and shift left after lithiation. The capacities of C@TiO 𝑥 batteries were lowered from 109.0 to only 79.2 mAh/g at 5 C. It is believed that the carbon coating protect the inner TiO 𝑥 core from phase transition so that nanosized rutile TiO2 was retained after lithiation at 0.5 C, which means lithiated rutile is not equivalent to lithium titanate. Instead, the lattice distortion occurs when Li ions are intercalated in the rutile TiO2 matrix. This means that the fast lithium-ion diffusion channel in the c axis of rutile is blocked by the carbon coating and phase transition was prohibited. Furthermore, high reversibility is observed in by the overlap of initial and final curves, which can be taken as an extra evidence for the high Coulombic efficiency.In this study, we propose the concept of aluminum and carbon co-doped non-stoichiometric titanium dioxide for in operando XRD study. Our aim is to further enhance the conductivity of titanium dioxide and its battery performance in lithium-ion batteries through the synergistic effects of heteroatom doping and non-stoichiometric treatment. This includes improvements in the capacity, impedance, cycling lifespan, and high-rate performance of the titanium dioxide material within the battery system.Keyword: Al-doped TiO2, C coated TiOx, in operando XRD, Anode materials, Li-ion batteries

Realization High-Voltage Stabilization of O3-Type Layered Oxide Cathodes for Sodium-Ion Batteries by Sn Simultaneously Dual Modification

The total global production of lithium-ion batteries (LIBs) used in electric vehicles and stationary energy storage devices has increased sharply to reach the targeted Net Zero by 2050. This leads to concerns about the future and long-term availability and cost of critical raw materials (cobalt, nickel, lithium and copper) employed in LIBs. Therefore, alternative new-generation batteries with comparable performance but using less critical raw materials are needed.Sodium-ion Batteries (NIBs) offer a wealth of possibilities for inexpensive and sustainable energy storage devices. To maximize their potential, new cathode materials with high energy densities and stable structures are required. Cobalt-free sodium transition metal oxides of O3 type are a predominant cathode for NIBs due to their appreciable specific capacity, reduction in the use of critical elements, and the potential to rival LiFePO4 in terms of energy density. However, rapid capacity fading caused by serious structural and interfacial degradation hamper this process.Herein, we provide a novel Sn-modified O3-type NaNi1/3Fe1/3Mn1/3O2 cathode with improved high-voltage stability by bulk Sn doping and surface coating simultaneously. The bulk substitution of Sn4+ stabilizes the crystal structure by alleviating the irreversible high voltage phase transition and lattice structure degradation. In the meantime, the spontaneously formed tin rich surface layer effectively inhibits surface parasitic reactions and improves interfacial stability during cycling. As a result, the Sn-modified NaNi1/3Fe1/3Mn1/3O2 cathode exhibited excellent cycling performance by an almost doubled capacity retention increase after 200 cycles within 2.0-4.1V. The influence of Sn modification on the crystal structure and electrochemical properties has been investigated for the first time, and the mechanism was studied through an extensive analysis by in situ XRD, HRTEM, FIB-SEM, XPS and Mössbauer spectroscopy.This work offers an industrially feasible strategy to simultaneously stabilize the bulk structure and interface for O3-type layered cathodes for SIBs and raises the possibility of similar effective strategies to be employed for other energy storage materials Figure 1

Mitigating the Degradation of Electrodes in Alkaline Water Electrolysis during Shutdown Mode by Interrupting Reverse Current

Alkaline water electrolysis (AWE) is a promising technology for large-scale hydrogen production using renewable energy sources (RES). However, AWE integrated with RES experiences shutdown mode due to their intermittency, resulting in reverse current through open flow path of high ionic conductivity. This induces irreversible phase changes, which lead to electrode degradation and inevitably reduce the performance of the AWE. Therefore, it is important to examine the degradation mechanism and identify effective methods to reduce reverse current in AWE. In this work, we developed AWE system which impedes hydroxide ion transfer using deionized (DI) water circulation when it undergoes a shutdown mode. Cutting off the flow of ionic charges prevents the electrodes from forming irreversible phase change, making long-term operation possible while securing durability. We examined how reduced ionic conductivity mitigates the side effects of reverse current using phase characterization and electrochemical performance tests. Based on these results, we established an optimal way to impede hydroxide ion transfer in shutdown condition of an AWE system integrated with RES. Our findings will overcome fatal shortcomings and operate more efficiently in AWE industry.

Monitoring of Energy Storage Mechanism of Zn/Meso-MnO2 Battery System Using X-Ray Absorption Fine Structure

As energy storage systems, LIBs, which are most frequently used, have excellent capacity, power, and long lifespan performance [1]. However, as the reserves of the raw minerals used—lithium and cobalt—are exhausted, prices are escalating. A further issue with LIB is that it heats up to a high temperature during charging, which leads to a string of fire or explosion catastrophes. To solve these safety or cost challenges, various next-generation batteries are being developed, and we are exploring about aqueous zinc ion battery (AZIB), which attracting attention as the next-generation battery due to outstanding safety and cost competitive advantage. Generally, zinc metal acting as an anode, has a high theoretical capacity of 820mAh/g as it is gives two electrons (2e-). Also, because of its sparse reactivity with water and ability to employ water-based electrolytes with strong ion conductivity and low ignition risk, it is particularly advantageous in terms of safety. There have been a variety of cathode materials utilized, such as manganese oxide, vanadium oxide, Prussian blue analogues (PBAs), polyanion compounds, and Chevrel phase compounds [2-4]. Especially, manganese dioxide (MnO2) has been addressed by prior studies that Zn2+ can be inserted into crystal structure because it exhibits several crystal structures (α, β, γ, δ, and λ) with tunnel-type or layer-type structure. Mn4+ ions occupying octahedral holes formed by hexagonal close-packed (hcp) oxide ions compose the fundamental unit of the crystal structure of MnO2 polymorphs. To construct a [MnO6] octahedral unit, each Mn4+ ion is precisely surrounded by six oxygen neighbors, and these units are connected by the edges and/or corners [5]. Understanding the energy storage mechanisms is essential for the one-step evolution of cathode materials for AZIB. However, these polymorphs significantly affect the electrochemical reaction, thus involving complex reaction mechanisms [5-7]. Additionally, it is extremely challenging to research the mechanisms of AZIB since protons (H+) are known to participate in the reaction by acting as charge transfer as well as Zn2+ ions. Therefore, while several efforts are being conducted to unveil the exact reaction mechanism, a mesoporous nanostructured material with a large specific surface area is adopted, which can more precisely grasp the electrochemical reaction studies of electrode/electrolyte surface [8,9]. X-ray absorption fine structure (XAFS) is a powerful technique used for the analysis of nanostructured materials, widely used in the field of battery research [10]. It involves the measurement of the absorption of X-ray by the material, which can provide information about oxidation state, chemical bonding of the materials and the local geometry structure during charge/discharge process. This analysis method gives great insight into the complex energy storage pathway of MnO2 materials with various polymorphs. Based on this knowledge, we synthesized ordered mesoporous β-MnO2 through nano-casting method by using KIT-6 as hard-template and used it as the cathode active material. As depicted in Figure 1, we performed ex-situ XAFS analysis at the states of charge during 2nd cycle to monitor energy storage mechanisms. The oxidation state changes could be quantitatively estimated by edge energy analysis by comparing the reference MnO2 and Mn2O3 samples. It was also possible to unveil further about the reaction mechanism at each voltage by examining the structural change in the local geometry of [MnO6] unit through a careful analysis of pre-edge region and EXAFS spectra. During discharge process, insertion mechanism, which causes relatively larger distortion in the local geometry compared to conversion mechanism, results in a increment of pre-edge intensity, which opposes the decline in pre-edge intensity due to the reduction of the oxidation state. This fact demonstrates that although H+ conversion could not have a significant effect on pre-edge intensity in the early discharge stage, Zn2+ insertion was the phenomenon responsible for the rise in pre-edge intensity during late discharge stage. In addition, through EXAFS spectra analysis, the irreversible change in corner sharing Mn-Mn bond distance during charge/discharge process could be seen that an irreversible phase transition of MnO2 occurred due to Zn2+ insertion, indicating clue to identify the cause of capacity fading. These findings contribute to further understanding of the reaction mechanisms and capacity fading phenomenon and suggest practical strategies for next-generation zinc-ion batteries.

Microwave Plasma Synthesis of Cathode Material for Lithium-Ion Batteries

Among LiB cathode materials, lithiated NMC (Li1Ni(1-x-y)MnxCoyO2) formulations with ≥90% nickel have the potential to increase the specific capacity of LiBs, which is the most direct route to increasing the energy density of the battery. Lithiated NMC (LiNixMnyCo (1-x-y)) has the α-NaFeO2-type crystal structure of LiCoO2, but is chemically more evolved; nickel and manganese are substituted for cobalt, decreasing toxicity and expense, and increasing specific capacity [1-3]. Pristine 90% Nickel-rich cathode material frequently performs with a baseline cycling stability of ~75% over 50 cycles, regardless of synthesis method [4, 5]. NMC morphology is described as having secondary particles made up of many smaller primary particles, which is advantageous to packing density when in application- the best performing materials report secondary particle size of up to 20 μm, with primary particle size of ≤ 1 μm [6]. Fig. 1. Particle morphology of secondary particles up to ~20μm made up of primary particles ≤1μm. Microwave plasma at atmospheric pressure provides a facile method for cathode material fabrication. With a working gas of air, ionized gas catalyzed immediate reaction to form cathode precursors from metal salts. This commercializable synthesis method provides a solution to the excessive time and energy waste as well as the environmental and health hazards which are inherent in the coprecipitation manufacturing method that dominates the current NMC production market. In this work, high capacity NMC compositions are produced using the plasma fabrication method. Method produced desired “meat-ball” particle morphology of secondary particles up to ~20μm made up of primary particles ≤1μm.Ni rich Ni-Mn-Co (NMC) cathode materials were characterized for their lithium-ion capacity. Specifically, pristine cathode material with 955 and 811 compositions were prepared and tested using coin cells. Li-NMC with 955 (90% Ni; 5% Mn; 5% Co) cycled with initial specific capacity of 215 mAhg-1, with coulombic efficiency 99% at 20 cycles. Similarly, Li-NMC with 811 composition (80% Ni, 10% Mn and 10% Co) exhibited 190 mAhg-1 capacity and coulombic efficiency >99% over 20 cycles. Cyclic voltammetry confirmed three expected phase changes upon lithiation and delithiation, with clear durability and reversibility after first cycle. Layered crystal structure is confirmed with highly desired particle morphology for best packing density. NMC particles as synthesized by the atmospheric plasma method exhibit baseline NMC performance characteristics. [1] Vanessa Pimenta, M.S., Dmitry Batuk, Artem M. Abakumov, Domitille Giaume, Sophie Cassaignon, Dominique Larcher, and Jean-Marie Tarascon, Synthesis of Li-Rich NMC: A Comprehensive Study. Chemistry of Materials, 2017. 29: p. 9923-9936. [2]Monu Malik, K.H.C., and Gisele Azimi, Effect of Synthesis Method on the Electrochemical Performance of LiNixMnCo1-x-yO2 (NMC) Cathode for Li-Ion Batteries: A Review. Rare Earth Metal Technology 2021, 2021. [3]Dong Ren, Y.S., Yao Yang, Luxi Shen, Barnaby D.A. Levin, Yingchao Yu, David A. Muller, and Héctor D. Abruña, Systematic Optimization of Battery Materials: Key Parameter Optimization for the Scalable Synthesis of Uniform, High-Energy, and High Stability LiNi0.6Mn0.2Co0.2O2 Cathode Material for Lithium- Ion Batteries. ACS Applied Materials & Interfaces, 2017. 9: p. 35811-35819. [4]Feng Wu, N.L., Lai Chen, Ning Li, Jinyang Dong, Yun Lu, Guoqiang Tan, Mingzhe Xu, Duanyun Cao, Yafei Liu, Yanbin Chen, Yuefeng Su, The nature of irreversible phase transformation propagation in nickelrich layered cathode for lithium-ion batteries. Journal of Energy Chemistry, 2021. 62: p. 351-358. [5]Ya-Ting Tsai, C.-Y.W., Jenq-Gong Duh Synthesis of Ni-rich NMC cathode material by re dox-assiste d deposition method for lithium ion batteries. Electrochimica Acta, 2021. 381. [6]Fengxia Xin, H.Z., Xiaobo Chen, Mateusz Zuba, Natasha Chernova, Guangwen Zhou, and M. Stanley Whittingham, Li−Nb−O Coating/Substitution Enhances the Electrochemical Performance of the LiNi0.8Mn0.1Co0.1O2 (NMC 811) Cathode. ACS Applied Materials & Interfaces, 2019. 11: p. 34889-34894. Figure 1

Towards Extreme Fast Charging of 4.6 V LiCoO2 Viamitigating High-Voltage Kinetic Hindrance

High-voltage LiCoO2 (LCO) is an attractive cathode for ultra-high energy density lithium-ion batteries (LIBs) in the 3 C markets. However, the sluggish lithium-ion diffusion at high voltage significantly hampers its rate capability. Herein, combining experiments with density functional theory (DFT) calculations, we demonstrate that the kinetic limitations can be mitigated by a facial Mg2++Gd3+ co-doping method. The as-prepared LCO shows significantly enhanced Li-ion diffusion mobility at high voltage, making more homogenous Li-ion de/intercalation at a high-rate charge/discharge process. The homogeneity enables the structural stability of LCO at a high-rate current density, inhibiting stress accumulation and irreversible phase transition. When used in combination with a Li metal anode, the doped LCO shows an extreme fast charging (XFC) capability, with a superior high capacity of 193.1 mAh g−1 even at the current density of 20 C and high-rate capacity retention of 91.3% after 100 cycles at 5 C. This work provides a new insight to prepare XFC high-voltage LCO cathode materials. Figure 1

Stabilizing Crystal Framework of an Overlithiated Li1+xMn2O4 Cathode by Heterointerfacial Epitaxial Strain for High-Performance Microbatteries.

To meet the increasing demands of high-energy and high-power-density lithium-ion microbatteries, overlithiated Li1+xMn2O4 (0 ≤ x ≤ 1) is an attractive cathode candidate due to the high theoretical capacity of 296 mAh g-1 and the interconnected lithium-ion diffusion pathways. However, overlithiation triggers the irreversible cubic-tetragonal phase transition due to Jahn-Teller distortion, causing rapid capacity degradation. In contrast to conventional lithium-ion batteries, microbatteries offer the opportunity to develop specific thin-film-based modification strategies. Here, heterointerfacial lattice strain is proposed to stabilize the spinel crystal framework of an overlithiated Li1+xMn2O4 (LMO) cathode by epitaxial thin film growth on an underlying SrRuO3 (SRO) electronic conductor layer. It is demonstrated that the lattice misfit at the LMO/SRO heterointerface results in an in-plane epitaxial constraint in the full LMO film. This suppresses the lattice expansion during overlithiation that typically occurs in the in-plane direction. It is proposed by density functional theory modeling that the epitaxial constraint can accommodate the internal lattice stress originating from the cubic-tetragonal transition during overlithiation. As a result, a doubling of the capacity is achieved by reversibly intercalating a second lithium ion in a LiMn2O4 epitaxial cathode with a complete reversible phase transition. An impressive cycling stability can be obtained with reversible capacity retentions of above 90.3 and 77.4% for the 4 and 3 V range, respectively. This provides an effective strategy toward a stable overlithiated Li1+xMn2O4 epitaxial cathode for high-performance microbatteries.

Fe doping induced cluster/spin glass state and metamagnetic transition in phase separated La0.5Sr0.5Mn1−xFexO3

We report the impurity doping effects in manganites La0.5Sr0.5Mn1−xFexO3 (0 ≤ x ≤ 0.2) and the field-induced metamagnetic transition in which the antiferromagnetic insulating phase transforms into ferromagnetic metallic phase. The Rietveld refined results of XRD data display no obvious structure change with a significant degree of Fe3+ doping on Mn sites. Significant ferromagnetism suppression and magnetic inhomogeneity tendency upon Fe3+-doping are evidenced, phase separated and spin-glass like states are identified. With applying a pulsed high magnetic field up to 50 T, a metamagnetic transition was induced, especially clear for x ≥ 0.1 compounds, which exhibited an irreversible phase transition from antiferromagnetic to ferromagnetic phase, and a saturation magnetization was obtained. The replacement of Mn3+ by Fe3+ ions eliminates the effects of lattice structure change on the magnetic and electronic properties because of the very similar ionic size of Mn3+ and Fe3+, but reduces the Mn3+/Mn4+ ratio and depopulates the number of available hopping sites and the hopping electrons, thus weakens the double exchange interaction. The occurrence of the AFM superexchange interaction via Fe3+–O2−–Fe3+ and Fe3+–O2−–Mn3+ bonds may bring about the competition between the antiferromagnetic ordering and the ferromagnetic ordering, leading to a cluster/spin-glass behavior in the samples with high Fe dopants concentration.

A layered/spinel heterostructured cathode for Li-ion batteries prepared by ultrafast Joule heating

Spinel LiMn2O4 is one of the most promising cathode materials due to its low cost, high discharge voltage (∼4.0 V), and non-toxicity. However, it suffers from insufficient cycling performance caused by irreversible phase transition and Mn dissolution. In addition, the low synthesis efficiency caused by the long heating time also plagues its application and depletes the cost merits of raw materials. Herein, we report a heterostructured cathode material of electrochemically-inert layered Li2MnO3 and active spinel LiMn2O4 phases, which is synthesized in seconds by ultrafast Joule heating. The heterostructure is rapidly formed as a result of the non-equilibrium process produced by the ultrafast Joule heating rate. The inert layered phase serves as a structure stabilization agent to suppress the structure damage and Mn dissolution, thus promising an excellent electrochemical performance with a high capacity retention of 83 % after 800 cycles at 5C. Our findings provide an efficient design and synthesis strategy for developing high-performance and low-cost cathode materials.

P2/O3 biphase integration promoting the enhancement of structural stability for sodium layered oxide cathode

O3-type sodium layered oxides have garnered significant attention as highly promising candidates for sodium ion batteries due to their high theoretical capacity. However, they often encounter challenges associated with complex and irreversible phase transitions and sluggish kinetics. To overcome these issues, herein we integrate the O3-type phase with the P2-type phase and systematically investigate the influence of different ratios of P2 phase in O3-type NaxLi0.05Mn0.55Ni0.3Cu0.075Mg0.025O2 pentanary layered oxides on the electrochemical performance by tuning the sodium contents. The LMC3-P2/O3-32 with optimized P2 phase ratio of 32.3 % exhibits a high reversible capacity of 157.0 mAh g−1 at a rate of 0.2C and excellent capacity retention rate of 63.5 % after 1000 cycles at 10C. The LCM3-P2/O3-32 also demonstrates good cycle life and rate capability in full cells when coupled with a hard carbon anode. In situ X-ray diffraction analyses confirm that the detrimental phase transformations to Na-poor O1 phase and the irreversible phase transitions occurred in the pure O3 cathode can be effectively suppressed in the P2/O3 biphasic cathode. The less Jahn-Teller active ions, enhanced phase transition reversibility and improved diffusion kinetics of Na+ ions are responsible for the improved cyclability and rate capability in the P2/O3 nanoscale intergrowth cathode. Our work shed light on the leverage of P2 and O3 phases through phase integration in layered oxides cathodes, which can serve as a guideline for the further development of high-performance cathode materials for advanced sodium ion batteries.

Enhancing the electrochemical performance of single-crystal LiNi0.8Co0.1Mn0.1O2 cathode material by phosphorus doping

High nickel ternary cathode materials display high specific capacity and low cost, but still suffer irreversible phase change, side reaction and particle cracking during the electrochemical reaction processes. Herein, a P-doped single crystal Ni-rich cathode material is designed, which shows excellent lithium-ion insertion/extraction capability. The phase transition (H1 → H2 → H3) is relieved by the accumulation of interfacial force due to P-doping, as which increases the charge density and promotes the electrostatic repulsion between oxygen layers. P-doping also leads to an increase of lattice parameter c, and the increased thickness of lithium layers and transition metal layers expands the two-dimensional diffusion channel of lithium-ion in the layered structure, facilitating the lithium-ion insertion/extraction processes. The doped ternary single crystal cathode material demonstrates a stable surface structure with resistance to environmental erosion. This work demonstrates that the P-doping is promising to further improve ternary single crystal cathode material for superior lithium-ion battery applications.

Elevating cycle stability of Ni-rich NCM811 cathode via single-crystallization integrating dual-modification strategy for lithium-ion batteries

Nickel-rich layered oxide LiNi0.8Co0.1Mn0.1O2 (NCM811), as an attractive next-generation cathode material for lithium-ion batteries, still encounters grievously poor cycling stability triggered by irreversible phase transition in the layered structure and side reactions at the particle surface. Herein, a straightforward sol-gel method was proposed to fabricate highly stable Na+-doped and carbon-coated NCM811 single crystal, where the sodium glutamate acts as the common source of carbon-coating and Na+-doping. The Na ions prefer to occupy Li-sites that can lower the Li+ diffusion energy barrier and raise the threshold energy of Ni2+/Li+ irreversible migration to facilitate boosting Li+ migration rate and structural reversibility, as confirmed by theoretical calculation in conjunction with experimentation. And the carbon coating constructs a protective layer to effectively suppress parasitic reactions at the particle surface for enhancing cycling stability upon cycles. Consequently, the modified NCM-1 cathode displays the initial discharge capacity of 213.8 mAh·g−1 at 0.1 C and distinguished cycling stability at 5 C after 500 cycles with only approximately 0.034% capacity fading per cycle, which will be a strong competitive cathode material for developing high-power and long-lifespan lithium-ion batteries.

Unraveling the Fast Na Diffusion Kinetics of NASICON at High Voltage via High Entropy for Sodium‐Ion Battery

AbstractVanadium based sodium superionic conductors (NASICON) have attracted unpreceded attention owing to their high structural stability and excellent Na+ ion diffusion. However, Na4VM(PO4)3 suffer from low‐rate capability and capacity decay at high voltage (≈4.0 V) due to low electronic conductivity and irreversible phase transition of V4+/V5+. Herein, a high entropy Na4VFe0.6Mn0.2Cr0.1(CoMgAl)0.1(PO4)3 (NVFP‐HE) NASICON material is designed, which allows the intrinsic effect of multi‐metal to achieve the excellent rate capability at high voltage, good ionic as well as electronic conductivity. This NVFP‐HE cathode not only delivers a high discharge capacity of 141.98 mAh g−1 at 1C, but also presents an exceptional capacity of 85.77 mAh g−1 at as high as 50C current rate. Additionally, NVFP‐HE can also retain 66.7% of initial capacity after 10 000 charge–discharge cycles at 50C. It is important to highlight that the high entropy mitigates the performance decay that arises from the irreversible phase change at 4 V. Interestingly, NVFP‐HE//HC full cell delivers 81 mAh g−1 at 0.2C. This high entropy effect and its proof of concept can allow to look for unique combinations and rationally designed advanced cathode materials for wide applications.

Recent irreversible retreat phase of Pine Island Glacier

AbstractPine Island Glacier (PIG), a part of the West Antarctic marine ice sheet, has recently undergone substantial changes including speed up, retreat and thinning. Theoretical arguments and modelling work suggest that marine ice sheets can become unstable and undergo irreversible retreat. Here, we use an ice-flow model validated by observational data to show that a rapid PIG retreat in the 1970s from a subglacial ridge to an upstream ice plain was self-enhancing and irreversible. The results suggest that by the early 1970s, the retreat of PIG had reached a point beyond which its original position at the ridge could not be recovered, even during subsequent periods of cooler ocean conditions. The irreversible phase ended by the early 1990s after almost 40 km of retreat and 0.34 mm added to global mean sea level, making PIG the main contributor from the Antarctic ice sheet in this period.

Optimized Electrocaloric Refrigeration in Lead-Free NaNbO3-Based Ceramics via AFE ↔ FE Phase Transition Modulation.

An outstanding challenge for eco-friendly ferroelectric (FE) refrigeration is to achieve a large adiabatic temperature change within a broad temperature range originating from the electrocaloric (EC) effect, which is expected to be realized in antiferroelectric (AFE) materials owing to the large entropy change during electric field and thermally induced phase transition. In this work, a large EC response over a wide response temperature range can be achieved slightly above room temperature via designing the phase transition of NaNbO3. An irreversible to reversible AFE-FE phase transition on heating induced by the introduction of CaZrO3 into NaNbO3 plays a key role in the optimized electrocaloric refrigeration. Accordingly, accompanying the local structure transformation corresponding to the B-site ions, the transition temperature between the square polarization-electric field (P-E) hysteresis loop (the irreversible AFE-FE phase transition induced by the electric field) and the repeatable double P-E hysteresis loop (the electric field induced reversible AFE-FE phase transition) was tailored to around room temperature, in favor of extending large entropy change to the wide temperature range. This work provides an efficient approach to designing lead-free EC materials with excellent EC performance, promoting the advancement of environmentally friendly solid-state cooling technology.

Irreversible semiconductor-to-semiconductor transition and highly enhanced photoconductivity of Y2S3 induced by structural modulation

In this study, we investigated the effects of pressure on Y2S3 by examining various properties such as conductance, band gap, photoconductivity, and crystal structure. To do this, we employed electrical transport measurements, UV–vis absorption spectroscopy, X-ray diffraction, Raman spectroscopy, and theoretical calculations. The results obtained from the electrical transport measurements revealed an irreversible semiconductor-to-semiconductor transition in Y2S3 at approximately 10 GPa. Additionally, we observed a gradual decrease in the band gap at low pressure, but a sharp drop starting at around 10 GPa, which corresponded to the change in transport properties. Moreover, the photoconductivity of the decompressed Y2S3 sample was found to be 2–3 orders of magnitude higher than that of the pristine sample. Our X-ray diffraction and Raman measurements provided clear evidence of an irreversible first-order phase transition occurring in Y2S3, transitioning from a monoclinic to an orthorhombic crystal structure at ∼10 GPa. This phase transition helps to explain the abrupt changes observed in transport, band gap, and photoconductivity. These findings were further confirmed by our first-principle calculations.

Effect of Temperature and Ratio for the Immobilization of Zinc Oxide in Aluminium Rich Ceramics

Zinc is one of the dangerous elements that is frequently present in municipal solid waste incinerator ash. When exceeding specific limits, there are various diseases and disorders caused by accumulation of zinc in nature as their characteristics is not biodegradable. By using zinc oxide to imitate zinc sludge, this study reveals the immobilization mechanisms that occur when zinc and ceramic precursors are used as waste-to-resources strategies. From the result, immobilization occur better at higher temperature at 10000C where the formation of Al2O4Zn is higher. Meanwhile, ratio 1:1 of ZnO and Al2O3 shows a better result of formation Al2O4Zn. Hence, it is possible to use the sintering process with precursors to turn hazardous wastes into secure products where the heavy metals can form phases that can demonstrate adequate stability due to irreversible phase transformation.

Phase stability and energy storage properties of polycrystalline antiferroelectric BaTiO3-substituted NaNbO3 thin films

Lead-free sodium niobate (NN) thin films with varying barium titanate (BT) content and 1 mol% manganese were deposited on platinized silicon substrates by chemical solution deposition. Microstructural analysis reveals a change in nucleation mechanism, and X-ray diffraction and Raman spectroscopy confirmed a composition-driven antiferroelectric (AFE) to ferroelectric (FE) phase transition at 0.01 < x < 0.03, providing a stability interval for the AFE phase despite increasing the tolerance factor. The thin films show well-shaped ferroelectric response under applied electric field, indicating an irreversible field-induced phase transition. The composition with 7 mol% BaTiO3 showed the most promising energy storage properties (Wrec ∼5.7 J/cm3 and 68% efficiency (η)), along with excellent thermal stability up to 120 °C and largely improved cyclic stability up to 5 * 106 bipolar cycles. These findings highlight the potential of NN-based thin films as lead-free candidates for energy storage, emphasizing the importance of stabilizing the AFE phase under electric fields for practical applications.

The Proactive Diagnostic Value of Thrombin-Antithrombin Complex and Antithrombin III in Disseminated Intravascular Coagulation

Introduction Disseminated intravascular coagulation (DIC) is a life-threatening condition with high mortality, necessitating timely and accurate diagnosis for effective management. However, current diagnostic systems can not recognize DIC at its reversible phase, causing suboptimal treatment outcomes. One reason is that most venous thrombosis cases are asymptomatic. Moreover, the focus on abnormalities in coagulation consumption often fails to identify DIC until in a later and irreversible phase. Consequently, the current diagnostic criteria for DIC lacks earlier laboratory indicators. Therefore, our objective was to evaluate the diagnostic potential of selected hemostatic biomarkers (thrombin-antithrombin complex (TAT), soluble thrombomodulin (sTM), tissue plasminogen activator inhibitor complex (tPAI-C), α 2-plasmin inhibitor plasmin complex (PIC) and anti-thrombin III (ATIII)) in assessing DIC before reaching its irreversible phase. Methods We included 451 patients from intensive care unit who met the following criteria:≥18 years old, non-perinatal period, and a hospitalization length of≥3 days, excluding those with primary hematologic diseases, decompensated liver cirrhosis or chemotherapy history. In total, 101, 57, and 293 patients were diagnosed with overt-DIC (decompensated DIC), pre-DIC (compensated DIC), and non-DIC, respectively. The DIC scores were calculated in accordance with the diagnostic criteria outlined by the International Society on Thrombosis and Haemostasis (ISTH). Day 0 was defined as the day on which hemostatic biomarkers were detected. Global parameters including prothrombin time (PT), fibrinogen (FIB), fibrinogen degradation product (FDP), d-dimer, and platelet count were collected on day 0, 1, 3, 5, and 7. The spearman correlation analysis was used to analyze the linear relation. Binary logistic regression analysis and receiver operating characteristic curves were used to calculate the area under the receiver operating characteristic curve (AUC). The cutoff value maximizes the sum of the sensitivity and specificity. P&amp;lt;0.05 was considered statistically significant. Results Correlation analysis revealed significant linear correlations between TAT, ATIII, and the global parameters relevant to DIC (pre-DIC and overt-DIC). Specifically, TAT exhibited positive correlation with d-dimer and FDP, while ATIII was correlated with PT, FIB, and platelet count. Of note, TAT/ATIII ratio on day 0 exhibited strong associations not only with fibrinolytic markers but also with coagulation parameters within a week, indicating its potential to be a valuable diagnostic and predictive tool for DIC assessment. Comparative analysis demonstrated elevated TAT and decreased ATIII levels in DIC group. Remarkably, the TAT/ATIII ratio demonstrated superior diagnostic performance compared to individual biomarkers. Among individual biomarkers, TAT/ATIII ratio had the highest AUC of 0.818 with a cutoff value of 22.1, followed by ATIII (AUC=0.752) and TAT (AUC=0.749). Moreover, when a combination of TAT and ATIII was applied, the AUC increased to 0.847 higher than TAT/ATIII ratio's, improving the diagnostic accuracy for DIC. TAT and ATIII in pre-DIC group were consistent with those observed in DIC group above: elevated TAT levels, decreased ATIII activity, TAT/ATIII ratio with superior diagnostic performance. Among individual biomarkers, TAT/ATIII ratio had the highest AUC 0.771 with a cutoff value of 22.1 that maximized the sum of sensitivity (55%) and specificity (89%), followed by TAT (AUC=0.73) and ATIII (AUC=0.707). The AUC of TAT combination with ATIII was 0.796, higher than AUC 0.771 of TAT/ATIII ratio, suggesting that TAT and ATIII may also identify the pre-DIC status and predict overt-DIC. Conclusion This study underscores the remarkable potential of TAT, ATIII, and the TAT/ATIII ratio in predicting DIC with accuracies of 73%, 71%, and 77%, respectively. Moreover, for patients with an ISTH-DIC score of &amp;lt; 5, the presence of following conditions-TAT level ≥10.8 ng/mL, ATIII activity ≤0.58, or TAT/ATIII ratio ≥22.1-indicates a likelihood of developing into irreversible DIC within 7 days. Integrating TAT, ATIII, and the TAT/ATIII ratio into the diagnostic process holds the potential to expedite clinical interventions during the pre-DIC state and enhance outcomes for DIC patients, further covering the shortage of current ISTH criteria.

Al‐doped ZnO‐Coated LiNi1/3Mn1/3Co1/3O2 Powder Electrodes: The Effect of a Coating Layer on The Structural and Chemical Stability of The Electrode / Electrolyte Interface

AbstractLiNi1/3Mn1/3Co1/3O2 (NMC‐111) is one of the most popular cathode materials in Li‐ion batteries. However, chemical and structural instabilities of the cathode/electrolyte interface at high charge cut‐off voltages cause capacity fading. Surface modifications using metal oxides are promising candidates to suppress capacity fading. Here a systematic study on the degradation mechanism of an uncoated NMC‐111 powder electrode is presented. Moreover, the effect of an Al‐doped ZnO (Al:ZnO) coating layer on the structural and chemical stabilities of NMC‐111 electrode cycled at high charge cut‐off voltages is analyzed using X‐ray photoelectron spectroscopy, scanning electron microscopy and analytical transmission electron microscopy as well as electrochemical testing. The coating is applied to commercial NMC‐111 powder using a microwave‐assisted sol‐gel synthesis method. In the case of uncoated NMC‐111 electrodes, pitting corrosion due to hydrofluoric acid attacking the electrode surface, cation mixing, and an irreversible phase transformation from a trigonal layered to a rock‐salt phase occurs, causing capacity fading. While, in the case of Al:ZnO – coated NMC‐111 electrodes, pitting corrosion, cation mixing, and the irreversible phase transformation are mitigated. Therefore, the capacity retention and rate capability are improved as the coating layer protects the electrode surface from the direct electrolyte exposure.