Cathode Materials For Lithium-ion Batteries Research Articles

Modification study of Mg/W-doped LiNi0.9Mn0.1O2 layered oxide cathode materials for lithium-ion batteries

Modification study of Mg/W-doped LiNi0.9Mn0.1O2 layered oxide cathode materials for lithium-ion batteries

Promoting homogeneous tungsten doping in LiNiO2 through a grain boundary phase induced by excessive lithium

LiNiO2 (LNO) is one of the most promising cathode materials for lithium-ion batteries. Tungsten element in enhancing the stability of LNO has been researched extensively. However, the understanding of the specific doping process and existing form of W is still not perfect. This study proposes a lithium-induced grain boundary phase W doping mechanism. The results demonstrate that the introduced W atoms first react with the lithium source to generate a Li-W-O phase at the grain boundary of primary particles. With the increase of lithium ratio, W atoms gradually diffuse from the grain boundary phase to the interior layered structure to achieve W doping. The feasibility of grain boundary phase doping is verified by first principles calculation. Furthermore, it is found that the Li2WO4 grain boundary phase is an excellent lithium ion conductor, which can protect the cathode surface and improve the rate performance. The doped W can alleviate the harmful H2↔H3 phase transition, thereby inhibiting the generation of microcracks, and improving the electrochemical performance. Consequently, the 0.3wt% W-doped sample provides a significant improved capacity retention of 88.5% compared with the pristine LNO (80.7%) after 100 cycles at 2.8-4.3 V under 1 C.

Local electronic structure modulation via S substitution enables fast-discharging capability for Li-rich Mn-based oxides cathodes

Anionic and cationic redox reaction contribute to the ultrahigh specific capacities of Li-rich Mn-based oxides cathodes (LMNC). However, the irreversible oxygen evolution and sluggish kinetics result in the continuous capacity decay and poor rate performance, which limited its application as cathode material in lithium-ion batteries. Herein, the local electronic structure of LMNC is appropriately modulated via S2− doping to alleviate oxygen release, stabilize the crystal structure stability, and facilitate Li+ diffusion via facile surface defect engineering. The effect of S2− doping site on the systematically energy is investigated by DFT. Under the guidance of this result, LNMC-S is prepared by co-precipitation and high-temperature solid-phase reaction method. The effect of doping concentration on electrochemical property of LMNC was systematically investigated. The results exhibit that S2− doping can effectively suppress the electronic insulation of Li2MnO3, enhance the transport dynamics of lithium ion and inhibit the phase transition of LMNC sample during charge-discharge process. Thereby, the modified sample exhibits superior electrochemical property, such as the 200th discharge capacity is 184.3 mAh·g−1 under 1C, with a capacity retention rate of 87.6 %. This paper is beneficial for enriching the existing theoretical findings and discoveries, providing theoretical guidance for the preparation of high-performance material.

Exploring Electrolyte Adsorption on the Different Types of Layered Cathode Surfaces in Lithium-Ion Batteries via a Universal Neural Network Potential Method.

LiNi x Mn y Co z O2 (NCM) is a promising cathode material for lithium-ion batteries. Their long-term stability and impedance growth as cycles are strongly influenced by the properties of the cathode electrolyte interface (CEI), formed by the reaction between the electrolyte and electrode surface. Understanding of these interactions at the atomic level of the NCM electrode surface and electrolyte will provide a new strategic approach for the design of a highly functional CEI layer. In this study, we explored the influence of Ni content in transition metal layers on surface energies under different synthetic conditions and terminations using a density functional theory (DFT) validated universal neural network potential (UNNP) method. Furthermore, we investigated the adsorption of ethylene carbonate (EC) and dimethyl carbonate (DMC) on the most favorable NCM surfaces. EC and DMC displayed similar adsorption energy trends; however, differences were observed in the preferred configurations, which can affect the formation of the CEI.

A Review of Mexican Contributions to Li2CuO2 and its Chemical Modifications as Cathode Materials for Lithium-Ion Batteries

Abstract. Over the past few decades, battery research has primarily focused on reducing costs and increasing energy density. There have been significant efforts to identify alternative cathode materials that could replace cobalt-based ones, with the goal of finding more environmentally friendly and cost-effective options. In this context, copper-based cathodes have emerged as promising candidates. The appeal of copper-based cathodes lies in their relatively high abundance, particularly in Mexico, their high theoretical energy density, and the potential to enhance their properties by altering their chemical structure. In recent years, numerous research initiatives in Mexico have aimed to make Li2CuO2 cathodes a viable option. This review examines the recent advances and future perspectives of these efforts, with a particular emphasis on the latest attempts to modify the synthesis route and incorporate multiple dopants to create synergistic effects. Resumen. Durante las últimas décadas, la investigación sobre baterías se ha enfocado principalmente en la disminución de costos y el incremento de la densidad energética. Se han realizado importantes esfuerzos para identificar materiales catódicos alternativos que podrían reemplazar a los materiales basados en cobalto, con el objetivo de encontrar opciones rentables y con menor impacto al medio ambiente. En este contexto, los materiales catódicos basados en cobre se han convertido en candidatos prometedores. El interés por los cátodos basados en cobre radica en su abundancia relativamente alta, particularmente en México, su alta densidad energética teórica y la cualidad de mejorar sus propiedades alterando su estructura química. En los últimos años, numerosas propuestas de investigación en México han tenido como objetivo hacer de los cátodos de Li2CuO2 una opción viable. Este resumen recopila los avances recientes y las perspectivas a futuro de estos esfuerzos, con especial énfasis en los últimos intentos de modificar la ruta de síntesis y, a su vez, incorporar múltiples dopantes para crear efectos sinérgicos.

Enhanced Cyclic Performance of Lithium-Ion Battery Based on Anthraquinone/SBA-15 Composite Cathode Prepared via Ultra-Sonication

In this study, novel organic/inorganic composites were fabricated by blending anthraquinone (AQ) with SBA-15 molecular sieve in varying ratios via ultrasonication, characterized structurally using XRD, SEM, and BET methods, and analyzed electrochemically as cathode materials for lithium-ion batteries via galvanostatic discharge/charge and electrochemical impedance spectroscopy. The composite with a 2:1 ratio of AQ and SBA-15 achieved a specific discharge capacity of 144.5 mAh/g at 0.2 C, which decreased to 63.3 mAh/g after 50 cycles, 8% higher than that of the pure AQ. The initial discharge platform of the composite was 2.28 V, which decreased to 2.10 V after 50 cycles, 50 mV higher than that of the pure AQ. This is because the loading of anthraquinone particles by the SBA-15 pore size structure facilitated the stabilization of the active materials, hindered the solubility of AQ in the electrolyte, and enhanced the cycling stability of the battery.

Effect of Rare Earth Ion Doping on the Performance of Lithium-Rich Cathode Materials for Lithium-Ion Batteries

Lithium-rich layered oxide cathode materials have the advantages of a high voltage and a high specific capacity. Their commercial applications have however been impeded by some disadvantages such as low initial coulombic efficiency and low cycle life. To overcome these issues, rare earth ion-doped lithium-rich layered oxide cathode materials are investigated in this work. The irreversible release of O2- in Li2MnO3 is suppressed by rare earth ions doping, which enhanced the initial coulombic efficiency of the materials. Meanwhile, the rare-earth ion radius used for doping is larger than the Mn4+ radius, which enlarges the (003)-crystalline plane spacing, resulting in a significant enhancement of the rate performance of the material.

Synthesis and Electrochemical Performance Enhancement of Li2MnSiO4 Cathode Material for Lithium‐Ion Batteries via Mn‐Site Ni Doping

AbstractIn exploring the potential of Li2MnSiO4 as a cathode material for lithium‐ion batteries (LIBs), the key challenges often involve enhancing electronic conductivity and lithium‐ion diffusion rates. To address these issues, this paper proposes the combination of solid‐state doping and a two‐step calcination process to successfully prepare the Li2Mn1−xNixSiO4 series of cathode materials, where Ni substitutes Mn at different doping amounts (x = 0, 0.02, 0.04, 0.06, 0.08). The use of chemically equivalent Ni2+ ions to replace Mn2+ ions is an effective method. Since the ionic radius of Ni2+ is smaller than that of Mn2+, this substitution can create more voids in the lattice structure. These increased voids provide smoother channels for the transport of electrons and lithium ions, thereby improving the material's electrical conductivity. At a Ni doping amount of 0.06, the material exhibits optimal electrochemical performance, achieving a discharge capacity of 155 mAh g−1 at 0.1 C, significantly superior to undoped lithium manganese silicate. The doping of Mn sites with Ni significantly improves the conductivity and lithium‐ion diffusion capabilities of Li2MnSiO4, revealing the tremendous potential of doping strategies in optimizing the performance of LIBs cathode materials.

A novel coating layer of mesoporous silica on LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode material for advanced lithium-ion batteries

NCM811 cathode material has many commercial features such as reasonable price, environmental friendliness and high specific capacity, yet it suffers from capacity attenuation during cycling. Silica (SiO2) coating strategy is a valid approach to enhance the capacity retention of NCM811. However, the insulating nature of coating layer reduces the electrochemical performance. Herein, a novel route is developed to alleviate this issue by using a mesoporous layer instead of bulk layer. The mesoporous layer is prepared by condensing a mixture of fine templates (Cetyltrimethylammonium bromide, CTAB) and tetraethyl orthosilicate (TEOS) on NCM811 particles and calcining them to remove templates. The structure, morphology, surface chemical state and electrochemical performance of samples are widely investigated. Results indicate that the mesoporous layer (SiO2–20 wt.% of CTAB) exhibits discharge capacities of 210 and 138 mAh g−1 at 0.1 C and 5C over 2.7–4.3 V, while those of bulk SiO2 coated sample are only 189 and 98 mAh g−1, respectively. This mesoporous layer offers a capacity maintenance of 87.3 % after 100 cycles, compared to only 69.3 % for pure NCM811 at 1 C. The mesoporous layer not only improves the discharge capacity of NCM811 but also reduces its capacity fading.

Nickel‐Manganese‐Based Layered Oxide for Sodium Ion Battery Cathode Materials

Sodium‐ion batteries (SIBs) have demonstrated significant potential as alternatives to conventional lithium‐ion batteries (LIBs) for modern grid and mobile energy storage applications, due to the abundant natural resources and low cost of sodium. Layered transition metal oxides (LTMOs) have attracted focused research attentions due to their high specific capacities, energy densities as well as the compatible preparation processes with those of LIBs cathode materials. Among these, Ni/Mn‐based LTMOs (NMLOs) are particularly noteworthy for their cost‐effectiveness and superior electrochemical performance, such as excellent capacity retention, voltage stability, high operating voltage and rate capability. In this review, we briefly introduce the synthesis methods of NMLOs, discuss the challenges, and summarize the solutions. The insights presented may contribute to the development of NMLOs based SIBs.

Diammonium Hydrogen Citrate-Assisted Spray Pyrolysis Synthesis of Nanostructured LiCoPO4 Microspheres as High-Voltage Cathode Material for Lithium-Ion Batteries.

Nanostructured LiCoPO4 (LCP) microspheres were successfully synthesized by one-step spray pyrolysis, adding an appropriate amount of diammonium hydrogen citrate (DHC) additive to the precursor solution. Comprehensive physical characterization confirmed that the obtained LCPs exhibited a desirable orthorhombic olivine structure with nanostructured morphology and a significant increase in specific surface area. This enhancement was attributed to the dispersion effect due to the carboxyl group and the evolution of the ammonium group of DHC during the pyrolysis process. The resultant LCP delivered a high initial discharge capacity of 132 mA h g-1 with 63.3% capacity retention (vs 103 mA h g-1 and 37.1% of bare-LCP) after 50 cycles at 0.1 C using the conventional electrolyte. Moreover, the electrochemical performance showed additional enhancement when a fluorinated electrolyte was introduced, resulting in initial and 50th discharge capacities of 141 and about 100 mA h g-1, respectively, at 0.1 C.

Discharging of Ramsdellite MnO2 Cathode in a Lithium-Ion Battery.

We report an application of our unbiased Monte Carlo approach to investigate thermodynamic and electrochemical properties of lithiated manganese oxide in the ramsdellite phase (R-MnO2) to uncover the mechanism of lithium intercalation and understand charging/discharging of R-MnO2 as a cathode material in lithium-ion batteries. The lithium intercalation reaction was computationally explored by modeling thermodynamically significant distributions of lithium and reduced manganese in the R-MnO2 framework for a realistic range of lithium molar fractions 0 < x < 1 in Li x MnO2. We employed interatomic potentials and analyzed the thermodynamics of the resultant grand canonical ensemble. We found ordered or semiordered phases at x = 0.5 and 1.0 in Li x MnO2, verified by configurational entropy changes and simulated X-ray diffraction patterns of partially lithiated R-MnO2. The radial distribution functions show the preference of lithium for homogeneous distributions across the one-dimensional 2 × 1 ramsdellite channels accompanied by alternating reduced/oxidized manganese ions. The occupation of the interstitial sites in the channels is correlated with the calculated voltage profile, showing a sharp voltage drop at x = 0.5, which is explained by the energy penalty of shifting lithium ions from stable tetrahedral to unstable octahedral sites. To facilitate this work, our in-house software, Knowledge Led Master Code (KLMC) was extended to support massive parallelism on high-performance computers.

The effect of heating rate on microstructure and electrochemical performance of nickel-rich layered oxides cathode materials

Nickel-rich layered oxides have attracted significant attention as promising cathode materials for lithium-ion batteries due to their high specific capacity, rate capability, and relatively low cost. However, the material still faces challenges such as harsh synthesis conditions, easy cation mixing and large residual alkali on the surface, severely limiting its practical applications. To overcome these drawbacks, this study successfully synthesized a series of LiNi0.8Co0.1Mn0.1O2 (NCM) cathode materials with different heating rates. The results indicate that appropriately reducing the heating rate can improve the cycling performance of the material and reduce cation mixing and surface residual alkalinity. Specifically, among the four samples, the LiNi0.8Co0.1Mn0.1O2 sample (NCM-2 °C min-1) exhibites a lower Li⁺/Ni²⁺ mixed arrangement and fewer surface residual alkalis, demonstrating good cycling performance and rate capability. The NCM-2 °C min-1 sample provides an excellent initial discharge capacity of 210.4 mAh g⁻¹ under 0.1 C conditions, and it achieves the highest capacity retention rate (85.9%) after 100 cycles at 1 C, while the capacity retention rates for NCM-1 °C min-1, NCM-3 °C min-1, and NCM-4 °C min-1 are 75.4%, 75.2%, and 71.2%, respectively. NCM-2 °C min-1 sample also showed excellent rate performance, especially at high rates. The discharge capacity remains at 151.6 mAh g-1 at 10 C, which is much higher than that of other samples (149.3 mAh g-1 for NCM-1 °C min-1, 123.5 mAh g-1 for NCM-3 °C min-1, and 120.6 mAh g-1 for NCM-4 °C min-1). The research of synthesis technology has important guiding significance for the synthesis of high-stability high-nickel layered oxide materials.

Lithium-rich manganese-based layered oxide cathode materials for lithium-ion batteries modified by MoS2 coatings with two-dimensional graphene-like structures

Lithium-rich manganese-based layered oxide cathode materials (LRMCs) have some unique advantages such as high theoretical capacity (≥ 250 mAh g−1) and high energy density. Therefore, they are deemed as a kind of cathode material for lithium-ion batteries with an excellent prospect of application. However, the redox of oxygen anion is able to generate irreversible lattice oxygen loss, leading to irreversible loss of capacity, bringing about a sharp drop of working voltage, and seriously restricting the commercialization of LRMCs. In this paper, MoS2 coating with two-dimensional graphene-like structure was coated on the surface of LRMCs materials for improving the cycling stability and rate performance. The MoS2 coating can provide a two-dimensional diffusion channel for the migration of lithium-ions, which facilitates the fast release of lithium-ions during cycling process. The results show that the first discharge capacity, initial Coulomb efficiency and rate performance of LRMCs are improved. When the current density is 1 C, the first discharge specific capacity of LRMCs@MoS2 reaches 227.69 mAh g−1, and the capacity retention ratio is 84.98 % after 100 cycles. When the current density is 5 C, it can still provide a discharge specific capacity of 137.87 mAh g−1, demonstrating excellent electrochemical performance. This study comes up a simple and practical idea to realize the modification of cathode materials for high performance lithium-ion batteries.

Surface Reconstruction Enhanced Li-Rich Cathode Materials for Durable Lithium-Ion Batteries.

Regulating the distribution of surface elements in lithium-rich cathode materials can effectively change the electrochemical performance of cathode materials. Considering that the enrichment of Mn element on the surface is the main reason for the irreversible phase transition and dissolution of its surface structure, which in turn is the main reason for performance degradation. Based on the molten salt-assisted sintering method, a lithium rich cathode material with surface rich Ni and Co is designed and prepared. The surface enrichment of Ni and Co effectively reduces the dissolution of Mn, promotes the occurrence of irreversible collapse of surface structure from layered phase to rock salt phase on the material surface, improves the stability of surface crystal phase structure, and improves the cycling stability of positive electrode materials. Notably, after 500 cycles at 1 C current density, the discharge-specific capacity attained 189.8 mAh g -1, with a capacity retention rate of 88.9%, indicating a 42.1% improvement in capacity retention. Molten salt treatment is widely used in the modification of positive electrode materials. The research work will provide new ideas for improving the stability of lithium rich materials and promoting their commercial applications.

Free-Standing Poly(vinyl benzoquinone)/Reduced Graphene Oxide Composite Films as a Cathode for Lithium-Ion Batteries.

Quinones with a rapid reduction-oxidation rate are promising high-capacity cathodes for lithium-ion batteries. However, the high solubility of quinone molecules in polar organic electrolytes results in low cycle stability, while their low electric conductivity causes low utilization of electrode materials. In this article, a new p-benzoquinone derivative, poly(vinyl benzoquinone) (PVBQ), is designed and synthesized, and a solution-based method of preparing free-standing PVBQ/reduced graphene oxide (RGO) composite films is developed. PVBQ has a high theoretical specific capacity (400 mA h g-1) because of its low dead moiety mass. In the produced composite films, PVBQ nanoparticles are uniformly dispersed on RGO sheets, which endows the composite films with high electric conductivity and inhibits the dissolution of PVBQ through strong adsorption. As a result, the composite films show a high active material utilization, high practical specific capacity, and excellent cycling stability. PVBQ in the composite membrane containing 60.2 wt % RGO deliver 244 mA h g-1 capacity after 200 charge-discharge cycles at a current density of 300 mA g-1. At a current density of 1500 mA g-1, the reversible specific capacity is still 170 mA h g-1. This work provides a high-performance cathode material for lithium-ion batteries, and the molecular structure and electrode structure design ideas are also instructive for developing other organic electrode materials.

Boosting the intrinsic kinetics of lithium vanadium phosphate via an electrochemically active cross-link framework

The monoclinic lithium vanadium phosphate Li3V2(PO4)3 (LVP) is considered a promising cathode for lithium-ion batteries (LIBs) due to its high working voltage (>4.0 V, vs. Li+/Li) and high theoretical specific capacity (197 mAh g−1). However, the electrochemical procedure accompanied by three-electron reactions in LVP has proven challenging due to the complexity or asymmetry of the reaction pathways, thus limiting its wide application. Herein, an electrochemically active cross-link framework of LVP, LiFe0.3Mn0.7PO4 (LFMP) and graphene are successfully synthesized by an in situ catalytic process, which enables stable cycling and high-rate capabilities up to 4.8 V (vs. Li+/Li). Graphene-like carbon can be formed in situ with VOx as the catalyst and polyvinyl alcohol as the carbon source, and LFMP also inhibits the growth of LVP particles, allowing rapid Li+ and electron transport in the cathodes. Both in situ and ex situ X-ray diffraction prove that the cross-link framework efficiently smooths the lattice mismatch and achieves highly reversible structural phase transitions. The prepared 0.9LVP·0.1LFMP is able to provide a superior rate capability of 123 mAh g−1 at 20 C. After 150 cycles, the 0.9LVP·0.1LFMP shows 97.4 % capacity retention even under a voltage of 4.8 V (vs. Li+/Li). This work develops a new strategy for the future design of high-voltage and high-power cathode materials for LIBs.

Application of a simple organic acid as a green alternative for the recovery of cathode metals from lithium-ion battery cathode materials

Industrialization, technology, and population growth have on one hand resulted in the rapid rise for energy demand and on the other hand led to the pursuit for alternative carbon neutral energy sources to satisfy demand, address climate change and promote sustainable development. The transition to renewable energy sources has resulted in the rapid rise in energy storage options with battery technologies at the forefront. Lithium-ion batteries (LIBs) have emerged as a leading battery energy storage option. The rise in LIB technology demand has resulted in a proportional increase in the demand for the various materials used in their manufacture. Primary sources of several of the LIB component materials largely consist of mining activities, however, recycling has emerged as a promising secondary material source. In this work, we evaluate the application of a green, organic acid treatment approach utilizing propionic acid in the recovery of key metals from LIB cathode materials. The study delved into exploring the application of both commercially sourced virgin LIB cathode powder (VCP) and recovered spent LIB cathode powder (SCP) and investigating the system leaching characteristics. The highest metal recoveries were obtained on leaching the SCP, with metal recoveries determined as 92.9%, 87.4%, 92.7% and 94.0% for Co, Li, Mn and Ni respectively. The difference in the recoveries on leaching metals from the VCP and SCP was under 5% for each metal. Further, the leaching model was determined as chemical reaction-controlled on using the SCP, and the activation energies were evaluated as 60.37 kJ/mol, 53.38 kJ/mol, 63.98 kJ/mol and 60.20 kJ/mol for Co, Li, Mn and Ni respectively, agreeing with the deduced chemical reaction-controlled leaching mechanism. By application of a simple organic acid, propionic acid, for organic acid leaching operations we contribute to the diversification of the lixiviant options for LIB waste treatment.

Phase compatible surface engineering to boost the cycling stability of single-crystalline Ni-rich cathode for high energy density lithium-ion batteries

Nickel-rich layered oxide is a promising cathode material for the next generation lithium-ion batteries (LIBs) because of its high energy density and cost efficiency. Unfortunately, it suffers from unsatisfying electrochemical performance owing to intrinsic interfacial and structural instability, which limits its application at scale. In this work, a phase compatible TiBO3 coating layer on single crystalline LiNi0.83Co0.11Mn0.06O2 (TBO-SC-NCM) is constructed via modified solid-state chemical reaction. The coating layer serves as a protective screen to mitigate the erosion of organic electrolyte towards TBO-SC-NCM. Furthermore, both titanium ions and boron ions successfully diffuse into the TBO-SC-NCM bulk phase during the annealing process, with titanium ions being uniformly distributed while boron ions accumulating close to the surface. The formation of strong Ti-O bond effectively inhibits the bulk phase structure degradation of TBO-SC-NCM. The near-surface enriched B-O bond greatly stabilizes the surface lattice oxygen at the deeply delithiated state. Additionally, the spread of layer spacing due to the doping of heterogeneous ions ensures the rapid diffusion of Li+, thus improving the rate performance of TBO-SC-NCM. As a h cathode materials.

Cobalt-free spinel–layered structurally integrated Li0.8Mn0.64Ni0.183Fe0.091O2 cathodes for lithium-ion batteries

Cobalt-free, Li-rich layered-spinel structurally integrated positive electrode (cathode) materials for lithium-ion batteries (LIBs), with nominal composition 0.6(Li1.2Mn0.56Fe0.08Ni0.16O2)∙0.4(LiFe0.2Mn1.4Ni0.4O4) which can otherwise be written as Li0.8Mn0.64Ni0.183Fe0.091O2 (FeSL) are synthesized via simple citric acid-assisted sol-gel route. Four different final annealing temperatures (550 °C, 650 °C, 750 °C, and 850 °C) were chosen to investigate their influence on electrochemical performance. The obtained composite materials contain spinel (space group Fd3¯m) as well as Li-rich layered phases (space group C2/m) as revealed by X-ray diffraction (XRD), HRTEM and cyclic voltammetry investigations. The excellent electrochemical performance of the composite material could be attributed to the structural stability achieved by the integration of spinel and layered components. Selected synthesized composite materials exhibit high discharge capacities close to 200 mAh g‐1. The FeSL750 shows better capacity retention (92(3)% at the 50th cycle and 82(5)% at the 70th cycle) and rate capability than the FeSL550 and FeSL650 samples. However, the FeSL850 sample shows different charge-discharge behaviour. The charge capacity corresponding to FeSL850 is found to increase up to the 20th cycle, then stabilizes and displays a capacity retention of almost 100 % at the 50th cycle and 91(1)% at the 70th cycle. The electrochemical mechanism of FeSL750 was elucidated via in operando XAS investigations, which reveal electrochemical activity from all transition metals.