Potential Anode Material Research Articles

Synthesis and electrochemical properties of ZnFe2O4/C as novel anode material for lithium ion battery

The ZnFe2O4/C nanofibers were synthesized by electrospinning method combined with heat treatment. The crystal structure, elemental valence, and morphology of expected compounds were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and scanning electron microscopy (SEM) techniques, respectively. The electrochemical performances of ZnFe2O4/C were tested by battery comprehensive testing system. The test results showed that ZnFe2O4/C owned high specific capacities under different current densities. At current density of 0.2 A g−1, the specific capacity was 624.5 mAh g−1 after 100 cycles. And when current density was increased to 0.5 A g−1, its capacity could maintain at 479.3 mAh g−1 after 500 cycles. The ZnFe2O4/C exhibited excellent cycle stability, too. So the ZnFe2O4/C composite is a potential anode material for lithium ion battery application.

Artificial SEI for Superhigh-Performance K-Graphite Anode.

Although graphite with its merits of low cost, abundance, and environmental friendliness is a potential anode material for potassium ion batteries (PIBs), it suffers from a limited cycle life due to a severe decomposition of the solid electrolyte interface (SEI) in organic electrolytes. Herein, a simple and viable method is demonstrated for the first time through which an ultra‐thin, uniform, dense, and stable artificial inorganic SEI film can be prepared on commercial graphite anodes and used with traditional carbonate electrolytes to achieve PIBs with long‐cycle stability and high initial Coulombic efficiency (ICE). Specifically, such commercial graphite anodes exhibit a long‐term cycling stability for more than 1000 cycles at 100 mA g−1 (a reversible capacity of around 260 mAh g−1) and a high average CE (around 99.9%) in traditional carbonate electrolytes with no discernable decay in capacity. More importantly, the commercial graphite anodes with the artificial inorganic SEI film in traditional carbonate electrolytes can deliver a high ICE of 93% (the highest ICE ever reported for PIBs anodes until now), which improves the performance of the PIB full cell. Considering the high ICE and long cycle stability performance, this study can promote the rapid deployment of PIBs on a commercial scale.

Rational design of microstructure and interphase enables high-capacity and long-life carbon anodes for potassium ion batteries

Disordered carbon is considered as a potential anode material for potassium ion batteries (PIBs) due to its advantages in rate capability compared to graphite. Nevertheless, its capacity is usually limited below 300 mAh g−1. Herein, we demonstrate the performance of low-cost pitch derived carbon could be significantly boosted through synergistic microstructure design and electrode/electrolyte interphase regulation. A considerable amount of mesopore is produced to provide the extra active sites for K ion storage and meanwhile, facilitate the charge transfer. The optimized carbon anode delivers a remarkable capacity of 460 mAh g−1 with outstanding rate capability up to 4.0 A g−1. In-situ Raman spectra reveal the superb performance originates from K ion storage in both the mesopore and disordered graphene layers. The construction of a robust solid electrolyte interphase in ethylene glycol diethyl ether derived electrolyte further improves the long-term stability, leading to an exceptional capacity retention of 80% after 2000 cycles under a current density of 1.0 A g−1. This strategy provides a facile approach to enhance the performance of carbon materials for PIBs via structure and interphase design.

Graphitic SiC: A potential anode material for Na‐ion battery with extremely high storage capacity

AbstractBulk SiC phases with tetrahedral arrangements have been identified several decades ago, and have been widely studied due to their potential applications. Until recently, Yaghoubi et al.'s experiment (Chem. Mater. 2018, 30, 7234) observed the existence of graphitic SiC with few SiC layers stacking, which implies the possible synthesis of such material in the future. In this work, we explored the potential application of graphitic SiC as the Na‐ion battery anode via the first‐principle simulation. Our results reveal that the theoretical capacity of graphitic SiC reaches up to 1339.44 mAh/g, which is almost the highest among the already known Na‐ion battery anodes. Together with the low diffusion barrier, moderate open circuit voltage and excellent electronic conductivity during the sodiation, we propose that the graphitic SiC is a potential material as Na‐ion battery anode. More importantly, we find that the intercalation strength of Na ions into C‐based multilayer materials (or the corresponding theoretical capacity, the operation voltage) could be enhanced by increasing the amount of covalent components in NaC bonds, which could be realized via doping by atom (such as Li, Be, B, Al, Si or P) with lower electronegativity than that of C atom.

Core–Shell Structured Fe7S8@C Nanospheres as a High-Performance Anode Material for Potassium-Ion Batteries

Fe₇S₈, a potential anode material, has been extensively investigated but still faces challenges because of its poor cycling performance resulted from a large volume expansion. In this work, a solvothermal approach was employed to synthesize quasicubic α-Fe₂O₃ nanoparticles followed by sequential phenol-formaldehyde resin and mesoporous SiO₂ coating. After sulfurization and the subsequent removal of the SiO₂ shell, a Fe₇S₈@medium thickness carbon coating has been successfully fabricated, which exhibits a large specific capacity, remarkable high-current property, and stable cyclic performance for potassium-ion batteries (PIBs). It delivers a 423.3 mAh g–¹ superior initial reversible capacity at 0.2 A g–¹, excellent rate performance of 212.6 mAh g–¹ at 2 A g–¹, and long cyclic life of 266.9 mAh g–¹ at 1 A g–¹ after 500 cycles. These remarkable potassium storage properties are related to the excellent stress self-cushioning effect due to the spherical nanoarchitecture and complete carbon covering.

MnCr2O4/graphene composite as a high-performance anode material for lithium-ion batteries

A simple, facile and scalable solid-state reaction technique is adopted to obtain phase pure MnCr2O4 (MCO), which is further embedded on graphene sheets to make MnCr2O4/Graphene (MCO/G) composite. As an anode for lithium ion batteries, for the first time, MnCr2O4/Graphene (MCO/G) composite exhibits a high reversible specific capacity of ̴ 1794 mAh g−1 (5 times higher than the theoretical capacity of graphite) at 50 mA g−1 for 100 cycles, along with a Coulombic efficiency of 99%. Further, a capacity of around 402 mAh g−1 is obtained at a high current density of 1 A g−1, which is still significantly higher than the capacity of graphite. The impressive electrochemical performance of MnCr2O4/Graphene (MCO/G) composite could be attributed to the effective alleviation of huge volume changes by graphene during cycling and the synergistic effect between the Mn and Cr mixed metal oxides. Furthermore, chemical, mechanical and structural integrity of the MnCr2O4/Graphene (MCO/G) composite anode have been validated using series of post-mortem analyses such as ex-situ XPS, XRD and HR-TEM. Detailed investigations on structural and electrochemical cycling stability of MnCr2O4/G (MCO/G) composite anodes recommend the title electrode as a potential next generation anode material for high capacity LIBs with scalability possibilities through cost effective approach.

In-situ constructing uniform polymer network for iron oxide microspheres: A novel approach to improve the cycling stability of the conversion electrodes through chemical interaction

Electrochemical conversion reaction provides potential high-capacity anode materials for Li-ion and Na-ion batteries. However, the inferior cyclability is seriously hindering their applications. Herein, a novel strategy is introduced to improve the performance of conversion-type Fe2O3-AHP composite by using an organic amino-hyperbranched polymer additive. The amino groups of polymers could coordinate with Fe3+ through chemical interaction, and make Fe2O3 particles self-assemble into unique microspheres in solvothermal process. Moreover, the polymer additive in-situ constructs 3D uniform elastic frame work on molecular level in Fe2O3-AHP composite, which could accommodate the volume change and stabilize the Fe2O3 structure during lithiation/delithiation or sodiation/desodiation processes. Therefore, compared with Fe2O3-AHP-500 in which AHP was removed by heat treatment, the Fe2O3-AHP microspheres exhibit excellent long-term Li-storage (98.3% capacity retention rate after 1000 cycles at 2.0 A g−1) and Na-storage cyclabilities and maintain the integrity of microsphere structure after cycling. Furthermore, the polymer additive makes the Fe2O3-AHP microsphere have plenty of nanopores, which facilitate electrolyte infiltration and ion diffusion and thus enhance the kinetic performance. The present study highlights a novel strategy of in-situ construction of stable network on molecular level using polymer additive via strong chemical interaction, which delivers inspiration optimizing the long-term cyclability of conversion-type materials.

Synthesis and electrochemical performance of LiVO3 anode materials for full vanadium-based lithium-ion batteries

Abstract: LiVO3 is prepared by the combustion method and applied as anode material for rechargeable lithium-ion batteries. The LiVO3 electrode material shows excellent electrochemical performance in the voltage window of 0.2-3V. It displays a high specific capacity and capable capacity retention. Moreover, a full vanadium-based cell is designed based on the LiVO3 anode and Li3V2(PO4)3 cathode. The full cell presents a stable cycling performance and good rate ability. This work suggests a potential vanadium-based anode material and the possibility of the full vanadium-based cell.

Building Zn-Fe bimetal selenides heterostructures caged in nitrogen-doped carbon cubic for lithium and sodium ion batteries

Due to the application of lithium-ion batteries in various convenient electronic devices and electric vehicles, their related study has attracted many researchers' interests. However, the practical application is limited by their fast capacity attenuation, low reversibility and slow charge rate. Sodium-ion batteries have attracted considerable attention in energy storage systems due to similar energy storage mechanisms with lithium-ion batteries and extensive sodium resources on earth. In recent years, Prussian blue analogs (PBAs) and transition metal selenides have attracted many researchers' attention due to their unique structures and high theoretical capacities and have been considered to be the most potential anode materials. However, they have the disadvantages of rapid volume expansion and capacity degradation in the process of lithium insertion/extraction. Here, ZnSe-Fe3Se4 heterostructures coated with N-doped carbon (ZnSe-Fe3Se4@NC) was successfully designed by one-step selenization of Zn-Fe PBA. This unique 3D hierarchical heterostructures can provide a stable environment for lithium ions and sodium ions transportation and shortens the transmission path, which greatly improves the performance of lithium-ion batteries and sodium-ion batteries. The Zn-Fe-Se@NC displays a discharge capacity of 1111.30 mA h g−1 after 100 cycles at 0.2 A g−1 for lithium-ion batteries and 368 mA h g−1 after 60 cycles at 0.1 A g−1 for sodium-ion batteries. This high capacity is mainly attributed to the three-dimensional hierarchical heterostructures coated by N-doped carbon.

A first-principle study of FeB6 monolayer as a potential anode material for Li-ion and Na-ion batteries

Two-dimensional (2D) graphene-like hexagonal borophene sheet (HBS) is a kinetically unstable configuration since the electrons of π-valence orbitals of HBS are less than those of graphene. Inspired by the planar hexacoordinate wheel-type Fe©B6H6, we theoretically designed a novel 2D material FeB6 where the HBS can be stabilized by Fe atoms located at the center of partial boron rings. Moreover, we also investigated the possibility of using FeB6 monolayer as a potential anode for Li-ion batteries (LIBs) and Na-ion batteries (NIBs). Our calculations showed that FeB6 monolayer had strong adsorption energies (2.89 eV for Li and 2.39 eV for Na), low diffusion barriers (0.24 eV for Li and 0.10 eV for Na) and high theoretical specific capacities (991 mAh/g for Li and 622 mAh/g for Na), which indicates that FeB6 monolayer can be a potential anode material for LIBs/NIBs.

Suppression of volume expansion by graphene encapsulated Co3O4 quantum dots for boosting lithium storage

Transition metal oxide has been attracting significant attention as a potential alternative anode materials for high-performance lithium-ion batteries. However, the materials still suffer from poor performance due to the large volume expansion during reversible electrochemical reaction between the materials and Li ions. Here, we report on successfully synthesized graphene encapsulated Co3O4 (GE-Co3O4) quantum dots (QDs) by a facile chemical reaction. We also demonstrate an improved performance in Li storage with GE/Co3O4 by suppression of volume expansion during charge/discharge processes. To evaluate the electrochemical characteristics for the lithium storage the composites were examined by cyclic voltammetry and charge/discharge process. The GE-Co3O4 showed a large reversible capacity of 820 mA h/g at a constant current density of 1000 mAg−1 even after 100 cycles and excellent rate capacity and cyclic stability compared to pristine Co3O4 QDs. The encapsulated graphene shell can obstruct the pulverization by inhibiting the volume expansion of Co3O4 QDs, which was supported by the fact that the morphology and structure of GE-Co3O4 QDs was not significantly changed after 100 cycles. We also confirmed through scanning Kelvin probe microscopy, transmittance electron microscopy, and energy-dispersive X-ray spectrometer that the morphology of GE-Co3O4 QDs was maintained whereas that of Co3O4 QDs was almost fully decomposed. The encapsulation of graphene can play important roles such as suppression of volume expansion and producing a sufficient opposing force to aggregation during the cycles, resulting in a long stable life cycle.

First-principles study of structural stability and lithium storage property of Si<sub><i>n</i></sub> clusters (<i>n</i> ≤ 6) adsorbed on graphene

Silicon/carbon composite is one of the most potential high-capacity anode materials for lithium-ion batteries. The interface state between silicon and carbon of silicon/carbon composite is an important factor affecting its electrochemical performance. In this paper, Si<sub><i>n</i></sub> (<i>n</i> ≤ 6) clusters with different numbers of Si atoms are constructed on graphene as a structural unit of carbon material. The geometric configuration, structure stability and electronic property of Si<sub><i>n</i></sub> clusters adsorbed on graphene (Si<sub><i>n</i></sub>/Gr) are studied by the first-principles method based on density functional theory (DFT). The results show that when the number of Si atoms <i>n</i> ≤ 4, the Si<sub><i>n</i></sub> clusters are preferentially adsorbed on graphene in a two-dimensional configuration parallel to graphene. When <i>n</i> ≥ 5, the Si<sub><i>n</i></sub> clusters are preferentially adsorbed on graphene in a three-dimensional configuration. With the increase of the number of Si atoms <i>n</i>, the thermodynamic stability of Si<sub><i>n</i></sub> clusters on graphene decreases significantly, the interface binding strength between Si<sub><i>n</i></sub> clusters and graphene decreases, and the charge transfer between Si<sub><i>n</i></sub> clusters and graphene becomes less. At the same time, the storage capacity of Li atoms in Si<sub><i>n</i></sub>/Gr complex is also studied. Li atoms are mainly stored on the graphene surface near Si<sub><i>n</i></sub> clusters and around Si<sub><i>n</i></sub> clusters. The complex synergistic effect of Si<sub><i>n</i></sub> clusters and graphene enhances the thermodynamic stability of Li adsorption. When <i>n</i> ≤ 4, storing two Li atoms is beneficial to improving the thermodynamic stability of <i>x</i>Li-Si<sub><i>n</i></sub>/Gr system, and the thermodynamic stability decreases with the increase of Li atom number. When <i>n</i> ≥ 5, the thermodynamic stability of <i>x</i>Li-Si<sub><i>n</i></sub>/Gr system decreases with the increase of Li atom number. In the <i>x</i>Li-Si<sub>5</sub>/Gr system, the C-C bond and Si-Si bond are mainly covalent bonds, while the Li-C bond and Li-Si bond are mainly ionic bonds with certain covalent properties.

Adsorption and diffusion of alkali metals (Li, Na, and K) on heteroatom-doped monolayer titanium disulfide.

Doping engineering is an effective modification strategy to enhance the electrochemical performance of electrode materials. In this paper, the impacts of heteroatom doping in monolayer titanium disulfide (TiS2) by substituting the S atom with the heteroatoms (B, C, N, O, F, and P) on the adsorption and diffusion capabilities of alkali metals (Li, Na, and K) have been systematically investigated using first-principles calculations to evaluate the material performance for application in alkali metal-ion batteries. The doping of most heteroatoms can promote the adsorption capability of alkali metal atoms on monolayer TiS2 as their adsorption energies decrease compared with the pristine system, particularly for p-type doping with C, N, and P. The diffusion energy barriers decrease when alkali metals approach the doping site of most heteroatom-doped TiS2, and the barriers near the doping site are extremely small (0.00-0.08 eV), whereas they slightly increase as alkali metals move away from the doping site. P doping has the lowest overall diffusion energy barrier for each metal. Thus, monolayer TiS2 with heteroatom doping, especially P doping, can be used as a potential anode material for alkali metal-ion batteries. This study can help comprehend the impacts of heteroatom doping and design high-performance electrode materials for rechargeable batteries.

Cd-Doped FeSe nanoparticles embedded in N-doped carbon: a potential anode material for lithium storage

Cd doped FeSe nanoparticles loaded on nitrogen-containing carbon (Fe3C–Cdn/C–N) composites were obtained and displayed a high specific capacity, excellent rate performance and ultra-stable long-term cycling stability.

Oxygen-substituted borophene as a potential anode material for Li/Na-ion batteries: a first principles study

Two-dimensional graphene-like hexagonal borophene sheets (HBSs) have a thermodynamically unsteady configuration since boron has one electron less than the carbon in graphene. To overcome this problem, we proposed a novel 2D graphene-like HBS oxide (h-B3O) in theory, which is designed by substituting partial boron atoms in a HBS with oxygen atoms. Molecular dynamics simulations indicate that h-B3O has good thermal stability. Besides, we also explored the potential of h-B3O monolayers as anodes for Li-ion batteries (LIBs) and Na-ion batteries (NIBs) by using first-principles calculations. The results indicated that the h-B3O monolayer has high adsorption energies (-2.33/-1.70 eV for Li/Na), low diffusion barriers (0.67/0.42 eV for Li/Na) and suitable average open-circuit voltages (0.36/0.32 V for LIBs/NIBs). Particularly, h-B3O has a large theoretical specific capacity of 1161 mA h g-1 for LIBs. Thus, benefiting from these characteristics, the h-B3O monolayer is considered as a promising candidate for an anode material for LIBs/NIBs.

Novel Fe4-based metal-organic cluster-derived iron oxides/S,N dual-doped carbon hybrids for high-performance lithium storage.

Metal-organic frameworks (MOFs) have been extensively used in the fabrication of new advanced electrode materials for lithium ion batteries (LIBs). However, low-productivity and high-cost are some of the main challenges of MOF-derived electrodes. Herein, we report a simple solvothermal procedure to fabricate novel Fe4-based metal-organic clusters (Fe-MOCs) with their subsequent conversion to an S,N dual-doped carbon framework incorporating iron oxides under a N2 atmosphere (namely Fe2O3@Fe3O4-SNC). The as-prepared Fe2O3@Fe3O4-SNC composite, owing to the strong interaction between the dual-doped carbon and iron oxides, shows excellent lithium storage performance as an anode with high pseudocapacitance. Furthermore, DFT computational analyses confirm that the hybrid shows excellent adsorption ability with a low energy barrier due to strong electronic interactions between the iron oxides and S,N-doped carbon matrix. In addition, Fe2O3@Fe3O4-SNC-based LIB shows high energy and power densities at the full-cell level, confirming this synthesis strategy to be a promising approach towards MOC-derived electrode materials for their application in LIBs and beyond-lithium batteries.

First-principles study on h-BSi3 sheet as a promising high-performance anode for sodium-ion batteries.

Seeking cheap, efficient and sustainable alternatives to lithium-ion batteries (LIBs), sodium-ion batteries (SIBs) has emerged as a realm of research, due to the abundance of Na in the earth's crust. We have investigated the relative performance of novel intrinsically metallic h-BSi3 (BS) sheet as an anode for SIBs, compared to LIBs, through Density Functional Theory studies. Our calculations show that BS has higher chemisorption interactions with Na than Li atoms while drawing substantial electron densities from both, turning them into cations. BS is able to reach a high specific capacity of 1127.62 mA h g-1 for Na, while only as half of that for Li, at ambient temperatures ranging 300-600 K. The moderate sodiation (0.77 V) and lithiation (0.79 V) voltages facilitate BS to prevent the SEI layer formation, metal plating and harmful dendrite growth and to maintain good energy density. BS retains good electronic and ionic conductivities after hosting both Na and Li adatoms, while the former diffuses with about as half the barriers as those of the latter, supporting faster charge/discharge rate and greater preservation of storage capacities in high current densities when BS is used as an anode in SIBs. Na adsorptions cause relatively lower structural deformations to BS, and refrain from forming clusters, leading to good cyclic stability. The superior electrochemical performance of Na, thus, makes BS a potential anode material for SIBs.

Boost sodium-ion batteries to commercialization: Strategies to enhance initial Coulombic efficiency of hard carbon anode

Sodium-ion batteries (SIBs) are regarded as one of the most promising candidates for large-scale energy storage system due to low cost and inexhaustible sodium reserves. The commercialize application of SIBs relies on the development of advanced cathode and anode materials. Among the various available anode materials, hard carbon material is considered to be the most potential anode material, which presents appropriate sodiation/desodiation electric potential, high capacity, and simple synthesis method. However, the insufficient initial Coulombic efficiency (ICE) of hard carbon severely restricts the practical commercialization in SIBs. Hence, we review the influence elements that cause an inadequate ICE of hard carbon, such as the decomposition of electrolytes, high defects concentration, excessive surface functional groups, and irreversible sodium ions and so on. In order to obtain a moderate ICE, strategies including structure and morphology modification, defect and surface engineering, composition adjustment, electrolyte and binder optimization, material pre-treatment are confirmed to be effective. This review provides a further understanding of obtaining hard carbon electrodes with high ICE, which will contribute to the prosperity of SIBs in the near future.

Pomegranate‐like high density LTO anode material for lithium‐ion batteries

In order to improve the rate performance and reduce the cost lithium ion anode, the Li4Ti5O12@TiO2 (LTO-TO) was prepared by a facile hydrothermal reaction method with a micro-scale TiO2 as the precursor. The morphologies and microstructures of the pomegranate-like LTO-TO were examined by scanning electron microscopy and transition electron microscopy. The results demonstrate that the nano-LTO particles are located on the surface of the micro TiO2. The electrochemical properties of the LTO-TO composites were characterized by galvanostatic charge/discharge. The as-prepared composites present a high capacity of 157.3 mAh g−1 at 0.5 C. Even at a high current density of 10 C, it can still maintain a high capacity of 105.4 mAh g−1 and remains 92.8% (95 mA g−1) after 450 cycles. These results indicate that the as-prepared LTO nano/micro-sphere may be a potential anode material for lithium-ion batteries.

Reduced graphene oxide thin layer induced lattice distortion in high crystalline MnO2 nanowires for high-performance sodium- and potassium-ion batteries and capacitors

The large-radius of both K- and Na-ions gives rise to a serious concern towards exploring high-performance electrode materials for potassium ion batteries (KIBs) and sodium ion batteries (SIBs), respectively. Herein, MnO2 nanowires coated with reduced graphene oxide (denoted MnO2@rGO) are demonstrated as excellent anode materials in KIBs and SIBs. The coating of rGO not only facilitates a lattice distortion in the spacing of high crystallinity MnO2 nanowires allowing the faster transfer of K- and Na-ions, but also creates an interfacial structure between rGO and MnO2. Both enhance the electronic conductivity and further protect the nanowires from degradation. As an anode for KIBs and SIBs, the MnO2@rGO nanowires deliver a stable cycling performance with capacity retention of 81.7% over 400 cycles and 75% after 500 cycles, respectively. The potassiation and depotassiation reaction mechanisms are also revealed. Furthermore, the uniqueness of our hybrid designs allows high crystallinity MnO2@rGO nanowires to be used as anodes for both K-ion capacitors (KICs) and Na-ion capacitors (SICs). Considering their easy synthesis, environmental benignity and low cost, MnO2@rGO nanowires are potential anode materials for Na- and K-ion based energy storage devices.