Properties Of Cathode Research Articles

A comprehensive study of nonuniformity properties of the LiCoO2 thin-film cathode fabricated by RF sputtering

The influence of nonuniformity properties of the LiCoO2 cathode film deposited by magnetron sputtering on the capacity of all-solid-state thin-film lithium-ion batteries (ASSLib) was studied. It was found that the film nonuniformity corresponds to the magnetron plasma density distribution and the angular distribution of sputtered particles. The capacity distribution of the ASSLib with LiCoO2 cathode depending on the distance to the substrate center was studied. The maximum capacity corresponded to the dense part of the toroidal region of the magnetron plasma. It was determined that the main causes of batteries capacity decline in the central part and on the edge of the substrate are the impurity phase of lithium cobaltate and the smaller thickness of the cathode layer, respectively.

Synthesis of Sr2(Co1.1;Mo0.9)O6-δ double perovskite and its electrochemical performance in the oxygen reduction reaction

Mixed ionic-electronic conductors composed of Sr2(Co;Mo)O6-δ double perovskites have been identified as potential candidates for symmetric Solid Oxide Fuel Cells, but their performance and stability under cathodic conditions remain unclear. Typically, a Co:Mo ratio of 1:1 leads to the formation of SrMoO4 as a by-product when the material is treated in air. In this study, we show that employing a glycine-nitrate combustion process with a high fuel ratio, along with an excess of cobalt, leads to a single-phase material with a double perovskite crystal structure (I4/m space group) after air calcination at high temperatures. Detailed Co and Mo speciation studies conducted using XPS and XANES spectroscopies are also presented to support these findings. Our electrochemical impedance spectroscopy study shows that this material exhibits excellent electrocatalytic response for the oxygen reduction reaction, with oxygen ion diffusion through the cathode being the rate-limiting process. Furthermore, the material shows strong chemical compatibility with (La;Sr)(Ga;Mg)O3-δ electrolytes at temperatures up to 1000 °C. For comparison purposes, we also present the properties of single perovskite cathodes with the composition Sr(Co0.95;Mo0.05)O3-δ.

Enabling Quasi-Zero-Strain Behavior of Layered Oxide Cathodes via Multiple-cations Induced Order-to-Disorder Transition.

The chemically pre-intercalated lattice engineering is widely applied to elevate the electronic conductivity, expand the interlayer spacing, and improve the structural stability of layered oxide cathodes. However, the mainstream unitary metal ion pre-intercalation generally produces the cation/vacancy ordered superstructure, which astricts the further improvement of lattice respiration and charge-carrier ion storage and diffusion. Herein, a multiple metal ions pre-intercalation lattice engineering is proposed to break the cation/vacancy ordered superstructure. Taking the bilayer V2O5 as an example, Ni, Co, and Zn ternary ions are simultaneously pre-intercalated into its interlayer space (NiCoZnVO). It is revealed that the Ni─Co neighboring characteristic caused by Ni(3d)-O(2p)-Co(3d) orbital coupling and the Co-Zn/Ni-Zn repulsion effect due to chemical bond incompatibility, endow the NiCoZnVO sample with the cation/vacancy disordered structure. This not only reduces the Li+ diffusion barrier, but also increases the diffusion dimension of Li+ (from one-dimension to two-dimension). Particularly, Ni, Co, and Zn ions co-pre-intercalation causes a prestress, which realizes a quasi-zero-strain structure at high-voltage window upon charging/discharging process. The functions of Ni ion stabilizing the lattice structure and Co or Zn ions activating more Li+ reversible storage reaction of V5+/V4+ are further revealed. The cation/vacancy disordered structure significantly enhances Li+ storage properties of NiCoZnVO cathode.

Improving the Performance of LiFePO4 Cathodes with a Sulfur-Modified Carbon Layer

LiFePO₄ (LFP) cathodes are popular due to their safety and cyclic performance, despite limitations in lithium-ion diffusion and conductivity. These can be improved with carbon coating, but further advancements are possible despite commercial success. In this study, we modified the carbon coating layer using sulfur to enhance the electronic conductivity and stabilize the carbon surface layer via two methods: 1-step and 2-step processes. In the 1-step process, sulfur powder was mixed with cellulose followed by heat treatment to form a coating layer; in the 2-step process, an additional coating layer was applied on top of the carbon coating layer. Electrochemical measurements demonstrated that the 1-step sulfur-modified LFP significantly improved the discharge capacity (~152 mAh·g−1 at 0.5 C rate) and rate capability compared to pristine LFP. Raman analyses indicated that sulfur mixed with a carbon source increases the graphitization of the carbon layer. Although the 2-step sulfur modification did not exceed the 1-step process in enhancing rate capability, it improved the storage characteristics of LFP at high temperatures. The residual sulfur elements apparently protected the surface. These findings confirm that sulfur modification of the carbon layer is effective for improving LFP cathode properties, offering a promising approach to enhance the performance and stability of LFP-based lithium-ion batteries.

Ionic conduction and cathodic properties of CaMO3 (M=Fe and Mn) electrode materials via molecular dynamics and first-principles simulations

Calcium-ion(Ca-ion) batteries are gaining ever-increasing attention for next-generation energy storage systems due to affordability, highly abundant, high energy density, high theoretical capacity, and low redox potential close to Li-ion. In this work, we deployed the first-principles and classical molecular dynamics simulations to investigate the electronic and diffusive properties of isostructural ternary perovskite CaMO3 (M= Fe and Mn). The transport properties at various temperatures from ion dynamics and electronic properties of CaMO3 perovskites are examined using classical molecular dynamics and quantum mechanical simulations, respectively. We present the microscopic origin of the diffusion of multivalent ions like Ca2+ within the crystal structure of perovskite material and the effects of two transition metals, manganese and iron. Dynamic studies of Ca-ions were performed using molecular dynamic simulation, which depicts the diffusivity and conductivity of Ca-ion in CaMO3 material. We find that the diffusivity in both the crystals increases with temperature; as a result, conductivity increases. Among both the crystals, CaFeO3 requires less activation energy for diffusion and ionic conduction than CaMnO3. Using density functional theory, we calculated specific capacity, electronic density of states, phase stability and equilibrium cell voltage, and charge transfer process during intercalation-deintercalation from first-principles calculations. The electronic behavior of these materials shows that CaFeO3 has better electronic and transport properties than CaMnO3.

Reactive crystallization regulation for synthesizing NCM811 precursor by different impellers

The spherical and dense precursors with a narrow particle size distribution are essential to achieve high electrochemical performance in cathode materials. Four newly designed impellers, including the punched-flow turbine (PFT), punched-flow disc turbine (PFDT), curved-inclined-blade disc turbine (CIBDT), and 6-folded-pitched turbine (FPT-6), are applied to prepare the precursors to investigate the interplay among the fluid flow state, precursors’ morphology and growth, and physicochemical properties of cathodes. The flow and mixing features of double impellers are predicted using computational fluid dynamics, indicating that the FPT-6 plays a crucial role in crystal nucleation while PFDT facilitates crystal growth. This concurrence can be corroborated by examining the performance of precursors synthesized using these four impellers. It is first found that the electrochemical performance is distinctly enhanced by utilizing different impellers to regulate the specified nucleation and growth stage. By increasing the nucleation rate with double impellers of FPT-6, the tap density and sphericity of the precursor and cathode materials are significantly improved. The discharge capacity of cooperative agitators (FPT-6+PT) is 2.1 times that of the only propeller turbine at a high current density (10 C). The later growth stage is suitably regulated by FPT-6 or PFDT; properly extended reactive time can enhance the sphericity and electrochemical performance. The dual mixed-impeller (PT/CIBDT) combines intense mixing and shear ability, attaining a dense spheroid with a highly smooth surface. The cycle retention of this cathode is increased by 10.35% after 200 cycles at 1 C compared to a commercial counterpart. A regulatory strategy for the reactive co-precipitation process to enhance precursor stability is proposed here. Furthermore, the optimal operation parameters derived from this strategy can be effectively applied to commercial cathode materials.

Effects of Coprecipitation Conditions on the Electrochemical Properties of Cobalt-Free LiNi0.9Mn0.1-xAlxO2 Cathodes.

Commercializing high-nickel, cobalt-free cathodes, such as LiNi0.9Mn0.1-xAlxO2 (NMA-90), hinges on effectively incorporating Al3+ during the hydroxide coprecipitation reaction. However, Al3+ coprecipitation is nontrivial as Al3+ possesses unique precipitation properties compared to Ni2+ and Mn2+, which impact the final precursor morphology and consequently the cathode properties. In this study, the nuance of Al3+ coprecipitation and its influence on the cycling stability of NMA with increasing Al3+ content is elucidated. While low reaction pH and ammonia concentration are suitable for producing Al-free LiNi0.9Mn0.1O2 (NM-90) effectively, the same coprecipitation environment leads to porous precursor morphology and poor cycle life in Al-containing LiNi0.9Mn0.08Al0.02O2 (NMA-900802) and LiNi0.9Mn0.05Al0.05O2 (NMA-900505). By systematically increasing the reaction pH and ammonia concentration for the Al-containing compositions, the precursor morphology becomes denser and the cathode cycling stability is greatly improved. It is hypothesized that the improvement in cycling stability stems from the reduction in Al(OH)3 nucleation, which promotes hydroxide particle growth with optimal Al3+ incorporation into the cathode lattice.

A Na-Li dual cation liquid metal battery with high electrode utilization and high cycling stability

Liquid metal batteries (LMBs) with Na anode exhibit the advantages of low-cost, high-safety, long-lifespan, and easy scale-up, making them promising for large-scale energy storage applications. However, the high solubility of Na and its sluggish kinetics in discharge products result in severe self-discharge and low cathode utilization, significantly hindering the development of Na-based LMBs. In this study, a stable Na-Li dual cation LMB with metal Sb cathode is designed based on the in-situ displacement reaction between Na and molten salts of lithium halides electrolyte. This design effectively suppresses the self-discharge of the battery, and the multistage discharge mechanism of the dual-cation system enhances cathode utilization. Moreover, the self-healing property of the Sb cathode protects the electrode against volume expansion and degradation, enhancing cycling performance. The Na-Li| LiCl-KCl-NaCl |Sb cell was constructed and operated at 485 °C. The battery retained 97.02 % of its capacity after 800 cycles at 0.6 C, with a decay rate of 0.00373 % per cycle. Furthermore, the battery achieves a cathode material utilization of 89 % at 0.6 C. These improvements effectively promote the development and application of LMBs.

Routes to Bidirectional Cathodes for Reversible Aprotic Alkali Metal–CO2 Batteries

AbstractAprotic alkali metal–CO2 batteries (AAMCBs) have garnered significant interest owing to fixing CO2 and providing large energy storage capacity. The practical implementation of AAMCBs is constrained by the sluggish kinetics of the CO2 reduction reaction (CO2RR) and the CO2 evolution reaction (CO2ER). Because the CO2ER and CO2RR take place on the cathode, which connects the internal catalyst with the external environment. Building a bidirectional cathode with excellent CO2ER and CO2RR kinetics by optimizing the cathode's internal catalyst and environment has attracted most of the attention to improving the electrochemical performance of AAMCBs. However, there remains a lack of comprehensive understanding. This review aims to give a route to bidirectional cathodes for reversible AAMCBs, by systematically discussing engineering strategies of both the internal catalyst (atomic, nanoscopic, and macroscopic levels) and the external environment (photo, photo‐thermal, and force field). The CO2ER and CO2RR mechanisms and the “engineering strategies from internal catalyst to the external environment–cathode properties–CO2RR and CO2ER kinetics and mechanisms–batteries performance” relationship are elucidated by combining computational and experimental approaches. This review establishes a fundamental understanding for designing bidirectional cathodes and gives a route for developing reversible AAMCBs and similar metal–gas battery systems.

Unveiling the potency of tetrahydropalmitine as a green anticorrosion material for 2024 aluminum alloy in acid-chloride environments

2024 aluminum alloy has garnered attention from researchers because of its numerous applications in the oil and gas, aerospace, and marine sectors. However, its constituent high Cu content (the primary alloying element) poses a significant challenge to its use, particularly in applications that demand high corrosion resistance. This is particularly troubling in oxygen-containing chloride systems. Herein, we developed a protection strategy for 2024 Al alloy in an acid-chloride environment (composed of 0.5 M NaCl and 0.25 M H2SO4) using natural tetrahydropalmitine (THP) isolated from Corydalis yanhusuo. THP was effectively characterized from its 1H NMR, 13C NMR, and FTIR spectra, and its anticorrosion potentials were methodically investigated by electrochemical, gravimetry and theoretical experiments. Upon the addition of THP to the test system, EIS measurements revealed a steady increase in the Nyquist semicircles, as well as the Bode impedance and phase angle plots, attaining an optimum inhibition efficiency of 91.5 % at 2.0 g/L THP. Tafel plots manifested mixed-type anticorrosion effects with dominant cathodic properties, ascribed to the ordered shielding effect of both the hydrogen evolution reaction and the oxidation of oxide-free ions. According to gravimetric corrosion assessment, the 2024 Al alloy mainly retained its protection over time in the presence of THP, exhibiting only minor decline in its protectability. This is attributed to the combined effect of stable oxide film formation and the adsorbed THP on the alloy surface. SEM afforded the proof of THP adsorption on 2024 Al while XPS offered clarity into its anticorrosion mechanism. Conceptual DFT parameters, molecular electrostatic potential and molecular dynamics simulation were used to comprehend the inhibition process of THP on Al surface. Generally, THP was proven to be a viable and sustainable bio-based anticorrosion material for the protection of 2024 Al alloy.

Preparation of functionalized porous chitin carbon to enhance the H2O2 production and Fe3+ reduction properties of Electro-Fenton cathodes for efficient degradation of RhB

The performance of Electro-Fenton (EF) cathode materials is primarily assessed by H2O2 yield and Fe3+ reduction efficiency. This study explores the impact of pore structure in chitin-based porous carbon on EF cathode effectiveness. We fabricated mesoporous carbon (CPC-700-2) and microporous carbon (ZPC-700-3) using template and activation methods, retaining nitrogen from the precursors. CPC-700-2, with mesopores (3–5 nm), enhanced O2 diffusion and oxygen reduction, producing up to 778 mg/L of H2O2 in 90 min. ZPC-700-3, with a specific surface area of 1059.83 m2/g, facilitated electron transport and ion diffusion, achieving a Fe2+/Fe3+ conversion rate of 79.9%. EF systems employing CPC-700-2 or ZPC-700-3 as the cathode exhibited superior degradation performance, achieving 99% degradation of Rhodamine B, efficient degradation, and noticeable decolorization. This study provides a reference for the preparation of functionalized carbon cathode materials for efficient H2O2 production and effective Fe3+ reduction in EF systems.

Morphology Controled LiFePO4 Electrodes Via Polyol Refluxing for Enhanced Lithium-Ion Battery Performance

In the synthesis of LiFePO4 cathodes with secondary nanorod structures and nano-plate morphologies, researchers utilized a polyol refluxing process. Notably, we achieved this without the use of characteristic structure directing agents. Through varying the reaction time, they were able to modulate the morphological characteristics of the synthesized samples.X-ray diffraction studies conducted on the prepared samples indicated a highly crystalline nature. This suggests that the synthesized cathodes possessed a robust and ordered atomic structure, which is crucial for their electrochemical performance.Electron microscopy investigations provided insights into the morphology of the samples obtained at different reaction times. Samples produced after 1 to 16 hours of polyol reaction exhibited secondary nanorod bundles. However, the sample recovered after 32 hours of polyol reaction displayed a distinct nano-plate morphology. These observations highlight the influence of reaction time on the final morphology of the synthesized cathodes.The dimensions of the obtained samples ranged from a few tens to a few hundred nanometers. This nano-scale size is advantageous for enhancing the electrode's surface area, which can facilitate rapid ion diffusion and electron transport during battery cycling.When employed in lithium test cells, the LiFePO4 cathodes synthesized for different durations delivered varying discharge capacities. Specifically, cathodes prepared under 1, 4, 8, 16, and 32 hours of reaction time exhibited discharge capacities of 161, 162, 171, 143, and 155 mAhg−1, respectively. Notably, all samples displayed a well-defined discharge plateau at 3.4 V, indicating stable electrochemical behavior during cycling.Remarkably, among the prepared electrodes, the LiFePO4 nanorod bundle cathode synthesized under 1 hour reaction time demonstrated the highest average reversible capacities. It maintained capacities of 123 and 103 mAhg−1 at C-rates as high as 3.2 and 6.4 C, respectively. This highlights the importance of reaction time in controlling the electrochemical performance of the synthesized cathodes.The crystal growth mechanism during the polyol refluxing method can be elucidated through several stages. These include precursor dissolution and nucleation, oriented crystal growth and alignment through self-assembly, aggregation, partial dissolution, and finally, complete re-crystallization. Understanding these mechanisms is essential for optimizing the synthesis process and tailoring the properties of LiFePO4 cathodes for various applications. Tarascon JM, Armand M. Issues and challenges facing rechargeable lithium batteries. Nature 2001;414:359–67Amatucci GG, Tarascon JM, Klein LC. CoO2, the end member of the LixCoO2 solid solution. J Electrochem Soc 1996;143:1114–23Ravet N, Chouinard Y, Magnan JF, Besner S, Gauthier M, Armand M. Electroactivity of natural and synthetic triphylite. J Power Sources 2001;97–98:503–7 Figure 1

A Novel Approach to Continuous and Scalable Synthesis of Cation-Disordered Rocksalt Cathodes

Cation disordered rocksalts (DRX) are an emerging class of high energy density LIB cathodes that can utilize earth-abundant and low-cost redox active transition metals. The DRX cathodes can be synthesized through a rich chemistry of transition metals, where commonly, metal-oxide precursors are combined with lithium source via ball-milling and calcined to achieve cation disordered phase. In this work, we present a new alternative synthesis method to the traditional solid-state synthesis, which provides scalable and continuous production of cathode precursors. A soft synthesis method in aqueous media was adopted to produce Mn-rich cathode precursors in large scale, through which homogenous mixing of the introduced transition metal cations was achieved. Here we report the electrochemical and structural properties of as-synthesized DRX cathodes with various Mn-compositions.

Exploring the Impact of Oxygen Doping in Li2FeS2 Cathode Materials for Li-Ion Batteries

Over the past few decades, rechargeable lithium-ion batteries have become popular for a variety of applications, such as electric vehicles, smart grids, and portable energy devices. However, due to their limited capacity, stability, and lifespan, they are not suitable for advanced transportation applications. To overcome these challenges, researchers have investigated the use of low-cost, high-energy-density, and safe positive electrode materials for secondary lithium batteries, including lithium iron sulfide. In this particular study, our focus is to investigate the effect of highly electronegative anion doping on the properties of lithium iron sulfide cathode through the solid-state method. Our approach involves using both in-situ and ex-situ observations to establish a correlation between the Redox behavior and structural properties of the prepared cathode materials. We have designed and characterized the material using various techniques, such as X-ray absorption spectroscopy (XAS) and synchrotron-based X-ray diffraction (XRD). Scanning electron microscope (SEM) measurement was conducted to study the morphology of the cathode material. Transmission electron microscopy (TEM) was employed to further study the microstructure of the cathode material at an atomic level. We analyzed the electron density distribution of the modified cathode material using XANES measurement and studied the structural properties through synchrotron-based XRD. Our study has revealed that oxygen-doping helps to improve material stability. As a result, the modified cathode (with optimal oxygen doping) exhibited a 50% capacity enhancement compared to pristine after 100 cycles. We also observed a shift to a higher voltage oxidation plateau of the oxygen-doped cathode material which is due to the influence of anion substitution on the electrochemistry and charge storage mechanisms. In summary, our detailed characterization and experimental results demonstrate the potential of oxygen-doped Li2FeS2 as a promising cathode material for advanced lithium-ion battery applications. The study's detailed characterization and experimental results will be presented, along with future perspectives.

High Areal Capacity Cation and Anionic Redox Solid-State Batteries Enabled by Transition Metal Sulfide Conversion.

Pure sulfur (S8 and Li2S) all solid-state batteries inherently suffer from low electronic conductivities, requiring the use of carbon additives, resulting in decreased active material loading at the expense of increased loading of the passive components. In this work, a transition metal sulfide in combination with lithium disulfide is employed as a dual cation-anion redox conversion composite cathode system. The transition metal sulfide undergoes cation redox, enhancing the electronic conductivity, whereas the lithium disulfide undergoes anion redox, enabling high-voltage redox conducive to achieving high energy densities. Carbon-free cathode composites with active material loadings above 6.0 mg cm-2 attaining areal capacities of ∼4 mAh cm-2 are demonstrated with the possibility to further increase the active mass loading above 10 mg cm-2 achieving cathode areal capacities above 6 mAh cm-2, albeit with less cycle stability. In addition, the effective partial transport and thermal properties of the composites are investigated to better understand FeS:Li2S cathode properties at the composite level. The work introduced here provides an alternative route and blueprint toward designing new dual conversion cathode systems, which can operate without carbon additives enabling higher active material loadings and areal capacities.

Effect of NMC-doping Concentration on the Structural Feature and Electrical Properties of Lithium Iron Phosphate Cathode for Use in Lithium-ion Batteries

T his study investigates the synthesis of Lithium Iron Phosphate (LFP) with NMC-doped cathode materials, aiming to enhance the performance of lithium-ion batteries. The NMC content was varied from 0.02 to 0.10wt%, and 1wt% of (NH4)3PO4 was added to all conditions to prevent phosphate loss during the calcination process. The composite powder was prepared using a straightforward mixed oxide method, with a calcination temperature of 600 °C for 5 hours under an argon gas flow. X-ray diffraction (XRD) analysis confirmed the successful formation of pure LFP with an orthorhombic crystal structure, devoid of any secondary phases. To further explore the impact of NMC doping on the structural characteristics, FTIR and Raman spectroscopy were employed. Results revealed that increasing NMC doping concentration beyond 0.02wt% led to the broadening of the PO43− symmetric stretching band at approximately 947 cm−1, indicating a higher degree of disorder in the LFP structures. This disorder was found to adversely affect electrochemical performance, resulting in decreased discharge capacity and increased impedance, as determined by electrochemical impedance spectroscopy (EIS), with higher concentrations of NMC and (NH4)3PO4. Scanning Electron Microscopy (SEM) analysis unveiled the presence of agglomerated particles ranging in size from 0.5 to 0.9 microns. Optimal conditions were identified with the addition of NMC doped at 0.02wt%, which exhibited a discharge capacity of approximately 119.41 mAh/g at 0.2 C, along with a low impedance of 200 Ohm. Moreover, the 0.02wt% sample demonstrated a promising linear trend in cycle performance, suggesting its potential for future applications in lithium-ion batteries.

Enhancing the electrochemical properties of Li-rich layered oxide cathodes by a facile Fe/Ti integrated modification strategy

Li-rich layered oxide cathodes have gained much attention due to their high specific capacity, high operating voltage, and environmental friendliness. However, poor rate performance, rapid capacity and voltage decay during cycling have hindered its commercial application. In this work, a Fe/Ti integrated modification strategy is proposed to construct a LiFeTiO4 spinel phase coating on the surface of Li1.2Mn0.54Ni0.13Co0.13O2, effectively reducing interfacial side reactions and suppressing the irreversible oxygen release, while doping with Fe3+ and Ti4+ ions can effectively broaden the lithium diffusion channel and enhance the structural stability. As a result, the modified sample with 2 wt% of Fe/Ti demonstrates excellent cycling stability with a superior capacity retention of 91% after 400 cycles at 1C and good rate performance with a high specific discharge capacity of 216 mAh g−1 at 2C. Moreover, the initial Coulombic efficiency of the modified sample is also improved. This integrated modification strategy offers a new design to promote the large-scale application of Li-rich Mn-based cathode materials.

Effect of Mo6+ induced valence changes of transition metal ions in Mn-rich layered cathode materials on electrochemical performance

Layered cathode materials for lithium-ion batteries have been extensively investigated; however, comparatively scant attention has been paid to Mn-rich layered cathode materials. Herein, LiNi0.5Mn0.5O2 cathode materials are doped to investigate the effect of doping elements on the electrochemical properties of Mn-rich layered cathodes. XRD (X-ray diffraction), XPS (X-ray photoelectron spectroscopy), and SQUID (superconducting quantum interference device) results reveal that Mo doping affects the electrochemical properties of the cathode materials by changing the valence state of transition metal ions. Due to the Mo6+ ions doping, a large proportion of Mn3+ ions present in LiNi0.5Mn0.5O2 were converted to Mn4+ ions, which alleviated the Jahn-Teller effect and reduced the elongated Mn-O octahedra, thus increasing the Li layer spacing and facilitating Li+ diffusion. Therefore, 1 % Mo-doped cathode exhibits a significantly improved Li-ion diffusion coefficient and superior rate performance with a specific discharge capacity of 103 mAh·g−1 at 5C. Meanwhile, the cathode materials significantly improve cycling performance due to the reduction in the amount of Mn3+. The current study provides guidelines for the modification of Mn-rich layered cathodes in the future.

Assessment of pyrazole Schiff base's corrosion inhibition effectiveness incorporating oxadiazole moiety on mild steel in 1 M HCl: A holistic theoretical and experimental analysis

Modern industries place a high value on reasonably priced, eco-friendly products that effectively stop metal breakdown. Hence, our goal was to create an ecologically acceptable pyrazole Schiff base (PSB) that would effectively preserve mild steel (MS) during pickling and descaling procedures. We achieved this by integrating oxadiazole, which demonstrated good anti-corrosion capabilities. A complete investigation was conducted using spectroscopic analysis, electrochemical techniques, and gravimetric measurement in 1 M HCl solution. The PSB inhibitor displayed considerable corrosion inhibition on MS. PSB exhibited both cathodic and anodic properties in its dual adsorption pattern, as shown by the electrochemical investigation. Polarization resistance (Rp) values rose with the PSB concentration from 50 to 300 ppm, peaking at 300 ppm with values ranging from 31.01 to 141.21 Ω.cm². At 300 ppm and 298 K, the inhibitor effectiveness reached 90.12 %. Electrochemical testing validated the protection against mixed-type corrosion, while surface examinations (SEM, EDS, CA, AFM) showed that PSB developed a protective antioxidant layer on the MS surface. According to theoretical DFT calculations, PSB adsorbs onto the steel surface in a flat alignment. The remarkable precision of the adsorption process was validated by the high coefficient of determination (R2 = 1) for both Langmuir and other adsorption isotherms. Computational, chemical, and electrochemical analyses all support PSB's superiority as a corrosion inhibitor. The incorporation of aryl and heterocyclic rings improves the PSB structure's molecular stiffness, which facilitates effective adsorption onto the MS surface. This feature creates novel prospects for material protection and corrosion prevention, presenting PSB as a viable and eco-friendly substitute for conventional corrosion inhibitors in industrial applications.

Superior fast-charging Ni-rich cathode via promoted kinetic-mechanical performance

The sluggish Li-ion kinetics restrict the rapid charging capabilities and contribute to the structural deterioration of Ni-rich cathode materials. Notably, crack propagation during repeated charging cycles deteriorates the electrochemical stability, which hinders the further development of high-energy-density batteries for electric vehicles (EVs). In this paper, we proposed a simple yet effective method to enhance the Li-ion diffusion and mechanical properties of Ni-rich cathodes via straightforward Zr doping. In-situ high-rate XRD reveals that the detrimental uneven delithiation under the fast-charging process has been largely alleviated. Particularly, a robust structure with higher modulus and fracture strength is constructed owing to the higher Zr-O bond. By mitigating the kinetic hindrance and increasing the particle’s stiffness, the proposed Ni-rich cathode shows an impressive 97.6 % capacity retention under a 5 C rate current. This work provides a facile and efficient strategy for large-scale production of fast-charging Ni-rich cathode materials.