Nickel-rich Cathode Materials Research Articles

Effect of crystal morphology of nickel-rich cathode materials on electrochemical stability and ion transport kinetics of sulfide-based all-solid-state batteries

Effect of crystal morphology of nickel-rich cathode materials on electrochemical stability and ion transport kinetics of sulfide-based all-solid-state batteries

Identification of critical moisture exposure for nickel-rich cathode active materials in lithium-ion battery production

Nickel-rich cathode materials are crucial for improving lithium-ion battery performance due to their potential for high energy densities. However, their sensitivity to humidity demands cost- and energy-intensive dry room production environments. This study examined the storage stability of a surface-treated nickel-rich cathode (≈ 91 mol% nickel) under industry-relevant scenarios to assess the required atmospheres and the impact of short moisture exposure on material and cell performance. Calendered and non-calendered cathodes were produced in a dry room with a dew point of −60 °C and then exposed to dew points of up to −20 °C and ambient atmosphere (dew point ≈ 5 °C). Analysis showed that calendered electrodes were more susceptible to carbonate formation at higher dew points. Cycling tests of single-layer full-pouch cells indicated that carbonate impurities, predominantly present on electrodes stored in ambient conditions, reduced energy efficiency during formation but did not significantly affect long-term performance. These findings suggest that less stringent dry room requirements could reduce production costs and energy consumption for high-performance lithium-ion battery cells.

Optimizing high-energy lithium-ion batteries: a review of single crystalline and polycrystalline nickel-rich layered cathode materials: performance, synthesis and modification

Layered Ni-rich Li [NixCoyMnz]O2 (NMC) and Li [NixCoyAlz]O2 (NCA) cathode materials have been used in the realm of extended-range electric vehicles, primarily because of their superior energy density, cost-effectiveness, and commendable rate capability. However, they face challenges such as structural instability, cation mixing, and surface degradation, which limit their practical application. This review comprehensively discusses the synthesis, modification, and performance optimization of nickel-rich cathodes, with a focus on single-crystal (SC) NMC cathodes. The unique properties and challenges of single-crystal nickel-rich cathodes are explored in comparison to polycrystalline (PC) cathodes, with a focus on performance-enhancing strategies such as doping and surface modification.

Understanding the Carbon Additive/Sulfide Solid Electrolyte Interface in Nickel-Rich Cathode Composites and Prioritizing the Corresponding Interplay between the Electrical and Ionic Conductive Networks to Enhance All-Solid-State-Battery Rate Capability.

All-solid-state lithium batteries, including sulfide electrolytes and nickel-rich layered oxide cathode materials, promise safer electrochemical energy storage with high gravimetric and volumetric densities. However, the poor electrical conductivity of the active material results in the requirement for additional conducive additives, which tend to react negatively with the sulfide electrolyte. The fundamental scientific principle uncovered through this work is simple and suggests that the electrical network benefits associated with the introduction of short-length carbons will eventually be overpowered by the increase in bulk resistance associated with their instability in the sulfide electrolyte. However, applying just the right amount of short carbon fibres minimizes degradation of the sulfide solid electrolyte and maximizes the electron movement. Therefore, we propose the application of a low-weight-percent carbon nanotubes (CNTs) coating on the nickel-rich cathode LiNi0.8Co0.1Mn0.1O2 (NCM811) along with large-aspect-ratio carbon nanofibers (CNFs) as the primary conductive additive. When only 0.3 wt % CNTs was utilized with 4.7 wt % CNFs, an initial Coulombic efficiency of 83.55% at 0.05C and a notably excellent capacity retention of 90.1% over 50 cycles at 0.5C were achieved along with a low ionic resistance. This work helps to confirm the validity of applying short carbon pathways in sulfide-electrolyte-based cathode composites and proposes their combination with a larger primary carbon additive as a solution to the ongoing all-solid-state battery rate and instability issues.

Spray pyrolysis feasibility of tungsten substitution for cobalt in nickel-rich cathode materials

Spray pyrolysis feasibility of tungsten substitution for cobalt in nickel-rich cathode materials

Improving high-voltage cycling and stabilizing the electrode-electrolyte interface of nickel-rich layered cathodes by magnesium doping

Next-generation lithium-ion batteries will rely on nickel-rich layered oxides as cathode materials, but these materials are associated with structural and voltage losses. Magnesium (Mg) doping helps improve the performance of the nickel-rich layered cathode material. The Mg-modified LiNi0·90Mn0·05Co0·05O2 (NMC-90) has been successfully synthesized through a co-precipitation technique followed by calcination at 850 °C. Modified NMC-90 exhibits better-organized layers and improved interfacial properties than pristine ones based on structural, chemical, and morphological studies. In a voltage range of 2.8–4.5 V, Mg (0.01 mol%)-doped NMC-90 (NMC-M1) composite cathode shows an excellent discharge capacity of 211.11 mAh/g, whereas pristine NMC-90 (NMC-M0) attains only 210.59 mAh/g at 0.1C with an initial coulombic efficiency of 89.5 % for NMC-M1 and 87.5 % for NMC-M0 cathode. The NMC-M1 cathode demonstrated an impressive enhancement in cyclability after 60 cycles compared to the NMC-M0 at 1C rate, in which the NMC-M1 cathode attains a high capacity retention of 80 % while the NMC-M0 cathode shows only 37 %. This study illustrates the importance of studying the effects of elemental doping on cell performance. It will drive the future development of cathode materials with high Ni and low Co content.

Modulating Grain Boundary Networks to Achieve Superior Chemomechanical Coupling Properties in Nickel-Rich Cathode Materials.

To forge ahead with the next generation of power batteries boasting superior energy density, nickel-rich layered oxides are regarded as some of the most promising cathode materials. However, challenges such as microcracks, which are attributed to the elevated nickel content of the materials, have posed impediments to their further development and application. Consequently, this article focuses on the understanding of the materials in the deep delithiation state, dissecting their degradation mechanisms through a dual lens of electrochemical and mechanical properties. The comprehensive analysis reveals that microcracks within the particles exhibit a degree of reversibility. However, with repeated Li+ de-/intercalation, these microcracks progressively propagate and permeate the entire particle, ultimately leading to particle fragmentation. Therefore, this study employs Dy2O3 as an inducer to facilitate the growth of primary crystal grains, reducing the internal porosity of the particles. This effectively enhances the conductivity and lithium-ion diffusion kinetics in deep lithium-ion deintercalation states of nickel-rich cathode materials. The modified material exhibits significant suppression of microcrack formation and growth during cycling, leading to notable improvements in its chemical-mechanical properties. These degradation mechanisms and modification strategies of Ni-rich cathodes offer valuable insights into the development of Ni-rich cathode materials tailored for electric vehicles.

Beyond dopant selection: The critical grain size window as a key performance dictator for Co-free, Ni-rich cathode materials

Despite the immense potential of cobalt-free, nickel-rich cathode materials to replace their cobalt-containing counterparts in lithium-ion batteries (LIBs), their widespread adoption remains hindered by performance limitations. While extensive research has explored various doping strategies to address this challenge, the reported benefits vary significantly, suggesting an incomplete understanding of dopant influence and thus hindering the full potential of these additives. Our investigation into the effect of various dopants on Li(Ni0.95Mn0.05)O2 performance yielded a surprising discovery: the LIB performance of transition metal-doped Li(Ni0.95Mn0.05)O2 becomes remarkably consistent across different dopant types, provided the calcination conditions are optimized. Regardless of dopant type, a critical grain size window is identified as a key factor influencing the performance of the doped Li(Ni0.95Mn0.05)O2. Calcination within a specific temperature range is paramount to control this previously overlooked performance determinant, which significantly impacts grain growth, primary particle morphology, and lattice structure. This novel insight allows us to demonstrate that cost-effective dopants such as Ti can achieve performance in stabilizing Li(Ni0.95Mn0.05)O2 comparable to that of more expensive, higher-valence alternatives (e.g., Nb, Ta, W, and Mo). This discovery paves the way for developing practical material design processes that meet the stringent requirements of the LIB industry.

In-situ cladding PEDOT:PSS on V-doped NCA cathodes for optimized interface and high electrochemical performance of Li-ion battery

The LiNi0.8Co0.15Al0.05O2 (NCA) nickel-rich layered cathode material is widely used for Li-ion batteries because of its excellent structural stability and high specific capacity. However, the Li/Ni mixing effect and the generation of interfacial secondary reactions in NCA cathode materials reduce the electrochemical properties of Li-ion batteries. Herein, we report a series of vanadium (V)-doped NCA cathode (VNCA) materials with different amounts of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) polymers in-situ coated on the surface using a liquid-phase method. The introduction of PEDOT:PSS coating not only improves the conductivity of NCA cathode materials but also protects the surface of cathode materials from cracking during the cycle. Electrochemical results show that the PEDOT:PSS (2 wt%) coating possesses high capacity retention rate (83.58%) after 200 cycles at 1 C, which is better than that of the sample without coating (66.7%). The PEDOT:PSS (2 wt%) coated cathode materials also display superior rate performance to VNCA at high magnification. This work provides new methods and theoretical guidance for the development of efficient ternary cathode materials for Li-ion batteries.

New 1D Nickel-Rich Ncm Cathode Materials for the Lithium-Ion Battery: Synthesis and Cyclic Stability Improvement

Lithium-ion batteries (LIBs) are considered the most promising energy system due to their low cost, high energy density, excellent performance, and long service life, implemented in several consumer devices such as cell phones, laptops, cameras, and electric vehicles [1]. In general, the chemical properties of LIA are constantly evolving, and from the point of view of cathode materials, layered LiMO2 oxides, in which M is a combination of Ni, Mn, and Co – the so-called NCM are attracting more and more attention and is considered a potential next-generation cathode material for LIA, due to their increased specific capacity (more than 150 mAh g-1) and thermal stability [2]. In addition, NCM-based cathodes can outperform the popular lithium-iron-phosphate LiFePO4 (LFP) cathodes in many areas, especially in terms of operating voltage, in which LFP-based LIBs can produce voltages below 3.4 V and suffer from high self-discharge rates. The composition of Ni, Mn, and Co can be significantly changed to optimize the capacity, performance, structural stability, and cost of lithium-ion batteries [3]. The data indicate that the B-doped NCM811 cathodes offer notable benefits, including higher capacity retention, improved rate capability, and lower mechanical strain in their charged state [4].In this study, we focus on synthesizing 1D LiNi0.8Co0.1Mn0.1O2 (NCM811) material by electrospinning method and its enhancement upon doping with Boron and morphological modifications. The electrospinning technique has already been used to obtain NCM material [5]. B-doped and undoped NCM811 nanofibers with the 1D structure were obtained by electrospinning method and characterized. The morphology and nanofiber structure of the resulting NCM811 samples (doped, un-doped) were studied using scanning electron microscope (SEM) and transmission electron microscope (TEM). X-ray phase analysis (XRD) studied the samples, and a series of peaks that entirely corresponded to the diffraction pattern of NCM811 were recorded. It is highly expected that the results may introduce some new ideas in the field of morphology modification and doping, which will be helpful for the rational design and manufacture of highly efficient cathode materials. Acknowledgments This research was funded by the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan (Grant No. AP19679855).

A synergistic modification strategy for enhancing the cycling stability and rate capacity of single-crystal nickel-rich cathode materials

Ni-rich layered LiNi0.8Co0.1Mn0.1O2 (NCM811) is considered to be one of the most promising cathode materials due to its advantages of high specific capacity, lower cost and environmental friendliness. However, the relatively high nickel content in the LiNi0.8Co0.1Mn0.1O2 layered cathode materials leads to the instability of the internal structure and surface of the materials during long-term cycling, which results in the deterioration of electrochemical performance. In this study, single-crystal NCM811 (SNCM811) was prepared using a convenient solid-state method. By doping Al into SNCM811 (SNCMAl) and purposefully low-temperature surface treatment with a small amount of LiPF6, a Ni-rich single-crystal NCM811 modified by both Al bulk doping and LiF surface coating (SNCMAl@LiF) was obtained. The reversible capacity of SNCMAl@LiF with a cutoff voltage of 2.7–4.3 V at 0.1C is 200.3 mAh·g−1. And the capacity retention of the single-crystal cathode materials is 92.4 % with capacity of 171.07 mAh·g−1 after 100 cycles at 1C. Even at high rate of 10C, the discharge specific capacity maintains 148.8 mAh·g−1, demonstrating excellent electrochemical performance. The dual-modified single-crystal material has the lowest potential difference and electrochemical impedance without intragranular cracks and crystal slips after 100 cycles. Stronger AlO bond in single crystals reduced the degree of cation mixing and maintained the stability of the layered structure. LiF-modified surface can promote the transfer of Li+, maintain the stability of the electrode/electrolyte interface and then improve the electrochemical performance of cathode materials. Al-doping and LiF-coating provides a guidance on how to enhance the electrochemical performance of Ni-rich single-crystal cathode materials.

Oxygen Dimerization as a Defect-Driven Process in Bulk LiNiO2.

To explore the possibility of oxygen dimerization-particularly, the formation of molecular oxygen-like species-in the bulk of LiNiO2 lithium ion cathode materials at high states of charge, we conduct a redox-product structure search inspired by recent methodological developments for point-defect structure prediction. We find that (1) delithiated Li1-x NiO2 (x = 1) has good kinetic stability toward decomposition into molecular oxygen and reduced transition-metal oxides but (2) defects can act as nucleation sites for oxygen dimerization. These results help reconcile conflicting reports on the formation of bulk molecular oxygen in LiNiO2 and other nickel-rich cathode materials, highlighting the role of defect chemistry in driving the bulk degradation of these compounds.

Unraveling Mechanism for Microstructure Engineering toward High-Capacity Nickel-Rich Cathode Materials.

Microstructural engineering on nickel-rich layered oxide (NRLO) cathode materials is considered a promising approach to increase both the capacity and lifespan of lithium-ion batteries by introducing high valence-state elements. However, rational regulation on NRLO microstructures based on a deep understanding of its capacity enhancement mechanism remains challenging. Herein for the first time, it is demonstrated that an increase of 14mAhg-1 in reversible capacity at the first cycle can be achieved via tailoring the micro and nano structure of NRLO through introducing tungsten. Aberration-corrected scanning transmission electron microscopy (STEM) characterization reveals that the formation of a modified microstructure featured as coherent spinel twin boundaries. Theoretical modeling and electrochemical investigations further demonstrate that the capacity increase mechanism is related to such coherent spinel twin boundaries, which can lower the Li+ diffusion barrier and thus allow more Li+ to participate in deeper phase transitions. Meanwhile, the surface and grain boundaries of NRLOs are found to be modified by generating a dense and uniform LiWxOy phase, which further extends its cycle life by reducing side reactions with electrolytes. This work enables a comprehensive understanding of the capacity-increased mechanism and endows the remarkable potential of microstructural engineering for capacity- and lifespan-increased NRLOs.

Surface Gradient Ni-Rich Cathode for Li-Ion Batteries.

Nickel-rich layered oxide cathode material LiNixCoyMnzO2 (NCM) has emerged as a promising candidate for next-generation lithium-ion batteries (LIBs). These cathode materials possess high theoretical specific capacity, fast electron/ion transfer rate, and high output voltage. However, their potential is impeded by interface instability, irreversible phase transition, and the resultant significant capacity loss, limiting their practical application in LIBs. In this work, a simple and scalable approach is proposed to prepare gradient cathode material (M-NCM) with excellent structural stability and rate performance. Taking advantage of the strong coordination of Ni2+ with ammonia and the reduction reaction of KMnO4, the elemental compositions of the Ni-rich cathode are reasonably adjusted. The resulted gradient compositional design plays a crucial role in stabilizing the crystal structure, which effectively mitigates Li/Ni mixing and suppresses unwanted surficial parasitic reactions. As a result, the M-NCM cathode maintains 98.6% capacity after 200 cycles, and a rapid charging ability of 107.5 mAh g-1 at 15 C. Furthermore, a 1.2 Ah pouch cell configurated with graphite anode demonstrates a lifespan of over 500 cycles with only 8% capacity loss. This work provides a simple and scalable approach for the in situ construction of gradient cathode materials via cooperative coordination and deposition reactions.

Application of collaborative perception computing in electrochemical impact analysis of nickel rich cathode material

As a high-performance lithium-ion battery cathode material, nickel rich cathode material (NRCM) has the characteristics of high capacity and long cycle life, which has attracted the attention of researchers. The electrochemical performance of NRCM is influenced by various factors. Traditional experimental methods require a lot of time and resources, and cannot fully reveal the complex interactions between these influencing factors. To address this issue, collaborative perception computing has been introduced into electrochemical analysis. In the electrochemical impact analysis of NRCM, multiple sensing nodes can be used to collect and share electrochemical performance data, and data processing and analysis can be carried out through collaborative sensing calculation methods. A comprehensive analysis of the effects of different factors on the performance of NRCM, as well as optimization of material structure and battery design, can greatly improve the efficiency of data collection. In this study, the electrochemical performance of NRCM would be analyzed using a collaborative perception based electrochemical analysis algorithm using collaborative perception computing. In the experiment, electrochemical analysis was conducted on the 523, 622, and 811 ratio schemes of LiNixCoyMn1-x-yO2 ternary cathode material LiNixCoyMn1-x-yO2. After experimental verification, the average discharge specific capacities of nickel cobalt manganese ternary cathode materials in the ratios of 523, 622, and 811 were 174.52MAh/g, 184.75MAh/g, and 200.73MAh/g, respectively. These results indicated that the 811 ratio of nickel cobalt manganese ternary cathode material exhibited the best performance in terms of discharge specific capacity, and had obvious advantages compared to the other two ratios. Collaborative perception computing has brought new research ideas and methods to the field of lithium-ion battery research, which has promoted further research and development of cathode material properties.

Recent advances of cobalt-free and nickel-rich cathode materials for lithium-ion batteries

Recent advances of cobalt-free and nickel-rich cathode materials for lithium-ion batteries

Enhancement of the electrochemical properties of the nickel-rich cathode material LiNi0.815Co0.15Al0.035O2 by WO3 coating

Enhancement of the electrochemical properties of the nickel-rich cathode material LiNi0.815Co0.15Al0.035O2 by WO3 coating

Nickel-rich ternary cathode material as a novel capping layer to improve lithium iron phosphate electrochemical performance

We use a facile high-temperature solid-phase method to coat a layer of Ni-rich ternary material (LiNi0.8Co0.1Mn0.1O2) on the surface of lithium iron phosphate. This active coating greatly improves the intrinsic conductivity of LiFePO4. Compared to the conventional carbon material cladding, since this cladding layer is electrochemically active, the problem of decreasing the proportion of active material due to the addition of a cladding layer can be avoided to a certain extent. Compared with the samples capped with conventional organic carbon source (151.2 mAh g−1) and inorganic carbon source (155.9 mAh g−1) at 0.2 C, the discharge specific capacity was as high as 165.7 mAh g−1. Capacity retention after 200 cycles is up to 98 %, which is much higher than that of glucose and graphene oxide (GO)-coated samples (95.9 %, 96.6 %). Even when charging and discharging cycles are performed at different multipliers (2C and 10C), the retention rate remains higher than the latter.

Surface modification of rare earth elements to enhance the electrochemical stability of Ni-rich Co-free cathodes

The Ni-rich Co-free cathode materials are considered the most optimistic choice for the long-term economic development of lithium-ion batteries (LIBs) due to the limited supply and high prices of cobalt. In this study, a uniform samarium oxide (Sm2O3) layer was coated on the surface of LiNi0.8Mn0.17Fe0.03O2 (NMF) cathode materials through wet subsequent heat treatment. Compared with the unmodified cathode materials, the modified cathode materials exhibit better electrochemical performance at high voltage. The specific discharge capacity of the modified cathode materials increased from 37.5 mAh g−1 (NMF) to 118.2 mAh g−1 after 200 cycles at 1 C and the retention rate increased from 21.18% to 69.77%. The samarium oxide coating effectively inhibits the reaction between the cathode materials and the electrolyte. Therefore, our study proposes a simple and scalable method for modifying nickel-rich cobalt-free cathode materials.

Dynamically constructing robust cathode-electrolyte-interphase on nickel-rich cathode by organic boron additive for high-performance lithium-ion batteries

Nickel-rich ternary cathode materials LiNi0.8Co0.1Mn0.1O2 (NCM811) have attracted broad attention due to their high voltage and high energy density for lithium-ion batteries. However, rapid capacity decay due to unstable particle surface inhibit the application. Artificial cathode electrolyte interface (CEI) is undoubtedly a more effective and simpler way to solve this issue. Here, stable and highly conductive in situ CEI is designed using a low-cost organic boron additive isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (ITD). Higher occupied molecular orbital energy endows ITD ability to participate in forming CEI. ITD-contained CEI can reduce nickel dissolving, resulting in a lower self-discharge rate, which is benefit from the uniform and stable CEI on the NCM811 surface. As expected, ITD-based CEI can restrain NCM811crystal cracking in Li||NCM811 half batteries, improving capacity retention from 29.4 % to 93.0 % after 200 cycles at 1C (1C = 200 mA g−1). It is worth mentioning that ITD–derived CEI is conducive to ion migration, which improve the rate capacity retention from 91.5 % to 95.5 %.