Anode Material For Li-ion Batteries Research Articles

GaN/graphene heterostructures as promising anode materials for Li-ion batteries

In this research, the properties of GaN monolayer, defective GaN monolayer with N vacancies (GaN-VN), and van der Waals (vdW) heterostructures composed of them and graphene (GaN/graphene, GaN-VN/graphene) are systematically investigated using density functional theory (DFT), which includes assessment of the structure's stability, mechanical property, electronic structure analysis, lithium adsorption and diffusion properties, maximum theoretical capacity, and average open-circuit voltage. The calculations show that two-dimensional GaN transforms from semiconductor to metal by forming nitrogen-vacancy defects. This increases lithium adsorption performance while ensuring rapid electron motion in the electrode during lithium adsorption and removal processes. The synergistic effect between the heterostructure layers and the presence of the built-in electric field improves the electron and ion conductivity and lowers the migration energy barriers. In addition, the maximum theoretical capacities of defective GaN-VN, GaN/graphene, and GaN-VN/graphene can reach 970 mAh/g, 884 mAh/g, and 890 mAh/g, respectively, far exceeding those of the conventional graphite anode material (372 mAh/g). The above advantages indicate that defective GaN-VN, GaN/graphene, and GaN-VN/graphene are potential replacements for lithium-ion battery anodes.

Sn@C microsphere prepared by electrostatic spinning as high-performance anode material for Li-ion batteries

Sn@C microsphere prepared by electrostatic spinning as high-performance anode material for Li-ion batteries

Multifunctional hexagonal-shaped zinc vanadate nanostructures for lithium-ion battery and NH3 gas sensor applications

Vanadium-based metal oxides are used in different fields like gas sensors, supercapacitors, and lithium (Li)-ion batteries due to their availability, layered structure, and facile synthesis. Herein, we report a temperature-effective strategy to synthesize hexagonal-shaped zinc vanadate (Zn2VO4 (ZVO)) nanostructures (NSs) via a facile hydrothermal method without any further doping of an element or carbon additive. The synthesized ZVO NSs provide large surface area, low energy band gap, and fast Li+ diffusion. When compared with the ZVO-120 (synthesized at 120 °C) and ZVO-160 samples, the ZVO-140 sample shows a lower energy band gap value of 2.57 eV with higher surface area (37 m2 g−1) and porous nature. As an anode material for Li-ion batteries, the ZVO-140 demonstrates superior rate capability (126 mA h g−1 at 1.5 A g−1) and excellent cycling performance (576 mA h g−1 after 100 cycles at 0.05 A g−1 and 327 mA h g−1 after 2000 cycles at 1 A g−1) as well as good Li+ diffusion coefficient (2.61 × 10−8 cm2 s−1). Due to these synergistic benefits, ZVO NSs are used for NH3 gas sensing application. The ZVO-140 sample exhibits excellent sensitivity (47.3%) at 190 °C with fast response/recovery time (136 s/128 s) and reliable stability towards NH3 gas (100 ppm) at 190 °C, when compared with counterparts (ZVO-120 and ZVO-160). This preparation strategy may initiate the design of advanced ZVO-based materials for multifunctional applications.

Spent graphite as promising carbon matrix for high performance SiO/C anode material of Li-ion battery

Commercialization of SiO/graphite (SiO/G) composite anode material has been partially conducted in modern-model Li-ion batteries but is still limited by its relatively high cost and inferior stability. Improving the Li-ion storage performance as well as lowering the manufacturing cost of SiO/G anode has been the ongoing target of many studies. Herein, a low cost SiO/G anode with good Li-ion storage performance is developed by facilely integrating SiO nanoparticles into spent graphite (SG) extracted from used LiFePO4 batteries. The loose SG particles after repeated charge/discharge cycles can be easily exfoliated and combined with the SiO nanoparticles during the mechanical ball-milling treatment. Further processing the composite into spherical structure by spray-drying and pyrolysis results in practically applicable anode materials. The SiO/SG/C anode with a SiO mass ratio of 30 % exhibits the best overall performance including an excellent rate capability (385 mAh g−1 at 3 A g−1) and encouraging cycle stability (442 mAh g−1 after 300 cycles at 1 A g−1). The coin-type full cells coupling the pre-lithiated spherical SiO/SG anode and NCM811 cathode delivers a high energy density of 461 Wh kg−1 (based on the active masses of both electrodes) and good cycle performance (74.4 % capacity retention at 0.5C after 100 cycles). This work not only provides a high performance yet low cost SiO/G anode material, but explores a high value added way for the reuse of SG, thus can practically push forward the development of LIBs.

A Multifunctional Interlocked Binder with Synergistic In Situ Covalent and Hydrogen Bonding for High-Performance Si Anode in Li-ion Batteries.

Silicon has garnered significant attention as a promising anode material for high-energy density Li-ion batteries. However, Si can be easily pulverized during cycling, which results in the loss of electrical contact and ultimately shortens battery lifetime. Therefore, the Si anode binder is developed to dissipate the enormous mechanical stress of the Si anode with enhanced mechanical properties. However, the interfacial stability between the Si anode binder and Cu current collector should also be improved. Here, a multifunctional thiourea polymer network (TUPN) is proposed as the Si anode binder. The TUPN binder provides the structural integrity of the Si anode with excellent tensile strength and resilience due to the epoxy-amine and silanol-epoxy covalent cross-linking, while exhibiting high extensibility from the random coil chains with the hydrogen bonds of thiourea, oligoether, and isocyanurate moieties. Furthermore, the robust TUPN binder enhances the interfacial stability between the Si anode and current collector by forming a physical interaction. Finally, the facilitated Li-ion transport and improved electrolyte wettability are realized due to the polar oligoether, thiourea, and isocyanurate moieties, respectively. The concept of this work is to highlight providing directions for the design of polymer binders for next-generation batteries.

Magnetite nanoparticles embedded on reduced graphene oxide as an anode material for high capacity and long cycle-life Li-ion battery

A facile and cost-effective method was developed for the synthesis of “magnetite/reduced graphene oxide” nanocomposite, as an anode material for lithium-ion batteries. The fabricated composite was characterized by different instrumental analyses including XRD, Raman, XPS, SEM, TEM, and FTIR, as well as various electrochemical (i.e. battery) tests. Such broad examination revealed the structure of the prepared material and its electrochemical behavior. It was found that the fabricated composite has a number of advantages over the currently utilized electrode materials such as cost efficiency, high Li ion storage (2528 mAh/g at 0.05 A/g at 1st discharge), cycle stability of 986 mAh/g over 100 cycles at a current density of 0.1 A/g, and eventually Coulombic efficiency of about 100 %. In comparison, the reduced graphene oxide (rGO) shows inferior performances, such as a constant capacity of 462 mAh/g, and a slower kinetics of the ion storage. Consequently, the synthesized low-cost anode material seems to be an attractive candidate for development of the next-generation energy-storage devices, used in electrical vehicles, and portable electronic instruments.

Preparation and electrochemical properties of PSi@PEDOT/GO as an anode material for Li-ion batteries

Preparation and electrochemical properties of PSi@PEDOT/GO as an anode material for Li-ion batteries

PtS2/WSe2 heterostructure for thermoelectric and Li-ion battery Applications: A First-Principles study

Van der Waals’ two-dimensional heterostructure engineering offers great potential in applications of electronic devices, battery applications, thermoelectric. Encouraged by the successful synthesis of PtS2/WSe2 heterostructure, we explore its potential in thermoelectric and Li-ion battery applications by first-principles calculations. Due to these multi-valley degenerate valence and conduction bands, a large power factor of 0.007 W/mK2 is attained. Due to the significant interface effect, PtS2/WSe2 heterostructure can strongly adsorb Li atoms with −2.69 eV adsorption strength on the middle of PtS2/WSe2 heterostructure layers. Also, an extremely fast Li diffusion rate was found in this heterostructure (as low as 20 meV), which is close to the recently reported MXene. Large theoretical volumetric storage capacity of 1283.98 mA h/cm3, in the meanwhile a rather low average Open-circuit voltage (0.07 V) also purports that PtS2/WSe2 heterostructure is a quite promising anode material in Li-ion batteries with high power densities and fast charge/discharge rates.

Construction of Carbon Nanofiber-Wrapped SnO2 Hollow Nanospheres as Flexible Integrated Anode for Half/Full Li-Ion Batteries.

SnO2 is deemed a potential candidate for high energy density (1494 mAh g-1) anode materials for Li-ion batteries (LIBs). However, its severe volume variation and low intrinsic electrical conductivity result in poor long-term stability and reversibility, limiting the further development of such materials. Therefore, we propose a novel strategy, that is, to prepare SnO2 hollow nanospheres (SnO2-HNPs) by a template method, and then introduce these SnO2-HNPs into one-dimensional (1D) carbon nanofibers (CNFs) uniformly via electrospinning technology. Such a sugar gourd-like construction effectively addresses the limitations of traditional SnO2 during the charging and discharging processes of LIBs. As a result, the optimized product (denoted SnO2-HNP/CNF), a binder-free integrated electrode for half and full LIBs, displays superior electrochemical performance as an anode material, including high reversible capacity (~735.1 mAh g-1 for half LIBs and ~455.3 mAh g-1 at 0.1 A g-1 for full LIBs) and favorable long-term cycling stability. This work confirms that sugar gourd-like SnO2-HNP/CNF flexible integrated electrodes prepared with this novel strategy can effectively improve battery performance, providing infinite possibilities for the design and development of flexible wearable battery equipment.

Carbon coating optimization on porous silicon as high-performance anode material via fluidized bed chemical vapor deposition

The carbon layer coating is a promising solution to volume expansion and low electron conductivity in silicon-based anodes during lithiation. While numerous methods exist to generate these carbon coatings, Fluidized Bed Chemical Vapor Deposition (FBCVD) has proven superior due to its capacity for producing remarkably uniform and consistent carbon layers, primarily as a result of efficient mass and heat transfer characteristics. However, its application in the context of lithium-ion battery anodes has been sparsely explored and has been principally limited to silicon oxide as the base material. In this paper, porous silicon (PSi) obtained through acid etching of AlSi alloy with an average particle size of 300 mesh was taken as raw materials, and a fluidized bed reactor was employed to realize a uniform and tightly packed carbon layer. Relatively speaking, the PSi@C30 in this work offers a simpler process and promising electrochemical performance, opening a new door for the preparation of high-performance silicon-carbon anodes by FBCVD. Besides, PSi and high-quality carbon layers with structural advantages enabled the authors to obtain high-performance silicon-carbon anode materials. The resulting PSi@C30 composite demonstrated excellent initial coulomb efficiency (88.8 %) and cycling stability (with 83 % capacity retention after 100 cycles at 0.5 A g-1 and a reversible capacity of 1408 mAh g-1). Such a cost-effective and user-friendly technique facilitates the application of FBCVD in silicon-based anode materials for Li-ion batteries, thus accelerating the industrialization of silicon-carbon anodes for high-performance Li-ion batteries in the future.

Superior electrochemical performance of self-assemble carbon layer dual-phase TiO2/Zn2Ti3O8 for Li-ion anode

The application of commercial TiO2 (c-TiO2) as the anode material in Li-ion batteries suffers from the poor ionic and electronic conductivities. Herein, Zn2Ti3O8/TiO2 composite was prepared by sintering the mixture of Zn(NO3)2 and commercial TiO2 with various Zn/Ti ratios, so as to introduce Zn2Ti3O8 with Li+ diffusion paths and create additional interfaces for Li+ migration and capacitive energy-storage. Then the composite was self-assembled with the carbon derived from citric acid (CA) to alleviate electronic conductivity. The carbon-coated Zn2Ti3O8/TiO2 composite delivers high charge/discharge capacities of 294.4/298.2 mAh g−1 at 0.1 A g−1 and a reversible capacity of 226.4 mAh g−1 after 1000 cycles at 0.5 A g−1. This work provides a new strategy for the application of c-TiO2 in Li-ion anode.

MOF-derived porous NiCo2O4 nanofile arrays as an efficient anode material for rechargeable Li-ion batteries

Due to their vast surface area and superior porosity structure, metal-organic frameworks (MOFs) derived materials have recently presented a significant promise for better lithium-ion batteries (LIBs). Herein, we synthesised MOF-derived porous NiCo2O4 nanofile arrays from a simple solvothermal technique followed by calcination at 450 °C. The prepared sample was characterized by X-ray diffraction, thermogravimetric, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller. The acquired nanofile array morphology achieved a large specific surface area of 189 m2/g can shorten the Li ions (Li+) transport and enhance the electrochemical performance. As expected, the prepared electrode reveals a discharge-specific capacity of around 1120 mAh/g at a 0.1 C rate. At 2 C rate, the electrode's specific capacity can still reach 210 mAh/g after 100 cycles. The pseudocapacitive nature of NiCo2O4 was determined by kinetic analysis, revealing the diffusion-controlled faradaic behaviour. Our prepared electrode material is considered an attractive option for the anode material in rechargeable Li-ion batteries because it has been proven to have a relatively good specific capacity and cycling stability.

Converting commercial Fe2O3 to effective anode material using glucose as “etching” agent

Fe2O3 is an appealing anode material due to its high specific capacity (1007 mAh g−1), low cost, natural abundance, and nontoxicity. However, its unstable structure during cycling processes has hindered its potential. In this study, we present a “green” synthesis method to fabricate stable porous Fe2O3 encapsulated in a buffering hollow structure (p-Fe2O3@h-TiO2) as an effective anode material for Li-ion batteries. The synthesis process only involves glucose as an “etching” agent, without the need for organic solvents or difficult-to-control environments. Characterizations of the nanostructures, chemical compositions, crystallizations, and thermal behaviors for the intermediate/final products confirm the formation of p-Fe2O3@h-TiO2. The synthesized Fe2O3 anode material effectively accommodates volume change, decreases pulverization, and alleviates agglomeration, leading to a high capacity that is over eleven times greater than that of the as-received commercial Fe2O3 after a long cycling process. This work provides an attractive, “green” and efficient method to convert commercially abundant resources like Fe2O3 into effective electrode materials for energy storage systems.

Synthetically encapsulated & self-organized transition metal oxide nano-structures inside carbon nanotubes as robust: Li-ion battery anode materials

We report a comparative study on the electrochemical performance of four different transition metal oxides encapsulated inside carbon nanotubes (oxides@CNT), along with reference data obtained on a bare-oxide. A key result here is that the encapsulation leads to superior cyclic stability, irrespective of the type of the oxide-encapsulate. This comparison also enables us to isolate the advantages associated with the encapsulation of oxide within the core cavity of CNT, as opposed to the case of oxide/CNT composites, in which oxide resides outside the CNT. Innovative use of camphor during sample synthesis enables precise control over the morphology of the filled CNT, which can either be in aligned-forest or in entangled geometry. The morphology appears to play a crucial role in tuning the magnitude of the specific capacity, whereas the encapsulation relates to the cyclic stability. Overall, the electrochemical data on various oxides@CNT bring forward interesting inferences pertaining to the morphology, filling fraction of the oxide-encapsulate, and the presence of oxide nano-particles adhering outside the CNT. Our results provide useful pointers for optimization of these critical parameters, thus paving the way for oxide@CNT for practical electrochemical applications.

Selective Synthesis of Perovskite Oxyhydrides Using a High-Pressure Flux Method.

Oxyhydrides with multi-anions (O2- and H-) are a recently developed material family and have attracted attention as catalysts and hydride ion conductors. High-pressure and high-temperature reactions are effective in synthesizing oxyhydrides, but the reactions sometimes result in inhomogeneous products due to insufficient diffusion of the solid components. Here, we synthesized new perovskite oxyhydrides SrVO2.4H0.6 and Sr3V2O6.2H0.8. We demonstrated that the addition of SrCl2 flux promotes diffusion during high-pressure and high-temperature reactions, and can be used for selective synthesis of the oxyhydride phases. We conducted in-situ synchrotron X-ray diffraction measurements to reveal the role of this flux and reaction pathways. We also demonstrated the electronic and magnetic properties of the newly synthesized oxyhydrides and that they work as anode materials for Li-ion batteries with excellent reversibility and high-rate characteristics, the first case with an oxyhydride. Our synthesis approach would also be effective in synthesizing various types of multi-component systems.

Synthesis of Si/C Composites by Silicon Waste Recycling and Carbon Coating for High-Capacity Lithium-Ion Storage.

It is of great significance to recycle the silicon (Si) kerf slurry waste from the photovoltaic (PV) industry. Si holds great promise as the anode material for Li-ion batteries (LIBs) due to its high theoretical capacity. However, the large volume expansion of Si during the electrochemical processes always leads to electrode collapse and a rapid decline in electrochemical performance. Herein, an effective carbon coating strategy is utilized to construct a precise Si@CPPy composite using cutting-waste silicon and polypyrrole (PPy). By optimizing the mass ratio of Si and carbon, the Si@CPPy composite can exhibit a high specific capacity and superior rate capability (1436 mAh g-1 at 0.1 A g-1 and 607 mAh g-1 at 1.0 A g-1). Moreover, the Si@CPPy composite also shows better cycling stability than the pristine prescreen silicon (PS-Si), as the carbon coating can effectively alleviate the volume expansion of Si during the lithiation/delithiation process. This work showcases a high-value utilization of PV silicon scraps, which helps to reduce resource waste and develop green energy storage.

A novel two-dimensional whorled TiB4 as a high-performance anode material for Li-ion and Na-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 2D TiB4 as an ideal anode material for Li/Na ion batteries. Our results indicate that Li/Na ions can be chemically and stably adsorbed on the surface of 2D TiB4. It is noteworthy that the Li capacity of 2D TiB4 is up to 2353.2 mA h g−1 and the Na capacity up to 1764.9 mA h g−1 with a guaranteed low diffusion barrier (0.24 eV for Li; 0.09 eV for Na). Therefore, our calculations show that TiB4 monolayer is an excellent anode material with great potential for ultra-high energy storage devices.

Charge Storage Mechanism in Electrospun Spinel-Structured High-Entropy (Mn0.2 Fe0.2 Co0.2 Ni0.2 Zn0.2 )3 O4 Oxide Nanofibers as Anode Material for Li-Ion Batteries.

High-entropy oxides (HEOs) have emerged as promising anode materials for next-generation lithium-ion batteries (LIBs). Among them, spinel HEOs with vacant lattice sites allowing for lithium insertion and diffusion seem particularly attractive. In this work, electrospun oxygen-deficient (Mn,Fe,Co,Ni,Zn) HEO nanofibers are produced under environmentally friendly calcination conditions and evaluated as anode active material in LIBs. A thorough investigation of the material properties and Li+ storage mechanism is carried out by several analytical techniques, including ex situ synchrotron X-ray absorption spectroscopy. The lithiation process is elucidated in terms of lithium insertion, cation migration, and metal-forming conversion reaction. The process is not fully reversible and the reduction of cations to the metallic form is not complete. In particular, iron, cobalt, and nickel, initially present mainly as Fe3+ , Co3+ /Co2+ , and Ni2+ , undergo reduction to Fe0 , Co0 , and Ni0 to different extent (Fe < Co < Ni). Manganese undergoes partial reduction to Mn3+ /Mn2+ and, upon re-oxidation, does not revert to the pristine oxidation state (+4). Zn2+ cations do not electrochemically participate in the conversion reaction, but migrating from tetrahedral to octahedral positions, they facilitate Li-ion transport within lattice channels opened by their migration. Partially reversible crystal phase transitions are observed.

A DFT study of TiC3 as anode material for Li-ion batteries

Two-dimensional monolayer titanium carbide (TiC3) was used to study as a suitable electrode material for lithium-ion batteries with first principles calculation. The monolayer TiC3 showed excellent structural stability, high mechanical stiffness and good electronic conductance behaviour. The adsorption of Li on the carbon rich composition of titanium carbide monolayer is predicted to be favourable. TiC3 structure has remained the same, preserving its metallicity after Li adsorption with attaining high electrical conductivity during lithiation/delithiation process. Especially, the theoretical specific capacity of TiC3 monolayer is high, up to 1916 mAh/g, which is five times higher than the practical graphite. The low open circuit voltage (0.26 V) and diffusion energy barrier (0.25 eV) are also beneficial for overall performance of LIBs. Importantly, during lithiation the change in area is very small and reaches only 8.1 % for full lithiation indicating that it can avoid the large volume expansion during charge/discharge cycles. Its excellent performance, including high melting temperature, dynamical and mechanical stability, can be credited to the rigidness of the TiC3. Given these advantages, that is, high specific capacity, low Li diffusion energy barrier, low open circuit voltage and high in-plane stiffness, TiC3 monolayer can be a promising anode material for lithium-ion batteries.

Density Functional Theory Study of Bilayer Borophene-Based Anode Material for Rechargeable Lithium Ion Batteries.

The bilayer borophene has been successfully fabricated in experiments recently and possesses superior antioxidation and robust metallic properties, which holds great promise for the future anode materials of Li-ion batteries. Herein, using first-principles calculations, two bilayer borophenes including P6/mmm or P6̅m2 symmetry groups with or without vacancy defects are comprehensively explored and acted as electrode materials with high performance in Li-ion batteries. The charge density difference, adsorption energies, and Bader charge analysis are calculated and discussed for single lithium adsorbed on bilayer borophene. The results shown that with the increase of lithium concentration, the adsorption energies are rapidly decreased due to the repulsion of boron atoms except for the P6̅m2 systems with double side adsorption and corresponding energies remain the narrow range. Meanwhile, the partial density of states shows metallic character after lithium adsorption and indicates good conductivity for the charge-discharge process. Furthermore, small diffusion barriers, low average open-circuit voltage, can be achieved, and large storage capacity is up to 930.2 mA h/g at the lower lithium content of 0.375. These results propose that bilayer borophene might be a good choice for anode material applications in future Li-ion batteries with fast ion diffusion and high power density.