Electrode Materials For Metal-ion Batteries Research Articles

P/n-Type Polyimide Covalent Organic Frameworks for High-Performance Cathodes in Sodium-Ion Batteries.

Covalent organic frameworks (COFs) are viewed as promising organic electrode materials for metal-ion batteries due to their structural diversity and tailoring capabilities. In this work, firstly using the monomers N,N,N',N'-tetrakis(4-aminophenyl)-1,4-phenylenediamine (TPDA) and terephthaldehyde (TA), p-type phenylenediamine-based imine-linked TPDA-TA-COF is synthesized. To construct a bipolar redox-active, porous and highly crystalline polyimide-linked COF, i.e., TPDA-NDI-COF, n-type 1,4,5,8-naphthalene tetracarboxylic dianhydride (NDA) molecules are incorporated into p-type TPDA-TA-COF structure via postsynthetic linker exchange method. This tailored COF demonstrated a wide potential window (1.03.6 V vs Na+/Na) with dual redox-active centers, positioning it as a favorable cathode material for sodium-ion batteries (SIBs). Owing to the inheritance of multiple redox functionalities, TPDA-NDI-COF can deliver a specific capacity of 67 mAh g-1 at 0.05 A g-1, which is double the capacity of TPDA-TA-COF (28 mAh g-1). The incorporation of carbon nanotube (CNT) into the TPDA-NDI-COF matrix resulted in an enhancement of specific capacity to 120 mAh g-1 at 0.02 A g-1. TPDA-NDI-50%CNT demonstrated robust cyclic stability and retained a capacity of 92 mAh g-1 even after 10 000 cycles at 1.0 A g-1. Furthermore, the COF cathode exhibited an average discharge voltage of 2.1 V, surpassing the performance of most reported COF as a host material.

Confined Mo2C/MoC heterojunction nanocrystals-graphene superstructure anode for enhanced conversion kinetics in sodium-ion batteries

Heterostructure design and integration with conductive materials play a crucial role in enhancing the conversion kinetics of electrode materials for metal-ion batteries. However, integrating nanocrystal heterojunctions into a conductive layer to form a superstructure is a significant challenge, mainly due to the difficulty in maintaining the structural integrity. Here we report a unique glucose-induced heterogeneous nucleation method that enables the independent manipulation of nucleation and growth of Mo2C/MoC heterojunction nanocrystals within 2D layers. Our investigations reveal that the rGO-Mo2C/MoC-rGO superstructure is formed by a topological transformation induced by subsequent heat treatment of the initial hydrothermally prepared rGO-MoO2-rGO precursor. This novel structure embeds Mo2C/MoC heterojunction nanocrystals within a 2D graphene matrix, providing enhanced mechanical stability, accelerated Na+ transport, and improved electron conduction. Ex situ XRD and Raman spectroscopy analyses reveal that the rGO-Mo2C/MoC-rGO superstructure significantly enhances the stability and reversibility of anodes. Leveraging these unique characteristics, the newly developed superstructural anode exhibits remarkable long-term cycling stability and outstanding rate performance. As a result, superstructure anodes demonstrate superior electrochemical capabilities, delivering a specific capacity of 106 mAh/g after enduring 5000 cycles at 1 A/g. Our study underscores the critical importance of superstructure design in propelling the advancement of battery materials.

Recent Progress and Perspectives on Metal–Organic Framework-Based Electrode Materials for Metal-Ion Batteries and Supercapacitors

Recent Progress and Perspectives on Metal–Organic Framework-Based Electrode Materials for Metal-Ion Batteries and Supercapacitors

A Comprehensive Review of Defects Genealogy in Olivines: From the Mineral World to Modern Electrode Materials

The “Learning from nature” strategy is currently going through a renaissance period in modern materials science. Valuable experience gained by observing existing natural materials—minerals—paves the way towards design and modification of prospective functional materials for energy storage, which typically inherit the peculiarities of the parental minerals. The faults and flaws of the crystal structure—its defects—play a crucial role in determining both mechanical and electrochemical properties of the electrode materials. In this review, we endeavored to rethink the defect chemistry in triphylite-type positive electrode materials for metal-ion batteries and reflected on it from the perspective of their mineral olivine counterparts, thus establishing important correlations between point defects in olivine minerals and related electrode materials, their origin and formation processes. This work is meant to review geoscience and materials science perceptions of defects in triphylite-type electrode materials for Li- and Na-ion batteries.

Activation Energy of Ion Diffusion in an Electrode Material: Theoretical Calculation and Experimental Estimation with LiCoVO4 as an Example

The development of electrode materials for metal-ion batteries is a complex and resource-demanding process. The optimization of this development process requires a combination of theoretical and experimental methods. The former is used to predict the properties of materials and the latter to confirm them. Thus, it is very important to understand how the results of the modeling and experiment are related. In this study, we compare the results of determining the activation energies of lithium ion diffusion in cobalt(II)-lithium vanadate(V), which we obtained by calculations from first principles within the framework of density functional theory (DFT), with the experimental results, which we achieved by applying electrochemical methods such as cyclic voltammetry and galvanostatic and potentiostatic pulses. Based on the experimental and theoretical data obtained for LiCoVO4, we hypothesize that the limitation of the practically realizable capacity of the material at about 1/3 of the theoretical one is due to its structural limitations that lead to the impossibility of involving all lithium ions in the current-forming process. This reason is fixed by the simulation results, but is not detected by the experimental results.

Computational insights into ionic conductivity of transition metal electrode materials for metal-ion batteries - A review

Charge/discharge rates and low-temperature performance of metal-ion batteries are strongly affected by the ionic conductivity of transition metal intercalation materials used in electrodes. Computational methods, based on crystal chemistry empirical approaches and rigorous density functional theory have become indispensable for the evaluation of ionic conductivity in such materials. During the last decade, hundreds of computational studies of various intercalation materials accumulated considerable knowledge regarding ionic conductivity. This review covers the modern crystal chemistry methods and their application to transition metal intercalation materials, as well as systematizes the available information retrieved from mostly density functional theory studies related to mechanisms of ionic conductivity/diffusivity with the focus on elementary migration acts of alkali cations. We consider in detail how the diffusion channel size and dimension, coordination, cation size, anion and transition metal type, oxidation state, state of charge/discharge, and other factors affect elementary migration acts of alkali cations. The review collects the design principles of new intercalation materials with high ionic conductivity being helpful for advanced energy storage technologies development.

First-principles studies of the two-dimensional 1H-BeP2 as an electrode material for rechargeable metal ion (Li+, Na+, K+) batteries

Finding high-performance electrode materials is one of the most effective ways to improve the energy density of current metal-ion batteries. MoS2-like 1H-BeP2 is intrinsically metallic before and after adsorption of metal ions and shows good electrical conductivity. Based on present first-principles calculations, 1H-BeP2 could be regarded as a potential promising electrode material for metal-ion batteries. Importantly, the fully Li (Na) phase X4BeP2 (X = Li, Na) for 1H-BeP2 exhibits a high theoretical capacity of 1510 mAh/g with up to one layer of potassium ions, outperforming most previously reported 2D candidates. Meanwhile, it is found that the open circuit voltage and diffusion barrier of 1H-BeP2 after fully adsorbed metal ions were as low as 0.17 V, 0.22 V and 0.34 V, respectively, which was surprising. Present studies would be helpful for the exploration of novel 1H-BeP2 type electrode materials for metal-ion batteries.

O- or/and S-functionalized Cr2C as electrode material for metal-ion (Li, Na, K, and Mg) batteries: A first principles study

MXenes are ideal electrode materials for metal-ion batteries due to their remarkable mechanical properties, high electronic conductivity, and hydrophilic. In this work, the electrochemical performance of O- or/and S-functionalized Cr2C as electrode material are studied by density functional theory. The Cr2CO2 and Cr2CS2 monolayers have the characteristics of favorable structural stability and high electrical conductivity. At the same time, they have low diffusion barriers for metal-ions (Li, Na, K, and Mg). Most notably, the maximum capacity of Cr2CO2 to Mg-ion and Cr2CS2 to Li-ion are up to 878.721 and 724.351 mA h g−1, corresponding to open circuit voltages of 0.164 and 0.117 V. Furthermore, bi-functionalized Cr2C monolayers are designed and investigated, the results indicate that the preparation of functionalized surfaces is more conducive to improving the capacity performance of specific metal-ions compared with bi-functionalized surfaces. This work provides new choices for the experimental research of MXene based electrode materials in the future.

Resolving the structure of V3O7·H2O and Mo-substituted V3O7·H2O.

Vanadate compounds, such as V3O7·H2O, are of high interest due to their versatile applications as electrode material for metal-ion batteries. In particular, V3O7·H2O can insert different ions such as Li+, Na+, K+, Mg2+ and Zn2+. In that case, well resolved crystal structure data, such as crystal unit-cell parameters and atom positions, are needed in order to determine the structural information of the inserted ions in the V3O7·H2O structure. In this work, fundamental crystallographic parameters, i.e. atomic displacement parameters, are determined for the atoms in the V3O7·H2O structure. Furthermore, vanadium ions were substituted by molybdenum in the V3O7·H2O structure [(V2.85Mo0.15)O7·H2O] and the crystallographic positions of the molybdenum ions and their oxidation state are elucidated.

Exploring the potential of Ti2BT2 (T = F, Cl, Br, I, O, S, Se and Te) monolayers as anode materials for lithium and sodium ion batteries

Introducing functional groups to two-dimensional transition metal borides (MBenes) is an effective way to ameliorate the properties of MBenes as electrode materials for rechargeable lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). Herein, we investigated the electrochemical performances of Ti2BT2 (T = F, Cl, Br, I, O, S, Se and Te) as anode materials for LIBs and SIBs using first-principles calculations. Firstly, the metallic nature of Ti2BT2 endows them with excellent conductivities. Besides, the phonon dispersions and ab initio molecular dynamics simulations (AIMD) were conducted to estimate the dynamic and thermal stability of Ti2BT2. Additionally, Ti2BSe2 has slight high specific capacity of 405 mA h g−1 for LIBs and Ti2BS2 possesses ultra-high specific capacity of 942 mA h g−1 for SIBs. Furthermore, the low diffusion energy barriers endow ultra-high charge/discharge rate and suitable open circuit voltages ensure the safety of battery performance. The encouraging results indicate that Ti2BSe2 and Ti2BS2 are outstanding candidates as electrode materials for LIBs and SIBs, respectively. Our work not only screened out excellent electrode materials for metal-ion batteries, but also provided constructive suggestions for the development of next-generation high-performance electrode materials.

Computational evaluation of ScB and TiB MBenes as promising anode materials for high-performance metal-ion batteries

Emerging as a new family of two-dimensional materials, transition-metal borides, namely MBenes, are expected to possess outstanding physical and chemical properties owing to their layered structures analogous to MXenes. Here, we explore the electrochemical properties of ScB and TiB monolayers as anode materials for lithium- and sodium-ion batteries by density-functional theory calculations. Our results reveal that Li/Na ions can be stably adsorbed on surfaces of both monolayers with moderate adsorption energy, rapid charge/discharge rate, higher storage capacity, and much lower diffusion energy barrier (0.108 eV for Li ion on ScB, 0.105 eV for Li ion on TiB, 0.072 eV for Na ion on ScB, and 0.063 eV for Na ion on TiB) as compared with other MBene monolayers currently reported. Meanwhile, the open-circuit voltages all fall in the range of 0--1 V for Li/Na ion on the monolayers, which may effectively suppress the formation of Li/Na dendrite on anodes during the charge/discharge process. Besides, at room temperature, Li adatoms could be adsorbed on the monolayers more stably than Na adatoms. Our work demonstrates that ScB and TiB monolayers should be promising two-dimensional anode materials for lithium-ion batteries and are less suitable for sodium-ion batteries. These results advance our understanding on the electrochemical performances of MBenes and provide important insights into the design and development of high-performance electrode materials for metal-ion batteries.

Revisiting the Structural Evolution of MoS2 During Alkali Metal (Li, Na, and K) Intercalation

Transition metal dichalcogenides, especially MoS2-based materials, have been actively investigated for application as high-performance electrode materials for metal-ion batteries. To further improv...

A review of π-conjugated polymer-based nanocomposites for metal-ion batteries and supercapacitors.

Owing to their extraordinary properties of π-conjugated polymers (π-CPs), such as light weight, structural versatility, ease of synthesis and environmentally friendly nature, they have attracted considerable attention as electrode material for metal-ion batteries (MIBs) and supercapacitors (SCPs). Recently, researchers have focused on developing nanostructured π-CPs and their composites with metal oxides and carbon-based materials to enhance the energy density and capacitive performance of MIBs and SCPs. Also, the researchers recently demonstrated various novel strategies to combine high electrical conductivity and high redox activity of different π-CPs. To reflect this fact, the present review investigates the current advancements in the synthesis of nanostructured π-CPs and their composites. Further, this review explores the recent development in different methods for the fabrication and design of π-CPs electrodes for MIBs and SCPs. In review, finally, the future prospects and challenges of π-CPs as an electrode materials for strategies for MIBs and SCPs are also presented.

Understanding and Calibration of Charge Storage Mechanism in Cyclic Voltammetry Curves.

Noticeable pseudo-capacitance behavior out of charge storage mechanism (CSM) has attracted intensive studies because it can provide both high energy density and large output power. Although cyclic voltammetry is recognized as the feasible electrochemical technique to determine it quantitatively in the previous works, the results are inferior due to uncertainty in the definitions and application conditions. Herein, three successive treatments, including de-polarization, de-residual and de-background, as well as a non-linear fitting algorithm are employed for the first time to calibrate the different CSM contribution of three typical cathode materials, LiFePO4 , LiMn2 O4 and Na4 Fe3 (PO4 )2 P2 O7 , and achieve well-separated physical capacitance, pseudo-capacitance and diffusive contributions to the total capacity. This work can eliminate misunderstanding concepts and correct ambiguous results of the pseudo-capacitance contribution and recognize the essence of CSM in electrode materials.

Structure-Performance Relationships of Covalent Organic Framework Electrode Materials in Metal-Ion Batteries.

Covalent organic frameworks (COFs) have shown great potential as high-performance electrode materials for metal-ion batteries in view of their relatively high capacity, flexibly designable structure, ordered porous structure, and limited solubility in electrolyte. To develop more attractive COF electrode materials, it is necessary to understand their structure-performance relationships. This Perspective focuses on discussing the relationships between structure (molecular structure, micro structure, and electrode structure) and performance (voltage, capacity, cycling stability, and rate performance) of COF electrode materials in metal-ion batteries. Among the reported COF electrode materials, those with all linkages being redox active based on C═O and C═N groups would be the most promising cathode materials because of their high capacity (∼500 mAh g-1), moderate working voltage (∼2 V vs Li+/Li), and good cycling stability. To accelerate practical application of COF electrode materials in metal-ion batteries, future work should pay more attention to function-oriented molecular structure design via theoretical simulations, as well as full-cell fabrication and evaluation. This Perspective will stimulate high-quality research that might lead to future commercialization.

α-TiPO4 as a Negative Electrode Material for Lithium-Ion Batteries.

To realize high-power performance, lithium-ion batteries require stable, environmentally benign, and economically viable noncarbonaceous anode materials capable of operating at high rates with low strain during charge-discharge. In this paper, we report the synthesis, crystal structure, and electrochemical properties of a new titanium-based member of the MPO4 phosphate series adopting the α-CrPO4 structure type. α-TiPO4 has been obtained by thermal decomposition of a novel hydrothermally prepared fluoride phosphate, NH4TiPO4F, at 600 °C under a hydrogen atmosphere. The crystal structure of α-TiPO4 is refined from powder X-ray diffraction data using a Rietveld method and verified by electron diffraction and high-resolution scanning transmission electron microscopy, whereas the chemical composition is confirmed by IR, energy-dispersive X-ray, electron paramagnetic resonance, and electron energy loss spectroscopies. Carbon-coated α-TiPO4/C demonstrates reversible electrochemical activity ascribed to the Ti3+/Ti2+ redox transition delivering 125 mAh g-1 specific capacity at C/10 in the 1.0-3.1 V versus Li+/Li potential range with an average potential of ∼1.5 V, exhibiting good rate capability and stable cycling with volume variation not exceeding 0.5%. Below 0.8 V, the material undergoes a conversion reaction, further revealing capacitive reversible electrochemical behavior with an average specific capacity of 270 mAh g-1 at 1C in the 0.7-2.9 V versus Li+/Li potential range. This work suggests a new synthesis route to metastable titanium-containing phosphates holding prospective to be used as negative electrode materials for metal-ion batteries.

Machine Learning Screening of Metal-Ion Battery Electrode Materials.

Rechargeable batteries provide crucial energy storage systems for renewable energy sources, as well as consumer electronics and electrical vehicles. There are a number of important parameters that determine the suitability of electrode materials for battery applications, such as the average voltage and the maximum specific capacity which contribute to the overall energy density. Another important performance criterion for battery electrode materials is their volume change upon charging and discharging, which contributes to determine the cyclability, Coulombic efficiency, and safety of a battery. In this work, we present deep neural network regression machine learning models (ML), trained on data obtained from the Materials Project database, for predicting average voltages and volume change upon charging and discharging of electrode materials for metal-ion batteries. Our models exhibit good performance as measured by the average mean absolute error obtained from a 10-fold cross-validation, as well as on independent test sets. We further assess the robustness of our ML models by investigating their screening potential beyond the training database. We produce Na-ion electrodes by systematically replacing Li-ions in the original database by Na-ions and, then, selecting a set of 22 electrodes that exhibit a good performance in energy density, as well as small volume variations upon charging and discharging, as predicted by the machine learning model. The ML predictions for these materials are then compared to quantum-mechanics based calculations. Our results reaffirm the significant role of machine learning techniques in the exploration of materials for battery applications.

(Invited) Nanoarray Cathode Design for Durable Zn Batteries

Rechargeable aqueous zinc battery, as a novel promising candidate for grid-scale energy storage, has drawn tremendous attention recently. Our group has been actively working in design nanostructured electrode materials for metal-ion batteries (Na, K, Zn) and electrocatalysts for metal-air batteries. In this talk, I will present our latest results on cathode materials for both Zn-ion battery and Zn-air battery. Specifically, we developed layered ZnOV nanosheets that are directly grown on a 3D graphite current collector. Meanwhile, the anode is also 3D Zn nanosheet array obtained by electro-deposition. As for the Zn-air battery cathode, we employed 3D conductive MOF and Ni-based LDH hybrid materials on conductive carbon support as the electrode both for aqueous alkaline and all-solid-state Zn-battery. The whole material system has a high conductivity, sufficient active sites and low transition energy that render highly reversible redox reaction and inhibition of dendrite formation, as well as extremely soft feature so that it can be appropriate for the application of flexible devices. The all-solid-state Zn-based batteries using CMNC@CC and Zn@CC as the electrodes displays outstanding performance when compared with most of the aqueous oxy/hydroxy or pristine MOFs based energy storage devices.We appreciate the financial support from Agency for Science, Technology, and Research (A*STAR) by AME Individual Research Grant (A1983c0026) and from Singapore MOE AcRF Tier 2 Grant (MOE2017-T2-1-073).

KTiOPO4-structured electrode materials for metal-ion batteries: A review

The success story of the triphylite-type LiFePO4 immediately boosted the development of numerous classes of polyanion-based electrode materials for metal-ion batteries. A number of advantages including thermal and structural stability, polyanionic inductive effect, and variety of crystal types and chemical compositions render these materials attractive for grid and large-scale applications ensuring high safety standards, environmental friendliness and cost benefits. In this review, we focus on a specific family of polyanion-based electrode materials adopting the KTiOPO4-type structure that captured particular attention recently due to the unique 3D-framework. This framework features thermal, structural and long-term electrochemical cycling stability, fast ionic transport, possibility to accommodate two alkali ions per transition metal cation enabling multi-electron transitions, and unprecedented high electrode potentials for a specific redox couple among all known polyanion materials. The recent advances and overview of KTiOPO4-type and related positive and negative electrode materials for metal-ion batteries are presented with a special emphasis on the interrelations between crystal structure peculiarities and electrochemical properties.

Construction of Bimetallic Selenides Encapsulated in Nitrogen/Sulfur Co-Doped Hollow Carbon Nanospheres for High-Performance Sodium/Potassium-Ion Half/Full Batteries.

Metallic selenides have been widely investigated as promising electrode materials for metal-ion batteries based on their relatively high theoretical capacity. However, rapid capacity decay and structural collapse resulting from the larger-sized Na+ /K+ greatly hamper their application. Herein, a bimetallic selenide (MoSe2 /CoSe2 ) encapsulated in nitrogen, sulfur-codoped hollow carbon nanospheres interconnected reduced graphene oxide nanosheets (rGO@MCSe) are successfully designed as advanced anode materials for Na/K-ion batteries. As expected, the significant pseudocapacitive charge storage behavior substantially contributes to superior rate capability. Specifically, it achieves a high reversible specific capacity of 311 mAh g-1 at 10 A g-1 in NIBs and 310 mAh g-1 at 5 A g-1 in KIBs. A combination of ex situ X-ray diffraction, Raman spectroscopy, and transmission electron microscopy tests reveals the phase transition of rGO@MCSe in NIBs/KIBs. Unexpectedly, they show quite different Na+ /K+ insertion/extraction reaction mechanisms for both cells, maybe due to more sluggish K+ diffusion kinetics than that of Na+ . More significantly, it shows excellent energy storage properties in Na/K-ion full cells when coupled with Na3 V2 (PO4 )2 O2 F and PTCDA@450 °C cathodes. This work offers an advanced electrode construction guidance for the development of high-performance energy storage devices.