Anode Material For Lithium-ion Batteries Research Articles

Well-Dispersed Bi nanoparticles for promoting the lithium storage performance of Si Anode: Effect of the bridging Bi nanoparticles

Silicon (Si) is considered a promising anode material for lithium-ion batteries (LIBs) due to its high theoretical specific capacity of up to 4200 mAh/g. However, the poor cycling and rate performances of Si induced by the low intrinsic electronic conductivity and large volume expansion during the lithiation/delithiation process limit its practical application. Herein, a novel silicon/bismuth@nitrogen-doped carbon (Si/Bi@NC) composite with nanovoids was synthesized and investigated as an advanced anode material for LIBs. In such a structure, ultrafine bismuth nanoparticles coupled with an N-doped carbon layer were introduced to modify the surface of Si nanoparticles. Subsequently, the lithiated LixBi has excellent high ionic conductivity and acts as a fast transport bridge for lithium ions. The introduced carbon coating layer and nanovoids can buffer the volume expansion of Si during the lithiation/delithiation process, thus maintaining structural stability during the cycling process. As a result, the Si/Bi@NC composite exhibits excellent electrochemical performance, providing a relatively high capacity of 955.8 mAh/g at 0.5 A/g after 450 cycles and excellent rate performance with a high capacity of 477.8 mAh/g even at 10.0 A/g. Furthermore, the assembled full cell with LiFePO4 as cathode and pre-lithium Si/Bi@NC as anode can provide a high capacity of 138.8 mAh/g at 1C after 90 cycles, exhibiting outstanding cycling performance.

Porous MnF2 with micro-nanostructures coated by a nitrogen doped carbon shell as an anode for enhanced lithium storage

MnF2, an intriguing anode material for lithium-ion batteries (LIBs), has garnered significant attention due to its high theoretical capacity. However, its commercial viability is impeded by issues such as volume expansion and poor conductivity. In this study, we present the development and fabrication of MnF2@NC microspheres with micro-nanostructured pores, comprising MnF2 nanoparticles encapsulated within a nitrogen-doped carbon shell. This was achieved through a combination of hydrothermal synthesis and fluorination techniques. The MnF2@NC composite exhibits a high level of porosity, effectively mitigating the significant volume expansion of MnF2 and facilitating efficient charge transport. Moreover, the incorporation of nitrogen-doped carbon shell enhances the overall structural and promotes electrical conductivity. Leveraging these inherent characteristics, the MnF2@NC electrode demonstrates exceptional electrical conductivity and superior long-term stability. The MnF2@NC electrode serves as an anode for LIBs, exhibiting a remarkable reversible capacity of 991.2 mAh/g at 0.1 A/g, exceptional cycle performance with a capacity retention of 872.2 mAh/g after 700 cycles at 1.0 A/g, and outstanding rate capability surpassing the reported outcomes of MnF2-based composite anodes. These results unequivocally demonstrate the suitability and potential applicability of MnF2@NC as high-capacity anodes for LIB.

Three-dimensional dual-layered conductive binder enables stable and high performance of SiOx/C anodes

Among practical anode materials for next-generation lithium-ion batteries (LIBs), SiOx has garnered substantial attention owing to its relatively low volumetric variation and high theoretical capacity. Nevertheless, the volumetric change of micro-SiOx remains a formidable challenge for existing adhesives. Here, we propose an innovative design strategy that amalgamates both rigidity and flexibility, in which rigid anion gum Arabic (GA), flexible acrylic random copolymer (ARC), and carbon nanotubes (CNTs) interwoven into a 3D network with strong interfacial adhesion and excellent mechanical properties. These attributes effectively restrict SiOx particles and favor a stable solid electrolyte interphase (SEI) layer formed on SiOx. Here, GA plays a pivotal role in dispersing CNTs and maintaining their consistent proximity to SiOx, thereby establishing stable electron conduction networks. The SiOx electrode still sustains a specific capacity of 760 mAh g−1 after 350 cycles under a high current of 1C. Additionally, at 0.2C, the SiOx electrode attains a notably high capacity of 1105 mAh g−1 with a capacity retention of 72.9 % at the 300th cycle, while exhibiting an excellent areal capacity of 1.4 mAh cm−2 even after 400 cycles. This work develops a straightforward yet highly efficacious approach for fabricating high areal capacity electrodes and offers promising prospects for improving the stableness of Si-based anodes.

Electrochemical elucidation of phosphorus-doped and 3D graphene aerogel surface-modified SiOx porous nanocomposite electrode material for high-performance lithium-ion batteries

Silicon oxide (SiOx) is promising as an earth abundant eco-friendly cost-effective anode material for lithium-ion batteries (LIBs), boasts a higher capacity compared to commercial graphite, garnering significant interest. Nevertheless, its practical application is hindered by issues related to poor cycling performance and low electronic conductivity. In this investigation, graphene aerogel-wrapped (GA) red phosphorus (P) doped SiOx (P-SiOx@GA) composite material is successfully constructed through ball-milling followed by freeze-drying and thermal treatment processes. The prepared materials are characterized the physico-chemical properties. The electrochemical performance is evaluated through Li-ion half and full (LiFePO4//P-SiOx@GA) cells configuration. The synthesized P-SiOx@GA electrode exhibits outstanding cyclic performance, demonstrating a specific capacity of 1094 mAh g−1 at 0.5C with a capacity retention of 80.3 % over 200 cycles in half-cell test. Furthermore, it demonstrates superior rate capability and delivers a reversible rate capacity of 754 mAh g−1 at 2C. Besides, the Li-ion punch cell configuration of LiFePO4//P-SiOx@GA shows good reversible capacity of 1.4 mAh at 0.5C over 300 cycles. The doping of P and porous 3D structure of GA forms an SiOx matrix network is facilitate the establishment of a 3D conductive pathway for electron transport and Li+ diffusion but also acts as a flexible matrix to accommodate the volume changes of SiOx. Therefore, the results and way of preparation promotes a practical feasibility of high-performance Si-based Li-ion batteries applications.

Carbonized polyacrylonitrile-coated three-dimensional porous TiP2O7 as a high-rate capability anode for lithium-ion batteries

TiP2O7 is a hopeful anode material for lithium-ion batteries (LIBs) due to its three-dimensional (3D) open skeletons, excellent ion transfer kinetics, and good structural stability. However, the inferior intrinsic electronic conductivity degrades seriously the electrochemical performance of LIBs. Herein, a strategy of carbonized polyacrylonitrile-coated TiP2O7 (TPO/cPAN) with 3D porous structures was proposed to enhance Li+-storage capability. The TPO/cPAN modified with 30 wt% polyacrylonitrile and calcined at 800 ℃ delivers superior long-term cycling stability at 0.5 A g−1 and excellent rate capacities of 558.7, 523.8, 477.5, 409.8, and 303.4 mAh g−1 at 0.1, 0.2, 0.4, 0.8, and 1.6 A g−1, respectively. Structural characterizations and electrochemical analysis reveal that the pyrolytic N-doped carbon layer markedly ameliorates the electron transferability and protects the electrode from organic electrolyte erosion. Meanwhile, the design of 3D porous structures and the generation of rich oxygen defects facilitate Li+ transport and pseudocapacitance energy storage. The work provides a novel pathway for optimizing the electron/ion migration of polyanionic electrode materials.

Graphene-wrapped Fe2TiO5 nanoparticles with enhanced performance as lithium-ion battery anode

Iron-titanium bimetallic oxide, Fe2TiO5 (FTO), is anticipated to exhibit superior electrochemical properties due to its high theoretical capacity. However, the practical large-scale utilization of FTO is severely hindered by its substantial capacity fading and subpar cycling performance. In this work, we propose a strategy to improve the electrochemical properties of FTO by carbon coating. To implement this strategy, we synthesize FTO nanoparticles (FTO NPs) coated with reduced graphene oxide (rGO) by a solvothermal method. When used as anode materials in lithium-ion batteries, FTO/rGO composite demonstrates a higher specific capacity (498.2 mAh g−1 after 100 cycles) than pristine FTO NPs, which is ascribed to the addition of rGO. The rGO with excellent conductivity facilitates efficient electron and ion transportation, and the composite structure of FTO NPs wrapped with rGO provides buffer space to alleviate the volume expansion during the charge/discharge process.

Preparation of carbon-coated Fe2 O3 @Ti3 C2 Tx composites by mussel-like modifications as high-performance anodes for lithium-ion batteries.

Fe2 O3 with high theoretical capacity (1007 mA h g-1 ) and low cost is a potential anode material for lithium-ion batteries (LIBs), but its practical application is restricted by its low electrical conductivity and large volume changes during lithiation/delithiation. To solve these problems, Fe2 O3 @Ti3 C2 Tx composites were synthesized by a mussel-like modification method, which relies on the self-polymerization of dopamine under mild conditions. During polymerization, the electronegative group (-OH) on dopamine can easily coordinate with Fe3+ ions as well as form hydrogen bonds with the -OH terminal group on the surface of Ti3 C2 Tx , which induces a uniform distribution of Fe2 O3 on the Ti3 C2 Tx surface and mitigates self-accumulation of MXene nanosheets. In addition, the polydopamine-derived carbon layer protects Ti3 C2 Tx from oxidation during the hydrothermal process, which can further improve the electrical conductivity of the composites and buffer the volume expansion and particle agglomeration of Fe2 O3 . As a result, Fe2 O3 @Ti3 C2 Tx anodes exhibit ~100 % capacity retention with almost no capacity loss at 0.5 A g-1 after 250 cycles, and a stable capacity of 430 mA h g-1 at 2 A g-1 after 500 cycles. The unique structural design of this work provides new ideas for the development of MXene-based composites in energy storage applications.

Cheverl phase Mo6Te8 nanoparticles as new anode materials for lithium-ion batteries

Lithium-ion batteries have become increasingly indispensable as a kind of energy conversion and storage device. Cheverl phase materials show potential advantages over transition metal chalcogenides in lithium-ion batteries, owing to their high three-dimensional open frameworks and good tolerance to a large current. Herein, Chevrel phase Mo6Te8 has been synthesized by high-temperature solid-phase reaction and modified with dopamine, resulting in Carbon and Nitrogen atoms anchored on the Mo6Te8 surface. During the C/N doping process, due to lattice gap and vacancy defects, C/N itself is adsorbed in the vacancy or lattice gap, resulting in lattice expansion, which makes the process of lithium ion deintercalation smoother. Compared with the original Mo6Te8, the specific capacity and conductivity of the composite Mo6Te8@C/N have significantly improved. With a maximum specific capacity close to 812 mAh g−1 at a current density of 0.1 A g−1 and a maximum capacity close to 436 mAh g−1 at a high current density of 1 A g−1, the excellent conductivity of Mo6Te8@C/N contributes to the diffusion of Li+, and the increased active site improves the efficiency of electron transfer. The direct comparison between MoTe2 and Mo6Te8@C/N clearly supports the advantages of Chevrel phase materials in batteries.

Construction of novel lithium-ion battery anode materials with superior rate performance through Fe/Li2O composite interface

Based on the “job-sharing” mechanism, we have designed novel anode materials for LIBs, consisting of nano-transition metal and lithium oxide particles. The composites exhibit excellent rate performance, maintaining a specific capacity of 29% of the stabilized capacity at 6 A g−1. Since neither metallic iron nor lithium oxide has lithium storage capacity, the lithium storage behavior of the composites is mainly related to the interface. Moreover, the interface facilitates the improvement of the ion diffusion ability and pseudocapacitance percentage of the composite material. This study provides new horizons for designing anode materials for high power density LIBs.

Iron-arsenide monolayers as an anode material for lithium-ion batteries: a first-principles study.

This theoretical investigation delves into the structural, electronic, and electrochemical properties of two hexagonal iron-arsenide monolayers, 1T-FeAs and 1H-FeAs, focusing on their potential as anode materials for lithium-ion batteries. Previous studies have highlighted the ferromagnetic nature of 1T-FeAs at room temperature. Our calculations reveal that both phases exhibit metallic behaviour with spin-polarized electronic band structures. Electrochemical studies show that the 1T-FeAs monolayer has better ionic conductivity for Li ions than the 1H-FeAs phase, attributed to a lower activation barrier of 0.38 eV. This characteristic suggests a faster charge/discharge rate. Both FeAs phases exhibit comparable theoretical capacities (374 mA h g-1), outperforming commercial graphite anodes. The average open-circuit voltage for maximum Li atom adsorption is 0.61 V for 1H-FeAs and 0.44 V for 1T-FeAs. The volume expansion over the maximum adsorption of Li atoms on both phases is also remarkably less than the commercially used anode material such as graphite. Furthermore, the adsorption of Li atoms onto 1H-FeAs induces a remarkable transition from ferromagnetism to anti-ferromagnetism, with minimal impact on the electronic band structure. In contrast, the original state of 1T-FeAs remains unaffected by Li adsorption. To summarize, both 1T-FeAs and 1H-FeAs monolayers have potential as promising anode materials for lithium-ion batteries, offering valuable insights into their electrochemical performance and phase transition behaviour upon Li adsorption.

P-n heterogeneous Sb2S3/SnO2 quantum dot anchored reduced graphene oxide nanosheets for high-performance lithium-ion batteries.

Antimony sulfide (Sb2S3) has a high theoretical specific capacity due to its two reaction mechanisms of conversion and alloying during the Li+-(de)intercalation process, thus becoming a promising lithium-ion battery (LIB) anode material. However, its poor inherent conductivity and large volume expansion during repeated Li+-(de)intercalation processes greatly hinder the in-depth development of Sb2S3 based LIB anode materials. Herein, an Sb2S3/SnO2@rGO composite was prepared by using an interface engineering technique involving metal-containing ionic liquid precursors, in which Sb2S3/SnO2 quantum dots (QDs) as p-n heterojunctions are uniformly anchored on the surface of reduced graphene oxide (rGO). The p-n heterogeneous interface between Sb2S3 and SnO2 QDs induces an internal electric field, promoting the electronic/ion transport during electrochemical reactions, and the QD-sized Sb2S3/SnO2 heterostructure with a larger surface area provides more active sites for Li+-(de)intercalation reactions. In addition, the rGO matrix acts as a buffer to prevent the aggregation of active Sb2S3 and SnO2 QDs, alleviate the volume expansion, and enhance the conductivity of the composite during repeated cycles. These advantages endow the designed Sb2S3/SnO2@rGO electrode with excellent reaction kinetics and good long cycling stability. As an anode material of LIBs, it can still provide a reversible specific capacity of 474 mA h g-1 after 2000 cycles at a high current density of 3.0 A g-1, which is superior to those of most of the previously reported Sb2S3-based carbon materials. The p-n heterostructure construction strategy of nano-metal sulfide/metal oxides in this work can provide inspiration for the design and synthesis of other advanced energy storage materials.

A first-principles study of 2D single-layer SiP as anode materials for lithium-ion batteries and sodium-ion batteries.

The promotion of lithium-ion batteries and sodium-ion batteries is limited by the deficiency of suitable anode materials with desired electrochemical properties. In this work, the models of 2D single-layer SiP are constructed to explore its potential as an anode material for LIBs and SIBs using density functional theory (DFT). The diffusion of Li in bulk SiP is anisotropic. There is a low diffusion energy barrier of 0.28 eV along the X-axis. The low surface exfoliation energy suggests that there is a high probability of preparing 2D single-layer SiP experimentally. Its structure stability is verified by ab initio molecular dynamics (AIMD) simulations at 300 K and 400 K. The intercalation and diffusion behaviors of Li/Na on 2D single-layer SiP indicate that Li/Na tends to diffuse along the X-axis direction of 2D single-layer SiP. The diffusion energy barrier of Li/Na on 2D single-layer SiP is lower compared to that of bulk SiP. The conductivity of 2D single-layer SiP is improved after lithiation due to the upshift of Fermi levels. 2D single-layer SiP has a lower average open circuit voltage (1.50 V for LIBs and 1.08 V for SIBs) and a high theoretical capacity (520 mA h g-1). Hence, 2D single-layer SiP can be an ideal anode material for LIBs and SIBs.

Rational design of three-dimensional pomegranate-shaped double-layer carbon-shell-coated Si nanoparticles as an excellent anode material for lithium-ion batteries

Double-layer carbon-shell-coated Si nanoparticles (Si@DCSS) exhibit a morphology similar to pomegranate. This structure effectively suppresses the volume change of Si in the process of ion transport, endowing Si@DCSS with excellent cyclic stability.

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.

Binder-free germanium nanoparticle decorated multi-wall carbon nanotube anodes prepared via two-step electrophoretic deposition for high capacity Li-ion batteries.

Germanium (Ge) has a high theoretical specific capacity (1384 mA h g-1) and fast lithium-ion diffusivity, which makes it an attractive anode material for lithium-ion batteries (LIBs). However, large volume changes during lithiation can lead to poor capacity retention and rate capability. Here, electrophoretic deposition (EPD) is used as a facile strategy to prepare Ge nanoparticle carbon-nanotube (Ge/CNT) electrodes. The Ge and CNT mass ratio in the Ge/CNT nanocomposites can be controlled by varying the deposition time, voltage, and concentration of the Ge NP dispersion in the EPD process. The optimized Ge/CNT nanocomposite exhibited long-term cyclic stability, with a capacity of 819 mA h g-1 after 1000 cycles at C/5 and a reversible capacity of 686 mA h g-1 after 350 cycles (with a minuscule capacity loss of 0.07% per cycle) at 1C. The Ge/CNT nanocomposite electrodes delivered dramatically improved cycling stability compared to control Ge nanoparticles. This can be attributed to the synergistic effects of implanting Ge into a 3D interconnected CNT network which acts as a buffer layer to accommodate the volume expansion of Ge NPs during lithiation/delithiation, limiting cracking and/or crumbling, to retain the integrity of the Ge/CNT nanocomposite electrodes.

Dispersed MnO2 nanoparticles/sugarcane bagasse-derived carbon composite as an anode material for lithium-ion batteries.

Bagasse-derived carbon electrodes were developed by doping with nitrogen functional groups and compositing with high-capacity MnO2 nanoparticles (MnO2/NBGC). The bagasse-derived biochar was N-doped by refluxing in urea, followed by the deposition of MnO2 nanoparticles onto its porous surface via the hydrothermal reduction of KMnO4. Different initial KMnO4 loading concentrations (i.e. 5, 10, 40, and 100 mM) were applied to optimize the composite morphology and the corresponding electrochemical performance. Material characterization confirmed that the carbon composite has a mesoporous structure along with the dispersion of MnO2 nano-particles on the N-containing carbon surface. It was found that the 5-MnO2/NBGC sample exhibited the highest electrochemical performance with a reversible capacity of 760 mA h g-1 at a current density of 186 mA g-1. It delivered reversible capacities of 488 and 390 mA h g-1 in cycle tests at 372 and 744 mA g-1, respectively, for 150 cycles and presented good reversibility with nearly 100% coulombic efficiency. In addition, it could exert high capacities up to 388 and 301 mA h g-1 even under high current densities of 1860 and 3720 mA g-1, respectively. Moreover, most of the prepared composite products showed high rate capability with great reversibility up to more than 90% after testing at a high current density of 3720 mA g-1. The great electrochemical performance of the MnO2/NBGC nanocomposite electrode can be attributed to the synergistic impact of the hierarchical architecture of the MnO2 nanocrystals deposited on porous carbon and the capacitive effect of the N-containing defects within the carbon material. The nanostructure of the MnO2 particles deposited on porous carbon limits its large volume change during cycling and promotes good adhesion of MnO2 nanoparticles with the substrate. Meanwhile, the capacitive effect of the exposed N-functional groups enables fast ionic conduction and reduces interfacial resistance at the electrode interface.

Biomass-derived N–P double-doped porous carbon spheres and their lithium storage mechanism

Biomass-derived carbon materials are widely studied and used in energy storage applications. Unfortunately, the disadvantages such as poor capacity and rate performance limit their development. Heteroatom doping can effectively improve the electrochemical properties of biomass-derived carbon materials. In this work, we designed and prepared environmentally friendly and cost-effective biomass (lotus root)-derived nitrogen-phosphorus (N–P) double-doped porous carbon spheres. When used as an anode material for a lithium-ion battery, the porous carbon spheres exhibited excellent stability performance (a reversible capacity of 739.6 mAh g−1 after 100 cycles at 0.1 A g−1 and 599.16 mAh g−1 after 215 cycles at 0.5 A g−1, respectively) and superior rate performance (a capacity of 187.22 mAh g−1 at 10 A g−1) due to the synergy of the heteroatomic doping and the layered porous spherical structure. The novel biomass-derived material based on N–P double-doped porous carbon spheres can serve as a cost-effective option for anode materials of lithium-ion batteries. Besides, an “adsorption-pore filling/intercalation” hybrid mechanism is proposed to understand the possible principle for superior lithium storage performance based on CV, ex-situ Raman and XRD results.

First-principles study of VS<sub>2</sub> ascathode material for Li-ion batteries

With the increase of performance requirements for lithium-ion batteries (LIBs), it is particularly important to study and develop new electrodes for lithium-ion batteries. In this work, a 3 × 3 × 1 supercell of VS<sub>2</sub> is constructed, and the possibility of using it as an anode material for lithium-ion batteries is study by the first-principles method based on density functional theory. Through the analysis of the energy band diagram, it is found that VS<sub>2</sub> has metallic properties. Combining the density of states diagram, the analysis shows that the energy band near the Fermi level of VS<sub>2</sub> is contributed by the 3d state of V and the 3p state electrons of S, which means that the conductive properties of VS<sub>2</sub> are largely affected by the 3d state of V and the 3p state electrons of S. Of the vacancies, bridge sites, and top sites of lithium adsorbing vanadium (V), the top site has the lowest adsorption energy, indicating that lithium will preferentially adsorb the top site of vanadium (V). Through first-principles molecular dynamics simulations of the top position of adsorbed vanadium (V), it is found that at a temperature of 300k, the total energy of the system and the magnitude of the total temperature fluctuation can reach a steady state, indicating that lithium can exist at the top position of stably adsorbed vanadium (V). Moreover, the interlayer spacing of the double-layer VS<sub>2</sub> reaches 3.67 Å, which is larger than the interlayer spacing of graphene. From the top position to the vacancy, its diffusion barrier is only 0.20eV. Its interlayer spacing is larger than the double-layer graphene’s, and its diffusion barrier is lower than graphene’s, indicating that lithium has very good diffusivity on the VS<sub>2</sub> surface, and lithium can migrate quickly on the VS<sub>2</sub> surface, which is conducive to the rapid charge-discharge process of LIB. In addition to excellent electrical conductivity, VS<sub>2</sub> has good mechanical properties. The calculated Young's modulus is 96.82N/m, and the Young's modulus and Poisson's ratio do not decrease after adsorbing lithium, indicating that the rigidity of VS<sub>2</sub> will not be reduced in the diffusion and migration process of lithium. On the other hand, it has excellent deformation resistance. In order to be more accurate and closer to the actual situation, a double-layer VS<sub>2</sub> model is constructed, with a maximum number of lithium atoms adsorbed between layers being 18. The calculated theoretical capacity of VS<sub>2</sub> (466 mAh/g) is higher than the theoretical capacity of graphene (372 mAh/g). Our results indicate that VS<sub>2</sub> has excellent electrical conductivity and mechanical stiffness, making it a promising cathode material for lithium-ion batteries.

Cycle life and influencing factors of cathode materials for lithium-ion batteries--a case study of lithium-cobalt oxides

Abstract Lithium-cobalt oxide has become a new generation of highly promising anode materials for lithium-ion batteries due to its low price, environmental friendliness, high platform voltage, and high theoretical capacity. In this paper, the working characteristics and related parameters of lithium-ion batteries are sorted out, and the influence factors of the decline mechanism of lithium-ion batteries are investigated from the perspective of chemical composition. Regarding the cycle life of lithium-ion battery cathode materials, this paper establishes a cycle life prediction model for lithium-ion batteries based on the LSTM model. It optimizes the hyperparameters of the model using the PSO algorithm. In addition, this paper also prepared lithium cobalt oxide cathode materials and carried out a validation analysis of the factors affecting their electrochemical performance. It is found that the cycle life prediction of lithium-ion battery based on LSTM has an RMSE of 3.27%, and the capacity of lithium cobalt oxide soft pack full battery decays from 249.81mAh to 137.04mAh at 26°C. The cycle life of its lithium cobalt oxide lithium-ion battery is around 250 cycles, and the average decay is 0.445mAh during one charge/discharge. Different charge/discharge cycles and diversity will have a significant effect on the cycle life of lithium-ion battery cathode materials, and it is necessary to pay attention to the parameter changes in the preparation of lithium cobalt oxide cathode materials in order to increase the cycle life of lithium-ion batteries.

STUDY OF THE PROCESS OF OBTAINING A COMPOSITE MATERIAL "SPHERICAL GRAPHITE – Fe2O3"

In this article, a study was conducted on the process of obtaining a composite material “spherical graphite – iron oxide”, with the aim of its further use as an anode material for lithium-ion batteries. The composite was obtained by depositing iron oxide nanoparticles on the surface of spherical graphite. The influence of the deposition process parameters on the physico-chemical properties of the composite has been studied. It was found that the following factors have a significant effect on the final properties of the composite: the nature of the precipitator, the density of graphite loading of the precipitation working solution, the aging time of the system, the ratio of di- and trivalent iron in solution. Solutions of ammonia and urea were studied as precipitators. In the case of using urea, the formation of iron oxide particles with smaller coherent scattering regions, that is, with smaller crystallite sizes, was noted. Amorphous Fe2O3 precipitates are more preferable in terms of using them as an anode material. With an increase in the loading density of the graphite deposition solution, an increase in the yield of iron oxide nanoparticles was observed, however, at loading densities above 15 g/l, large iron oxide aggregates were formed. With an increase in the aging time of the deposition system, an improvement in the distribution of iron oxide nanoparticles over the surface of spherical graphite and a decrease in nanoparticle aggregates were noted. An increase in the molar fraction of Fe2+ in the precipitation solution has a similar effect. Based on the experimental data obtained, the optimal modes of the iron oxide deposition process were determined. Under these conditions, a sample of spherical graphite coated with Fe2O3 nanoparticles with average particle sizes of 30-50 nm was obtained. The oxide content in the sample was 3.7%. Electrochemical studies of the lithium-ion battery layout have shown that spherical graphite modified with iron oxide shows a reversible capacity increased to 370 mA∙h/g and greater stability of work.