Nickel Manganese Oxide Research Articles

Effect of the succinonitrile additive, electrode processing, and N/P ratios in the performance of high‐voltage lithium‐ion batteries using LiNi0.5Mn1.5O4 cathode

AbstractThe progressive improvement in the gravimetric energy density of lithium‐ion batteries (LIBs) leads to electrolyte design, positive electrode, and full‐cell optimization processes. The spinel lithium nickel manganese oxide (LiNi0.5Mn1.5O4, LNMO) is one of the potential candidates for the next generation of LIBs applied for electric vehicles due to high working potential (4.75 V vs. Li+/Li), affordable price, and environmental friendliness. Nevertheless, the degradation of cycling performance at high potential induces massive challenges for commercializing LNMO‐based batteries. This study investigated the impact of succinonitrile (SN), electrode processing, and N/P ratios to strengthen the LNMO half‐cell and graphite||LNMO full‐cell performance. According to the performance in half‐cell, the sample contained 85 wt% LNMO: 7.5 wt% C65: 7.5 wt% PVDF/NMP combining with the electrolyte 1.5 M LiPF6 in EC:EMC:DMC (2:1:7 – v/v) at 0.5 wt% SN seems to be the optimal condition for further full‐cell. In addition, the full‐cell with N/P = 1.3 displays a remarkable initial capacity of 118.75 mAh g−1, a Coulombic efficiency of 91.64%, and a superior gravimetric energy density of 537.71 mWh g−1. Moreover, it maintains a capacity retention of around 58% at the current density of 0.1C after 100 cycles. As a result, this study presents an optimal solution to augment the material's potential for commercialization in the immediate future.

Zr-Doped High-Voltage Spinel LiNi0.5Mn1.5O4 Manufactured via the Coprecipitation Method.

Lithium nickel manganese oxide (LiNi0.5Mn1.5O4, LNMO) provides an elevated operating potential of 4.7 V and a theoretical capacity of 147 mAh g-1, without the need for expensive cobalt. Zr-doped LNMO was synthesized using the coprecipitation technique with Couette-Taylor flow. FE-SEM images and TEM SAED patterns revealed that Zr-doped LNMO formed truncated octahedral structures with exposed (100) crystal facets. When compared to undoped LNMO, Zr-doped LNMO exhibited superior electrochemical performance. Electrochemical evaluations showed that Zr0.1-LNMO achieved 85.9% rate capability at 10 C, significantly outperforming the 69.1% of bare LNMO. In addition, Zr0.1-LNMO exhibited high stability, maintaining 76.8% of the discharge capacity even after 100 cycles.

Tailoring of Ultrasmall NiMnO3 Nanoparticles: Optimizing Synthesis Conditions and Solvent Effects

Nickel manganese oxide (NiMnO3) combines magnetic and dielectric properties, making it a promising material for sensor and supercapacitor applications, as well as for catalytic water splitting. The efficiency of its utilization is notably influenced by particle size. In this study, we investigate the influence of thermal treatment parameters on the phase composition of products from alkali co-precipitation of nickel and manganese (II) ions and identify optimal conditions for synthesizing phase-pure nickel manganese oxide. Ultrafine nanoparticles of NiMnO3 (with sizes as small as 2 nm) are obtained via liquid-phase ultrasonic dispersion, exhibiting a narrow size distribution. A systematic exploration of the solvent nature (water, N-methyl-2-pyrrolidone, dimethyl sulfoxide, dimethylformamide) on the efficiency of ultrasonic dispersion of NiMnO3 nanoparticles is provided. It is demonstrated that particle size is influenced not only by absorbed acoustic power, dependent on the physical properties of the used solvent (boiling temperature, gas solubility, viscosity, density) but also by the chemical stability of the solvent under prolonged ultrasonic treatment. Our findings provide insights for designing ultrasonic treatment protocols for nanoparticle dispersions with tailored particle sizes.

Improving the Performance of the Layered Nickel Manganese Oxide Cathode of Sodium-Ion Batteries by Direct Coating with Sodium Niobium Oxide.

This research highlights the efficacy of NaNbO3 as a coating for P2-Na2/3Ni1/3Mn2/3O2 cathodes in sodium-ion batteries. The coating enhances the kinetic behavior and cyclability of the electrochemical cells, as shown by electrochemical measurements. XRD analysis indicates that Nb does not incorporate into the cathode structure, implying a physical interaction between the coating and the cathode material. XRF analysis and EDX mapping confirm the actual composition and uniform dispersion of elements throughout the sample, while the electron micrographs evidence the occurrence of NaNbO3 particles modifying the surface of the layered oxide. The Ni4+/Ni3+ and Ni3+/Ni2+ redox pairs, along with the partially reversible oxidation of oxide to peroxide anions, contribute significantly to cell capacity, as revealed by XPS spectra. This last effect and the appearance of a co-intercalated phase at high voltage are positive factors to provide fast kinetics. Cyclic voltammograms show that samples coated with 2-3% NaNbO3 have superior rate capability, with high capacitive response and apparent diffusion coefficients. These samples also have low impedance at the electrode-electrolyte interface, which helps deliver a high capacity at 5C. Further cycling at 1C shows improved cyclability in the bare and 3% coated samples, due to their higher diffusion coefficients on charging. Notably, the 3% NaNbO3-coated sample exhibits excellent cyclability below 0 °C, making it a promising cathode material for sodium-ion batteries.

New Suggestion of Highly Durable Electrode Design for Ordered Mesoporous Ni-Mn Binary Transition Metal Oxide Anode Material in Lithium-Ion Batteries.

Anode materials storing large-scale lithium ions gradually decrease electrochemical performance due to severe volume changes during cycling. Therefore, there is an urgent need to develop anode materials with high electrochemical capacity and durability, without deterioration arising due to the volume changes during the electrochemical processes. To date, mesoporous materials have received attention as anode materials due to their ability to mitigate volume expansion, offer a short pathway for Li+ transport, and exhibit anomalous high capacity. However, the nano-frameworks of transition metal oxide collapse during conversion reactions, demanding an improvement in nano-framework structure stability. In this study, ordered mesoporous nickel manganese oxide (m-NMO) is designed as an anode material with a highly durable nanostructure. Interestingly, m-NMO showed better cycle performance and higher electrochemical capacity than those of nickel oxide and manganese oxide. Operando small-angle X-ray scattering and ex situ transmission electron microscopic results confirmed that the binary m-NMO sustained a highly durable nanostructure upon cycling, unlike the single metal oxide electrodes where the mesostructures collapsed. Ex situ X-ray absorption spectroscopy proved that nickel and manganese showed different electrochemical reaction voltages, and thus undergoes sequential conversion reactions. As a result, both elements can act as complementary nano-propping buffers to maintain stable mesostructure.

Device optimization of all inorganic CsPbBr3/LNMO based multi-layered perovskite light harvesters for broader capturing of solar spectrum

All inorganic Cesium lead bromide (CsPbBr3) planar perovskites have garnered enormous significance in photovoltaic applications owing to its outstanding stability against oxygen, heat and moisture. However, the power conversion efficiencies of the CsPbBr3 planar perovskites are quite low primarily due to the inferior range of light absorbance and interfacial charge recombination losses. This issue can be successfully resolved with a novel multi-absorber architecture approach which incorporates dual absorbers consisting of a lower band gap Lanthanum Nickel Manganese Oxide (La2NiMnO6 or LNMO) material along with the wider band gap CsPbBr3 material so that the light absorbance regime could be well extended for maximal utilization of the solar spectrum. Therefore, this article incorporates numerical modeling and guided optimization of all inorganic ITO/ETL/CsPbBr3/La2NiMnO6(LNMO)/HTL dual absorbers-based heterojunction structure to improvise the power conversion efficiency of CsPbBr3 based single absorber PSCs. The critical device’s parameters, such as; absorber layer and carrier transport layer thickness, defect density, temperature, doping concentration, frequency response, capacitance effects, Mott-Schottky effects as well as series and shunt resistances are thoroughly optimized and evaluated using Solar Cell Capacitance Simulator (SCAPS-1D) simulator. The proposed dual absorber layer composition produces a substantial enhancement in performance with a peak power conversion efficiency (PCE) of 26.98 %, short circuit current (Jsc) of 39.75 mA/cm2, open circuit voltage (Voc) of 0.85 V, and fill factor (FF) of 77.98 % at a device defect density of 1015 cm−3 outperforming the 11 % of PCE attained with the experimentally reported CsPbBr3 single junction counterpart along with PSCs with various dual absorbers-based composition.

Next-Generation Batteries through Advanced 3D Electrode and Material Concepts

With the rise of renewable energy sources, energy storage solutions become increasingly important as they represent a key feature for secure and constant power supply. In this regard, battery systems play a crucial role in accelerating the transition towards sustainable and green energy sources. To meet the rising global demand, further advancement of the battery technology is imperative. One optimization pathway is to use battery materials that are more sustainable while also yielding improved electrochemical performance, contributing to both environmental and functional advancements. However, innovation must go beyond the material level, and new electrode design approaches for an efficient combination of high power and high energy systems are necessary.In this context, the three-dimensional (3D) battery concept with its increased exposed electrode surface, shows a great promise for enhanced electrochemical performance compared to the conventional flat designs of state-of-the-art electrodes. Targeting at the bottleneck of high power/high energy density systems, the incorporation of micro-structured channels within the electrodes improves lithium-ion diffusion pathways and minimize strain from volume expansion during electrochemical cycling.Our focus is the investigation of 3D electrode architectures generated by laser-processing techniques such as ultrafast laser ablation and laser-assisted printing. Working with ultrafast lasers offers the possibility to process materials while reducing thermal impact and allows the creation of well-designed and controllable electrode surface topographies. The adoption of this concept has already shown great impact in enhancing the high-rate capability and lifetime of conventional electrodes in lithium-ion batteries.[1-3] Expanding the scope, this work explores the applicability of laser-generated 3D electrode architectures to next-generation battery active materials such as high-voltage lithium nickel manganese oxide (LNMO) composites. On anode side, silicon/graphite and amorphous carbon is extensively investigated for lithium-ion batteries and sodium-ion batteries, respectively. To understand the impact of the manufacturing process, electrochemical evaluations are complemented by findings from laser-induced breakdown spectroscopy, SEM-EDX, Raman measurements, and Auger electron spectroscopy.In conclusion, this contribution highlights the promising advancements achieved by applying laser-generated 3D electrode architectures to next-generation battery materials and aims to provide valuable insights into this exciting frontier of battery research.[1] W. Pfleging, Nanophotonics 7 (2018) 549–573.[2] W. Pfleging, Int. J. Extrem. Manuf. 3 (2021) 012002.[3] M. Zaeh, Appl. Energy 303 (2021), 117693.

Tailoring cathode materials: A comprehensive study on LNMO/LFP blending for next generation lithium-ion batteries

Lithium-ion batteries (LIBs) play a crucial role in diverse applications, including electric vehicles, portable electronics, and grid energy storage, owing to their commendable features, such as high energy density, extended cycle life, and low self-discharge rates. Despite their widespread use, the growing market demands continuous efforts to enhance LIBs performance, particularly in terms of energy density and cycling stability. This paper details the development of a lithium nickel manganese oxide (LNMO - LiNi0·5Mn1·5O4)/lithium iron phosphate (LFP - LiFePO4) blended cathode for high-performance LIBs. The study investigates the impact of blending LFP and LNMO, examining morphological and electrochemical aspects. The usage of resonant acoustic mixing (RAM) technology is demonstrated to be a promising approach to improve the distribution of LFP and LNMO particles, leading to increased electrochemical performance. The blended LNMO/LFP cathode exhibits a specific capacity exceeding 125 mAh g−1 at C/10 and a capacity retention exceeding 80 % after 1000 cycles at 1C versus lithium. Moreover, in a full-cell configuration, the blended electrode displays a capacity retention close to 74 % after 100 cycles, showcasing a nearly 30 % improvement compared to the pure LNMO cathode. This research highlights the potential of blended cathode materials in advancing the capabilities of LIBs.

Inclusion of Anion Additives in the Inner Solvation Shell to Regulate the Composition of Solid Electrolyte Interphase

AbstractAn innovative approach to electrolyte engineering in carbonate electrolytes is introduced by incorporating high donor number dual anion additives into the conventional electrolyte system (1 M NaPF6 EC:PC). The active engagement of anions in the primary solvation shell effectively hinders the reduction of solvent molecules by reducing the Lowest Unoccupied Molecular Orbital (LUMO) of Na+‐solvent‐anion complex as compared to the LUMO of pure solvents or Na+‐solvent complex. The participation of anions leads to the formation of a thinner and an inorganic‐rich Solid Electrolyte Interphase on the hard carbon anode enhancing Initial Coulombic Efficiency and significantly improving its kinetics. Moreover, the system with dual anion additives exhibits oxidative stability up to 4.5 V, effectively mitigating the undesired side reactions at high voltage operation of the layered sodium nickel manganese oxide cathode. The addition of dual anion additives proves instrumental in suppressing structural degradation and transition metal dissolution during the long cycling performance of the layered oxide cathode in a sodium‐ion full cell. The synergistic effects of this dual anion additive added electrolyte on both the anode and the cathode ultimately ensured prolonged cycling of the sodium‐ion full cell. The electrolyte engineering approach outlined in this study opens the door to advancing next‐generation high‐voltage sodium batteries.

Lightweight Carbon-Metal-Based Fabric Anode for Lithium-Ion Batteries.

Lithium-ion battery electrodes are typically manufactured via slurry casting, which involves mixing active material particles, conductive carbon, and a polymeric binder in a solvent, followed by casting and drying the coating on current collectors (Al or Cu). These electrodes are functional but still limited in terms of pore network percolation, electronic connectivity, and mechanical stability, leading to poor electron/ion conductivities and mechanical integrity upon cycling, which result in battery degradation. To address this, we fabricate trichome-like carbon-iron fabrics via a combination of electrospinning and pyrolysis. Compared with slurry cast Fe2O3 and graphite-based electrodes, the carbon-iron fabric (CMF) electrode provides enhanced high-rate capacity (10C and above) and stability, for both half cell and full cell testing (the latter with a standard lithium nickel manganese oxide (LNMO) cathode). Further, the CMFs are free-standing and lightweight; therefore, future investigation may include scaling this as an anode material for pouch cells and 18,650 cylindrical batteries.

Atomic-Scale Characterization of Microscale Battery Particles Enabled by a High-Throughput Focused Ion Beam Milling Technique.

The cathode materials in lithium-ion batteries (LIBs) require improvements to address issues such as surface degradation, short-circuiting, and the formation of dendrites. One such method for addressing these issues is using surface coatings. Coatings can be sought to improve the durability of cathode materials, but the characterization of the uniformity and stability of the coating is important to assess the performance and lifetime of these materials. For microscale particles, there are, however, challenges associated with characterizing their surface modifications by transmission electron microscopy (TEM) techniques due to the size of these particles. Often, techniques such as focused ion beam (FIB)-assisted lift-out can be used to prepare thin cross sections to enable TEM analysis, but these techniques are very time-consuming and have a relatively low throughput. The work outlined herein demonstrates a FIB technique with direct support of microscale cathode materials on a TEM grid that increases sample throughput and reduces the processing time by 60-80% (i.e., from >5 to ∼1.5 h). The demonstrated workflow incorporates an air-liquid particle assembly followed by direct particle transfer to a TEM grid, FIB milling, and subsequent TEM analysis, which was illustrated with lithium nickel cobalt aluminum oxide particles and lithium manganese nickel oxide particles. These TEM analyses included mapping the elemental composition of cross sections of the microscale particles using energy-dispersive X-ray spectroscopy. The methods developed in this study can be extended to high-throughput characterization of additional LIB cathode materials (e.g., new compositions, coating, end-of-life studies), as well as to other microparticles and their coatings as prepared for a variety of applications.

Chronoamperometric analyses of lithium insertion/extraction kinetics of lithium nickel manganese oxide using the diluted electrode method

Understanding the electrode kinetics of Li insertion materials used in Li-ion batteries is important for deducing the power capabilities of the batteries. However, examining the inherent reaction kinetics of these materials is difficult because Li-ion diffusion in the electrolyte within electrode pores is the rate-determining step in conventional electrodes, which mainly comprise active materials. Herein, the Li insertion kinetics of Li[Ni1/2Mn3/2]O4 is analyzed using the diluted electrode method. Results of charge/discharge tests performed at a constant voltage (chronoamperometry) reveal that both, charging (Li extraction) and discharging (Li insertion) in the diluted electrode (Li[Ni1/2Mn3/2]O4 content: 10 wt%), are much faster than those in conventional electrodes (88 wt%). The diluted electrode delivers half the capacity of Li[Ni1/2Mn3/2]O4 in only 20 and 200 s for charging and discharging, respectively, at high overvoltages. This indicates that the reaction kinetics is asymmetric between the charging and discharging processes; charging occurs approximately 10 times faster than discharging. Based on the overvoltage and temperature dependences of the reaction kinetics, phenomenological kinetic equations for the Li insertion/extraction of Li[Ni1/2Mn3/2]O4 are determined. The results of this study not only provide important knowledge for establishing the Li insertion kinetics but are also useful for understanding the power capabilities of all-solid-state batteries.

Manganese and copper-coated nickel oxide nanoparticles synthesized from Carica papaya leaf extract induce antimicrobial activity and breast cancer cell death by triggering mitochondrial caspases and p53

Abstract In the present work, manganese–copper co-infused nickel oxide nanoparticles (MnCu co-doped NiO NPs) were formulated via a green process using Carica papaya extract. The MnCu co-doped NiO NPs were characterized by X-ray diffraction (XRD), UV–Vis, Fourier transform infrared, field emission scanning electron microscope, energy dispersive X-ray analysis, and photoluminescence (PL) spectrum. The XRD pattern demonstrated that synthesized MnCu co-doped NiO NPs exhibit cubic structure. On the PL spectrum, various surface defects were identified. MnCu co-doped NiO NPs exhibited ferromagnetic properties at 37°C. The antimicrobial activity of green synthesis MnCu co-doped NiO NPs against human pathogens (Escherichia coli, Streptococcus pneumoniae, Bacillus megaterium, Bacillus subtilis, Shigella dysenteriae, Pseudomonas aeruginosa) and Candida albicans as fungal strains were demonstrated. The MnCu co-doped NiO NPs treatment considerably reduced MDA-MB-231 cell viability while not disturbing HBL-100 cell viability. Different fluorescent staining analyses revealed that MnCu co-doped NiO NPs induced nuclear and mitochondrial damage to improve free radical production, altering mitochondrial membrane protein potential, which led to apoptotic cell death in MDA-MB-231 cells. The MnCu co-doped NiO NP treatment enhanced pro-apoptotic protein expression and inhibited the cell cycle at the S phase in MDA-MB-231 cells. This makes it easy, cheap, and environmentally friendly to make MnCu co-doped NiO NPs using C. papaya extract, which has excellent antimicrobial properties.

Metal ratio and bimetal nanoarchitectonics of ammonia-based fluoride complex induced nickel hydroxide and manganese oxide composites as active materials of an energy storage device

Nickel and manganese compounds are widely applied as efficient battery-type active materials for energy storage devices, due to high theoretical capacities and abundant redox states for generating redox reactions to store charges. Morphology plays significant roles on energy storage ability. Structure directing agent (SDA) is widely reported to have ability for modulating configurations of active materials and to achieve excellent surface properties. In this work, it is the first time to use NH4BF4 and NH4HF2 as structure directing agents for synthesizing nickel manganese compounds derived from ZIF67 as active materials of energy storage devices. Bimetallic compounds are composed of nickel hydroxide and manganese oxide, which presents the favorable two-dimensional flower-like structure with high surface area and abundant redox states. The largest specific capacitance (CF) of 1358.2 F/g corresponding to the capacity of 226.4 mAh/g are achieved for the bimetallic compound synthesized using the Ni to Mn precursor ratio of 1 to 1 (NiMn11). The energy storage device assembled using NiMn11 and reduced graphene oxide on Ni foams presents a maximum energy density of 11.45 Wh/kg at the power density of 0.35 kW/kg, and excellent long-term stability with the CF retention of 85.6% and Coulombic efficiency of 87.5% after 10,000 cycles.

Fabrication of polypyrrole conductive matrix covered MnNi2O4 nanocomposite as a positive electrode material for asymmetric supercapacitor applications

In this study, we successfully prepared a polypyrrole conductive matrix (PPY) covered manganese nickel oxide (MnNi2O4) nanocomposite via co-precipitation and a chemical oxidative polymerization route.

Effect of Particle Size and Polytypes on Redox Reversibility of Layered Na0.76Ni0.38Mn0.62O2 Electrode

Interest in sodium ion batteries (SIBs) has considerably increased in recent years for low-cost and sustainable energy storage systems. Among positive electrode materials in SIBs, layered sodium nickel manganese oxides such as O3-type NaNi0.5Mn0.5O2 and P2-type Na0.67Ni0.33Mn0.67O2 and their derivatives have been extensively investigated. Despite their high capacity delivered by Ni2+/4+ redox processes, significant surface-electrolyte reactivity with Ni and inferior structural integrity due to phase transformations eventually lead to capacity fade over cycling. To suppress the problems, substitution for Ni and/or Mn, surface coating, and morphology modification have been applied. In lithium ion batteries, tunning morphology without altering chemical compositions has shown improved electrochemical properties for layered lithium cathode materials, LiNixMnyCoyO2 (NMC, x + y + z = 1). For example, single-crystal NMC of micron-scale particles limit the surface reactivity and particle cracking, which is beneficial for cycle life. Another way is spherical secondary particles in micron-size where primary nanoparticles are composed of. Due to the hierarchical morphology, detrimental surface reactions are suppressed while ionic and electronic conductivity are preserved. Those strategies are expected to be advantageous for the counterparts of SIBs, however less studies have been carried out.In this study, we focus on the strategy of secondary spherical particles for layered sodium nickel manganese oxides. To understand the effect of secondary particle size, two different diameters of 4 µm and 10 µm were synthetized using (Ni0.38Mn0.62)OH2 and Na2CO3. In addition, different heating temperatures were used as polytypes are an interesting character for layered sodium oxides. Heating at 700 °C and 900 °C produces different polytypes of P3- and P2-type Na0.76Ni0.38Mn0.62O2, respectively. Increased temperature tends to enlarge primary particle size and yields NiO impurity, while no influence on the spherical morphology is found.To examine the redox stability depending on voltage ranges as well as polytypes, 10 µm of P3- and P2-type Na0.76Ni0.38Mn0.62O2 were galvanostatically cycled at four diverse voltage ranges (1.6-4.4 V, 1.6-3.8 V, 2.5-4.4 V, and 2.5-3.8 V) in non-aqueous sodium cells. When the lower cut-off voltage is 2.5 V, charge/discharge profiles on the first cycle are almost identical regardless of polytypes. The difference occurs below 2.0 V where a sloping plateau is observed in P2-type Na0.76Ni0.38Mn0.62O2 while a flat plateau is found in P3-type Na0.76Ni0.38Mn0.62O2. Those dissimilarity originates from the phase transition of P2-P’2 and P3-O3 as confirmed by ex-situ XRD. The widest voltage range of 1.6-4.4 V results in capacity fade, which is more significant for P2-type Na0.76Ni0.38Mn0.62O2. The narrowest voltage range of 2.5-3.8 V permits the best cyclability where no apparent phase changes occur. Decreased lower cut-off voltage to 1.6 V, keeping the upper cut-off voltage at 3.8 V, deteriorates slightly the cycle life, which is again more pronounced for P2-type Na0.76Ni0.38Mn0.62O2. In the voltage range of 2.5-4.4 V, however, capacity notably decays, retaining only 57% and 51% of their initial capacity after 60 cycles for P3- and P2-type Na0.76Ni0.38Mn0.62O2, respectively. These results indicate that reactions beyond 3.8 V are detrimental to capacity retention for both polytypes, and P3-type Na0.76Ni0.38Mn0.62O2 shows enhanced cyclability.4 µm of P3- and P2-type Na0.76Ni0.38Mn0.62O2, galvanostatically cycled at two voltage ranges (1.6-4.4 V and 1.6-3.8 V), show same trends as those of 10 µm: significant capacity fade in the voltage range of 1.6-4.4 V, and worse capacity retention for P2-type Na0.76Ni0.38Mn0.62O2. It is worth noting the capacity fade is more pronounced than that for 10 µm.Given that no influence of secondary particle size on the phase changes, confirmed by ex-situ XRD, degradation of Na0.76Ni0.38Mn0.62O2 driven by surface reactions is suspected to play an important role for the capacity fade. To understand further, cross-sectional morphology for 4 µm and 10 µm of P3-type Na0.76Ni0.38Mn0.62O2 was examined. Pristine electrode of 4 µm sample exhibits some pores within the secondary particles, which is barely modified during the first cycle between 1.6 and 4.4 V. After 100 cycles, pulverized secondary particles are observed, accelerating electrolyte penetration into the particle interior. In the case of 10 µm, tightly packed primary particles are shown at pristine electrode and no significant microcracks appear on the secondary particles after charge to 3.8 V. Further charge to 4.4 V develops the microcracks and the prevalent microcracks are also observed after discharge to 1.6 V. After 100 cycles, the microcracks are more developed, however exposed internal surface is lower compared to that of 4 µm. This reduces the exposure of internal surface to the infiltrated electrolyte, retarding the degradation of active materials. Figure 1

A Scalable Approach to Synthesize Cobalt-Free LNMO Cathode Materials for High Energy Density Lithium Ion Batteries

The rapid growing demand for electric vehicles (EVs) has highlighted the need for high-energy-density batteries. The cathode material plays a vital role in achieving this goal[1]. As the limitations of cathode capacity improvement are approached, the pursuit for high-voltage materials becomes a viable option[2]. Lithium nickel manganese oxide LNMO (LiNi0.5Mn1.5O4) stands out due to its remarkable attributes including a substantial reversible capacity, excellent thermal stability, cost-effectiveness, environmental friendliness, and a high energy density[3]. Moreover, its cobalt-free composition aligns with sustainability objectives. Despite extensive research, the large-scale production and deployment of LNMO remain formidable challenges.In this study an industrially applicable co-precipitation method-based scalable synthesis strategy is introduced. The LNMO spheres with controlled various sizes and morphologies were successfully fabricated by adjusting the pH environment during synthesis carefully (Fig. 1A). Scanning electron microscopy (SEM) revealed the presence of uniformly spherical particles with dimensions of appr. 6, 9, and 14 µm and unique morphological characteristics (Fig. 1Ad-f). Synchrotron X-ray diffraction (SXRD) of LNMO samples revealed a deviation from the optimal Ni-to-Mn ratio of 1:3 (Fig. 1B)[4,5]. This variation results from the pH-dependent metal ion precipitation dynamics during synthesis, introducing a fascinating dimension to LNMO material fabrication. As potential cathode materials for lithium-ion batteries, these samples underwent a thorough electrochemical evaluation as part of our research. Among the synthesized LNMO samples, LNMO-9 demonstrated the most promising specific capacity, surpassing approximately 138 mAh/g and working under high voltage of 4.75 V (Fig. 1C). Furthermore, the characterizations of the materials were also thoroughly investigated by a variety of advanced characterization techniques, including Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM).This research reveals a strategy for synthesizing LNMO materials with certain regulated features and presents a successful strategy for industrial manufacturing as well. Particularly in the context of the EV industry, this research acquires critical significance in answering the growing demand for high-performance, sustainable energy storage systems. Fig. 1 (A) Illustration of the synthesis process of LNMO-x samples with SEM images of (a‒c) NiMn-x precursors and (d‒f) LNMO-x products. (B) SXRD patterns with Rietveld refinements and (C) charge/discharge profile of LNMO-x samples. Reference [1] H.-H. Ryu, G.-C. Kang, R. Ismoyojati, G.-T. Park, F. Maglia, Y.-K. Sun, Intrinsic weaknesses of Co-free Ni–Mn layered cathodes for electric vehicles, Materials Today. (2022) S1369702122000645. https://doi.org/10.1016/j.mattod.2022.03.005.[2] T. Liu, A. Dai, J. Lu, Y. Yuan, Y. Xiao, L. Yu, M. Li, J. Gim, L. Ma, J. Liu, C. Zhan, L. Li, J. Zheng, Y. Ren, T. Wu, R. Shahbazian-Yassar, J. Wen, F. Pan, K. Amine, Correlation between manganese dissolution and dynamic phase stability in spinel-based lithium-ion battery, Nat Commun. 10 (2019) 4721. https://doi.org/10.1038/s41467-019-12626-3.[3] Y. Xue, L.-L. Zheng, J. Wang, J.-G. Zhou, F.-D. Yu, G.-J. Zhou, Z.-B. Wang, Improving Electrochemical Performance of High-Voltage Spinel LiNi 0.5 Mn 1.5 O 4 Cathode by Cobalt Surface Modification, ACS Appl. Energy Mater. 2 (2019) 2982–2989. https://doi.org/10.1021/acsaem.9b00564.[4] A. Gomez, G. Dina, S. Kycia, The high-energy x-ray diffraction and scattering beamline at the Canadian Light Source, Review of Scientific Instruments. 89 (2018) 063301. https://doi.org/10.1063/1.5017613.[5] H.M. Rietveld, A profile refinement method for nuclear and magnetic structures, J Appl Crystallogr. 2 (1969) 65–71. https://doi.org/10.1107/S0021889869006558. Figure 1

Understanding the Role of Lithium Borate as the Surface Coating on High Voltage Single Crystal LiNi0.5Mn1.5O4

AbstractThe high‐voltage spinel lithium nickel manganese oxide (LNMO) with an operating voltage of 4.8 V is a promising cathode material for next‐generation lithium‐ion batteries (LIBs). However, LNMO/graphite (LNMO/Gr) full cells suffer capacity fading, which limits their practical applications. In this study, lithium metaborate (LBO) is applied on the LNMO surface to improve the full cell performance via a dry mixing method. The LBO‐coated LNMO delivers much better cycling stability than the uncoated LNMO in full cells with a practical 3 mAh cm−2 areal capacity. Different characterizations are performed to understand the coating effect to track the boron and its impact on the cathode, electrolyte, and anode. The LBO‐coated LNMO owns a 5 nm cathode electrolyte interphase (CEI) with mitigated phase change after long‐term cycling. The uncoated LNMO has negligible CEI with obvious phase change. However, no boron can be detected on the surface of the coated sample. Electrolyte and anode analyses indicate that the coating acts as an additive reservoir, gradually dissolves into the electrolyte, and generates BF4− species. As a result, Nickel/Manganese (Ni/Mn) dissolution from LNMO and the extensive generation of solid electrolyte interphase (SEI) on the anode side is mitigated, thus improving the full‐cell cycling stability to a great extent.

An insight of photoelectrochemical driven urea oxidation from nickel manganese oxide nanostructures

Nickel manganese spinel oxide finds tremendous application in electronic and electrochemical devices because of its high redox activity and better durability. Here, we have stabilized nickel rich, nickel manganese oxide Ni6MnO8 through chemical route and studied their application in electrochemical urea oxidation. The as-prepared Ni6MnO8 affords a two-fold high performance toward urea oxidation reaction as photoanode with a maximum peak current density of 44.58 mAcm−2 and exhibited low overpotential of 1.39 V at 10 mAcm−2. Smaller Tafel slope value (16 mV/decade) and 12 h chronoamperometry stability show faster rate kinetics and better durability as photoanode electrocatalyst for urea electrocatalysis. The robust photoelectrochemical urea oxidation is due to Ni2+/Ni3+ redox active species. The present work is sunlight-driven and sustainable approach for hydrogen production and remediation for urea-rich wastewater. It is the first time Ni6MnO8 used as promising photoanode for urea electrocatalysis.

High-efficient removal of Oxygen(O2) impurity from H2 flow on nickel-manganese Oxide: Regulating the exposed crystal plane, structure-activity relationship and determination of active sites

The presence of oxygen (O2) impurity in hydrogen produced by water electrolysis can pose safety hazards when hydrogen is used as a power source. Therefore, oxygen (O2) impurities must be removed from H2 flow to meet the strict purity requirements. In this work, nickel manganese oxide is applied to remove oxygen from H2 flow. It is synthesized via the co-precipitation method using different precipitants, manganese and nickel precursors. The results of the oxygen removal test show that NiMn-4 catalyst, prepared using oxalic acid, manganese acetate and nickel nitrate as the precursors, has the best performance in removing oxygen impurities from the hydrogen flow. The catalyst could retain an oxygen removal efficiency of nearly 70 % at the reaction temperature of 80 °C. Also, XRD, Raman spectra and HRTEM analysis results show that the crystal phase of NiMn-4 (Ni6MnO8) exhibits much stronger crystallinity than the other catalysts and has (400) and (222) planes of Ni6MnO8. H2/O2-TPD and H2-TPR analysis results indicate that NiMn-4 catalyst has much more adsorbed oxygen species, overflow hydrogen and hydrogen consumption at per specific surface area compared to the other catalysts. The XPS results of Ni2p and O1s imply that there is much higher valence of Ni (Ni3+).