Materials For Lithium-ion Batteries Research Articles

Electrochemical Activation Inducing Rocksalt-to-Spinel Transformation for Prolonged Service Life of LiMn2O4 Cathodes.

LiMn2O4 spinel is emerging as a promising cathode material for lithium-ion batteries, largely due to its open framework that facilitates Li+ diffusion and excellent rate performance. However, the charge-discharge cycling of the LiMn2O4 cathode leads to severe structural degradation and rapid capacity decay. Here, an electrochemical activation strategy is introduced, employing a facile galvano-potentiostatic charging operation, to restore the lost capacity of LiMn2O4 cathode without damaging the battery configuration. With an electrochemical activation strategy, the cycle life of the LiMn2O4 cathode is extended from an initial 1500 to an impressive 14 000 cycles at a 5C rate with Li metal as the anode, while increasing the total discharge energy by ten times. Remarkably, the electrochemical activation enhances the diffusion kinetics of Li+, with the diffusion coefficient experiencing a 37.2% increase. Further investigation reveals that this improvement in capacity and diffusion kinetics results from a transformation of the redox-inert LiMnO2 rocksalt layer on the surface of degraded cathodes back into active spinel. This transformation is confirmed through electron microscopy and corroborated by density functional theory simulations. Moreover, the viability of this electrochemical activation strategy has been demonstrated in pouch cell configurations with Li metal as the anode, underscoring its potential for broader application.

Mitigating degradation and modulating electronic structure via an epitaxial perovskite protection for Li-rich layered oxides

Li-rich layered oxides are highly promising cathode materials for the next-generation lithium-ion batteries due to their extraordinary specific capacity and hence high energy density. However, their practical application is hindered by the structural and surface instabilities as well as sluggish reaction kinetics. Herein, a low-crystallinity perovskite oxide (NdTiO3) is developed to epitaxially conform the surface of a typical Li-rich layered oxide Li1.2Mn0.54Ni0.13Co0.13O2 to overcome these drawbacks. Experimental and computational results confirm that this surface phase not only mitigates structural deformation and interfacial side reactions, but also can modulate the electronic structure of Li2MnO3 for the higher electron conductivity. As a result, the epitaxially-protected cathode material displays much better cycle stability (222.02 mA h g−1 after 200 cycles at 1C compared to 185.06 mA h g−1 for the uncoated one) and excellent rate capability (155.71 mA h g−1 at 5C). A pouch-type full cell using commercial graphite anode demonstrates an energy density (381.38 Wh kg−1 based on the cathode and anode) and a capacity retention of 91.1% after 100 cycles.

Combination of silicene and boronene as a potential anode material for high-performance lithium-ion batteries: Insights from first principles

Material design is essential for the development and preparation of new materials. In this paper, a new two-dimensional heterostructure material (B@Si) consisting of boronene and silicene is designed and used as an anode material for lithium-ion batteries in order to improve the performance of lithium-ion batteries, and the structural properties, stability, electronic properties, and performance as an anode material for lithium-ion batteries are systematically investigated by first-principle calculations of the B@Si heterostructure. The results show that the B@Si heterostructure is energetically, thermodynamically and dynamically stable, and although the Dirac cone in the energy band structure of silicene disappears after the formation of the heterojunction, the overall electrical conductivity of the material improves considerably and the electron transport rate is faster. Due to the synergistic effect, Li has more stable adsorption sites and lower diffusion barriers than boronene and silicene in the B@Si heterostructure, higher theoretical specific capacity (1208 mAhg−1), and stronger mechanical properties (C11 = 296.6 N/m, C22 = 142.8 N/m). The volume expansion in the fully lithiated state is also only 8 %. These advantages indicate that B@Si heterostructures are good potential anode materials for high-performance Li-ion batteries.

An innovative double-Shell layer nitrogen and sulfur co-doped carbon-Encapsulated FeS composite for enhanced lithium-Ion battery performance

FeS, with its high theoretical capacity and natural abundance, holds significant promise as an anode material for lithium-ion batteries (LIBs). However, its practical application is constrained by poor electrical conductivity and substantial volume expansion during cycling, which impair charge–discharge efficiency and cycling stability. To overcome these challenges, we developed a nitrogen and sulfur co-doped carbon-encapsulated FeS composite with a hollow double-layer structure (HDL-FeS@NSC). Utilizing sulfur spheres as a sacrificial template, our inside-out synthesis strategy produces a unique material design. The HDL-FeS@NSC composite exhibits significant improvements in electrochemical performance compared to pure FeS. These enhancements are due to its increased specific surface area, which facilitates lithium-ion diffusion; a shortened Li+ diffusion pathway; structural stability that mitigates volume expansion; and an optimized carbon layer that boosts conductivity. The HDL-FeS@NSC-70 anode demonstrates a specific capacity of 879.6 mAh/g after 600 cycles at 1.0 A/g and retains 558.0 mAh/g at 5.0 A/g. Additionally, the lithium storage mechanism has been thoroughly investigated using in-situ techniques. These results suggest that the HDL-FeS@NSC composite anode has the potential to significantly enhance lithium-ion battery performance, offering a promising solution for next-generation energy storage systems.

Electric-Thermal Analysis of Power Supply Module in Graphitization Furnace

Graphite, a key anode material in lithium-ion batteries, primarily relies on the Acheson graphitization furnace (AGF) for production. This research focuses on the power supply module of the AGF, particularly the electrodes and their power transmission clamps. A three-dimensional transient electric-thermal-fluid coupling model was developed to numerically analyze the temperature and electric field distributions during operation. The study revealed that heat conduction through furnace electrodes dominates temperature rise. Notably, clamping plates within transmission clamps exhibit high temperatures and gradients, posing a thermal failure risk. Efficient cooling plate design with liquid-cooled channels is crucial for temperature control. Additionally, maintaining high electrode temperatures reduces resistivity, lowering power consumption in the power supply module. This study provides insights into optimizing AGF power supply module design, emphasizing the importance of effective cooling strategies for clamping plates and the benefits of maintaining elevated electrode temperatures for energy efficiency.

Construction of 2D/1D rGO/H2Ti3O7 composite as anode for high performance lithium-ion batteries

Ultrafine one-dimensional (1D) H2Ti3O7 nanowires were prepared by a hydrothermal reaction with high concentration of KOH as base source. Then 2D/1D rGO/H2Ti3O7 architecture was constructed and investigated as the anode material for lithium-ion batteries. Benefiting from the addition of rGO nanosheets and the retention of ultrafine 1D H2Ti3O7 nanowires, the rGO/H2Ti3O7 electrode presented superior electrochemical performance with excellent rate capability, long cycling stability and high capacity in half cells. It delivered high reversible capacities of 274 mAh g−1 at 0.1 A g−1 and 163 mAh g−1 at 1 A g−1, as well as a long-term cycling performance (259.3 mAh g−1 at 0.2 A g−1 after 1000 cycles). The excellent electrochemical performance of the composite can be attributed to the unique architecture with smaller diameter of 1D H2Ti3O7 nanowires and conductive rGO nanosheets to shorten the transmission distance of electrons and Li+ and improve the electrical conductivity in rGO/H2Ti3O7 composite.

Preparation and electrochemical properties of nitrogen-doped starch hard carbon anode materials for lithium-ion battery

Here, we report the synthesis of hard carbon materials (CSHs) made from corn starch and their application as an anode in lithium-ion batteries. The study shows that the microstructure and electrochemical properties of CSHs are affected by nitrogen doping. It is found that nitrogen is embedded in the carbon layer with graphite nitrogen, pyridyl nitrogen, and pyrrole nitrogen, so that the surface morphology was changed and reduced the disorder of the materials. The electrochemical test results show that the introduction of nitrogen elements can increase the reversible capacity of the material, with the first discharge capacity reaching above 426.35 mAh g−1, and the rate performance also improves. When melamine and pre-carbonized corn starch are carbonized at a mass ratio of 1:9, the obtained material has a reversible capacity of 122.04 mAh g−1 at a rate of 2 C. During the carbonization process, the nitrogen in melamine is doped into the carbon materials, improving the electrochemical performance of the material.

Electrochemical properties of tungsten doped LiNi0.9Co0.1O2 lithium-ion battery cathode materials

High-nickel layered cathode materials for lithium-ion batteries have received widespread attention in new energy vehicles for their excellent specific energy and cost advantages, and are considered to be the most promising cathode materials for high-energy density lithium-ion batteries. Despite its many advantages, poor thermal stability and rapid capacity degradation have greatly limited its large-scale application. Ion doping is considered to be an effective way to improve its drawbacks, and in this paper, a series of W-doped LiNi0.9Co0.1O2 cathode materials were prepared using WO3 as a tungsten source. Among them, 1 mol% W doping was the most effective, and its reversible capacity of 204.44 mA g −1 still had 93.25 % capacity retention after 100 this cycles at 1C. Combined with DFT calculations, it is found that the introduction of W does not change the original layered structure and the material transitions from semi-metallic to metallic at lower doping concentrations, resulting in more electrons occupying the Fermi energy levels to enhance its electrical conductivity and leading to an elevated spin state and a lower oxidation state of Ni.

Dual-coated single-crystal LiNi0.6Co0.2Mn0.2O2 as high-performance cathode materials for lithium-ion batteries

Dual-coated single-crystal LiNi0.6Co0.2Mn0.2O2 as high-performance cathode materials for lithium-ion batteries

Magnesiothermic reduction SiO coated with vertical carbon layer as high-performance anode for lithium-ion batteries

Silicon monoxide (SiO), as one of the most competitive anode materials for lithium-ion batteries (LIBs), has received considerable attention. Nevertheless, poor initial Coulombic efficiency (ICE) and larger volume change are the main obstacles to the application of SiO. Here, we suggest a controllable route for the modification of micro-sized SiO via magnesiothermic reduction. To prevent the excessive growth of Si grains caused by the overheating reaction, the solid-state thermal reaction between Mg and SiO is achieved by mixing a certain proportion of NaCl at a suitable temperature, resulting in a loose surface and porous structure of SiO particles, which is conducive to the transportation of lithium ions and electrons. Combined with chemical vapor deposition (CVD), the carbon-coated SiOx composites (M-SiOx@C-R, where R is the molar ratio for Mg and SiO) exhibit unique morphology structure and remarkable electrochemical characteristics. As expected, the vertical carbon network improves the conductivity and alleviates the volume expansion of SiOx. Notably, the M-SiOx@C-0.75 electrode offers a large initial specific capacity of 2283.17 mAh g−1 with a higher ICE of 86.03 % at 100 mA g−1. Furthermore, the full cells using M-SiOx@C-0.75 composite as the negative electrode and LiNi0.8Co0.1Mn0.1O2 (NCM811) as the positive electrode were assembled. After 150 cycles, the full cell still delivers a high specific capacity of 72.22 mAh g−1 (with a retention rate of 47 %). This work provides a feasible route for the fabrication of applicable SiO-based anode materials.

Solid-State Construction of CuO-Cu2O@C with Synergistic Effects of Pseudocapacity and Carbon Coating for Enhanced Electrochemical Lithium Storage.

The pseudocapacitive effect can improve the electrochemical lithium storage capacity at high-rate current density. However, the cycle stability is still unsatisfactory. To overcome this issue, a multivalent oxide with a carbon coating represents a plausible technique. In this work, a CuO-Cu2O@C composite has been constructed by a one-step bilayer salt-baking process and utilized as anode material for lithium-ion batteries. At a current density of 2.0 A g-1, the as-prepared composite delivered a stable discharge capacity of 431.8 mA h g-1 even after 600 cycles. The synergistic effects of the multivalence, the pseudocapacitive contribution from copper, and the carbon coating contribute to the enhanced electrochemical lithium storage performance. Specifically, the existence of cuprous suboxide improves the electrochemical conductivity, the pseudocapacitive effect enhances the lithium storage capacity, and the presence of carbon ensures cycle stability. The testing results show that CuO-Cu2O@C composite has broad application prospects in portable energy storage devices. The present work provides an instructive precedent for the preparation of transition metal oxides with controllable electronic states and excellent electrochemical performance.

In-situ assembly of 3D VS2/Reduced graphene oxide with superior lithium ion storage performance: The role of heterojunction

VS2 is a potential anode material for lithium-ion batteries (LIBs) due to its advantageous properties. Herein, a novel three-dimensional (3D) VS2/reduced graphene oxide (rGO) heterostructure (VS2-rGO) was fabricated by in-situ assembly of caterpillar-like VS2 nanosheets on rGO. This 3D VS2-rGO with a well-defined heterojunction interface is engineered to mitigate the volumetric expansion of VS2 during Li + intercalation/deintercalation cycles. This optimized design promotes enhanced conductivity across the heterojunction, facilitating efficient electron and ion transport. The VS2-rGO electrode shows higher reversible capacity and better rate performance (644.02 mA h g−1 at 0.1 A g−1 after 140 cycles, 526.66 mA h g−1 at 2 A g−1) as compared to the pure VS2 electrode (433.69 mA h g−1 at 0.1 A g−1 after 140 cycles, 63.91 mA h g−1 at 2 A g−1). Ex-situ XRD analysis suggests that the Li + storage mechanism in the VS2-rGO electrode involves the initial intercalation, followed by intercalation and conversion. The lower Li + diffusion barrier within the VS2-rGO heterojunction (0.183 eV) compared to the VS2 layers (0.225 eV), as predicted by first-principles calculations, resulting the enhanced Li + transport kinetics and improved cycling performance of the VS2-rGO electrode material. This work offers novel perspectives for the influence of heterojunctions on LIBs.

Facile preparation of MnO/Mn3O4 anode from commercial manganese(II) oxalate dihydrate and its advanced lithium storage performance

Manganese oxides are considered a highly promising anode material in lithium ion batteries (LIBs) because of their high theoretical capacity, abundant sources, relatively low voltage hysteresis, nontoxic and cost-effectiveness. Nevertheless, the practical application of these materials faces many challenges such as poor lifespan and serious volume variation during operation. Herein, MnO/Mn3O4–600 composite was obtained based on a single-step pyrolysis procedure from commercial manganese(II) oxalate dihydrate (MOD, C2H4MnO6). The MnO/Mn3O4–600 anode exhibits an exceptionally high reversible capacity of 1041.8 mAh g−1 at the current density of 200 mA g−1, and a remarkable lifespan at 1000 mA g−1. The outstanding performance benefits from the formation of porous structures on nanoparticles, which not only mitigate volume changes and prevent the aggregation of internal MnO/Mn3O4 nanoparticles, but also enhance the ion diffusion. The in-depth insights into the (de)lithiated mechanism of the electrode are investigated by in situ X-ray diffraction (XRD) technique. Moreover, when applied in a full cell, the MnO/Mn3O4–600 anode demonstrates exceptional electrochemical property.

One step for the construction of MnCO3-Mn3O4 composite for the high-performance lithium-ion batteries

In this work, MnCO3-Mn3O4 composite materials were prepared by one-step solvothermal method. The structure, morphology and chemical composition were characterized and analyzed. As the anode materials of lithium-ion batteries, the formed MnCO3-Mn3O4 composites on the basis of initial KMnO4/DMF weight ratio of 1:40 and 1:20 delivered the specific discharge capacities of 654.8 and 598.7 mA h g−1 after 100 cycles at a current density of 1.0 A g−1. The testing results indicate that MnCO3-Mn3O4 composite has significant advantage in electrochemical lithium storage capacity and can be utilized as one prospective anode material for the high performance lithium-ion batteries.

Enhanced interfacial and cycle stability of 4.6 V LiCoO2 cathode achieved by surface modification of KAlF4

Lithium cobalt oxide is one of the most popular cathode materials for lithium-ion batteries. Due to its relatively low capacity, increasing the output voltage is often necessary to release more capacity. However, subjecting cathode materials to high charging potentials inevitably induces surface-side reactions, compromising the integrity of the crystal structure and accelerating capacity degradation. Therefore, the stability of cathode materials at high voltage becomes crucial for lithium-ion batteries. In this study, we employed the ternary compound KAlF4 (KAF) as a surface modification coating for LiCoO2 (LCO). With the optimized ratio (1 wt%) of KAF, coated LCO cathodes exhibited enhanced capacity retention, excellent cycling, and rate stability. In the high voltage range of 3.0–4.6 V, the specific capacity of the initial discharge at a rate of 0.5 C reached 198.30 mA h g−1. Remarkably, the coated LCO retained 91.56 % of its initial capacity after 200 cycles at 0.5 C. Even at a high rate of 5 C, the coated sample retained a discharge capacity of 120.87 mA h g−1, significantly higher than that of bare LCO (80.24 mA h g−1). After a thorough investigation into the structure changes before and after cycling, we elucidated the mechanism of KAF coating in improving the stability of high-voltage LCO cathodes. The results indicated that KAF forms a stable passivation layer on the surface of LCO, which suppresses cracking and corrosion during charging and discharging, eventually stabilizes the crystal structure, and enhances the cycling stability of LCO.

Self-assembled Si-based anode combined with electrostatic spinning method to realize high-performance lithium-ion batteries

Addressing the volume expansion when silicon and metal oxides alone are used as anode materials for lithium-ion batteries. This study used a simple self-assembly method and electrostatic spinning technique to prepare silicon@copper oxide@carbon nanofibres (CNFs) anodes with dual modification. The high rigidity of metal oxide CuO and the excellent cycling stability of CNFs effectively reduce the buildup of silicon particles, alleviate the volume expansion effect, and improve the electrical conductivity, which leads to better cycling stability and larger specific capacity of lithium-ion batteries. An excellent reversible specific capacity of 748.5 mAh g‐1−1 was observed after 800 cycles at a high current density of 1 A g−1. In addition, the surface of Si@CuO@CNFs electrodes remains smooth and undamaged after 800 cycles, and the increase in cross-sectional thickness is about 68 %, which is significantly smaller than the 300 % increase in cross-sectional thickness of pure Si anode and effectively improves the specific capacity of Li-ion batteries. This research optimizes the design of silicon-based anode materials with simple and mature process technology, which makes an indispensable contribution to developing high-efficiency, long-life, and environmentally friendly lithium-ion batteries. The easy availability and non-polluting nature of the materials used also effectively reduce the reliance on rare or expensive elements, minimize the production process's environmental impact, and vigorously promote the global energy transition and low-carbon green development strategy.

Hollow Ni/NiO@N-doped porous carbon for lithium ion battery anode based on dual-buffering strategy

As a promising anode material of lithium-ion batteries (LIBs), the poor electrical conductivity and severe volume expansion during cycling of nickel oxide (NiO) greatly limit its practical application. Here, a hollow nitrogen-doped porous carbon-loaded hollow Ni/NiO nanocomposite (Ni/NiO@HNC) was obtained by introducing Ni2+ into hollow covalent organic framework (HCOF) and then calcining the Ni2+/HCOF. The as-prepared Ni/NiO is nanoscale and hollow, which effectively accommodates the expanded volume of NiO. Hollow nitrogen-doped porous carbon (HNC) obtained from HCOF can further accommodate the expanded volume of NiO. The residual Ni and HNC can improve the electrical conductivity of Ni/NiO@HNC greatly. The regular pores of HNC inherited from HCOF facilitate the Li+ transfer. Thus, the Ni/NiO@HNC-2 composites exhibited outstanding cycle stability and rate performance when utilized as anode materials in LIBs. Even after 200 cycles at 0.1 A g−1, the capacity was still kept at 695.1 mAh g−1. The work provides an idea to prepare LIBs anodes based on dual-buffering strategy.

Zinc Dicyanamide: A Potential High-Capacity Negative Electrode for Li-Ion Batteries.

We demonstrate that the β-polymorph of zinc dicyanamide, Zn[N(CN)2]2, can be efficiently used as a negative electrode material for lithium-ion batteries. Zn[N(CN)2]2 exhibits an unconventional increased capacity upon cycling with a maximum capacity of about 650 mAh·g-1 after 250 cycles at 0.5C, an increase of almost 250%, and then maintaining a large reversible capacity of more than 600 mAh·g-1 for 150 cycles. Such an increased capacity is primarily attributed to the increased level of activity in the conversion reaction. A combination of conversion-type and alloy-type mechanisms is revealed in this anode material via advanced characterization studies and theoretical calculations. This mechanism, observed here for the first time in transition-metal dicyanamides, is probably responsible for the outstanding electrochemical performance. We believe that this study guides the development of new high-capacity anode materials.

Formation of hollow stepped FePBA@rGO anode for high-performance lithium-ion batteries

Prussian blue and its analogues (PBAs) have been considered promising anode materials for lithium-ion batteries (LIBs) owing to their high theoretical capacity and cost-effectiveness. However, they often encounter challenges such as poor electronic conductivity and structural instability. Herein, we introduce a hollow stepped FePBA framework structure coated with reduced graphene oxide (FePBA@rGO). This sophisticated design significantly improves electronic conductivity and optimizes the diffusion pathways for lithium ions, leading to exceptional cycling stability and rate performance. The FePBA@rGO-15 anode developed in this study shows a notable rate capability of 294 mAh g−1 at a current density of 2 A g−1. More significantly, it demonstrates exceptional lithium storage performance, maintaining a capacity of 1245 mAh g−1 after 600 cycles at a current density of 1 A g−1. Density functional theory simulations further support our findings by illustrating that the robust interface between FePBA and rGO significantly accelerates the reactions kinetics of Li+ within the FePBA framework. This study represents a significant advancement towards improving the capacity and cycling stability of PBA-based anode materials, offering promising prospects for future battery applications.

Enhancing Rapid Li+/Na+ Storage Performance via Interface Engineering of Reduced Graphene Oxide-Wrapped Bimetallic Sulfide Nanocages.

Transition-metal sulfide is considered to be an admirable transformational electrode material due to low cost, large specific capacity, and good reversibility in lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). Herein, the reduced graphene oxide-wrapped open bimetallic sulfide (NiS2-Co3S4@rGO) nanocage, derived from nickel-cobalt Prussian blue, was obtained by two-step calcination. There are luxuriant pore structures in the nanocage composite with a specific surface area of 85.28 m2 g-1, which provides plentiful paths for rapid transmission of Li+/Na+ and alleviates the volume stress caused by insertion and extraction of alkali metal ions. The excellent interface combination of bimetallic sulfide wrapped in reduced graphene oxide improves the conductivity and overall performance of the battery. Thanks to the special interface engineering, the open NiS2-Co3S4@rGO nanocage composite displays rapid lithium storage properties with an average diffusion coefficient of 8.5 × 10-13 cm2 s-1. Moreover, after 300 cycles, the reversible capacity of the composite is 1113.2 mAh g-1 at 1 A g-1. In SIBs, the capacity of the open NiS2-Co3S4@rGO composite is 487.9 mAh g-1 when the current density is 5 A g-1. These preeminent performances demonstrate the enormous development prospects of bimetallic sulfide nanocage as anode material in LIBs and SIBs.