Li-ion Diffusion Research Articles

Artificial Electron Channels Enable Contact Prelithiation of Li-Ion Battery Anodes with Ultrahigh Li-Source Utilization.

Contact prelithiation is widely used to compensate for the initial capacity loss of lithium-ion batteries (LIBs). However, the low utilization of the Li source, which suffers from the deteriorated contact interfaces, results in cycling degeneration. Herein, Li-Ag alloy-based artificial electron channels (AECs) are established in Li source/graphite anode contact interfaces to promote Li-source conversion. Due to the shielding effect of the Li-Ag alloy (50 at. % Li) on Li-ion diffusion, the dry-state interfacial corrosion is restricted. The unblocked electronic conduction across the AEC-involved interface not only facilitates the Li-source conversion but also accelerates the prelithiation kinetics during the wet-state process, resulting in an ultrahigh Li-source utilization (90.7 %). Implementing AEC-assisted prelithiation in a LiNi0.5Co0.2Mn0.3O2 pouch cell yields a 35.8 % increase in energy density and stable cycling over 600 cycles. This finding affords significant insights into the construction of an efficient prelithiation technology for the development of high-energy LIBs.

Reversible Configurations of 3-Coordinate and 4-Coordinate Boron Stabilize Ultrahigh-Ni Cathodes with Superior Cycling Stability for Practical Li-Ion Batteries.

Ultrahigh-Ni layered oxide cathodes are the leading candidate for next-generation high-energy Li-ion batteries owing to their cost-effectiveness and ultrahigh capacity. However, the increased Ni content causes larger volume variations and worse lattice oxygen stability during cycling, resulting in capacity attenuation and kinetics hysteresis. Herein, a Li2SiO3-coated Li(Ni0.95Co0.04Mn0.01)0.99B0.01O2 ultrahigh-Ni cathode that well-addresses all the above issues, which is also the first time to realize the real doping of B ions is demonstrated. The as-obtained cathode delivers a reversible capacity of up to 237.4 mAh g-1 (924 Wh kg-1 cathode) and a superior capacity retention of 84.2% after 500 cycles at 1C in pouch-type full-cells. Advanced characterizations and calculations verify that the boron-doping is existed in terms of 3-coordinate and 4-coordinate configurations and their high electrochemical reversibility during de-/lithiation, which greatly stabilizes oxygen anions and impedes Ni-ion migration to Li layer. Furthermore, the B-doping engineers the primary particle microstructure for better relaxing the lattice strain and accelerating Li-ion diffusion. This work advances the energy density of cathode materials into the domain of above 900 Wh kg-1, and the concept will inspire more intensive study on ultrahigh-Ni cathodes.

Construction of Ordered and Fast Lithium Ion Channels in Gel Electrolytes for Li-SPAN Batteries.

As one of the most promising battery systems, the lithium sulfur battery is expected to be widely used in fields of high energy density demands. Owing to the unique solid-solid conversion mechanism, there is no shuttle effect for the Li-SPAN (sulfurized polyacrylonitrile) battery. However, the compatibility between Li anode and carbonate electrolyte has not been resolved, which prevents the SPAN from practical applications. Herein, an organic-inorganic gel carbonate electrolyte is proposed to stabilize interphases and structures of both the anode and cathode, where polyimide (PI) is used for electrolyte gelation, which can assist in the uniform distribution of inorganic components at the electrolyte interface. Furthermore, ZnS nanodots loaded on two-dimensional MoS2 flakes provide abundant Li-ion diffusion paths, improve the transfer kinetic of Li ions, and induce uniform nucleation and deposition of Li. This gel electrolyte ensures Li symmetric cells a long-term cycle life of more than 900 h under the condition of deep lithium plating/stripping at 5 mAh cm-1. Li∥Cu cells exhibit a prolonged lifespan of 800 h with a CE of 98.3%. Furthermore, the Li-SPAN battery shows stability of more than 850 cycles, with the capacity retention of 85.1%. This work provides an approach for high-energy Li-SPAN batteries with carbonate-based electrolytes.

Mitigating the Kinetic Hysteresis of Co-Free Ni-Rich Cathodes via Gradient Penetration of Nonmagnetic Silicon.

Co-free Ni-rich layered oxides are considered a promising cathode material for next-generation Li-ion batteries due to their cost-effectiveness and high capacity. However, they still suffer from the practical challenges of low discharge capacity and poor rate capability due to the hysteresis of Li-ion diffusion kinetics. Herein, based on the regulation of the lattice magnetic frustration, the Li/Ni intermixing defects as the primary origin of kinetic hysteresis are radically addressed via the doping of the nonmagnetic Si element. Meanwhile, by adopting gradient penetration doping, a robust Si-O surface structure with reversible lattice oxygen evolution and low lattice strain is constructed on Co-free Ni-rich cathodes to suppress the formation of surface dense barrier layer. With the remarkably enhanced Li-ion diffusion kinetics in atomic and electrode particle scales, the as-obtained cathodes (LiNixMn1-xSi0.01O2, 0.6≤x≤0.9) achieve superior performance in discharge capacity, rate capability, and durability. This work highlights the coupling effect of magnetic structure and interfacial chemicals on Li-ion transport properties, and the concept will inspire more researchers to conduct an intensive study.

Stabilization of single crystal LiNi0.90Mn0.05Co0.05O2 via ZrO2 dual-functional coating enables superior performance for solid-state lithium battery

Chlorine-rich argyrodites with ultrafast Li-ion conductivities exhibits great potential as solid electrolytes for all-solid-state lithium batteries. However, the poor interfacial stability and slow ion dynamics between Li5.5PS4.5Cl1.5 (Cl1.5) and high nickel layered cathode hinder the achievement of superior battery performances. Here, the prepared ZrO2 coating film was found to perform two functions: enhancing the bulk and interfacial stability of single crystal LiNi0.90Mn0.05Co0.05O2 (NCM911) towards sulfide, and facilitating Li-ion transport rates across the interface. A Li2ZrO3 phase with fast Li-ion diffusion rate generates during cycling and further improve the layered-structure integrity of NCM911 and interfacial stability toward the Cl1.5 electrolyte, which are due to the reduction of lattice oxygen release from NCM911 and the isolation of direct contact between the two materials. As a result, these effects enable superior electrochemical performances for the ZrO2-coated NCM911 than the bare sample in Cl1.5-based all-solid-state lithium batteries at varying C-rates and different operating temperatures. It delivers high initial discharge capacities of 156.6 mAh g−1 at 2C and retains 86.0 % of its capacity after 1000 cycles at room temperature, and displays an initial discharge capacity of 172.6 mAh g−1 at 0.5C under 60 °C and 142.4 mAh g−1 at 0.1C under –20 °C, respectively. This dual-functional surface modification strategy provides guidelines to stabilize high-nickel cathode in sulfide-based all-solid-state lithium batteries.

Recent Advancements of Graphene and Some Selected Graphene-Based Electrode Materials for Lithium-Ion Battery

Graphene is a two-dimensional monolayer of carbon atoms arranged in a hexagonal lattice consisting of sp2 hybridized conjugated carbon atoms and serves as a promising electrode material for lithium-ion batteries (LIBs) owing to its superior properties, including a high specific surface area (2630 m2g-1), a high theoretical capacity (744 mAhg-1), excellent electrical conductivity, and a wide electrochemical potential window. Despite having these superior properties, the restacking as well as the van der Waals forces of attraction among the graphene layers and the long path for Li-ion diffusion are factors that reduce the specific surface area and active site for Li-ion storage, which in turn influence the electrochemical performance of LIBs. The functionalization of graphene to porous graphene, graphene quantum dots, and graphene oxides, as well as the integration of graphene with other foreign materials such as transitional metal oxides, various heteroatoms (boron, nitrogen, sulfur, etc.), and covalent organic frameworks (COF), are the two main strategies that have been widely applied to improve the properties of graphene for Li-ion battery applications. In this review, recent works regarding the performance of graphene and graphenebased electrode materials for LIBs applications were reviewed and presented in detail. Moreover, various graphene fabrication techniques in terms of quality and quantity of graphene produced as well as the future overview of graphene and some selected graphene-based materials for LIBs applications have been assessed and summarized.

Unraveling Asymmetric Electrochemical Kinetics in Low-Mass-Loading LiNi1/3Mn1/3Co1/3O2 (NMC111) Li-Metal All-Solid-State Batteries

In this study, we fabricated a Li-metal all-solid-state battery (ASSB) with a low mass loading of NMC111 cathode electrode, enabling a sensitive evaluation of interfacial electrochemical reactions and their impact on battery performance, using Li1.3Al0.3Ti1.7(PO4)3 (LATP) as the solid electrolyte. The electrochemical behavior of the battery was analyzed to understand how the solid electrolyte influences charge storage mechanisms and Li-ion transport at the electrolyte/electrode interface. Cyclic voltammetry (CV) measurements revealed the b-values of 0.76 and 0.58, indicating asymmetry in the charge storage process. A diffusion coefficient of 1.5 × 10−9 cm2⋅s−1 (oxidation) was significantly lower compared to Li-NMC111 batteries with liquid electrolytes, 1.6 × 10−8cm2⋅s−1 (oxidation), suggesting that the asymmetric charge storage mechanisms are closely linked to reduced ionic transport and increased interfacial resistance in the solid electrolyte. This reduced Li-ion diffusivity, along with the formation of space charge layers at the electrode/electrolyte interface, contributes to the observed asymmetry in charge and discharge processes and limits the rate capability of the solid-state battery, particularly at high charging rates, compared to its liquid electrolyte counterpart.

Accelerating Li-Ion Diffusion in LiFePO4 by Polyanion Lattice Engineering.

Despite the widespread commercialization of LiFePO4 as cathodes in lithium-ion batteries, the rigid 1D Li-ion diffusion channel along the [010] direction strongly limits its fast charge and discharge performance. Herein, lattice engineering is developed by the planar triangle BO3 3- substitution on tetrahedron PO4 3- to induce flexibility in the Li-ion diffusion channels, which are broadened simultaneously. The planar structure of BO3 3- may further provide additional paths between the channels. With these synergetic contributions, LiFe(PO4)0.98(BO3)0.02 shows the best performance, which delivers the high-rate capacity (66.8 mAhg-1 at 50 C) and long cycle stability (ultra-low capacity loss of 0.003% every cycle at 10 C) at 25°C. Furthermore, excellent rate performance (34.0 mAhg-1 at 40 C) and capacity retention (no capacity loss after 2500 cycles at 10 C) at -20°C are realized.

Dual-Seed Strategy for High-Performance Anode-Less All-Solid-State Batteries.

Interest in all-solid-state batteries (ASSBs), particularly the anode-less type, has grown alongside the expansion of the electric vehicle (EV) market, because they offer advantages in terms of their energy density and manufacturing cost. However, in most anode-less ASSBs, the anode is covered by a protective layer to ensure stable lithium (Li) deposition, thus requiring high temperatures to ensure adequate Li ion diffusion kinetics through the protective layer. This study proposes a dual-seed protective layer consisting of silver (Ag) and zinc oxide (ZnO) nanoparticles for sulfide-based anode-less ASSBs. This dual-seed-based protective layer not only facilitates Li diffusion via multiple lithiation pathways over a wide range of potentials, but also enhances the mechanical stability of the anode interface through the in situ formation of a Ag-Zn alloy with high ductility. The capacity retention during full-cell evaluation is 80.8% for 100 cycles when cycled at 1mA cm-2 with 3 mAh cm-2 at room temperature. The dual-seed approach provides useful insights into the design of multi-seed concepts in which, from a mechanochemical perspective, various lithiophilic materials synergistically impact upon the anode-less interface.

Interface Stability and Reaction Mechanisms of Li3YCl5Br with High-Voltage Cathodes and Li Metal Anode: Insights from Ab Initio Simulations.

Recent advancements in battery technology emphasize the critical role of solid electrolytes in enhancing the performance and safety of next-generation batteries. In this study, we investigate the interface stability and reaction mechanisms of Li3YCl5Br, a promising halide-based solid electrolyte, in contact with high-voltage Ni-Mn-Co (NMC) cathodes and a Li metal anode using ab initio molecular dynamics simulations. Our findings reveal that Li3YCl5Br reacts with charged NMC cathodes. This reaction involves changes in the oxidation states of Br- anions in Li3YCl5Br and d-element cations in NMC, as well as the diffusion of Li ions from the solid electrolyte to the cathode to maintain charge balance. The reaction is confined to the interface, suggesting bulk stability. Conversely, the Li/Li3YCl5Br interface exhibits significant instability, with a chemical reaction that results in substantial structural changes and the formation of LiCl and LiBr at the solid electrolyte surface and metallic Y at the Li anode surface. These insights provide valuable information for optimizing interfacial design, aiming at improving the performance and reliability of all-solid-state batteries using halide solid electrolytes.

Ti3C2Tx MXene coated 3D ordered macroporous germanium anodes for Li-ion batteries with enhanced cycling stability and fast Li-ion mobility

The current trend in electronic device development and electric vehicle technology has resulted in A growing need for negative electrode materials that possess high capacity and quick Li-ion transport properties. Ge-based materials are considered the very promising candidates owing to their high theoretical capacity and facile alloying reaction with Li. In order to enhance the rate of Li-ion diffusion and account for the volume change of over 300 %, a Ti3C2Tx MXene coated 3D ordered macroporous germanium (3DOM Ge@MXene) structure was successfully developed. The 3DOM Ge@MXene provides a 1490 mAh g−1 initial reversible capacity at 0.32 A g−1. Additionally, after 100 cycles, it displays a consistent cycling ability of 1034 mAh g−1. The MXene coating also improves the material's Li-ion rapid transfer performance, with Li-ion diffusion coefficient of 1.35 × 10−10 cm2s−1 for anodic and 2.2 × 10−10 cm2s−1 for cathodic.

Enhancing Electrochemical Performance of Si@CNT Anode by Integrating SrTiO3 Material for High-Capacity Lithium-Ion Batteries

Silicon (Si) has attracted worldwide attention for its ultrahigh theoretical storage capacity (4200 mA h g−1), low mass density (2.33 g cm−3), low operating potential (0.4 V vs. Li/Li+), abundant reserves, environmentally benign nature, and low cost. It is a promising high-energy-density anode material for next-generation lithium-ion batteries (LIBs), offering a replacement for graphite anodes owing to the escalating energy demands in booming automobile and energy storage applications. Unfortunately, the commercialization of silicon anodes is stringently hindered by large volume expansion during lithiation–delithiation, the unstable and detrimental growth of electrode/electrolyte interface layers, sluggish Li-ion diffusion, poor rate performance, and inherently low ion/electron conductivity. These present major safety challenges lead to quick capacity degradation in LIBs. Herein, we present the synergistic effects of nanostructured silicon and SrTiO3 (STO) for use as anodes in Li-ion batteries. Si and STO nanoparticles were incorporated into a multiwalled carbon nanotube (CNT) matrix using a planetary ball-milling process. The mechanical stress resulting from the expansion of Si was transferred via the CNT matrix to the STO. We discovered that the introduction of STO can improve the electrochemical performance of Si/CNT nanocomposite anodes. Experimental measurements and electrochemical impedance spectroscopy provide evidence for the enhanced mobility of Li-ions facilitated by STO. Hence, incorporating STO into the Si@CNT anode yields promising results, exhibiting a high initial Coulombic efficiency of approximately 85%, a reversible specific capacity of ~800 mA h g−1 after 100 cycles at 100 mA g−1, and a high-rate capability of 1400 mA g−1 with a capacity of 800 mA h g−1. Interestingly, it exhibits a capacity of 350 mAh g−1 after 1000 lithiation and delithiation cycles at a high rate of 600 mA hg−1. This result unveils and sheds light on the design of a scalable method for manufacturing Si anodes for next-generation LIBs.

Phonon-Lithium Ion Interactions: A Case Study of LiM(SeO3)2 (M = Al, Ga, In, Sc, Y, and La).

Li ion diffusion is fundamentally a thermally activated ion hopping process. Recently, soft lattice, anharmonic phonon, and paddlewheel mechanism have been proposed to potentially benefit the ion transport, while the understanding of vibrational couplings of mobile ions and anions is still very limited but essential. Herein, we accessed the ionic conductivity, stability, and especially, lattice dynamics in LiM(SeO3)2 (M = Al, Ga, In, Sc, Y, and La) with two different types of oxygen anions within a LiO4 polyhedron, namely, edge-shared and corner-shared with MO6 polyhedra, the prototype of which, LiGa(SeO3)2, has been theoretically reported before with the similar structural features to NASICON and later experimentally synthesized with the room temperature conductivity ∼0.11 mS cm-1. It is interesting to note that LiM(SeO3)2 with a higher Li phonon band center shows higher Li conductivity, which is in contradiction to the conventional understanding of the importance for soft lattice to superionic conductors. The anharmonic and harmonic phonon interactions as well as the couplings between the vibration of the edge-bonded or corner-bonded anion in Li polyanions and the Li ion diffusion have been studied in detail. With transition metal M changing from La, Y, In, Ga, Al, and Sc, anharmonic phonons increase with reduced activation energy for Li diffusion. The phonon modes dominated by the edge-bonded oxygen anions contribute more to the migration of the Li ion than those dominated by the corner-bonded oxygen anions because of the greater atomic interaction between the Li ion and the edge-bonded anions. Thus, rather than the overall lattice softness, attention shall be given to reduce the frequency of the critical phonons contributing to Li ion diffusion as well as to increase the anharmonicity, i.e., through asymmetric Li polyhedra, for the design of Li ion superionic conductors for all-solid-state batteries.

Understanding the impact of porosity on Li-ion diffusion enhancement in micro-sized silicon particles for advanced batteries

Lithium-ion batteries (LIBs) require advanced and practical anode materials, such as porous silicon (PSi), which can meet these expectations due to their rapid Li-ion diffusion rates and structural relaxation. Several studies have focused on the structural design of PSi or its composites to improve Li-ion diffusion; however, no systematic and quantitative evaluations of the impact of porosity on Li-ion diffusion and battery performance have been reported. Therefore, to understand the impact of porosity on Li-ion diffusion, we developed micro-sized porous silicon (m-PSi) particles with various porosities via metal-assisted chemical etching (MACE) method using different concentrations of AgNO3 (0.02–0.08 M). Among the as-prepared samples, m-PSi-0.06 (prepared using 0.06 M AgNO3) with ∼70 % porosity achieved a maximum Li-ion diffusion rate of 2.35 × 10−9 cm2 s−1. This led to a high-rate capability, enhanced Li-ion storage, and better cyclic retention of 61.4 % compared to the non-porous micro-sized Si (m-Si) (5.8 %) sample at a current density of 0.1 A g−1. Furthermore, the optimal porosity of m-PSi-0.06 resulted in an impressive rate capability of 760 mAh g−1 at a high current density of 4 A g−1 with a recovery rate of 80 %. The improved efficiency of m-PSi-0.06 is attributed to its optimized mesoporosity, which ensures sufficient space for Li-ion storage and shortens the effective transmission path to accelerate Li-ion diffusion. Moreover, the mesopores provide a greater number of active sites for the reversible adsorption of Li ions, thereby improving the capacitive behavior of the anode. In contrast, the highly nanoporous m-PSi-0.08, with a pore diameter of 1–3 nm, impeded Li-ion movement and restricted diffusion. These results reveal that a high nano porosity hinders Li-ion diffusion, whereas an optimal mesoporosity ensures swift diffusion in m-PSi anodes. These insights could guide the design of Si-based anode materials for advanced LIBs.

The role of sodium in the electrochemical tuning of Li2TiSiO5 anodes across ceramic and glass phases

This study investigates the enhancement of Li2TiSiO5 anode material through Na doping via two routes: melt-quenching (route I) and subsequent heat treatment (route II). A 5 % Na-doped ceramic sample significantly improves Li-ion mobility and discharge capacity (215 mA h g−1 at 10 mA g−1), sustaining 45 mA h g−1 at a high rate of 1 A g−1. However, higher doping levels hinder performance, indicating Li-ion path obstruction and non-conductive impurities. Intriguingly, undoped Li2TiSiO5 glass exhibits superior electrochemical performance, with a discharge capacity of 340 mA h g−1 at 10 mA g−1 and high-rate endurance (81 mA h g−1 at 1 A g−1). This research provides insights into phase-dependent optimization, highlighting the glass phase's inherent benefits for Li-ion diffusion. It addresses a significant research gap, offering critical understanding for advancing high-energy-density anode materials in next-generation batteries.

Recent advances in functionalized separator for dendrites‐free and stable lithium metal batteries

AbstractLithium (Li) metal anode is considered the “Holy grail” for the most promising next‐generation rechargeable lithium metal batteries (LMBs) because of ultra‐high theoretical specific capacity, ultra‐low reduction potential and small density. However, uncontrolled lithium dendrite growth and inevitable side reaction seriously hindered the application of practical LMBs because of the deteriorating electrochemical performances and exacerbating the safety issues of LMBs. Thus, improving the electrochemical performances of LMBs by constructed of functionalized separator is promising for overcoming the above‐mentioned challenges due to its' significantly advantages, such as enhancing mechanical and thermal stability, regulating the diffusion and migration of Li ions, homogenizing Li ion flux, forming protective layer on Li anode surfaces, etc. The relational investigations have significantly increased since 2020, while the comprehensive reviews on this research direction are relatively rare, especially in the detailed mechanism aspects. In this review, an overview in functionalized separator for stable LMBs is discussed in detail. Firstly, the current issues of LMBs are in‐depth discussion and the general strategies are summarized. Subsequently, the requirements and limitations of separator, as well as the advantages of functionalized separator are summarized and reviewed. Most importantly, the protection mechanisms and research advances of advanced functionalized separator are comprehensively discussed and summarized. Furthermore, the applications of functionalized separator in rechargeable lithium metal‐based full cells are reviewed. Finally, the challenges and potential opportunities for the future development and rational design of functionalized separator are highlighted in rechargeable LMBs to obtain future research directions related to the significant strategy of constructing dendrite‐free and stable LMBs.

The role of crystallographic orientation on surface properties and ion transport in lithium germanate (Li2GeO3) anodes: A computational approach

The performance of lithium-ion batteries (LIBs) hinges on the surface properties of their anodes. Compared to the bulk material, the anode surface is more susceptible to environmental changes during lithium (Li) intake and release, directly impacting factors like capacity, cycling stability, and charge/discharge rates. Lithium germanate (Li2GeO3, LGO) has emerged as a promising anode material due to its fast Li-ion conduction. While numerous studies have explored performance improvements through various methods, including defect engineering. However, there is currently a lack of atomistic-level understanding of the surface structure. Consequently, despite the importance of precisely understanding the surface to manipulate its different properties, specific surface details of LGO remain unclear. This knowledge gap hinders precise manipulation of surface properties for optimal performance.This study addresses this critical need by employing theoretical calculations to predict the structural, electrochemical characteristics, and Li-ion transport behavior in LGO surfaces. Our results indicate that polar surfaces exhibit lower formation energies compared to non-polar surfaces. Further investigation revealed that Li-terminated surfaces possess the lowest surface energy among various surface terminations. Interestingly, the work function calculations displayed an opposite trend to surface formation energy, with polar surfaces exhibiting the lowest work function values.To explore Li-ion transport, we employed ab initio molecular dynamics simulations. Notably, the (003) surface displayed the highest Li-ion diffusion rate among all considered surfaces.Further analysis of the (001) surface, which exhibited similar diffusion pathways to the (003) surface, revealed a lower diffusion rate.To understand this disparity, nudged elastic band (NEB) simulations were used to estimate the energy barriers for Li-ion migration along each pathway in both structures. Despite sharing similar pathways, the energy barriers in the (003) surface were significantly lower than those in the (001) surface. This finding suggests that the intrinsic energy landscape of the surface plays a crucial role in dictating Li-ion transport behavior.

Mechano-thermochemical preparation of nanostructured (FeCoNiCr/Mn)3O4 high and medium entropy oxides: Structural, microstructural, magnetic and Li-ion storage characterization

Mechano-thermochemical synthesis of (FeCoNiCrMn)3O4 high-entropy oxide (HEO) and (FeCoNiCr)3O4 medium-entropy oxide (MEO), and their structural, microstructural, magnetic, surface and electrochemical characteristics are investigated. Ball milling substantially reduces crystalline sizes of oxide precursors, causing their partial solid-state dissolution, driving the rapid formation of HEO and MEO during the subsequent thermal treatment. Nanostructured HEO prepared at 900 °C (HEO-900) comprises single-phase octahedral crystals mostly within the range 60–80 nm, while MEO-900 crystals (80–120 nm) exhibit a greater degree of agglomeration. The contribution of oxygen vacancies to total surface oxygen in MEO-900 (20.6 %) is lower than that of HEO-900 (27.6 %). HEO-900 exhibits a superior reversible Li-ion storage capacity of 1050.6 mAh/g after 300 cycles at 100 mA/g, outperforming MEO-900. However, at the higher current density of 500 mA/g, MEO-900 shows superior performance, with a reversible capacity of 432.2 mAh/g (70.3 % retention) after 750 cycles. The charge transfer resistance of fresh HEO-900 (359.0 Ω) is greater than that of MEO-900 (241.4 Ω), and the average Li-ion diffusion coefficient in HEO-900 (10-13.3 cm2 s−1) is lower than that on MEO-900 at (10-13.1 cm2 s−1) due to the greater structural complexity of the former. Full cells incorporating HEO-900 and MEO-900 anodes with LiFePO4 cathode demonstrate an energy density of 296.4 and 274.6 Wh kg−1, respectively. The saturation magnetization of HEO-900 and MEO-900 is significantly high at 33.98 and 33.80 emu/g, respectively, enabling the easy magnetic recovery of electrodes made from these compounds in spent LIBs.

Carbon-decorated hydrated V10O24 nanorods for high-performance lithium-ion battery cathodes

This study reports the successful synthesis of carbon-decorated hydrated V10O24 (HVO@C) nanorods using a facile hydrothermal method. The synthesized material was comprehensively characterized using XRD, FTIR, Raman, TGA/DSC, BET, SEM, and HRTEM to reveal its structure and morphology, and the resulting electrode's electrochemical performance as a lithium-ion battery (LIB) cathode was evaluated for the first time. The HVO@C nanorods exhibited a remarkable initial capacity of 292.5 mAh g−1 at 75 mA g−1 current rate, exceeding most of the reported V2O5-based LIB cathodes. Notably, the HVO@C electrode retained a good capacity retention of 67.1 % and a slower capacity loss rate of 0.26 % after 125 cycles compared to most V2O5-based counterparts with shorter lifespans. This outstanding performance could be due to a synergistic interplay of structural characteristics. The large interlayer spacing within the nanorods facilitated unimpeded Li-ion diffusion, while the short diffusion path minimized transport limitations. Furthermore, the strategic incorporation of carbon coating enhanced electrical conductivity and structural stability, leading to enduring LIB battery performance. These results indicate that in-situ carbon-decorated hydrated V10O24 nanoparticles have great potential as a promising cathode electrode for LIBs with exceptional performance.

F-doping effects on microstructure and electrochemical performance of cathode material Li1.2Mn0.54Ni0.13Co0.13O2

Lithium-rich manganese-based (Li-rich Mn-based) cathode materials possess high specific capacity, low self-discharge rate and steady working voltage, but cycle performance and rate performance need to be further improved. In this study, cathode materials Li1.2Mn0.54Ni0.13Co0.13O2-xFx (x = 0, 0.02, 0.05, 0.08) are synthesized by the co-precipitation method with the two-step calcination process. And the F-doping effects on the microstructure and the electrochemical performance are investigated in the cathode materials Li1.2Mn0.54Ni0.13Co0.13O2. The results indicate that among all the F-doped cathode materials, the crystal lattice parameters are increased, order degree and stability of the layered structure are improved. As for x = 0.05, cathode material Li1.2Mn0.54Ni0.13Co0.13O1.95F0.05 (LMO-F0.05) shows the best cycle performance and rate performance with its capacity retention rate 87.7% after 100 cycles at 0.2 C and discharge capacity 117 mAh g−1 at 5 C high power. It can be seen that F doping is a simple and crucial strategy to promote the Li ion diffusion and develop high performance layered cathode materials.