Cathode Materials For Lithium-ion Batteries Research Articles

Facile Synthesis of Hollow V2O5 Microspheres for Lithium-Ion Batteries with Improved Performance

Micro-nanostructured electrode materials are characterized by excellent performance in various secondary batteries. In this study, a facile and green hydrothermal method was developed to prepare amorphous vanadium-based microspheres on a large scale. Hollow V2O5 microspheres were achieved, with controllable size, after the calcination of amorphous vanadium-based microspheres and were used as cathode materials for lithium-ion batteries. As the quantity of V2O5 microspheres increased, the electrode performance improved, which was ascribed to the smaller charge transfer impedance. The discharge capacity of hollow V2O5 microspheres could be up to 196.4 mAhg−1 at a current density of 50 mAg−1 between 2.0 and 3.5 V voltage limits. This sheds light on the synthesis and application of spherical electrode materials for energy storage.

Influence of Cr and Mg co-doping on electrochemical performance of quaternary cathode materials for lithium-ion battery

Influence of Cr and Mg co-doping on electrochemical performance of quaternary cathode materials for lithium-ion battery

LiFe0.05Mn1.95O4 as a high-rate cathode material for lithium-ion batteries

LiFe0.05Mn1.95O4 as a high-rate cathode material for lithium-ion batteries

Mo Doping to Modify Lattice and Morphology of the LiNi0.9Co0.05Mn0.05O2 Cathode toward High-Efficient Lithium-Ion Storage.

The Ni-rich Co-poor layered cathode (LiNixCoyMn1-x-yO2, x ≥ 0.9) is a candidate for the next-generation lithium-ion batteries due to its high specific capacity and low cost. However, the inherent structural instability and slow kinetics of Li+ migration hinder their large-scale application. Mo doping is proposed to enhance the crystal structure stability of LiNi0.9Co0.05Mn0.05O2 and to ensure the preservation of the spherical secondary particles after the cycle. The characterization results indicate that Mo doping not only significantly relieves the lattice strain accompanied by H2 → H3 phase transition but also alleviates particle stress accumulation to avoid pulverization. The Mo-modification allows the generation of uniform fine primary particulates and further agglomeration into the smooth secondary particles to inhibit electrolyte penetration. Hence, the Mo-modified sample NCM90-1%Mo displays an excellent capacity retention of 85.9% after 200 cycles at 0.5 C current density, which is 23.8% higher than that of the pristine NCM90. In addition, with the expansion of the Li slab to accelerate Li+ diffusion and the fine primary particles to shorten the Li+ pathway, the NCM90-1%Mo sample exhibits a high discharge capacity of 150 mAh g-1 at 5 C current density. This work provides a new thought for the design and construction of high-capacity cathode materials for the next-generation lithium-ion batteries.

Unraveling the chemical and structural evolution of novel Li-rich layered/rocksalt intergrown cathode for Li-ion batteries

The prototype material, Li1.23Ru0.41Ni0.36O2, is proposed to gain the deep and comprehensive understanding of chemical and structural changes of the novel layered/rocksalt intergrown cathodes. Synchrotron-based X-ray absorption spectra and resonant inelastic X-ray scattering reveal that both cationic and anionic redox evolves in the charge compensation process of the intergrown material, while synchrotron-based extended X-ray fine structure spectra and in situ X-ray diffraction measurements demonstrates that the intergrown material undergoes minimal local- and long-range structural variations at deep de/lithiation. This work highlights the great potential of the intergrown structure to inspire the design of advanced cathode materials for lithium-ion batteries.

Understanding the influence of sulfur configuration on the electrochemical reaction pathway for lithium storage in molybdenum sulfides

Molybdenum sulfides are highly regarded as conversion-type electrodes with exceptional performance potential in lithium-ion batteries (LIBs). However, elucidating their lithium (Li) storage behavior has proven challenging due to the intricate sulfur (S) coordination with molybdenum atoms, which has impeded the realization of high energy densities in future Li storage systems. In this study, we investigate the electrochemical redox reaction pathways of molybdenum sulfide, specifically exploring the impact of various S configurations, including terminal, bridging, and apical S. We employ a comprehensive approach, involving extensive electrochemical measurements and depth X-ray photoelectron spectroscopy (XPS) profiling. In contrast to the multi-step conversion reactions observed in MoS2, sulfur-enriched molybdenum sulfides exhibit a unique single-step Li-ion storage mechanism. As a consequence of the pronounced effect of S configuration on the activation energy barrier during charging and discharging, the redox reaction voltage with Li ions exhibits variations. This versatility verifies that molybdenum sulfides have the potential to serve as both anode and cathode materials in lithium-ion batteries. Furthermore, we propose the incorporation of reduced graphene oxide (rGO) composites to address inherent limitations of molybdenum sulfides, including low electrical conductivity and irreversible reactions. The robust interaction between molybdenum sulfides and oxygen functional groups in rGO enhances rate capability and ensures a stable cycling lifespan. Through this systematic investigation, we suggest a comprehensive insight into the electrochemical reaction pathways governing Li storage behavior in molybdenum sulfides with distinct S configurations. This contributes to the fundamental understanding of these materials and their potential applications in advanced energy storage systems.

Improved electrochemical performance of Co-free Ni-rich cathode material for lithium-ion battery through multi-element composite modification

Layered Co-free Ni-rich materials are considered as promising cathode for lithium-ion batteries (LIBs) due to their high energy density and low cost advantages. However, the serious chemical-mechanical instability and poor cycle life of Co-free Ni-rich cathode materials could hinder their commercialization. Herein, we successfully prepared Mg/Ti/Sb co-doped and CeO2-coated LiNi0.9Al0.1O2 cathode material (M-LNA90) using a composite modification strategy with four inexpensive metal elements. Compared with the unmodified pristine LiNi0.9Al0.1O2 cathode material (P-LNA90), the cycling stability, rate performance, and discharge capacity of the M-LNA90 cathode were significantly improved, and the high-voltage performance was also excellent. At a high voltage of 2.8–4.5 V and 1 C, the capacity retention of M-LNA90 after 100 cycles reached 90.2 % (from 200 mAh g–1 to 181 mAh g–1), which was much higher than that the 60.1 % of P-LNA90 (from 192 mAh g–1 to 115 mAh g–1). Meanwhile, the structure and surface stability of M-LNA90 cathode showed excellent, which effectively suppressed particle cracking and interfacial side reactions. This work provides a new insight for the composition optimization and future design of layered Ni-rich cathode materials.

An ultrathin LiF film coated on NCM electrode surface via magnetron sputtering for optimized structure stability and cycling performance

Nickel-riched layered oxide cathode is one of the most promising cathode materials for high energy density lithium-ion batteries, but the capacity decay and poor cycling stability due to the occurrence of side reactions at the electrode-electrolyte interface are huge obstacles preventing its performance. Surface coating is an effective method to solve this problem. In this paper, nanoscale LiF films were deposited on the surface of Ni0.83Co0.11Mn0.06O2 (NCM811) by magnetron sputtering, which effectively improved the electrochemical performance of NCM811 in half-cells. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) showed that LiF was uniformly deposited onto the electrode surface and was not embedded in the cathode particles. After 100 cycles at 0.5C, the discharge specific capacity of the coated modified NCM was 181.82 mAh/g with a retention rate of 93.95%, which was much higher than that of the original NCM811 at 160.84 mAh/g with a capacity retention rate of 83.11%, while the capacity remained basically unchanged. In addition, the modified rate capability was also significantly improved, with the discharge specific capacity of the modified sample at 5C being 167.26 mAh/g, which was 12.45% higher than that of the uncoated sample at 148.73 mAh/g. The deposited LiF film can protect the electrode interface, inhibit the decomposition of electrolyte and thus protect the positive electrode, and stabilize the structure of the particles.

.Boosting lithium storage in covalent triazine framework for symmetric all-organic lithium-ion batteries by regulating the degree of spatial distortion

Covalent triazine frameworks (CTFs) with tunable structure, fine molecular design and low cost have been regarded as a class of ideal electrode materials for lithium-ion batteries (LIBs). However, the tightly layered structure possessed by the CTFs leads to partial hiding of the redox active site, resulting in their unsatisfactory electrochemical performance. Herein, two CTFs (BDMI-CTF and TCNQ-CTF) with higher degree of structural distortion, more active sites exposed, and large lattice pores were prepared by dynamic trimerization reaction of cyano. As a result, BDMI-CTF as a cathode material for LIBs exhibits high initial capacity of 186.5 mAh/g at 50 mA g−1 and superior cycling stability without capacity loss after 2000 cycles at 1000 mA g−1 compared with TCNQ-CTF counterparts. Furthermore, based on their bipolar functionality, BDMI-CTF can be used as both cathode and anode materials for symmetric all-organic batteries (SAOBs), and this work will open a new window for the rational design of high performance CTF-based LIBs.

Using Hierarchically Structured, Nanoporous Particles as Building Blocks for NCM111 Cathodes.

Nanoparticles have many advantages as active materials, such as a short diffusion length, low charge transfer resistance, or a reduced probability of cracking. However, their low packing density makes them unsuitable for commercial battery applications. Hierarchically structured microparticles are synthesized from nanoscale primary particles by targeted aggregation. Due to their open accessible porosity, they retain the advantages of nanomaterials but can be packed much more densely. However, the intrinsic porosity of the secondary particles leads to limitations in processing properties and increases the overall porosity of the electrode, which must be balanced against the improved rate stability and increased lifetime. This is demonstrated for an established cathode material for lithium-ion batteries (LiNi0.33Co0.33Mn0.33O2, NCM111). For active materials with low electrical or ionic conductivity, especially post-lithium systems, hierarchically structured particles are often the only way to produce competitive electrodes.

Revealing proton-coupled exchange mechanism in aqueous ion-exchange synthesis of nickel-rich layered cathodes for lithium-ion batteries

Ion exchange is a promising synthetic method for alleviating severe cation mixing in traditional layered oxide materials for lithium-ion batteries, leading to enhanced structural stability. However, the underlying mechanisms of ion exchange are still not fully understood. Such a fundamental study of the ion-exchange mechanism is needed for achieving the controllable synthesis of layered oxides with a stable structure. Herein, we thoroughly unearth the underlying mechanism that triggers the ion exchange of Ni-rich materials in aqueous solutions by examining time-resolved structural evolution combined with theoretical calculations. Our results reveal that the reaction pathway of ion exchange can be divided into two steps: protonation and lithiation. The proton is the key to achieving charge balance in the ion exchange process, as revealed by X-ray adsorption spectroscopy and inductive coupled plasma analysis. In addition, the intermediate product shows high lattice distortion during ion exchange, but it ends up with a most stable product with high lattice energy. Such apparent discrepancies in lattice energy between materials before and after ion exchange emphasize the importance of synthetic design in structural stability. This work provides new insights into the ion-exchange synthesis of Ni-rich oxide materials, which advances the development of cathode materials for high-performance lithium-ion batteries.

Trilithium salt of tetrahydroxyanthraquinone: A high-voltage and stable organic cathode material for rechargeable lithium metal and lithium-ion batteries

Organic cathode materials (OCMs) have drawn considerable attention for lithium batteries but suffer from unfavorable dissolution problem and thus inferior cycling performance. Salification is a simple approach to restrain the dissolution but most reported lithium-salt-type OCMs are still unable to achieve good cycling stability due to poorly conjugated and/or asymmetric structure. Herein, we report a novel air-stable, largely conjugated, and symmetric organic lithium salt synthesized from 1,4,5,8-tetrahydroxyanthraquinone (THAQ), namely Li3THAQ. It possesses a layered crystalline structure with large interlayer spacings, which is relatively stable in the reversible conversion between Li4THAQ and Li2THAQ. Benefiting from this, Li3THAQ exhibits exceptional electrochemical performance within 2.0–3.6 V, including high reversible capacity (192 mAh g−1), high discharge potential (2.93 V vs. Li+/Li), high rate capability (75 % capacity retention at 5000 mAh g−1 vs. 50 mAh g−1), and high cycling stability (95 % capacity retention after 500 cycles). Additionally, it can be also matched with natural graphite anode to construct a Li-ion full-cell, which was rarely reported for OCMs. In brief, Li3THAQ shows great advantages in structure stability, electrochemical performance, and practicability compared to its counterparts, and the in-depth mechanism understanding provides important insights into the development of lithium-salt-type OCMs.

Improved structure stability and performance of a LiFeSO4F cathode material for lithium-ion batteries by magnesium substitution.

Tavorite LiFeSO4F with high Li-ion conductivity has been considered a promising alternative to LiFePO4. However, its poor cycle stability and low electronic conductivity limit the practical application of Tavorite LiFeSO4F. In the present study, we employ a solvothermal method to produce magnesium-substitution LiMgxFe1-xSO4F (x = 0, 0.02, 0.04) cathode materials in which the Mg substitutes the Fe(2) sites. The first-principles calculations demonstrate that Mg-substitution could reduce the bandgap of LiFeSO4F and increase its electronic conductivity to 2.5 × 10-11 S cm-1. Meanwhile, CI-NEB and BV calculations reveal that the diffusion energy barrier of lithium along the (100) direction after Mg substitution is lower than the pristine sample, and the electrochemical inactive Mg2+ could improve the structure stability. The results show that the Mg-substituted LiFeSO4F exhibits enhanced cycle stability and rate performance compared with the pristine LiFeSO4F, suggesting that the use of electrochemically inactive ion substitution may be critical for the development of high-performance LiFeSO4F cathode materials for lithium-ion batteries.

Correction: Achieving dynamic stability of single-crystal low-Co Ni-rich cathode material for high performance lithium batteries

Correction for ‘Achieving dynamic stability of single-crystal low-Co Ni-rich cathode material for high performance lithium batteries’ by Adil Saleem et al., J. Mater. Chem. A, 2024, 12, 30831–30841, https://doi.org/10.1039/D4TA04698F.

First-principles evaluation of MnO2 polymorphs as cathode material in lithium-ion batteries

MnO2 polymorphs show distinct advantages and disadvantages when used as cathode material for Li-ion batteries (LIBs).

Redox-active, photoluminescent porous polymers based on spirofluorene-bridged N-heterotriangulenes and their feasibility as organic cathode materials.

Novel microporous polymers were synthesized through Yamamoto polymerization of selectively brominated spirofluorene-bridged N-heterotriangulenes. Extensive characterization, including combustion analysis, ToF-SIMS, IR, and Raman spectroscopy, confirmed the elemental composition and integrity of the polymers. The amorphous polymers, observed by scanning electron microscopy as globular particles aggregating into larger structures, exhibited remarkable thermal stability (decomposition temperatures > 400 °C) and BET surface areas up to 690 m2 g-1. Dispersions of the tert-butyl-substituted polymer in different solvents displayed bathochromically shifted emission with remarkable solvatochromism. The polymer is reversibly oxidized at +3.81 V (vs. Li/Li+) in composite electrodes with carbon black and reaches specific capacities up to 26 mA h g-1 and excellent cycling stability when implemented as cathode material in lithium-ion batteries. Our results highlight the potential of spirofluorene-bridged N-heterotriangulenes as versatile building blocks for the development of functional redox-active porous polymers.

Enhanced Li-ion intercalation kinetics and lattice oxygen stability in single-crystalline Ni-rich Co-poor layered cathodes

Ba/Al co-doping effectively lower the calcination temperature, greatly reduces Li/Ni mixing and expands the c-axis parameter, and stabilizes the lattice oxygen, resulting in enhanced Li-diffusion kinetics and excellent cycle life.

Research on Application of Graphene in Lithium Ion Battery Cathode Materials

Research on Application of Graphene in Lithium Ion Battery Cathode Materials

Cycle life and influencing factors of cathode materials for lithium-ion batteries--a case study of lithium-cobalt oxides

Abstract Lithium-cobalt oxide has become a new generation of highly promising anode materials for lithium-ion batteries due to its low price, environmental friendliness, high platform voltage, and high theoretical capacity. In this paper, the working characteristics and related parameters of lithium-ion batteries are sorted out, and the influence factors of the decline mechanism of lithium-ion batteries are investigated from the perspective of chemical composition. Regarding the cycle life of lithium-ion battery cathode materials, this paper establishes a cycle life prediction model for lithium-ion batteries based on the LSTM model. It optimizes the hyperparameters of the model using the PSO algorithm. In addition, this paper also prepared lithium cobalt oxide cathode materials and carried out a validation analysis of the factors affecting their electrochemical performance. It is found that the cycle life prediction of lithium-ion battery based on LSTM has an RMSE of 3.27%, and the capacity of lithium cobalt oxide soft pack full battery decays from 249.81mAh to 137.04mAh at 26°C. The cycle life of its lithium cobalt oxide lithium-ion battery is around 250 cycles, and the average decay is 0.445mAh during one charge/discharge. Different charge/discharge cycles and diversity will have a significant effect on the cycle life of lithium-ion battery cathode materials, and it is necessary to pay attention to the parameter changes in the preparation of lithium cobalt oxide cathode materials in order to increase the cycle life of lithium-ion batteries.

First-principles study of VS<sub>2</sub> as anode material for Li-ion batteries

With the increase of performance requirements for lithium-ion batteries (LIBs), it is particularly important to study and develop new electrodes for lithium-ion batteries. In this work, a 3×3×1 supercell of VS<sub>2</sub> is constructed, and the possibility of using it as an anode material for lithium-ion batteries is study by the first-principles method based on density functional theory. Through the analysis of the energy band diagram, it is found that VS<sub>2</sub> has metallic properties. Combining the density of states diagram, the analysis shows that the energy band near the Fermi level of VS<sub>2</sub> is contributed by the 3d state of V and the 3p state electrons of S, which means that the conductive properties of VS<sub>2</sub> are largely affected by the 3d state of V and the 3p state electrons of S. Of the vacancies, bridge sites, and top sites of lithium adsorbing vanadium (V), the top site has the lowest adsorption energy, indicating that lithium will preferentially adsorb the top site of vanadium (V). Through first-principles molecular dynamics simulations of the top position of adsorbed vanadium (V), it is found that at a temperature of 300 K, the total energy of the system and the magnitude of the total temperature fluctuation can reach a steady state, indicating that lithium can exist at the top position of stably adsorbed vanadium (V). Moreover, the interlayer spacing of the double-layer VS<sub>2</sub> reaches 3.67 Å, which is larger than the interlayer spacing of graphene. From the top position to the vacancy, its diffusion barrier is only 0.20 eV. Its interlayer spacing is larger than the double-layer graphene’s, and its diffusion barrier is lower than graphene’s, indicating that lithium has very good diffusivity on the VS<sub>2</sub> surface, and lithium can migrate quickly on the VS<sub>2</sub> surface, which is conducive to the rapid charge-discharge process of LIB. In addition to excellent electrical conductivity, VS<sub>2</sub> has good mechanical properties. The calculated Young's modulus is 96.82 N/m, and the Young's modulus and Poisson’s ratio do not decrease after adsorbing lithium, indicating that the rigidity of VS<sub>2</sub> will not be reduced in the diffusion and migration process of lithium. On the other hand, it has excellent deformation resistance. In order to be more accurate and closer to the actual situation, a double-layer VS<sub>2</sub> model is constructed, with a maximum number of lithium atoms adsorbed between layers being 18. The calculated theoretical capacity of VS<sub>2</sub> (466 mAh/g) is higher than the theoretical capacity of graphene (372 mAh/g). Our results indicate that VS<sub>2</sub> has excellent electrical conductivity and mechanical stiffness, making it a promising cathode material for lithium-ion batteries.