Potential For Lithium-ion Batteries Research Articles

High porosity, excellent mechanical strength, interpenetrating network-reinforced double network regenerated cellulose separators for lithium-ion battery

Cellulose material is emerging as a promising alternative to polyolefin separators in lithium-ion batteries (LIBs) due to its wide availability, electrolyte wettability and thermal stability. Based on the non-solvent induced phase separation, dissolving and regenerating the cellulose material by environmentally friendly solvents and non-solvent enables the efficient and pollution-free preparation of porous regenerated cellulose separator (RCS), greatly expanding their application potential in LIBs. However, the mechanical strength of pure RCS still hardly satisfactory, due to the weak intermolecular bonding and loose porous structure. Therefore, this study introduced an acrylic acid/acrylamide (AA/AM) polymer cross-linking system forming an interpenetrating network with the cellulose framework to produce a double network regenerated cellulose separator (DN-RCS) with high mechanical strength and high porosity. At meantime, the special functional group on AA/AM can influence the transport process of Li+ and PF6− in the electrolyte, helping to form a stable interface on the electrolyte/lithium anode surface to reduce the formation of lithium dendrites. The results showed that DN-RCS possessed excellent mechanical strength and porosity compared to RCS. The high ionic conductivity of DN-RCS (1.03 mS cm−1) enabled the assembled cell with excellent cycling stability (90.8 % at 0.5C for 100 cycles) and rate performance (65.2 % at 5C). This work provides a further feasible strategy for the preparation of a high-performance cellulose-based separator.

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.

Prediction of cluster energy of lithium clusters from codescriptors with application in 2D porous graphene

A lithium metal anode has a high energy density, but its applications face numerous challenges, particularly the irregular deposition of lithium dendrites, which form due to the aggregation of lithium clusters, posing serious safety risks. Research has revealed that small lithium clusters have the potential to enhance the electrode potential in Lithium-ion batteries (LIBs), and cluster energy affects the stability of lithium clusters. Modern computational tools and DFT calculations of lithium clusters can provide invaluable insights into their chemical, physical, and structural properties. However, calculating structural properties through large-scale experiments can be time-consuming and expensive. To overcome the challenges inherent in studying lithium clusters, this study employs a novel approach. We construct molecular graphs for the most stable structures and leverage CoM Polynomial computations to generate codescriptors, enabling efficient and accurate predictions of cluster energy for diverse lithium cluster configurations. The curvilinear regression analysis filters out highly significant regression equations and highly predictive codescriptors. Additionally, we investigated two molecular structures of porous graphene, namely linear and triangular, and obtained topological codescriptors’ analytical expressions by utilizing the CoM Polynomial in each case. A deeper understanding of both lithium clusters and porous graphene properties is essential for optimizing LIBs’ performance and stability.

Amorphous AlPO4 Layer Coating Vacuum Thermal Reduced SiOx with Fine Silicon Grains to Enhance the Anode Stability.

Micrometer-sized silicon monoxide (SiO) is regarded as a high-capacity anode material with great potential for lithium ion batteries (LIBs). However, the problems of low initial Coulombic efficiency (ICE), poor electrical conductivity, and large volume change of SiO inevitably impede further application. Herein, the vacuum thermal reduced SiOx with amorphous AlPO4 and carbon double-coating layers is used as the ideal anode material in LIBs. The vacuum thermal reduction at low temperature forms fine silicon grains in the internal particles and maintains the external integrity of SiOx particles, contributing to mitigation of the stress intensification and the subsequent design of multifunctional coating. Meanwhile, the innovative introduction of the multifunctional amorphous AlPO4 layer not only improves the ion/electron conduction properties to ensure the fast reversible reaction but also provides a robust protective layer with stable physicochemical characteristics and inhibits the volume expansion effect. The sample of SiOx anode shows an ICE up to 87.6% and a stable cycling of 200 cycles at 1 A g-1 with an initial specific capacity of 1775.8 mAh g-1. In addition, the assembled pouch battery of 1.8 Ah can also ensure a cycling life of over 150 cycles, demonstrating a promising prospect of this optimized micrometer-sized SiOx anode material for industrial applications.

A Universal In-Situ Interfacial Growth Strategy for Various MXene-Based van der Waals Heterostructures with Uniform Heterointerfaces: The Efficient Conversion from 3D Composite to 2D Heterostructures.

Two-dimensional (2D) van der Waals heterostructures endow individual 2D material with the novel functional structures, intriguing compositions, and fantastic interfaces, which efficiently provide a feasible route to overcome the intrinsic limitations of single 2D components and embrace the distinct features of different materials. However, the construction of 2D heterostructures with uniform heterointerfaces still poses significant challenges. Herein, a universal in-situ interfacial growth strategy is designed to controllably prepare a series of MXene-based tin selenides/sulfides with 2D van der Waals homogeneous heterostructures. Molten salt etching by-products that are usually recognized as undesirable impurities, are reasonably utilized by us to efficiently transform into different 2D nanostructures via in-situ interfacial growth. The obtained MXene-based 2D heterostructures present sandwiched structures and lamellar interlacing networks with uniform heterointerfaces, which demonstrate the efficient conversion from 3D composite to 2D heterostructures. Such 2D heterostructures significantly enhance charge transfer efficiency, chemical reversibility, and overall structural stability in the electrochemical process. Taking 2D-SnSe2/MXene anode as a representative, it delivers outstanding lithium storage performance with large reversible capacities and ultrahigh capacity retention of over 97% after numerous cycles at 0.2, 1.0, and 10.0 Ag-1 current density, which suggests its tremendous application potential in lithium-ion batteries.

Understanding the influence of sulfur configuration on the electrochemical reaction pathway for lithium storage in molybdenum sulfides

Molybdenum sulfides are highly regarded as conversion-type electrodes with exceptional performance potential in lithium-ion batteries (LIBs). However, elucidating their lithium (Li) storage behavior has proven challenging due to the intricate sulfur (S) coordination with molybdenum atoms, which has impeded the realization of high energy densities in future Li storage systems. In this study, we investigate the electrochemical redox reaction pathways of molybdenum sulfide, specifically exploring the impact of various S configurations, including terminal, bridging, and apical S. We employ a comprehensive approach, involving extensive electrochemical measurements and depth X-ray photoelectron spectroscopy (XPS) profiling. In contrast to the multi-step conversion reactions observed in MoS2, sulfur-enriched molybdenum sulfides exhibit a unique single-step Li-ion storage mechanism. As a consequence of the pronounced effect of S configuration on the activation energy barrier during charging and discharging, the redox reaction voltage with Li ions exhibits variations. This versatility verifies that molybdenum sulfides have the potential to serve as both anode and cathode materials in lithium-ion batteries. Furthermore, we propose the incorporation of reduced graphene oxide (rGO) composites to address inherent limitations of molybdenum sulfides, including low electrical conductivity and irreversible reactions. The robust interaction between molybdenum sulfides and oxygen functional groups in rGO enhances rate capability and ensures a stable cycling lifespan. Through this systematic investigation, we suggest a comprehensive insight into the electrochemical reaction pathways governing Li storage behavior in molybdenum sulfides with distinct S configurations. This contributes to the fundamental understanding of these materials and their potential applications in advanced energy storage systems.

Few-layer V2C/MWCNT with high ionic accessibility for lithium-ion storage.

A V2C MXene has a high theoretical capacity and low diffusion barrier, showing tremendous potential in lithium-ion batteries. However, most reports on V2C focus on a multilayered structure that is stacked, which diminishes the ionic accessibility and results in unsatisfactory cycling stability. Therefore, we synthesized a few-layer V2C (f-V2C) material and added multi-walled carbon nanotubes (MWCNTs). The formed f-V2C/MWCNT provides abundant pores, which enhance ionic accessibility, so that Li+ can easily enter the layer space. The introduction of MWCNTs can further separate the f-V2C, expand the specific surface area, reduce the charge transfer resistance, and heighten the structural stability. The experiments reveal that f-V2C/MWCNT has a high specific capacity of 531 mA h g-1 at 0.1 A g-1 after 100 cycles. Even at a high current density of 5.0 A g-1, the specific capacity can still reach 166 mA h g-1. Moreover, the f-V2C/MWCNT structure shows good cycling stability with a capacity retention rate of 95% after 1000 cycles at 5.0 A g-1. The above findings indicate that f-V2C/MWCNT has great application potential in the field of Li+ storage.

Reviewing the Cost–Benefit Analysis and Multi-Criteria Decision-Making Methods for Evaluating the Effectiveness of Lithium-Ion Batteries in Electric Vehicles

Lithium-ion batteries (LIBs) have a wide range of applications in different fields, starting with electronics and energy storage systems. The potential of LIBs in the transportation sector is high, especially for electric vehicles (EVs). This study aims to investigate the efficiency and effectiveness of, and justification for, the application of LIBs in the field of transport, primarily in EVs. The research focuses on single and multi-criteria evaluations of the efficiency of LIBs. Previous studies in which LIBs were evaluated using cost–benefit analysis (CBA) and multi-criteria decision-making methods (MCDM) were analysed. An electronic literature search of the Web of Science, Scopus, and other relevant databases was performed. The literature was searched using the keywords: “lithium-ion batteries”; “multi-criteria decision-making”; “cost-benefit analysis”; “energy storage”; “vehicles”; “PROMETHEE” (or other MCDM method)”. A total of 40 scientific articles concerning the application of CBA (of which are 20%) and MCDM methods between 1997 and 2023, worldwide, were analysed. The results show multiple applications of both CBA and MCDM methods. The main findings of the areas of application were summarised and future research was discussed.

Online Fast Charging Model without Lithium Plating for Long-Dimensional Cells in Automotive Applications

The internal negative electrode potential in lithium-ion batteries (LIBs) is intricately linked to the lithium-ion intercalation and plating reactions occurring within the cell. With the expansion of cell sizes, the internal negative electrode potential distribution gradually becomes inconsistent. However, the existing negative electrode potential estimation models and fast charging strategies have not yet considered the impact of consistency, and the model estimation accuracy will be greatly influenced by different temperatures and charging rates. This study proposes an online lithium-free fast charging equivalent circuit model (OLFEM) for estimating the negative electrode potential terminal voltage and developing fast charging strategies of long-dimensional LIBs in real vehicles. This study employs distributed reference electrodes integrated into long-dimensional LIBs and compares the negative electrode potential measured in the vicinity of both the negative and positive tabs. Subsequently, based on the lowest negative electrode potential point, model parameters were obtained at different temperatures and charging rates. This model is further verified under different operating conditions. Finally, a fast-charging strategy without lithium plating is developed in real-time based on the negative electrode potential estimated by the model. The results demonstrate that long-dimensional cells exhibit a lower negative electrode potential on the positive tab side. Across various temperatures and charging rates, the calibrated model achieves a negative electrode potential estimated error within 25 mV, and the estimation error for terminal voltage is within 5 mV. The proposed fast-charging method prevents lithium plating and charges the cell up to 96.8% within an hour. After 100 cycles, the cell experiences a capacity degradation of less than 2%, and the disassembly results indicate that no lithium precipitation has occurred. The methods outlined in this study provide valuable insights for online fast charging of large-dimensional batteries without lithium plating.

Controlled synthesis of hollow Si-C microspheres and its potential as an anode material in lithium-ion batteries

Hollow structure has great potential in lithium-ion batteries, especially in Si-based anode materials. Unlike the usual templating process, here, we report a template-free synthetic strategy to build hollow microspheres of Si-C hybrid materials, which combines an in-situ polymerization process to form precursor and magnesiothermic reduction towards the inner cavity. As a result, the hollow Si-C microspheres exhibit improved cycling performance (768.7 mA h g−1 after 100 cycles at 0.84 A g−1) and good rate capability (497.1 mA h g−1 at 8.4 A g−1) when used as an anode material in lithium-ion batteries. This work provides a controllable and industrially-scalable operation based on cheap source to synthesize hollow Si-C hybrid materials, which combines the advantage of hollow structure and carbon matrix to achieve better electrochemical performance than the solid one.

Nitrogen-Doped Hollow Carbon Spheres Based on Schiff Base Reaction as an Anode Material for High-Performance Lithium and Sodium Ion Batteries.

Nitrogen-doped carbon has great potential in lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs), considering N-doping can not only improve the surface wettability of carbon materials, but also accelerate charge transfer by generating additional defects. However, designing carbon materials with a high nitrogen content and uniform distribution using conventional doping methods remains a challenge. In this study, a hollow carbon sphere with an ultrahigh nitrogen content of 9.58 wt % was successfully fabricated by rationally designing Schiff base chemistry (PTA-NHCS-700). Stable hierarchical pore structures, moderate defects, and large specific surface areas were formed during the carbonization process. Excellent electrochemical performance was observed in LIBs (204.2 mAh g-1 after 7000 cycles at 5 A g-1 ) and SIBs (154.2 mAh g-1 after 10000 cycles at 5 A g-1 ). This study not only promotes the development of efficient carbon anode materials for LIBs and SIBs, but also provides a novel idea for the doping of heteroatoms with special chemical structures.

Ag nanoparticles grafted vanadium carbide MXene as a superior anode material for lithium-ion battery: High capacity and long-term cycle capability

V 2 CT x MXene shows excellent potential in lithium-ion batteries (LIBs) due to its unique two-dimensional structure and rich surface chemistry. However, the low Li + -storage capacity contributed by the innate low conductivity seriously hinders its commercial application. Herein, Ag nanoparticles are grafted on the V 2 CT x MXene by a one-step reduced silver nitrate (AgNO 3 ). The obtained Ag nanoparticles are directly reduced from AgNO 3 by the -OH terminations of V 2 CT x MXene, which promote the conductivity of V 2 CT x /Ag. Besides, the Ag nanoparticles in the layered body structure have excellent structural strength, which boost the whole durability of the LIB by inhibiting the aggregation of V 2 CT x MXene. Further, the dependence of the battery performances on the Ag contents is investigated. We find that the most favorable Ag content is 4.0 at% which can simultaneously favor the transferability of electron and ion and the electrochemical kinetics to the most considerable extent. The V 2 CT x /Ag-40 achieves a specific capacity of 631 mAh g −1 at 0.05 A g −1 after 50 cycles, and even maintains a specific capacity of 298 mAh g −1 at 5 A g −1 after long-term 2000 cycles. The adopted in situ reduction strategy and the excellent electrochemical property of V 2 CT x /Ag nanostructure may be relevant for future anode material in LIBs. We focused on the in situ reaction mechanism and the treated V 2 CT x has a greatly improved specific capacity. • V 2 CT x /Ag MXene was synthesized by one step solution in situ reaction and the reaction mechanism was analyzed. • V 2 CT x /Ag MXene exhibited superior electrochemical performance for LIBs. • The effect of different content of surface AgNPs on V 2 CT x MXene was analyzed.

A kind of Co-based coordination compounds with tunable morphologies and its Li-storage mechanism

The metal-organic coordination compounds have shown great potential in lithium-ion batteries (LIBs) because of the moderate preparation conditions, high specific surface area, and diverse topological structures. Herein, a kind of Co-based coordination compounds with tunable morphologies are synthesized via a microwave-assisted solvothermal method by adjusting the molecular ratios between cobalt salts and phloroglucinol (PG) (Co-PG-x, x = 1, 2 and 3) for LIBs anode. Among them, Co-PG-2 with a unique flower structure, composed of ultra-thin flakes, has exhibited the most active sites (C=O, C=C groups of benzene ring and Co2+) and the highest specific surface areas. When applied as the anode of LIBs, Co-PG-2 has displayed excellent cycle stability (a high reversible capacity of 752 mAh g−1 at 1 A g−1 after 500 cycles) and an outstanding rate performance (up to 5 A g−1). Moreover, practical application is demonstrated by the full cells, composed of Co-PG-2 electrode and when paired with LiFePO4 in the full cells, it delivers a reversible capacity of 85 mAh g−1 at 0.2 A g−1 after 50 cycles. In a word, these Co-based coordination compounds have exhibited extraordinary prospects for renewable organic materials applied in lithium storage.

Kinetically-controlled formation of Fe2O3 nanoshells and its potential in Lithium-ion batteries

• A wet chemical synthetic protocol was developed to build uniform Fe 2 O 3 nanoshells. • Hexamethylenetetramine was critical in modulating the precipitation kinetics. • This protocol was successful in building Fe 2 O 3 coatings around various substrates. • A nondestructive surface treatment could be achieved by this anhydrous protocol. • The cycling performance of LiNi 0.5 Mn 1.5 O 4 greatly improved after Fe 2 O 3 coating. The construction of uniform metal oxide nanoshells has been widely considered as an effective protocol for the protection of high energy cathodes in lithium-ion batteries. Solution-based synthetic routes have recently become feasible to build such protective shells, but are challenged by the incidental damage to cathodes since an acidic condition is usually needed to prevent the fast precipitation of active metal cations in aqueous solutions. Here, by switching to anhydrous solution, we demonstrate the possibility of creating Fe 2 O 3 nanoshells by taking advantage of the much-reduced ionic activity of Fe 3+ in ethanol without the involvement of corrosive environment. Hexamethylenetetramine is identified as an efficient growth controller, whose slow decomposition is critical to modulate the growth kinetics of the formed metal hydroxide precursor, forming core@shell structures with the shell thickness controlled at nanometer accuracy. This synthetic protocol is successful in building uniform Fe 2 O 3 coatings around various substrates, particularly LiNi 0.5 Mn 1.5 O 4 , a well-known high energy cathode whose applications are challenged by poor cycling performance related to the high working voltage. This surface treatment for LiNi 0.5 Mn 1.5 O 4 is effective in improving the electrochemical behavior of the cathode with a successful suppression of its structural degradation as well as a substantial improvement in its high temperature stability.

Self-template formation of porous yolk-shell structure Mo-doped NiCo2O4 toward enhanced lithium storage performance as anode material

• Mo-doped NiCo 2 Co 4 was prepared in yolk-shell structure with a porous core. • The anode exhibited highly reversible capacity and excellent rate performance. • The pathway of Li + transportation was shortening by yolk-shell structure. • Electrolyte infiltration was enhanced by providing more active surface. Hollow ternary metal oxides have shown enormous potential in lithium-ion batteries (LIBs), which is ascribed to their complex chemical composition, abundant active defect sites, and the synergy effect between metals. In this work, we synthesized Mo-doped NiCo 2 O 4 porous spheres with yolk-shell structure by using a simple self-templating method. Surprisingly, other than the yolk-shell structure we had obtained, the inner core of the yolk-shell was also porous, which could fully enhance the electrolyte infiltration and promote the transmission of lithium ions (Li + ) and electrons (e − ). The diameter of the porous core in the yolk-shell sphere was about 530 nm, and the outer shell's thickness was up to 110 nm. In addition, the unique pores in the core appeared in the diameter of about 85 nm. With this structure, the volume expansion of the anode could be well inhibited during charge/discharge. It exhibited prominent electrochemical performance with high reversible capacity (1338 mA h g −1 at 100 mA g −1 ), satisfactory cycle life (1360 mA h g −1 after 200 cycles at 100 mA g −1 ), and exceptional rate capability (820 mA h g −1 at 2000 mA g −1 ) as anode material in LIBs.

Estimation of Potentials in Lithium-Ion Batteries Using Machine Learning Models

Electrochemical mechanisms in lithium-ion batteries (LIBs) pose a significant challenge in deriving models that are highly accurate, have low computational complexity, and enable real-time state and parameter estimation. In this article, we propose a machine learning model as an important building block of a physics-based ANCF-e model that was recently proposed for LIBs. This machine learning model is used to estimate nonlinear potentials, including the open-circuit potential, electrolyte potential, and lithium-intercalation overpotential. Such an estimation is shown to result in a much smaller computational complexity and therefore can enable real-time state and parameter estimation. Three different machine learning architectures are explored, including multilayer perceptron, radial basis function (RBF)-based neural networks, and support vector machines. The training of these machine learning models is carried out using current profiles obtained with an electric vehicle model from driving cycles as inputs and ANCF-e model-based outputs. The underlying ANCF-e model is validated both through a high-fidelity numerical approach, including COMSOL and an experimental test using commercial LIBs. Both validations are carried out under both constant current discharging and dynamic load cycles. The resulting performance using these machine learning models is compared using different metrics, including estimation errors, convergence rates, training time, and computational time. The results indicate that an RBF-based neural network leads to better estimation of the underlying potentials in LIBs and that all machine learning models require a computational time that is 95% smaller than a physics-based approach for this estimation.

Self-assembled homogeneous SiOC@C/graphene with three-dimensional lamellar structure enabling improved capacity and rate performances for lithium ion storage

SiOC as an alternative silicon-based material possesses great potential in lithium ion batteries due to its high reversible capacity, tunable chemical component and various synthetic route. However, large-scale production of SiOC powders grinded from SiOC bulks is restricted in commercial application because of the poor electrical conductivity. Herein, three dimensional (3D) lamellar SiOC@C/rGO composite is fabricated through hydrothermal reaction and electrostatic self-assembly process, in which SiOC powders encapsulated by amorphous carbon layers are homogeneously dispersed in graphene sheets. Cfree nanoclusters in SiOC, carbon layers on SiOC surface and graphene supporters in the composite establish the multidimensional interconnected conductive architecture and possess favorable interfacial adhesion. Therefore, SiOC@C/rGO exhibits high specific capacity (676 mAh g−1 at 200 mA g−1) and remarkable rate capability (306.4 mAh g−1 at 4000 mA g−1). The full cell assembled with this anode and LiFePO4 cathode also demonstrates stable voltage platform and good performance for 200 cycles. The excellent performance of SiOC@C/rGO profits from the synergistic effect of robust construction, multidimensional conductive architecture and chemical. CompositionThe proposed strategy can also be developed to prepare other materials with graphene layer to enhance their electrical conductivity for commercial application.

Insight into structural and electrochemical properties of Mg‐doped LiMnPO 4 /C cathode materials with first‐principles calculation and experimental verification

The LiMnPO4 material has the advantages of abundant raw materials, safety and environmental protection, low price, high theoretical capacity, high stable working voltage platform and so on, showing great potential in lithium-ion batteries. Dissimilar metal ion doping can essentially improve the electronic conductivity of LiMnPO4 and the material's charge and discharge performance, which is an ideal method to improve the electrochemical performance of LiMnPO4. In this paper, the optimal doping concentration of Mg-doped solid solution material was calculated by first principles. At the same time, the corresponding content of LiMn1−xMgxPO4/C cathode material was synthesized by hydrothermal method for experimental verification, so as to prepare the cathode material with excellent electrochemical performance. The results show that the doping of Mg cations does not change the phase of the main phase, but significantly changes the crystal structure parameters. The regulation of the band width directly affects the electronic conductivity of the material, which is directly proportional to the electrochemical performance. EIS and CV test results show that a proper amount of magnesium doping can effectively reduce the impedance of the material, and can effectively alleviate the polarization phenomenon of LiMnPO4 electrode material, accelerate the diffusion rate of Li+, and it is easier to obtain high capacity battery. LiMn23/24Mg1/24PO4/C showed the best electrochemical performance, with an initial capacity of 153.8 mAh/g at 0.05C ratio and a capacity retention rate of 97.5% after 100 cycles at 0.05C ratio. The theoretical calculation is in good agreement with the experimental results, which indicates that the theoretical calculation based on first principles can effectively provide a more reliable theoretical basis for experimental design and subsequent improvement.

Facile and Efficient Fabrication of Branched Si@C Anode with Superior Electrochemical Performance in LIBs.

One-dimensional Si nanostructures with carbon coating (1D Si@C) show great potential in lithium ion batteries (LIBs) due to small volume expansion and efficient electron transport. However, 1D Si@C anode with large area capacity still suffers from limited cycling stability. Herein, a novel branched Si architecture is fabricated through laser processing and dealloying. The branched Si, composed of both primary and interspaced secondary dendrites with diameters under 100nm, leads to improved area capacity and cycling stability. By coating a carbon layer, the branched Si@C anode shows gravimetric capacity of 3059 mAh g-1 (1.14 mAh cm-2 ). At a higher rate of 3 C, the capacity is 813 mAh g-1 , which retained 759 mAh g-1 after 1000 cycles at 1 C. The area capacity is further improved to 1.93 mAh cm-2 and remained over 92% after 100 cycles with a mass loading of 0.78mg cm-2 . Furthermore, the full-cell configuration exhibits energy density of 405Wh kg-1 and capacity retention of 91% after 200 cycles. The present study demonstrates that laser-produced dendritic microstructure plays a critical role in the fabrication of the branched Si and the proposed method provides new insights into the fabrication of Si nanostructures with facility and efficiency.

Electrochemically driven amorphization of (Li-)Ti-P-O nanoparticles embedded in porous CNTs for superior lithium storage performance

Amorphous materials have many advantages over their crystalline states in transfering Li+ without restriction of defects, tolerating large volume change during the charging/discharging process and achieving a higher potential in lithium-ion batteries (LIBs). Crystalline LiTi2(PO4)3/TiP2O7 nanoparticles embedded in porous CNTs were constructed firstly by sol-gel and calcination, in which sulfonated polymer nanotubes as both carbon source and template. Afterwards, amorphous (Li-)Ti-P-O nanoparticles embedded in porous CNTs were formed by electrochemical activation. Due to amorphous (Li-)Ti-P-O nanoparticles providing the multi-channel transport of Li+ and the porous carbon matrix preventing the gathering and pulverization of (Li-)Ti-P-O nanoparticles during the electrochemical process, (Li-)Ti-P-O/C hybrid nanotubes exhibit stable cyclic performances and good rate capacities (the capacities of Li-Ti-P-O/C and Ti-P-O/C hybrid nanotubes possess 388.9 and 457.2 mAh g−1 at 0.2 A g−1 after 500 cycles, and maintain 155.0 mAh g−1 at 5 A g−1 after 500 cycles and 123.3 mAh g−1 at 5 A g−1 after 3000 cycles, respectively). This paper provides a feasible method for the preparation of other anode materials with superior lithium storage performance.