Electrode Materials For Lithium-ion Batteries Research Articles

Improved cycle stability and high-rate capability of LiNbO3-coated Li3VO4 as anode material for lithium-ion battery

Lithium vanadate (Li3VO4) has garnered considerable attention as an alternative negative electrode material for non-aqueous lithium-ion batteries due to its high capacity, energy efficiency, and stable discharge voltage. Nonetheless, the Li3VO4 material displays a low rate capability, attributed mainly to its poor intrinsic electronic conductivity. Here, we report the synthesis of lithium niobate LiNbO3-coated Li3VO4 (LVO@LNO) using a one-pot sol-gel method. The resulting LVO@LNO demonstrates a high reversible capacity of approximately 530 mAh/g, which is more than double that of free Li3VO4. To explore the effect of the LNO coating process on the morphological and structural properties, Raman, XRD, operando XRD, XPS, SEM and HTEM analyses were conducted. To explain the enhancement of electronic conductivity in our modified material after a LiNbO3 coating, we conducted an Ex-Situ electrochemical impedance (EIS) and Density Functional Theory (DFT) computational study. Additionally, we designed a full cell utilizing a 1 wt% LNO-coated LVO anode and NMC-811 cathode. The cell yielded an output voltage of approximately 2.8 V with a high initial specific capacity of 350 mAh/g versus to the anode, at 1C with a capacity retention of 85 % after 100 cycles.

On the prospects of using B4C3 as a potential electrode material for lithium-ion batteries

Lithium-ion batteries (LIBs) served as promising energy-storage solutions for various applications, from portable electronics to electric-vehicles. There is a growing demand for high-performance electrode materials with improved storage capacity, high cyclic stability, low energy barriers, reduced material toxicity, and cost-effectiveness. This study explores the electrochemical feasibility of B4C3 monolayer as an anode material for LIBs using density functional theory (DFT) computations and molecular dynamic (MD) simulations. The optimum anodic nature of B4C3 is reported based on its structural, electronic, diffusion, storage behaviour, and lithiation studies. The adsorption sites for Li atoms were systematically explored. The lithium saturation requires the adsorption of 29 lithium atoms on B4C3 while preserving stability confirmed by Ab-initio molecular dynamics (AIMD) simulations and ensuring favorable transport characteristics during the lithiation process based on Hirshfeld charge analysis and steric interaction calculations. The storage capacity of the host B4C3 is calculated as 2770.2 mAhg−1 which is notably higher than that of graphite anode. The computed value of open circuit voltage is 0.62 V per Li. The value of diffusion coefficient and ionic conductivity σ is 0.7 × 10−8 m2/s and 0.78 S/m respectively which predicts excellent overall anodic operation of the material. The transition barrier of the Li ions in the material is determined through Cl-NEB, which shows the lowest value of 0.06 eV along the x-axis.

Endogenous Interfacial Mo-C/N-Mo-S Bonding Regulates the Active Mo Sites for Maximized Li+ Storage Areal Capacity.

Active sites, mass loading, and Li-ion diffusion coefficient are the benchmarks for boosting the areal capacity and storage capability of electrode materials for lithium-ion batteries. However, simultaneously modulating these criteria to achieve high areal capacity in LIBs remains challenging. Herein, MoS2 is considered as a suitable electroactive host material for reversible Li-ion storage and establish an endogenous multi-heterojunction strategy with interfacial Mo-C/N-Mo-S coordination bonding that enables the concurrent regulation of these benchmarks. This strategy involves architecting 3D integrated conductive nanostructured frameworks composed of Mo2C-MoN@MoS2 on carbon cloth (denoted as C/MMMS) and refining the sluggish kinetics in the MoS2-based anodes. Benefiting from the rich hetero-interface active sites, optimized Li adsorption energy, and low diffusion barrier, C/MMMS reaches a mass loading of 12.11mgcm-2 and showcases high areal capacity and remarkable rate capability of 9.6mAhcm-2@0.4mAcm-2 and 2.7mAhcm-2@6.0mA cm-2, respectively, alongside excellent stability after 500 electrochemical cycles. Moreover, this work not only affirms the outstanding performance of the optimized C/MMMS as an anode material for supercapacitors, underscoring its bifunctionality but also offers valuable insight into developing endogenous transition metal compound electrodes with high mass loading for the next-generation high areal capacity energy storage devices.

MOF-derived cobalt nanoparticles in silicon suboxide-based anodes for enhanced lithium storage

The ultra-high theoretical capacity of silicon-based (Si) materials makes them promising anode materials for high energy density lithium-ion batteries. Unfortunately, the dramatic volume change (∼300%) and low electrical conductivity of silicon have severely hindered the commercial use of silicon anodes. Silicon suboxide (SiOx) is one of the ideal candidates for high energy density batteries due to its reduced swelling and lower cost as compared to silicon. However, it remains a huge challenge to address the low conductivity, low (initial) coulombic efficiency and apparent volume effects of SiOx. In this paper, SiOx/Co@C composite anode materials loaded with metal Co nanoparticles were uniformly and efficiently prepared by using 3-aminopropyl triethoxysilane (APTES) as silicon source and Co-MOF as Co source via molecular self-assembly strategy. The experimental results and density functional theory (DFT) calculation showed that the catalytic action of embedded Co nanoparticles had activated the silico-oxygen bond of SiOx and the irreversible product Li2O, thereby improving the initial coulombic efficiency (ICE) and enhancing the reversible capacity. At the same time, the metal Co with mechanical rigidity and electrical conductivity alleviated the volume fluctuation during alloying and improved the charge transfer capacity and ion transport rate of the composite. When compared with SiOx@C anodes, SiOx/Co@C-600 composites showed higher initial CE, superior cyclic stability and good rate performance. In particular, the successful matching of the anode with the lithium iron phosphate (LFP) cathode in full cell systems validated the possibility of its practical application. This work provides important insights into the application of Si-based materials in lithium-ion battery electrode materials and the development of high energy density batteries.

Phase Engineering via Aluminum Doping Enhances the Electrochemical Stability of Lithium-Rich Cobalt-Free Layered Oxides for Lithium-Ion Batteries.

Lithium-rich, cobalt-free oxides are promising potential positive electrode materials for lithium-ion batteries because of their high energy density, lower cost, and reduced environmental and ethical concerns. However, their commercial breakthrough is hindered because of their subpar electrochemical stability. This work studies the effect of aluminum doping on Li1.26Ni0.15Mn0.61O2 as a lithium-rich, cobalt-free layered oxide. Al doping suppresses voltage fade and improves the capacity retention from 46% for Li1.26Ni0.15Mn0.61O2 to 67% for Li1.26Ni0.15Mn0.56Al0.05O2 after 250 cycles at 0.2C. The undoped material has a monoclinic Li2MnO3-type structure with spinel on the particle edges. In contrast, Al-doped materials (Li1.26Ni0.15Mn0.61-xAlxO2) consist of a more stable rhombohedral phase at the particle edges, with a monoclinic phase core. For this core-shell structure, the formation of Mn3+ is suppressed along with the material's decomposition to a disordered spinel, and the amount of the rhombohedral phase content increases during galvanostatic cycling. Whereas previous studies generally provided qualitative insight into the degradation mechanisms during electrochemical cycling, this work provides quantitative information on the stabilizing effect of the rhombohedral shell in the doped sample. As such, this study provides fundamental insight into the mechanisms through which Al doping increases the electrochemical stability of lithium-rich cobalt-free layered oxides.

Spatially confined synthesis of TiNb2O7 quantum dots onto mesoporous carbon and Ti3C2TX MXene for boosting lithium storage

TiNb2O7 has been emerged as one of the most promising electrode materials for high-energy lithium-ion batteries. However, limited by the slow electron/ion transport kinetics, and insufficient active sites in the bulk structure, the TiNb2O7 electrode still suffers from unsatisfactory lithium storage performance. Herein, we demonstrate a spatially confined strategy toward a novel TiNb2O7-NMC/MXene composite through a triblock copolymer-directed one-pot solvothermal route, where TiNb2O7 quantum dots with a particle size of 2–3 nm are evenly embedded into N-doped mesoporous carbon (NMC) and Ti3C2TX MXene. Impressively, the as-prepared TiNb2O7-NMC/MXene anode exhibits a high reversible capacity (486.2 mAh g−1 at 0.1 A g−1 after 100 cycles) and long cycle lifespan (363.4 mAh g−1 at ss1 A g−1 after 500 cycles). Both experimental and theorical results further demonstrate that such a superior lithium storage performance is mainly ascribed to the synergistic effect among 0D TiNb2O7 quantum dots, 2D Ti3C2TX MXene nanosheets, and N-doped mesoporous carbon. The strategy presented also opens up new horizon for space-confined preparation of high-performance electrode materials.

Research Progress in Modified Graphite Negative Electrode Materials for Lithium-Ion Batteries

Research Progress in Modified Graphite Negative Electrode Materials for Lithium-Ion Batteries

Revealing the Dynamic Lithiation Process of Copper Disulfide by in Situ TEM.

Transition metal oxides, fluorides, and sulfides are extensively studied as candidate electrode materials for lithium-ion batteries driven by the urgency of developing next-generation higher energy density lithium batteries. These conversion-type electrode materials often require nanosized active materials to enable a "smooth" lithiation and de-lithiation process during charge/discharge cycles, determined by their size, structure, and phase. Herein, the structural and chemical changes of Copper Disulfide (CuS2) hollow nanoparticles during the lithiation process through an in situ transmission electron microscopy (TEM) method are investigated. The study finds the hollow structure of CuS2 facilitates the quick formation of fluidic Li2S "drops," accompanied by a de-sulfurization to the Cu7S4 phase. Meanwhile, the metallic Cu phase emerges as fine nanoparticles and grows into nano-strips, which are embedded in the Li2S/Cu7S4 matrix. These complex nanostructured phases and their spatial distribution can lead to a low de-lithiation barrier, enabling fast reaction kinetics.

Theoretical prediction of B5C8 monolayer as a high-performance anode material for lithium-ion batteries

The demand for high-performance energy storage systems has stimulated intensive research on high-performance electrode materials for lithium-ion batteries (LIBs). Two-dimensional (2D) materials have emerged as promising candidates for anode materials due to their unique structural and physicochemical properties. Based on first-principles calculations, we propose a 2D material, B5C8 monolayer, as an excellent anode material for LIBs. B5C8 monolayer exhibits inherent metallicity and outstanding dynamic, mechanical, and thermal stability. Furthermore, B5C8 monolayer shows not only remarkably high storage capacity (2856 mA h g−1) but also low barrier energy (0.25 eV) and small volume change (2.1%). More importantly, B5C8 possesses strong wettability toward commonly used electrolytes in LIBs, namely, solvent molecules and metal salts, indicating prime compatibility. Based on the above distinguished findings, we hope B5C8 monolayer can act as a well-balanced performance anode material for LIBs.

Surface-enriched Co engineering promoting electronic conductivity for single-crystalline Ni-based layered oxide cathodes

Single-crystalline layered oxides are at the forefront of the development of high-energy lithium-ion battery (LiB) electrode materials, offering prolonged durability by circumventing the crack-related structural reconstruction and mechanical collapse seen in their polycrystalline counterparts. However, the sluggish carrier transport in large-crystalline particles impedes their rate capability. While most research has prioritized improving ion diffusion, the pivotal role of electron transport in electrochemical kinetics has been relatively overlooked. Herein, we enhance the kinetics of charge transfer and inhibit Mn dissolution from the bulk lattice by modulating the cobalt concentration on the surface of a single-crystalline Ni-based layered oxide cathode, LiNi0.5Co0.2Mn0.3O2. Liquid pouch-type full cells employing surface Co-concentrated cathodes exhibit exceptional high-temperature (55 °C) specific capacity (193.6 mAh g−1 at 0.2C), capacity retention (90.1 % after 2000 cycles at 1 C), and impressive rate performance at 12C. Moreover, by utilizing the varying composition-related kinetics in the composite cathode of sulfide-based all-solid-state batteries (ASSBs), we find that surface-enriched Co modification enhances the electronic percolation within the composite cathode, significantly contributing to the rate performance of ASSBs, beyond the effect of ion diffusion. This research underscores the significance of electronic properties in single-crystalline layered oxides for achieving high-power LiBs and ASSBs.

Dynamic and Reversible Blending Interface on Polyoxovanadate Electrode for High-Performance Lithium-Ion Batteries.

Solid electrolyte interphase (SEI) plays a critical role in the performance of lithium-ion batteries (LIBs). In contrast to the clear interface between the traditional consecutive electrode materials and SEI, ionic polyoxometalates (POMs) as electrode could bilaterally diffuse with SEI and form a blending interface for superior electrochemical performance. POMs have recently aroused much interest as electrode materials in LIBs due to their structural flexibility, high capacity, and cycling stability. However, the interface evolution between POM-based electrodes and SEI, which is critical for Li+ ion transportation, has rarely been explored. Herein, we choose Li10[V12B18O60H6] (LVB) as an example to investigate the formation and structural evolution of the electrode-electrolyte interface. Time-of-flight secondary ion mass spectrometry together with X-ray photoelectron spectroscopy demonstrates the evolution of a blending layer at the interface containing typical SEI components, a polyanion from LVB and a phosphate anion from decomposition products of LiPF6. In the blending layer, ion migration takes place between the P-related inorganic species and the polyanion during the Li+ insertion/extraction reaction. Such a compatible blending layer favors Li+ transportation and the reversibility of the redox reactions, as supported by a series of electrochemical analyses. This work provides detailed insights into understanding the interface evolution of the LVB electrode and demonstrates the importance of interfacial engineering to induce proper interface layers in the development of high-performance POM-based electrodes for LIBs.

Carbon-coated Ni2P nanoparticles coated on CNTs synthesized by an in-situ solid-state method for high-performance hybrid supercapacitors and lithium-ion batteries

The pursuit of electrode materials with excellent performance in both supercapacitors and lithium-ion batteries holds the potential to streamline the construction of hybrid electrochemical energy storage systems and contribute to cost reduction. In this paper, we introduce a novel nanocomposite—carbon-coated Ni2P nanoparticles coated on CNTs (CNTs@(Ni2P@C))—via an in-situ one-step solid-state method. This design not only prevents the aggregation of Ni2P nanoparticles with a size of 5–8 nm but also mitigates its volume change during charging and discharging cycles. Simultaneously, it establishes a rapid electron transfer pathway between CNTs and Ni2P nanoparticles, enhancing the electron transport kinetics within the synthesized nanocomposite. The synthesized CNTs@(Ni2P@C) nanocomposite exhibits high performance in both SCs and LIBs. An ultra-high specific capacity of 378.5 mAh g−1 (2725.2 F g−1) at 1 A g−1 and a good rate capacity (189.3 mAh g−1 at 20 A g−1) are achieved when used in supercapacitors. The hybrid supercapacitor device assembled using the synthesized nanocomposite exhibits a high specific capacity of 84.3 mAh g−1 at 1 A g−1 and excellent capacity retention of 92 % after 10,000 cycles. A high energy density of 67.47 Wh kg−1 can be delivered at a power density of 0.84 kW kg−1. When used in LIBs, the synthesized nanocomposite exhibits a reliable reversible specific capacity of 329 mAh g−1 at 0.1 A g−1 after 100 cycles and a high capacity retention of 90 % after 5000 cycles at 2.0 A g−1. The proposed in-situ solid-state method and the synthesized CNTs@(Ni2P@C) nanocomposite will strongly promote the development of difunctional electrode materials for supercapacitors and lithium-ion batteries.

A Conjugated Coordination Polymer with Benzoquinone as Electrode Material for All Organic Symmetric Lithium-ion Batteries.

Carbonyl rich conjugated polymer electrode materials for lithium-ion batteries possessed the advantages of strong molecular design ability, abundance and high theoretical capacity. In this work, a Co2+ coordinated conjugated polymer using 2,3,5,6-tetraamino-p-benzoquinone (TABQ) as building block was constructed and developed as electrode material for all organic symmetric lithium-ion batteries, outputting a specific capacity of over 100 mAh g-1 after 50 cycles at 50 mA g-1. Performances of Co-TABQ in half cells were explored. The Co-TABQ cathode delivered a capacity of 133.3 mAh g-1 after 150 cycles at 20 mA g-1. When cycled at higher current density of 500 mA g-1, the capacity gradually increased to 109.4 mAh g-1 after 4000 cycles. The Co-TABQ anode displayed a stable capacity of 568.6 mAh g-1 at 1 A g-1. The charge transfer within the electrode was greatly reduced due to the metallic centers in the extended conjugated skeleton, and the reversible Li+ storage was achieved by the active C=O and imine groups. This work showed the great potential of metal mediated conjugated polymer in Lithium-ion batteries.

.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.

Electrochemical elucidation of phosphorus-doped and 3D graphene aerogel surface-modified SiOx porous nanocomposite electrode material for high-performance lithium-ion batteries

Silicon oxide (SiOx) is promising as an earth abundant eco-friendly cost-effective anode material for lithium-ion batteries (LIBs), boasts a higher capacity compared to commercial graphite, garnering significant interest. Nevertheless, its practical application is hindered by issues related to poor cycling performance and low electronic conductivity. In this investigation, graphene aerogel-wrapped (GA) red phosphorus (P) doped SiOx (P-SiOx@GA) composite material is successfully constructed through ball-milling followed by freeze-drying and thermal treatment processes. The prepared materials are characterized the physico-chemical properties. The electrochemical performance is evaluated through Li-ion half and full (LiFePO4//P-SiOx@GA) cells configuration. The synthesized P-SiOx@GA electrode exhibits outstanding cyclic performance, demonstrating a specific capacity of 1094 mAh g−1 at 0.5C with a capacity retention of 80.3 % over 200 cycles in half-cell test. Furthermore, it demonstrates superior rate capability and delivers a reversible rate capacity of 754 mAh g−1 at 2C. Besides, the Li-ion punch cell configuration of LiFePO4//P-SiOx@GA shows good reversible capacity of 1.4 mAh at 0.5C over 300 cycles. The doping of P and porous 3D structure of GA forms an SiOx matrix network is facilitate the establishment of a 3D conductive pathway for electron transport and Li+ diffusion but also acts as a flexible matrix to accommodate the volume changes of SiOx. Therefore, the results and way of preparation promotes a practical feasibility of high-performance Si-based Li-ion batteries applications.

АPPLICATION OF ELECTROCHEMICALLY PREPARED Sn-Co ALLOY POWDERS AS ANODE MATERIAL FOR LITHIUM-ION BATTERIES

The electrochemical behavior of active electrode (anode) materials (AEMs) for lithium-ion battery (LIB), prepared with Sn-Co powders electrodeposited in three different current modes, was investigated. It is shown that AEM with Sn-Co powder, obtained in constant-potential mode, has the highest tin content (82.1 wt. %) and the best performance and stability in operation. The anode material, made with this Sn-Co powder, shows a first-cycle charge capacity of 450 mAh g-1, which decreases to 295 mAh g-1 for 10 battery cycles at a current load of 0.8 mA (0.1C). The data also showed that the AEM with Sn-Co powder, deposited in pulse-potential mode, which has the lowest tin content (24.5 wt. % Sn) but the highest dispersity compared to the other powders tested, shows better performance than that of a powder with a tin content of 68.6 wt. %, obtained in constant-current mode. It can be concluded that for the high electrochemical activity of the anode materials, prepared with Sn-Co powders, both the high tin content and the high dispersity and morphological uniformity of the powders are of great importance.

Layered CoS@NC in situ loaded onto Ti3C2Tx MXene as an efficient lithium-ion battery anode.

Due to its large capacity and relatively high conductivity, cobalt sulfide has been considered an excellent electrode material for lithium-ion batteries, but its extreme volume change during charging and discharging and lower conductivity than graphite limits its development. In this work, composite nanosheets of MXene and N-doped carbon-confined cobalt sulfide nanosheets (CoS@NC/MXene) were synthesized by growing the Co metal-organic framework of ZIF-67 onto MXene sheets, followed by sulfidation treatment. Different from normal ZIF-67 generally prepared in methanol, this work fabricates ZIF-67 in aqueous solution, which induces ZIF-67 to undergo some degree of hydrolysis and form more dispersed Co layered hydroxides mounted onto MXene. Also, the MXene incorporation imparts better water stability to ZIF-67(Co) and helps maintain its morphology during the sulfidation. CoS@NC/MXene has a conductive network supported by MXene and enhanced by NC, as well as a 3D hierarchical porous structure offered by the rational combination of its components. These favorable characteristics allow CoS@NC/MXene to deliver a capacity of 691 mA h g-1 at 200 mA g-1 in the 100th cycle and retain the specific capacity of 382 mA h g-1 at a higher current density of 8000 mA g-1.

“Zero” Porosity High Loading NMC622 Positive Electrodes for Li-Ion Batteries

LiNi0.6Mn0.2Co0.2O2 (NMC622) is a widely used positive electrode material for lithium-ion batteries, including electric vehicles. In this work, we investigated the effects of porosity, ranging from “zero” to the typical 35%, on the electrochemical behavior of high-loading NMC622 electrodes. Although it is well known that the energy density of the electrode increases with increasing areal capacity and decreasing porosity, NMC-positive electrodes with exceedingly low porosity (e.g., near zero) and high loading (e.g., 4 mAh cm−2) have not been investigated. Here, we report an intriguing observation that the “zero porosity” NMC electrode can have higher capacity at low C-rates, and the volumetric energy density significantly increases to 1739 Wh l−1 compared to 805 Wh l−1 of conventional electrodes of 35% porosity. We performed cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) to help understand this observation. This work provides new insights into the effects of porosity on the electrochemical behavior of high-loading positive electrodes.

A methodology to synthesize easily oxidized materials containing Li ions in an inert atmosphere

A simple methodology to synthesize easily oxidized materials with Mn3+ and V3+ ions, which are used as emerging high-capacity positive electrode materials for lithium-ion batteries, is proposed.

Exploring the structural stability and electrochemical performance of B doped T-graphene nanotubes from first-principles calculations.

The structural stability and electrochemical performance of intrinsic and B doped T-graphene nanotubes with different tube lengths are systematically studied by using first-principles calculations within the framework of density functional theory (DFT). The results show that with the increase of tube length, the adsorption energy of both intrinsic and B doped T-graphene nanotubes exhibits regular oscillations, and B doping is beneficial for elevating the adsorption ability of T-graphene nanotubes. The density of states show that intrinsic T-graphene nanotubes are zero band gap semiconductors, and the orbitals' electronic states cross the Fermi level to form a p-type semiconductor, indicating that B doping greatly improves the conductivity of the system. The results of migration behavior demonstrate that B doping can effectively reduce the diffusion barrier of lithium ions on their surface, especially in B doped T-graphene nanotubes with a tube length of N = 1, resulting in more effective migration behavior and excellent rate performance. These findings provide a theoretical basis for the development and application of negative electrode materials for lithium-ion batteries.