High-performance Anode Materials Research Articles

Facile flame synthesis of S-doped Fe2O3 on carbon cloth as superior anode material for sodium-ion battery

Take advantage of its superior theoretical specific capacity, Fe2O3 based nanocomposites are promising candidates for sodium ion batteries (SIBs). However, the complicate synthetic procedure hinders their further application. Herein, a facile ethanol diffusion flame synthesis approach is developed to prepare S-doped Fe2O3 composite on carbon cloth. The morphology of the Fe2O3 can be easily controlled by tuning the composition of the fuel and duration time of the flame treatment. Optimized composite with flake-like structure and heteroatom S-doped Fe2O3 (S/Fe2O3@CC-2) displayed enhanced electrochemical sodium storage performances. Specifically, sample S/Fe2O3@CC-2 maintained a reversible discharge capacity of 464.3 mAh g−1 after 150 cycles at 0.2 A g−1. Besides, at current densities of 0.4, 0.8, 1.6 and 3.2 A g−1, capacities of 393.8, 311.2, 277.5 and 218.9 mAh g−1 could be maintained, respectively. Kinetic analysis implies that S/Fe2O3@CC-2 manifested an improved capacitive-controlled sodium storage process. This work will shed light on facile and low-cost approach for the synthesis of high-performance anode materials for SIBs.

One-dimensional van der Waals V2Se9 as a conversion-type anode material for advanced Li rechargeable batteries

Volume expansion of active materials during lithium storage is one of the main issues in Li-ion batteries (LIBs) that should be addressed. In particular, large volume changes and particle cracking are problematic for electrode materials based on conversion reaction, which are considered attractive anode materials with high energy densities. In this study, a one-dimensional van der Waals (1D vdW) material, V2Se9, is proposed as a conversion-type anode material for LIBs. The V2Se9 electrode material has a 1D chain molecular structure with vdW interactions between chains to form a bulk crystal structure. The spaces between the 1D chains act as structural buffers and provide short Li+ diffusion paths that can improve the electrochemical performance of the electrode materials. The V2Se9 electrode exhibits a high reversible capacity of 563.3 mAh g−1 at 100 mA g−1 and a high rate capability of 109.1 mAh g−1 at 3200 mA g−1. The capacity retention of V2Se9 electrodes is 83.72% after 100 cycles. Synchrotron X-ray diffraction and X-ray absorption spectroscopy reveal the formation of Li2Se and V metal, indicating that Li ion storage occurs via the conversion reaction. The structural stability of V2Se9 is demonstrated using SEM measurements of the discharged and charged V2Se9 electrodes during cycling. These results demonstrate the reaction mechanism of V2Se9 and highlight the potential of 1D vdW materials as high-performance anode materials in LIBs.

Tuning the electrochemical performance of Cr2B2 MBene anodes for Li and Na-ion batteries through F and Cl-functionalization: A DFT and AIMD study

In an era in which sustainable energy sources and electric vehicles are prevalent, the development of efficient anode materials is paramount to address the pressing demand for improved energy storage technologies. After the graphene revolution, many other 2D materials such as graphene, MXene (atomically thin layer of Transition Metal Carbide/Nitride/Carbonitride), TMDC (Transition Metal Dichalcogenide), and MBene (atomically thin layer of Transition Metal Borides) have emerged as potential high-performance anode materials. A recent study demonstrated the possibility of synthesizing chromium-based MBenes for the first time, and the electrochemical performance of Cr2B2 as a potential anode material has also been studied theoretically. Inspired by this, the current study utilized density functional theory and ab initio molecular dynamics simulations to probe the role of Cl and F-functionalization of Cr2B2 MBenes as anode materials for rechargeable lithium-ion batteries (LIB) and sodium-ion batteries (NIB). The electronic structure, adsorption, diffusion, and storage capacity of Li (Lithium) and Na (Sodium) were systematically investigated. This study revealed that Cr2B2F2 and Cr2B2Cl2 exhibit excellent conductivity due to their intrinsic metallic properties. In addition, they have low diffusion energy barriers for Li and Na ions (0.13/0.14 and 0.20/0.20 eV for Cr2B2F2 and Cr2B2Cl2, respectively) facilitating rapid charge/discharge rates. The calculations further unveiled a notable Li-ion storage capacity of 818 mAh g-1 for 2D Cr2B2Cl2, accompanied by a moderate open-circuit voltage (OCV) range of 0.38 V to 0.98 V, illustrating its potential as a superior anodic material for LIBs. Similarly, Cr2B2F2 demonstrated a substantial Na-ion storage capacity of 655 mAh g-1, coupled with a reasonably ranged average OCV of 0.20 V to 0.71 V, positioning it as a compelling candidate for NIBs. In all, this investigation has identified two superior electrode materials for alkali-ion batteries, which can spark additional interest in exploring MBene as a promising candidate for advancing next-generation anode materials.

A novel two-dimensional whorled CrB4 and MoB4 as high-performance anode material for metal ion batteries

Finding high-storage-capacity anode materials has been a focus of ion-battery research. Two-dimensional (2D) materials have shown promise as high-performance electrode-materials as they have developed gradually. Here we examined the viability of 2D CrB4 and MoB4 monolayers as optimal anode-materials for Li/Na/K ion batteries using first-principles DFT calculations. Preliminary investigations showed that both materials exhibited thermodynamic, structural, and mechanical stability. We found thata strongly negative adsorption energy can help instabilizingthe adsorption of metal-ions on materials surface instead of clustering, that ensures metal-ion-batteries stability. The maximum theoretical storage capacities of Li, Na, and K ions adsorbed on the CrB4 monolayer surface were 1689,1126 and 750 mA h g−1, respectively, while those on the surface of MoB4 were 1155,770 and 513 mA h g−1, respectively. Additionally, calculated open-circuit voltages for Li-ions (0.84,0.82 V), Na-ions (0.25,0.32 V), and K-ions (0.85,0.81 V) for CrB4 and MoB4 monolayers, respectively. Electronic properties showed that increasing the metal ions concentration enhanced both materials’ electrical conductivity and remained the metallic in nature after adsorption. However, Li/Na/K energy barriers are nevertheless consistent with various typical 2D anode materials. The light shaded on 2D MoB4 and CrB4 is anticipated to identify new anode materials for LIBs, NIBs, and KIBs.

Hexagonal Mg2B2 and Ca2B2 monolayers as promising anode materials for Li-ion and Na-ion batteries.

Exploring new high-performance anode materials is of great significance for next generation renewable energy technologies. Two-dimensional (2D) transition metal borides, named as MBenes, are receiving increasing attention in energy storage fields due to their structure-and-composition diversities and high electrical conductivities. Expanding the family of hexagonal MBenes to non-transition metal borides, we report two hexagonal IIA metal M2B2-typed MBenes and demonstrate the feasibility of exfoliation and application as anode materials for Li-ion batteries (LIBs) and Na-ion batteries (SIBs) using ab initio calculations. The predicted 2D Mg2B2 and Ca2B2 monolayers exhibit robust thermal and mechanical stabilities, inherent metallic properties, electrical conductivities, and excellent electrode performance. The outstanding theoretical specific capacities of Mg2B2 and Ca2B2 for Li/Na ions reach up to 764/527 and 859/527 mA h g-1, respectively. Furthermore, the average open-circuit voltages (OCVs) of Mg2B2 and Ca2B2 range from 0.275 to 0.395 V, indicating their suitability for anode materials. Additionally, the low diffusion energy barriers of Mg2B2 and Ca2B2 for Li/Na ions at delithiated/desodiated states (27/14 and 16/12 meV) and lithiated/sodiated states (187/58 and 52/34 meV) illustrate their excellent charge-discharge capabilities. These intriguing findings demonstrate the superior performance of the predicted IIA metal boride monolayers as promising anode materials for LIBs and SIBs and break through the limitations of transition metal MBenes as anode materials in terms of overall performance. Our study opens the door to the application of the main group metal MBenes in ion energy storage.

Two-dimensional graphene+ as an anode material for calcium-ion batteries with ultra-high capacity: a first-principles study.

Multivalent-ion batteries have garnered significant attention due to their high energy density, low cost, and superior safety. Calcium-ion batteries (CIBs) are regarded as the next-generation energy storage systems for their abundant natural resources and bivalent characteristics. However, the absence of high-performance anode materials poses a significant obstacle to the progress of battery technology. Two-dimensional (2D) Dirac materials have excellent conductivity and abundant active sites, rendering them promising candidates as anode materials. A novel 2D Dirac material known as "graphene+" has been theoretically reported, exhibiting prominent properties including good stability, exceptional ductility, and remarkable electronic conductivity. By using first-principles calculations, we systematically investigate the performance of graphene+ as an anode material for CIBs. Graphene+ exhibits an ultra-high theoretical capacity (1487.7 mA h g-1), a small diffusion barrier (0.21 eV), and a low average open-circuit voltage (0.51 V). Furthermore, we investigate the impact of the electrolyte solvation on the performance of Ca-ion adsorption and migration. Upon contact with electrolyte solvents, graphene+ exhibits strong adsorption strength and rapid migration of Ca-ions on its surface. These results demonstrate the promising potential of graphene+ as a high-performance anode material for CIBs.

Enhancement of multilayer lithium storage in a β12-borophene/graphene heterostructure with built-in dipoles.

The combination of borophene with a supporting metallic layer is beneficial in stabilizing its structure and promoting its application in energy storage. Here, through first-principles calculations, we screen a β12-borophene/graphene (β12-B/G) heterostructure with superior structural integrity, strong interlayer binding, and high thermodynamic stability among different B/G heterostructures. Besides, it is noteworthy that β12-B/G has been recently synthesized, further opening the possibility of expanding its use in energy storage. Then the selected target is systematically investigated as an anode material for lithium-ion batteries (LIBs). Compared with each monolayer component, multiple lithium-ion adsorption is achieved in the β12-B/G heterostructure, resulting in an ultra-high theoretical specific capacity of 2267 mA h g-1. In addition, a lower diffusion energy barrier indicates faster electron transport and lithium-ion diffusion in the β12-B/G heterostructure. Notably, the multilayer lithium adsorption avoids the formation of dendritic deposits, as evidenced by complete ionization of the cationic layers. Moreover, the disparity in the work functions of the individual layers gives rise to a built-in dipole in β12-B/G, further enhancing the multilayer lithium storage and ion migration. All these results suggest that the construction of borophene-based heterostructures with built-in dipoles is a feasible way to design high-performance LIB anode materials.

Sulfur-doped carbon nanofibers as stable and high performance anode materials for sodium-ion batteries

CNF-2S has good cycling performance in sodium ion half/full batteries.

Dual heteroatom-doped biomass-derived porous carbon anode for superior sodium storage

The green preparation of anode materials is desirable for high-performance sodium-ion batteries. In this paper, a N/S co-doped porous carbon was prepared from longan shell via a facile and low-cost route. Heteroatom doping increases the defect sites to facilitate Na+ storage and improves the electronic conductivity of the carbon material. The N/S co-doped porous carbon prepared using CS(NH2)2 with a ratio of 1:2 displays the highest specific capacity of 314.7 mAh g−1 after 200 cycles at 0.1 A g−1. In addition, a reversible specific capacity of 202.5 mAh g−1 is maintained after 1000 cycles at 1 A g−1. This work offers a new strategy for designing high-performance anode materials for sodium energy storage applications.

Organoboron flank-substituted donor-acceptor polymer anode with ultra-long cycling stability for lithium ion batteries.

The tunable structure and other properties of organic materials suggest that they can potentially solve the shortcomings of traditional anodes such as graphite. We successfully introduced an organoboron unit into the thiophene-based polymer PBT-2 to construct a donor-acceptor polymer anode. The charge delocalization and LUMO energy level resulting from the unique structure of this material enabled good redox activity and a very stable electrochemical performance in electrochemical tests, with a reversible capacity of 262 mA h g-1 at 0.5 A g-1 and >10 000 cycles at 1 A g-1 with a decay of 0.056‰ per cycle. Accordingly, targeted structural design to overcome the shortcomings of active units such as thiophene can effectively regulate their electrochemical performance, providing a solution for the development of high-performance anode materials for use in lithium ion batteries.

Novel nitrogen-doped carbon-coated SnSe2 based on a post-synthetically modified MOF as a high-performance anode material for LIBs and SIBs.

SnSe2 with high theoretical capacity has been identified as an emerging anode candidate for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). However, the rate performance and cycling performance of this material in practical applications are still limited by unavoidable volume expansion and low conductivity. In this work, we designed and synthesized nitrogen-doped carbon-coated SnSe2/C-N composites using 2-aminoterephthalic acid (C8H7NO4) as a nitrogen-containing compound for modification by hydrothermal and vacuum calcination methods to achieve efficient utilization of active sites and optimization of the electronic structure. The carbon skeleton inherited from the Sn-MOF precursor can effectively improve the electronic conduction properties of SnSe2. N-doping in the Sn-MOF can increase the positive and negative electrostatic potential energy regions on the molecular surface to further improve the electrical conductivity, and effectively reduce the binding energy with Li+/Na+ which was determined by Density Functional Theory (DFT) methods. In addition, the N-doped carbon skeleton also introduces a larger space for Li+/Na+ intercalation and enhances the mechanical properties. In particular, the post-synthetically modified MOF-derived SnSe2/C-N materials exhibit excellent cyclability, with a reversible capacity of 695 mA h g-1 for LIBs and 259 mA h g-1 for SIBs after 100 cycles at 100 mA g-1.

Unveiling the potential of a BCN-biphenylene monolayer as a high-performance anode material for alkali metal ion batteries: a first-principles study.

Inspired by a freshly synthesized two-dimensional biphenylene carbon network, which features a captivating combination of hexagonal, square, and octagonal rings, we explored a similar biphenylene network composed of boron, carbon, and nitrogen (bpn-BCN) using first-principles calculations. There are six possible phases of borocarbonitrides, which are isoelectronic to biphenylene carbon networks with a stoichiometric ratio of 1 : 1 : 1 for boron (B), carbon (C), and nitrogen (N) atoms. All possible isoelectronic structures of the BCN combination of biphenylene networks are found to be stable, according to first-principles calculations. However, the geometry has a relatively large number of robust C-C and B-N bonds and strong partially ionic-covalent B-C and C-N bonds inside these bpn-BCN monolayers are effectively more stable. Furthermore, we employed first-principles calculations to investigate the electrochemical properties of the most stable geometry of BCN biphenylene as a potential anode material for alkali metal (AM) ion batteries. A global search has been made to find the most favourable alkali metal ion adsorption sites. The biphenylene monolayer has octagonal, square, and hexagonal motifs with different adsorption strengths. Furthermore, the partially ionic bond of B-N (due to the electronegativity difference) also supports the alkali metal ions for adsorption. The electronic properties of the stable phase of bpn-BCN reveal its narrow bandgap semiconductor nature. The ion diffusion calculations show a low activation barrier for Li, Na, and K of 0.65 eV, 0.26 eV, and 0.23 eV, respectively, indicating a fast charge/discharge rate. Furthermore, the theoretical capacities of the BCN biphenylene monolayer for Li (1057.33 mA h g-1), Na (647.27 mA h g-1), and K (465.98 mA h g-1) are found to be greater than those of commercial graphite. The average open-circuit voltage for AM decreases with increasing metal ion concentrations. It falls within a reasonable range of 0.34-1.89 V. Our results show that the BCN biphenylene monolayer could be a promising anode material in alkali metal ion rechargeable batteries.

First principles study of a triazine-based covalent organic framework as a high-capacity anode material for Na/K-ion batteries.

The rational design of high-performance anode materials is crucial for the development of rechargeable Na-ion batteries (NIBs) and K-ion batteries (KIBs). In this study, based on density functional theory (DFT) calculations, we have systematically investigated the possibility of a bilayer triazine-based covalent organic framework (bilayer TCOF) as an anode for NIBs and KIBs. The calculation of the electronic band structure shows that the bilayer TCOF is a direct band gap semiconductor with a band gap of 2.01 eV. After the adsorption of Na/K at the most favorable sites, the bilayer TCOF transitions from a semiconductor to a metal state, guaranteeing good electronic conductivity. The low diffusion barriers of the bilayer TCOF are 0.45 and 0.26 eV, respectively, indicating a fast diffusion rate of Na/K ions. In addition, the bilayer TCOF has a theoretical storage capacity of up to 628 mA h g-1. Finally, it is found that the average voltage of the bilayer TCOF for NIBs and KIBs is 0.53 and 0.48 V, respectively. Based on these results, we can conclude that the bilayer TCOF may be a suitable anode material for NIBs and KIBs.

Optimal carbon layer wrapped one-dimensional CoTe2 nanorods for fast and robust potassium storage

CoTe2 as a high-performance anode material for potassium ion batteries still faces much challenges that hinder its electrochemical performance, including poor intrinsic electronic conductivity, slow reaction kinetics, and significant volume...

Nanostructured Composites as High-Performance Anode Materials for Supercapacitors - Synthesis, Engineering Strategy, and Challenges

As electric vehicles continue to rise in popularity, the quest for enhancements in their operational range and overall performance has led to an increasing demand for energy storage solutions with both high energy density and superior cycle performance. In response to this demand, supercapacitors have emerged as a highly promising technology, largely due to their exceptional cycle stability and rapid charge-discharge capabilities. Central to the advancements in supercapacitor technology is the development of anode electrode materials, which play a critical role in augmenting the energy storage capacity and efficiency of these devices. This article explores the synthesis and engineering strategies of nanocomposites, which are at the forefront of anode electrode material innovation. These nanocomposites, under their unique structural and compositional attributes, offer enhanced electrical conductivity and electrochemical properties, thereby significantly improving the performance of supercapacitors. However, despite the promising advances, there remain substantial challenges that need to be addressed. These include issues related to the scalability of production processes, the durability of materials under operational stress, and the optimization of the nanocomposites for specific applications. The article concludes by underscoring the need for ongoing research and development efforts aimed at overcoming these hurdles, which will be crucial for the realization of next-generation supercapacitors that meet the growing performance demands of electric vehicles and other applications.

A novel Tetrahexcarbon as a high-performance anode material for Na-ion and K-ion batteries

The search for high storage capacity anode materials has been an important topic in the field of ion batteries. With the gradual development of two-dimensional (2D) materials, their potential as high-performance electrode materials have been demonstrated. Here, using first principles calculations, we investigate the feasibility of novel Tetrahexcarbon as a high-performance anode material for Na/K ion batteries. Our results indicate that Na/K ions can be chemically and stably adsorbed on the surface of Tetrahexcarbon. It is noteworthy that the Na capacity of Tetrahexcarbon is up to 2233.3 mAh g-1 and the K capacity up to 744.4 mAh g-1 with a guaranteed low diffusion barrier (0.14 eV for Na; 0.18 eV for K). Therefore, our calculations show that Tetrahexcarbon is an excellent anode material with great potential for ultra-high energy storage devices.

Scalable synthesis of N/S co-doped hard carbon microspheres as a high-performance anode material for sodium-ion batteries

Hard carbon is a promising anode material for sodium-ion batteries (SIBs) due to its abundance. However, it exhibits low reversible capacity and slow kinetics if inappropriate microstructural features are developed during synthesis. Herein, N/S co-doped phenolic resin-based hard carbon microspheres are prepared by a scalable strategy, and the electrochemical performance is assessed both in half cells and full cells. We demonstrate that the expanded interlayer spacing, the increased active sites, and the enhanced capacitive behavior result in the enhanced reversible capacity and promoted kinetics for Na+ storage. The sample with appropriate doping amount exhibits an initial charge capacity of 536.8 mAh g−1 at 50 mA g−1 and maintains 445.9 mAh g−1 after 1000 cycles at a current density of 1 A g–1 in a Na-metal half cell. Coupled with a carbon-coated Na4Fe3(PO4)2P2O7 (NFPP) cathode, the full cell exhibits a capacity of 92.5 mAh g−1 after 90 cycles, with a capacity retention of 91.6%. This work provides a facile and scalable method for synthesizing high-performance hard carbon anode materials for SIBs.

Green Synergy Conversion of Waste Graphite in Spent Lithium-Ion Batteries to GO and High-Performance EG Anode Material.

The increasing demand for graphite and the higher lithium content than environment abundance make the recycling of anode in spent lithium-ion batteries (LIBs) also become an inevitable trend. This work proposes a simple pathway to convert the retired graphite to high-performance expanded graphite (EG) under mild conditions. After the oxidation and intercalation by FeCl3 for the retired graphite, H2O2 molecules are more likely to penetrate into the extended layers. And the gas phase diffusion caused by the produced O2 from the redox reaction between FeCl3 and H2O2 further promotes lattice expansion of interlayers (0.535nm), which is beneficial to the stripping of graphene oxide (GO) with fewer layers. The EG exhibits excellent electrochemical performances in both LIBs and sodium-ion batteries (SIBs). It delivers 331.5mAhg-1 at 3C (1C=372mAg-1) in LIBs, while it achieves 176.8mAh g-1 at 3C (1C=120mAg-1) in SIBs. Then the capacity retains 753.6 (LIBs) and 201.6 (SIBs)mAhg-1 after a long-term cycling of 500 times at 1C, respectively. The full cells with the EG electrodes after prelithium/presodiation also show excellent cycle stability. Thus, this work offers another referable strategy for the recycling of waste graphite in spent LIBs.

SnO2-coated SiO2@C core-double-shell nanospheres as high-performance anode materials for lithium-ion batteries

SnO2-coated SiO2@C core-double-shell nanospheres as high-performance anode materials for lithium-ion batteries

Effects of Secondary Phase on Electrochemical Performance of Co-Free High Entropy Spinel Oxide Anodes for Lithium-Ion Batteries

High entropy oxide (HEO) anode materials have recently gained significant attention in lithium-ion batteries (LIBs) due to their exceptional cycling stability, high specific capacity, and unique adjustable properties. The exclusive feature of HEO allows the use of endless element combinations to create new electrode materials with exciting and unexplored properties. In the context of Li-ion battery anode materials, unlike conventional thinking, where a single-phase high entropy oxide (HEO) is considered sufficient and necessary for delivering good electrochemical performance, we report here that this is not a necessary condition. This study demonstrates the advantages of a secondary phase in HEO. Two types of Co-free high entropy spinel oxide (HESO) are synthesized using solvothermal and hydrothermal methods, resulting in single-phase cubic HESO (HESO (C)) and binary-phase (cubic + tetragonal) HESO (HESO (C+T)), respectively. The secondary tetragonal spinel phase introduces phase boundaries and defects/oxygen vacancies in HESO (C+T), which can improve the redox kinetics and reversibility during electrode lithiation/delithiation. The minor tetragonal phase in the HESO (C+T) anode sustains after cycling, largely reducing the morphology deterioration due to improved reversibility, thus contributing to enhanced cyclability. Density functional theory calculation is performed to assess the phase stability of cubic spinel, tetragonal spinel, and rock-salt structures, and validate the cycling stability of the HEO electrodes upon lithiation/delithiation. This is the first time that the effects of a secondary phase in HEO on the electrochemical properties have been reported. A HESO (C+T)||LiNi0.8Co0.1Mn0.1O2 full cell delivers an energy density of ~610 Wh kg−1, demonstrating a great potential of the HESO (C+T) for use in LIBs. The results provide useful guidelines for designing new high-performance anode materials for LIBs.