Metal-ion Battery Anodes Research Articles

Unraveling the enhanced sodium-storage mechanism in a strongly bonded 2D honeycomb borophene/boron phosphide heterostructure

The growing modern demand for battery capacity is driving the development of high-capacity metal-ion battery anodes for future energy storage. Two-dimensional (2D) material-based heterostructures have shown advantages as alternative anodes due to their enhanced adsorption capacity. The lightweight nature of honeycomb borophene (HB) is beneficial for serving as a high-capacity anode but is constrained by structural instability arising from electron deficiency. In this study, using first-principles calculations, we propose a HB/boron phosphide (BP) heterostructure as an anode for both lithium-ion batteries and sodium-ion batteries (SIBs). The heterostructure engineering not only stabilizes the HB structure but also leads to a bonding heterostructure instead of common van der Walls type. The HB/BP demonstrates robust structural stability and reversibility when multiple ions are stored. In addition, the HB/BP offers stable storage sites and low diffusion barriers for lithium (0.31 eV) and sodium (0.28 eV), indicating rapid charging–discharging performance. Notably, the predicted maximum sodium storage capacity reaches 2402 mAh/g, surpassing that of the constituent monolayers and most 2D heterostructures. The underlying mechanism for high storage capacity is elucidated through detailed charge image model analysis, offering atomistic-scale insights for constructing high-capacity anodes. All results suggest that the presented HB/BP is a promising anode candidate for SIBs and opens an avenue for stabilizing HB in energy storage.

High performance potassium/sodium-ion storage enabled by anchoring cobalt atoms on sulfur vacancies in WS2 nanosheets

Transition metal dichalcogenides (TMDs) as anodes have presented significant potential in alkali-ion batteries. Nevertheless, they are generally vulnerable to low conductivity and sluggish ion diffusion as well as severe volume variation. Here, a strategy of filling metal atoms into anion vacancies is proposed and applied to the example of WS2. More specifically, sulfur vacancies are produced and partially filled by Co atoms simultaneously in WS2 (denoted as Co@WS2-SV), creating a highly reactive micro-structure composed of Co-W-S, which can not only effectively provide more active sites, but also boost the charge transfer and reaction kinetics. Consequently, the as-prepared Co@WS2-SV exhibits superior K+ storage performance, which includes an ultrahigh reversible capacity of 382.9 mAh g−1 at 0.05 A g−1. Besides, Co@WS2-SV still maintain a capacity of 112.6 mAh g−1 after 1100 cycles at 2 A g−1 while the capacity fades to ∼0 mAh g−1 after only 800 cycles for WS2. Simultaneously, Co@WS2-SV also displays outstanding rate capability (338.7 mA h g−1 at 2 A g−1) and acceptable cycling performance (264.2 mA h g−1 at 1 A g−1 after 100 cycles) for sodium storage. The strategy in our study provides new way of precisely designing the other TMDs anodes for metal-ion batteries.

Sodium into γ-Graphyne Multilayers: An Intercalation Compound for Anodes in Metal-Ion Batteries.

The bulk synthesis of γ-graphyne has been recently achieved and evidenced a multilayered structure, which suggests its potential exploitation as a substitute of graphite-based anode materials for metals heavier than lithium (Li). In fact, each of its regular pores of sub-nanometric size features an optimal environment for hosting a single sodium (Na) ion, as reported here by means of accurate electronic structure calculations. We show that the graphyne/Na ion coupling mimics that found on the graphene/Li ion in terms of metal-single layer interaction and equilibrium distance. More importantly, in contrast to what is found for graphite, we demonstrate that graphyne intercalation compounds with Na are thermodynamically stable and feature an optimal storage capacity of 372 mAh·g-1. These findings, together with a limited crystal structure expansion upon Na intercalation, a low metal diffusion barrier as well as high electrical conductivity, pave the way to the development of novel graphyne-based anodes for efficient Na-ion batteries.

Breaking new ground in metal-ion battery anodes: First principles design of Dirac nodal line semimetallic carbon materials

With the rapid development of electronic devices, the demand for batteries has gradually increased, and existing batteries can no longer satisfy it. In this paper, a three-dimensional honeycomb carbon material is designed and termed pmma-C32. The mechanical stability, dynamic stability, thermal stability, and mechanical stability were investigated through first-principles molecular dynamics, phonon spectrum, and the Born-Huangkun criterion. The calculation results show that pmma-C32 not only has good thermodynamic stability, but also has static stability. Similar to graphene, pmma-C32 exhibits semi-metallic characteristics, featuring two Dirac node lines with high Fermi velocity, indicating a high capacity for electron transport. As a metal-ion battery material, pmma-C32 exhibits higher theoretical capacity(836.8, 732.2, and 418.4 mA h/g for Li, Na, and K), lower diffusion barrier (0.06–0.12 eV for Li, 0.10–0.11 eV for Na, and 0.05–0.06 eV for K), and lower open circuit voltage (0.34 V for Li, 0.37 V for Na, and 0.74 V for K). These remarkable properties endow semimetallic pmma-C32 as a promising anode material for metal-ion batteries, providing fast charge and discharge rates. This research not only broadens the family of three-dimensional carbon materials, but also greatly improves the performance for universal metal-ion battery anode materials through material structure design.

Anchored Bi with cobalt polyphthalocyanine enhances the reversibility of Bi2Te3 anode for endurable lithium-ion storage

As an intermetallic material, Bi2Te3 possesses great potential in lithium-ion batteries due to its attractive layered structure, intrinsic excellent conductivity and impressive theoretical specific capacity. However, the phase decomposition and the huge volume variation leading to rapid capacity fading hinder the further application of Bi2Te3 in lithium-ion batteries. In this study, two dimensional Bi2Te3 encapsulated in cobalt polyphthalocyanine (CoPPc) is synthesized by a facile recrystallization method, and its electrochemical properties and lithium storage mechanism are comprehensively studied. The Bi2Te3@CoPPc electrodes exhibit outstanding cycling stability with a specific capacity of 551.9 mAh g−1 at 100 mA g−1 and 628.5 mAh g−1 at 500 mA g−1 after 500 cycles, benefiting from the configured composite layered structure and the amiable interaction of Bi2Te3 and CoPPc. Our experimental and theoretic results demonstrate that the electron redistribution induced by the incorporation of CoPPc with charge accumulation around Bi2Te3 and low potential region around Co efficiently facilitates the fast lithium-ion transportation resulting in outstanding rate performance. Our explorative strategy of electron redistribution proposes a new avenue to enhance the catalysis activity and durability of alloy anodes in metal-ion batteries.

Possibility of defective monolayer graphene as potential anode material of metal-ion batteries

The necessitates exploration in the field of rechargeable metal ion batteries demands safe, cost-efficient, and face significant challenges in their development. Defect engineering may be helpful for the ion storage and diffusion in the battery anodes. In this paper, we use density functional theory to investigate the adsorption and diffusion behavior of Li, Mg, and Al atom on single vacancy (SV), Stone-Wales vacancy (SWV), double vacancy (DV) and quadruple vacancy (QV) defective monolayer graphene. It is evident that metal exhibits the strongest adsorption strengthen at the defect center. The DV and QV defective graphene shows the ideal diffusion energy barrier for three metals. Importantly, the QV structure exhibit maximum storage capacities of the 775 mAh/g for Li, 911 mAh/g for Mg, and 1543.4 mAh/g for Al respectively. Additionally, their open-circuit voltages are all in a very safe range. This study can support a strong basis for the experimental research for metal-ion battery anodes.

Biotene: Earth-Abundant 2D Material as Sustainable Anode for Li/Na-Ion Battery.

Natural ores are abundant, cost-effective, and environmentally friendly. Ultrathin (2D) layers of a naturally abundant van der Waals mineral, Biotite, have been prepared in bulk via exfoliation. We report here that this 2D Biotene material has shown extraordinary Li-Na-ion battery anode properties with ultralong cycling stability. Biotene shows 302 and 141 mAh g-1 first cycle-specific charge capacity for Li- and Na-ion battery applications with ∼90% initial Coulombic efficiency. The electrode exhibits significantly extended cycling stability with ∼75% capacity retention after 4000 cycles even at higher current densities (500-2000 mA g-1). Further, density functional theory studies show the possible Li intercalation mechanism between the 2D Biotene layers. Our work brings new directions toward designing the next generation of metal-ion battery anodes.

Graphyne-based 3D porous structure and its sandwich-type graphene structure for alkali metal ion battery anode materials.

In order to develop candidate materials for more metal ion battery anodes, a three-dimensional (3D) porous structure 3D-PGY was designed based on graphyne, and a sandwich structure graphene/PGY/graphene (G/PGY/G) was constructed by adjusting the distance between two layers of graphene with 3D-PGY as the middle layer. Systematic calculations have shown that 3D-PGY is thermally and mechanically stable even at temperatures up to 1000 K. Li can migrate in multiple diffusion directions in two structures because of its smaller radius while Na and K ions can only migrate through the larger pores. The energy barriers of Li, Na and K ions in 3D-PGY are 0.18, 0.43 and 0.27 eV respectively. After forming the sandwich structure with graphene, the minimum energy barriers of Li, Na and K ions are decreased to 0.12, 0.37 and 0.24 eV, respectively. As the anode for Li, Na, and K ion batteries, the theoretical specific capacities of 3D-PGY are about 558 mA h g-1, and the average open circuit voltages of 3D-PGY and G/PGY/G are about 0.48/0.52/0.29 and 1.08/1.04/1.39 V, respectively. Finally, using ab initio molecular dynamics simulations, the diffusion coefficients for 3D-PGY at different temperatures, as well as for G/PGY/G at 400 K were obtained. The Li, Na and K ions in both structures can diffuse rapidly and have good rate capabilities. These excellent performances show that the graphyne-based 3D porous structure and its sandwich-type graphene structure are very promising for the development of new battery materials.

Monolayer TiC—A high-performance Dirac anode with ultralow diffusion barriers and high energy densities for Li-ion and Na-ion batteries

Two-dimensional Dirac materials have stimulated substantial research interest as binder-free anodes in metal-ion batteries, owing to their ultrahigh electronic conductivity, large specific area, and higher energy density. Here, using first-principles density functional theory calculations, we have investigated the feasibility of monolayer TiC as a potential anode material for Li/Na-ion batteries. The results indicate that monolayer TiC exhibits excellent dynamical and thermal stability. The electronic structure of monolayer TiC shows semimetallic characteristics with a Dirac cone at the M high symmetry point and the formation of Ti or C vacancies transforms the Dirac cone into a nodal loop or a nodal surface, respectively. Thus, monolayer TiC possesses superior electrical conductivity, which can be further enhanced by the formation of Ti or C vacancies in the material. Furthermore, the calculated adsorption energy values of -0.85 and -0.46 eV for Li-ion and Na-ion, respectively, indicate that Li/Na atom adsorption over monolayer TiC is a favorable process. The density of states plots show that after the adsorption of a single Li/Na atom, monolayer TiC maintains its metallic state, which is advantageous for the diffusion of stored electrons. Most remarkably, monolayer TiC exhibits energy densities of 2684 and 2015 mWh/g for Li and Na, respectively, which are significantly higher than commercial graphite and most other 2D anode materials. The fully loaded TiC anode exhibits excellent cycle stability with volume expansions as low as 0.13 and 0.11%, for Li and Na, respectively. Furthermore, an ultrafast diffusivity with low energy barriers of 0.02 and 0.10 eV is found in monolayer TiC for Li-ion and Na-ion, respectively, which suggests that it has an excellent charge/discharge capability. These exceptional properties make monolayer TiC an excellent candidate as an anode material for Li-ion and Na-ion batteries. Finally, SiC(111) has been proposed as a candidate substrate for monolayer TiC due to its minimal lattice mismatch.

B3S2 monolayer as an anode material for Na/K-ion batteries: a first-principles study.

Two-dimensional (2D) materials used as anodes in metal-ion batteries have attracted increased attention due to their high specific surface area, abundant active sites and good electronic properties. Searching for 2D materials with high storage capacities and low diffusion energy barriers is one of the most effective ways to design novel anode materials. In this work, based on first-principles calculations, we design a new 2D B3S2 monolayer with high thermodynamic and dynamic stability. The obtained B3S2 monolayer has a high cohesive energy, ensuring the feasibility of experimental synthesis. These characteristics of the B3S2 monolayer prompt us to explore its application as an anode material. The B3S2 monolayer exhibits not only a metallic nature but also a low diffusion energy barrier (0.037 eV) and open-circuit voltage (0.09 V). More importantly, the B3S2 monolayer shows a very high theoretical capacity of 1658 mA h g-1 as an anode material for sodium-ion batteries, which is comparable to other similar or common 2D materials. All of these intriguing properties make the B3S2 monolayer a promising 2D anode material for sodium-ion batteries.

Comparative studies of hexagonal boron phosphide/V2CS2 heterostructure and homogeneous bilayers as metal-ion battery anodes.

Heterostructures can not only maintain/avoid the desired characteristics/defects of their monolayers, but also have synergistic effects due to the contribution of an internal electric field from the heterostructure interlayer. Hexagonal boron phosphide (h-BP) and V2CS2 were constructed into heterostructure (h-BP/V2CS2) and homogeneous bilayers (Dh-BP and DV2CS2), which were studied comparatively for their storage performances as anodes for metal (Li/Na/Mg/Ca)-ion batteries (LIBs/NIBs/MIBs/CIBs) using first-principles. The h-BP/V2CS2 can adsorb five layers of Mg atoms while Dh-BP cannot adsorb any Mg atoms; heterostructures with a maximum adsorption concentration are stable at room temperature, while Dh-BP structures are unstable in the same cases, which make Dh-BP unsuitable as LIB/NIB/MIB/CIB anodes. h-BP/V2CS2 completely exceeds DV2CS2 in capacity, average OCV or interlayer barrier for LIBs/NIBs/MIBs/CIBs owing to its stronger internal electric field. In particular, for MIBs/NIBs, the capacity of heterostructure is 1219/732 mA h g-1, which is much higher than the 753/226 mA h g-1 of DV2CS2; the average OCV of heterostructure is 0.07/0.35 V, as low as half of that of DV2CS2. The excellent storage performance of the heterostructure in NIBs/MIBs makes it very worthy of attention due to the urgent need for NIBs/MIBs with high energy density.

First-principles study of ZIF-8 as anode for Na and K ion batteries

Zeolitic imidazolate frameworks (ZIFs) have been investigated experimentally as anodes for Na and K ion batteries. In this work, atomic ZIF-8 models with Zn vacancies have been constructed and the adsorption and diffusion properties of alkali metal atoms are analyzed by density functional theory (DFT) calculations. Zinc vacancies have strong adsorption energy for alkali metal atoms, especially when the first atom is inserted. Additionally, the intercalation of alkali metal atoms would reduce energy band gap of ZIF-8 from 4.85 eV to 4.31 eV for Na and 3.82 eV for K. Moreover, alkali metal atoms can diffuse smoothly in ZIF-8, and the energy barriers are 0.10 eV for Li, 0.45 eV for Na and 0.66 eV for K, respectively. This work deeply explores the interaction mechanism between alkali metals and ZIF-8 theoretically, and provides a reference for the future design of porous carbon materials as anodes for metal ion batteries.

Ti2CT2 MXene as Anodes for Metal Ion Batteries: From Monolayer to Bilayer to Pillar Structure.

The electrochemical performances of Ti2CT2 (T = F, O, and OH) MXenes with different layer structures (monolayer, bilayer, and pillared structures) as anodes for mono-/multivalent metal ion (Li+, Na+, Mg2+, and Al3+) batteries (MIBs) were studied via first-principles simulations. First, metal ions (MIs) adsorbed on Ti2CT2 monolayers were investigated to reveal the influence of MXene terminated groups on MIB performance. This indicated that O-terminated MXenes would be more suitable as electrodes. In particular, the theoretical capacity of Mg2+ on a Ti2CO2 monolayer could be more than 1500 mA h g-1. Then, MIs intercalated into MXene bilayers were considered to better understand the charging/discharging mechanism. In a Ti2CO2 bilayer with larger interlayer spacing, monovalent MIs and Mg2+ could form a multilayer accompanied by drastic expansion/contraction of the electrode, which still needs to be solved. Finally, imidazolium-based ionic liquids were used to preintercalate into MXene due to the matching size of the imidazolium cation, which effectively improved MXene stability and inhibited the self-stacking of layered MXenes. Our research would be helpful for theoretically regulating MXene functional groups and adjusting the interlayer spacing of MXenes via selecting guest molecules for designing MIBs and other energy storage devices.

Ti3C2 MXene-derived Li4Ti5O12 nanoplates with in-situ formed carbon quantum dots for metal-ion battery anodes

Two-dimensional (2D) material Ti3C2 MXenes have recently been used in electrode composites for lithium-ion batteries (LIBs) for their excellent electrical conductivity and accordion-like nanosheet morphology. However, Ti3C2 has low specific capacity and fast degradation rate upon cycling after inevitably coupling with surface species during synthesis. In this work, Ti3C2 is used as Ti-source for Li4Ti5O12 (LTO) and C-source for carbon quantum dots (CQDs) in a one-step hydrothermal process. The resultant LTO product (M-LTO) inherits the nanosheet morphology of Ti3C2 with uniformly anchored CQDs. The highly electronic conductive CQDs optimize the transmission path of ions which reduces the diffusion barrier of ions, and they further increase the density of states of the material which effectively improving the conductivity of M-LTO. Remarkable electrochemical performances including high initial specific capacity, long lifetime and excellent low temperature capacity are demonstrated for this type of electrode in LIBs, sodium ion batteries (SIBs) and lithium-magnesium ion hybrid batteries (LMIHBs). This paper offers a new strategy to the rapidly expanding research on the application of transition metal MXenes in electrodes for metal-ion batteries.

Fe3+-Derived Boosted Charge Transfer in an FeSi4P4 Anode for Ultradurable Li-Ion Batteries.

Ion and electron transportation determine the electrochemical performance of anodes in metal-ion batteries. This study demonstrates the advantage of charge transfer over mass transport in ensuring ultrastable electrochemical performance. Additionally, charge transfer governs the quality, composition, and morphology of a solid-electrolyte interphase (SEI) film. We develop FeSi4P4-carbon nanotube (FSPC) and reduced-FeSi4P4-carbon nanotube (R-FSPC) heterostructures. The FSPC contains abundant Fe3+ cations and negligible pore contents, whereas R-FSPC predominantly comprises Fe2+ and an abundance of nanopores and vacancies. The copious amount of Fe3+ ions in FSPC significantly improves charge transfer during Li-ion battery tests and leads to the formation of a thin monotonic SEI film. This prevents the formation of detrimental LiP and crystalline-Li3.75Si phases and the aggregation of discharging/recharging products and guarantees the reformation of FeSi4P4 nanocrystals during delithiation. Thus, FSPC delivers a high initial Coulombic efficiency (>90%), exceptional rate capability (616 mAh g-1 at 15 A g-1), and ultrastable symmetric/asymmetric cycling performance (>1000 cycles at ultrahigh current densities). This study deepens our understanding of the effects of electron transport on regulating the structural and electrochemical properties of electrode materials in high-performance batteries.

Three-Dimensional Porous h-BC2N Based on BN Chains and Prismane C8 Units for Alkali Metal Ion Battery Anodes.

Here, a new three-dimensional (3D) porous h-BC2N was designed via the assembly of prismane C8 and boron nitride chains as the candidates for alkali metal ion battery anodes. By systematic calculations, it is found that h-BC2N is both thermally and mechanically stable, even at a temperature as high as 1000 K. Li ions can migrate with multiple diffusion directions in h-BC2N, and the minimum diffusion barrier is only 0.10 eV lower than that of graphite. The theoretical specific capacity of the h-BC2N anode for Li is 549 mAh/g, which is higher than that reported for graphite. h-BC2N is also a promising anode for sodium (NIBs) and potassium ion batteries (KIBs) whose specific capacities are also large (549 mAh/g), and the energy barriers are 0.35 and 0.19 eV, respectively. Additionally, LIBs, NIBs, and KIBs exhibit voltage stability upon charging/discharging and good cycling stability. This theoretical exploration may open a new frontier in the search for more practical 3D porous structures as LIBs, NIBs, and KIBs anodes.

Perovskite-Type SrVO3 as High-Performance Anode Materials for Lithium-Ion Batteries.

Perovskite-type oxides, characterized by excellent multifunctional physical and chemical properties, are widely used in ferroelectric, piezoelectric, energy conversion, and storage applications. It is shown here that the perovskite-type SrVO3 can achieve excellent electrochemical performance as lithium-ion battery anodes thanks to its high electrically and ionically conductivity. Conducting additive-free SrVO3 electrodes can deliver a high specific capacity of 324 mAh g-1 at a safe and low average working potential of ≈0.9 V vs Li/Li+ together with excellent high-rate performance. A high areal capacity of ≈5.4 mAh cm-2 is obtained using an ultrathick (≈120 μm) electrode. Moreover, the fully lithiated SrVO3 electrode exhibits only 2.3% volume expansion that is explained by a simple solid-solution Li+ -storage mechanism, resulting in good cycling stability of the electrode. This study highlights the perovskite-type SrVO3 as a promising Li+ -storage anode and provides opportunities for exploring a variety of perovskite oxides as next-generation metal-ion battery anodes.

Nanosized VC synthesized by disproportionation reaction in molten salts as a promising anode for lithium/sodium-ion batteries

Nanosized VC with an average particle size of ∼40 nm was synthesized by disproportionation of V(IV) ions on acetylene black template in molten (Na,K)Cl at 950 °C holding for 5 h. The as-synthesized VC has exhibited desirable electrochemical performances as an anode in lithium-ion batteries (LIBs), delivered a reversible discharge capacity of 597.8 mAh g−1 at 0.1 A g−1 and ∼397.8 mAh g−1 at 0.5 A g−1 in 200 consecutive cycles. It is noteworthy that nanosized VC also displayed impressive charge-discharge capacities in sodium-ion batteries (SIBs), released ∼252.5 mAh g−1 at 0.1 A g−1. This work provides a new insight into the preparation of high-performance carbide ceramics as anodes in metal-ion batteries.

Investigation of Potential of Si76, C32, B16N16, Al38P38 as Anodes in Metal-Ion Batteries

Investigation of Potential of Si76, C32, B16N16, Al38P38 as Anodes in Metal-Ion Batteries

A Dirac nodal surface semi-metallic carbon-based structure as a universal anode material for metal-ion batteries with high performance.

The rapid development of electronic devices requires high power storage batteries. However, reported 3D carbon-based materials are semiconductors or metals and are used in Li- or Na-ion batteries with low capacities. Thus, it is of interest to discover whether there is a universal semi-metallic material for use in high performance Li-, Na-, and K-ion batteries. Inspired by the recent synthesis of 3D carbon-based materials, in the research reported here, a 3D regular porous structure (bct-C56) is designed using graphene sheets. The porous carbon-based material has mechanical, dynamic, thermal, and mechanical stabilities. Interestingly, bct-C56 exhibits semi-metallic features with two Dirac nodal surfaces with mirror symmetry, as well as high Fermi velocities, indicating high electron-transport abilities. More excitingly, its theoretical capacities are 743.8, 478.2, and 425.0 mA h g-1, with diffusion barriers of 0.05-0.12, 0.07-0.12, and 0.03-0.05 eV, average OCVs of 0.31, 0.45, and 0.59 V, and volume expansion levels of 1.2%, 0.02%, and 3.1%, in Li-, Na-, and K-ion batteries, respectively. All these excellent characteristics suggest that semi-metallic bct-C56 is a universal anode material for use in metal-ion batteries with a fast charge-discharge rate. In this research, not only was a new material with a Dirac nodal surface feature designed, but it also offers an approach for the creation of high performance and universal metal-ion battery anodes with 3D porous carbon materials.