High-rate Lithium Storage Research Articles

Coordinate regulation of amorphous carbon microspheres and crystal structure of iron oxalate for high rate lithium storage ability

Iron oxalate is one of the highly potential anode materials for lithium-ion batteries, but its widespread application is limited by slow electron transfer rate and sluggish electrochemical reactions. Herein, iron oxalate/amorphous carbon microspheres (FeC2O4/PCC) composite with uniformly mixed crystalline phase for more stable active sites and three-dimensional conductive network, was synthesized via the in-situ self-polymerization, carbonization of β-cyclodextrin and recrystallization technique under solvothermal condition. The self-aggregation progress and kinetics of recrystallization accelerate the crystalline phase transformation of iron oxalate and the morphology reconstruction of micron-grade polygonal prism particles. Based on the fast electron migration facilitated by three-dimensional conductive network of PCC and exceptionally stable structure and Li+ diffusion channels endowed by strengthening effect of recrystallization, FeC2O4/PCC-15 % exhibits long cycling life and outstanding ability for high-rate lithium storage: the specific capacities of 1231.50 and 1128.75 mAh g−1 after 500 cycles at current densities of 3 and 5 A g−1, with capacity retention rates of 90.79 % and 81.08 %, respectively. Furthermore, according to electrochemical capacity contribution analysis, PCC also can remarkably enhance the reversible lithium storage ability of interfacial capacitive effects and conversion reaction even under high current density. This work provides a new modification pathway for the application of transition metal oxalate systems in fast charging field.

Promoting nitrogen-doped porous phosphorus spheres for high-rate lithium storage

Phosphorus anode has shown great potential for the high-rate and high-energy–density lithium-ion batteries. Nevertheless, it still suffers from possible electrode cracking, ion-transport restrictions, and active-particle decomposition resulting from repeated alloying/de-alloying. To address the aforementioned issues, a nitrogen-doped flower-like porous phosphorus (f-P) sphere has been developed. The abundant micro-mesopores facilitate ion diffusion and enhance the internal bonding strength of the electrode. Concurrently, the doped nitrogen promotes the generation of a favorable solid electrolyte interphase constructed by fast-ion-conductors. As a result, the f-P exhibits a high-rate capacity of 735mAh g−1 at 20 A g−1 and maintains high Coulombic efficiencies over 900 cycles at 10 A g−1. Furthermore, coin full-cells comprising the f-P anode and lithium cobalt oxide cathode demonstrate stable operation at a high current density of 6 mA cm−2. The combination of a porous structure and doping strategy represents a viable approach for strengthening the durability of electrodes and optimizing the ion transport kinetics of advanced alloy anode materials.

Stabilizing Graphite Anode in Electrolytes with Nanoscale Anion Networking for High-Rate Lithium Storage

Stabilizing Graphite Anode in Electrolytes with Nanoscale Anion Networking for High-Rate Lithium Storage

Oxygen vacancy modulated Ti2Nb10O29 anodes for high-rate lithium storage

Ti2Nb10O29 (TNO) is a prospective anode for lithium-ion batteries (LIBs) because of its high theoretical capacity, high energy density, and safer operating voltage. However, the lower conductivity and slower lithium-ion diffusion characteristic lead to performance degradation and accelerated capacity degradation. In this work, we developed a novel and simple urea-assisted heat treatment method to enrich oxygen vacancies in TNO anodes. Oxygen vacancy introduction leads to the formation of Ti3+ and Nb4+ and the optimization of electronic structure, which provide more active sites for ion insertion and accelerate electron transport and migration. The optimized sample (TNO-M) demonstrates excellent high-rate capacity and cyclic stability. Specifically, the reversible capacity is 155.4 mAh/g at 10C. A capacity retention ratio of 97.87 % can be maintained after 200 cycles at 1C. Even after 500 cycles at 5C, TNO-M can still deliver a high capacity of 156.4 mAh/g. The strategy of developing high-capacity and high-rate anodes provides a new inspiration for the applications of fast charging of energy-dense LIBs.

(Invited) Stabilizing Graphite Anode in Electrolytes with Micelle-Like Nanostructures for High-Rate Lithium Storage

Graphite stands out as the preferred anode material in commercial lithium-ion batteries (LIBs). However, its limited compatibility with diverse solvent molecules poses a significant challenge in selecting electrolyte solvents for LIBs. The issue arises from the co-intercalation of solvent molecules into the graphite layer alongside Li ions, resulting in layer exfoliation. This constraint has left few alternatives, primarily relying on ethylene carbonate (EC)-based mixed solvents. Consequently, the translation of electrolyte advancements from the past three decades into practical LIBs has been hindered. In this study, we present electrolytes exhibiting a micelle-like structure designed at nanoscale to impede the liquid-phase exfoliation of the graphite layer. The micelle-like electrolyte structure, derived from concentrated long-chain lithium salts, effectively segregates Li ions from free diethylene carbonate (DOL) solvent molecules. This segregation mitigates interactions between graphite particles and free solvent molecules during Li intercalation. Our proposed mechanism provides refreshed insights, highlighting the significance of the concentrated long-chain lithium salts (LiTFSI) for the graphite stability rather than the widely accepted Li coordination structure or solid electrolyte interphase. These findings offer a pivotal guideline for enhancing LIB performance by overcoming electrolyte limitations on graphite anodes.

Thermodynamic anti-agglomeration based selenium-doped tin oxide network: Enhancing cycling stability of high-rate lithium storage

In this work, the grain line-cutting effect induced by selenium doping into SnO2 aggregation was proposed to prepare uniformly distributed SnO2/Se nanoparticles (SnO2/Se NPs) network with thermodynamic anti-agglomeration force during high-temperature sintering. These SnO2/Se NPs offers abundant active sites, reduced volume expansion and fast Li+ diffusion ability, especially the enhanced electronic conductivity due to oxygen vacancies introduced by doping. More importantly, the thermodynamic anti-agglomeration of SnO2/Se NPs effectively suppresses the Sn coarsening and Li2O/Sn phase segregation during repeated charge/discharge processes. Consequently, the SnO2/Se NPs anode delivers excellent reversible capacity of 515 mAh g−1 after 500 cycles at 1 A g−1, and the SnO2/Se NPs||LiFePO4 full cells maintains a high-rate capacity of 109 mAh g−1 at 0.3 A g−1. The SnO2/Se NPs anode is compatible with high concentration polymer electrolyte (HCPE), which shows a capacity of 520 mAh g−1 after 100 cycles at 0.2 A g−1 in solid state batteries. This study provides a new insight for improving the cyclic stability of conversion-alloying anodes, offering their promising prospects for the full batteries and solid-state batteries.

Ultrahigh rate and cycling properties of Li2CuTi3O8 anode derived from HKUST-1 copper source for high-performance lithium-ion batteries

Rational design and preparation of titanium-based anode materials with superior fast charge and discharge are a key focuses of the lithium-ion batteries research. Herein, a novel and facile synthesis of uniformly carbon-coated Li2CuTi3O8 (LCuTO) nanoparticles with excellent high-rate lithium storage properties is presented using HKUST-1 with pore structure and active metal sites as a copper source. The well-designed LCuTO@HKUST with carbon bridges between the particles and the carbon layer on the outer surface offers high electronic conductivity for fast charge and discharge. The LCuTO@HKUST exhibits extraordinary lithium storage performance: high capacity (251.8 mAh/g after 1000 cycles at a current density of 1.0 A/g), a superior high-rate capability (160.3 mAh/g after 500 cycles at 3.0 A/g and 138.1 mAh/g after 500 cycles at 5.0 A/g), and excellent cycle reversibility and cycle stability under various current densities. In addition, the lower Li+ migration barrier in LCuTO@HKUST demonstrated by density functional theory (DFT) calculations is beneficial to the long-cycle stability and high-rate performance. The proposed preparation method and the strategy of using the MOF as a metal source for lithium-ion battery anode materials provide a new approach for advanced fast charge–discharge energy storage applications.

High-Energy Symmetric Li-Ion Battery Enabled by Binder-Free FeOF-MXene Heterostructure with Doubly Matched Capacity and Kinetics.

Fluorides are viewed as promising conversion-type Li-ion battery cathodes to meet the desired high energy density. FeOF is a typical member of conversion-type fluorides, but its major drawback is sluggish kinetics upon deep discharge. Herein, a heterostructured FeOF-MXene composite (FeOF-MX) is demonstrated to overcome this limitation. The rationally designed FeOF-MX electrode features a microsphere morphology consisting of closely packed FeOF nanoparticles, providing fast transport pathways for lithium ions while a continuous wrapping network of MXene nanosheets ensures unobstructed electron transport, thus enabling high-rate lithium storage with enhanced pseudocapacitive contribution. In/ex situ characterization techniques and theoretical calculations, both reveal that the lithium storage mechanism in FeOF arises from a hybrid intercalation-conversion process, and strong interfacial interactions between FeOF and MXene promote Li-ion adsorption and migration. Remarkably, through demarcating the conversion-type reaction with a controlled potential window, a symmetric full battery with prelithiated FeOF-MX as both cathode and anode is fabricated, achieving a high energy density of 185.5Whkg-1 and impressive capacity retention of 88.9% after 3000 cycles at 1Ag-1. This work showcases an effective route toward high-performance MXene engineered fluoride-based electrodes and provides new insights into constructing symmetric batteries yet with high-energy/power densities.

Integrated Li3VO4 and boron doped carbon microspheres with high tap density for high-rate and durable lithium storage

As an essential representative of novel anode materials with high capacity and safe voltage, Li3VO4 (LVO) still suffers from the challenges of low electronic conductivity and low tap density of nanostructures. Herein, a strategy of nanoization and recombination is proposed to synthesize the integrated LVO and boron doped carbon microspheres (LVO/BC-MS-550) with high tap density via a chemical crosslink method to improve the Li-ion storage performance. LVO/BC-MS-550 is consisted of the well-dispersed LVO nano-crystals in tightly stacked carbon spheres derived from the cross-linked network of boric acid (BA) and polyvinyl alcohol (PVA). By introducing conductive and continuous carbon framework, the LVO crystals are controlled to grow in the confined region with mitigated volume changes, as well as the enhanced electronic conductivity. Benefiting from the constructive advantages, LVO/BC-MS-550 anode delivers a specific capacity of 512.1 mAh g−1 at the current density of 0.2 A g−1 (0.34 C) after 300 cycles, and ultra-long cycling performance of 231.8 mAh g−1 over 5000 cycles at the charging/discharging current density of 4/2 A g−1, exhibiting rapid pseudo-capacitance reaction kinetics. This work provides valuable insights into the fabrication of in situ three-dimensional crosslinked carbon and LVO composites for alternative grid-scale electrochemical applications.

Interfacial carbon tailoring of porous SiOx/carbon nanotube hybrids towards high-rate lithium storage

Fast charging Lithium-ion batteries (LIBs) is highly required with the massive development of the electric vehicle market. Integrating silicon with carbon nanotubes (CNTs) has shown great promise for constructing high-rate anodes of LIBs. However, current reported silicon axially coated CNTs electrodes fail to provide a robust conductive connection within the interfacial layer, causing unsatisfactory rate performance. In this paper, a series of novel coaxial hollow nanocables of SiOx/C coated CNTs composite were presented based on a simple sol–gel method and subsequent calcination. Due to the uniform composition of carbon and SiOx at sub-nanometer scale in the coating layer, a strong 3D conductive network is formed between the internal carbon nanotubes and the neighboring electrode particles. When utilized as LIBs anodes, such novel hybrids manifest high reversible capacity (511 mA h g−1 remained after 500 cycles at 0.5 A g−1), high-rate capability (232 mA h g−1 at 5 A g−1) and ultra-long high-current cycling stability (396 mA h g−1 remained after 1000 cycles at 1.0 A g−1). The structural characterization and electrochemical dynamics analysis show that the synergistic effect of abundant mesoporous channels in the coating layer and strong carbon 3D conductive network makes this unique composite structure exhibit excellent electrochemical performance. This work sheds novel light on the wisely design of advanced Si-based anodes with enhanced fast charging performance.

Enhanced high-rate lithium storage of nanosphere composites with in-situ formed graphene interface bridging Ni3Sn4-based nanoparticles and carbon matrix

The nanosphere composites with in-situ formed graphene interface bridging intermetallic Ni3Sn4-based nanoparticles and carbon matrix (Ni3Sn4@g-C) are successfully fabricated through a facile organic–inorganic coordination complex-derived method. In this novel composite, numerous Ni3Sn4-based nanoparticles with a size of 10 ∼ 80 nm are homogeneously decorated in a carbon nanosphere with a diameter of 200 ∼ 400 nm, and at the interfaces between Ni3Sn4-based nanoparticles and the carbon matrix, several layers of graphene are in-situ formed during the fabrication process due to the catalytic effect of Ni species. When used as the anode in lithium ion batteries (LIBs), intermetallic Ni3Sn4 alloy can not only effectively alleviate the severe volume variation of Sn due to the incorporation of Ni component, but also further improve the mechanical stability and enhance the electrical conductivity of the resultant product owing to the formation of the graphene interface layers. As a result, the hierarchical Ni3Sn4@g-C composite displays high reversible capacities (547.0 mAh/g after 200 cycles at 200 mA g−1, and 542.8 mAh/g after 500 cycles at 1000 mA g−1), excellent cycling stability and superior rate properties (341.3 mAh/g even at a high rate of 2 A g−1). The unique microstructures and special introduction of Ni element in the hierarchical Ni3Sn4@g-C nanospheres are responsible for the enhanced electrochemical lithium storage properties.

Reconstructing 2D metallic Sn4P3 with high-conductive interlayer towards high-rate lithium storage

Lithium-ion batteries are extensively utilized in various applications but face challenges in terms of anode performance. Commercial graphite possesses a low theoretical capacity of mAh g−1, which falls short of the desired performance. Alternatively, tin phosphide (Sn4P3) possesses a remarkable theoretical capacity of 1230 mAh g−1, making it a highly promising candidate. However, Sn4P3, being a semiconductor, faces challenges such as poor conductivity as well as substantial volume expansions during the lithiation–delithiation process. Herein, we fabricated a 2D Sn4P3 nanocomposite with high-conductive-interlayer via a breaking-reconstructing strategy. In this process, the 2D Sn4P3 layers were first achieved by a liquid-exfoliation method, revealing their unique metallic properties by density-functional-theory calculations. Besides, the 2D conductive-interlayer Sn4P3 demonstrated good electrochemical performance, including high reversible capacity, stable cyclic life, and high-rate capabilities. Alternating current impedance spectroscopy analysis further revealed that low charge-transfer resistance and a high lithium ion diffusion coefficient, contributing to the enhanced electrochemical performance. These findings demonstrate the significance of exfoliating Sn4P3 into layered structures and highlight the potential of 2D conductive-interlayer Sn4P3 nanocomposites as promising candidates for high-performance anodes.

Sandwich-like N-doped carbon coated SnNb2O6 nanosheets for high-rate and long-life lithium storage

A novel sandwich-like N-doped carbon coated SnNb2O6 nanosheets (SNO@NC) has been successfully fabricated through a facile calcination of SNO/polyaniline hybrid composites, which were obtained by the polymerization of aniline on SNO nanosheets. A controllable growth of NC nanolayer on the lamellar SNO surfaces endows the as-prepared SNO@NC with hierarchical sandwich-like structure, excellent conductivity and appropriate oxygen vacancies, which greatly restrains the volume expansion of SNO and improve Li ion diffusion abilities during intercalation/deintercalation reaction. As a result, the SNO@NC anode delivers a high reversible capacity of 609.2 mAh g−1 at 100 mA g−1 and 422.4 mAh g−1 at 1000 mA g−1, greatly higher than that of pure SNO (429.2 mAh g−1 at 100 mA g−1 and 166.9 mAh g−1 at 1000 mA g−1). Meanwhile, extremely long cycling stability with a low capacity decay rate (0.017% per cycle over 3000 cycles) has been achieved. This work proposes a novel strategy for engineering hierarchical pore sandwich-like SNO-based anode materials for Li ion batteries.

Nitrogen-Doped Amorphous Carbon/Dual-Phasic TiO2 Nanocomposite Electrodes Derived from Ti-Based Metal–Organic Frameworks Designed with a Mixed Linker Combination for High-Rate Lithium Storage

Nitrogen-Doped Amorphous Carbon/Dual-Phasic TiO₂ Nanocomposite Electrodes Derived from Ti-Based Metal–Organic Frameworks Designed with a Mixed Linker Combination for High-Rate Lithium Storage

γ-Graphyne adjusted diffusion–capacitance behavior of lithium titanate for boosting high-rate and wide-temperature lithium storage

Pursuing high power density and wide-temperature environmental adaptability is vital to broadening the utilization of lithium titanate (LTO) anodes in start-stop batteries of electric vehicles. Here, we introduce γ-graphyne, an emerging carbon allotrope composed of sp- and sp2-hybridized carbon, to encapsulate LTO particles via a one-pot ball milling. γ-Graphyne with a two-dimensional π-conjugated structure contains abundant electron-rich acetylene linkages in favor of fast electron conduction and, more importantly, it is a promising Li-ion host delivering a certain capacitance within the typical potential window of LTO. The optimum LTO/γ-graphyne composite shows outstanding rate capability (83 % retention of 10C compared to 0.5C), long-term cycling stability (91 % retention over 1000 cycles at 2C), and high low-temperature retentivity (102 mAh g−1 at −20 °C after 500 cycles at 1C, 63 % utilization of that at 25 °C). The impressive performance arises from adjusted diffusion–capacitance Li storage behavior with significantly reduced plateau-potential polarization and enhanced interfacial ionic migration capability. This work highlights an electrochemical active, highly conductive alkyne carbon candidate endowing full-climate applications of LTO anodes.

Long-range disordered MoO2 with rich oxygen vacancies for high-rate and durable lithium storage

Transition metal oxides (TMOs) with high theoretical capacity hold great promise to replace the current graphite for lithium-ion battery, but they are limited by unsatisfactory high-rate and cycling stability. Herein, we demonstrated the mechanisms of oxygen vacancies and long-range disordered structure of MoO2-δ for high-rate and durable lithium storage, which aims at solving the trade-off between the capacity and high-rate and/or cycling stability on universal TMOs anodes. Series of experiments and density functional theory results demonstrate that oxygen vacancies in MoO2-δ could increase its electronic conductivity and optimize the Li-ion migration pathway as well as energy barrier for improving the Li-ion migration dynamics and high-rate performance, meanwhile the robust cycling stability of MoO2-δ anode is benefitted from the isotropic character of its long-range disordered structure and the corresponding derived ability to buffer the volume changes. As expected, the target MoO2-δ shows the high discharge capacity (1631.3 mA h g−1 at 0.2 A g−1), excellent rate capability (average capacities of 592.6 mAh g−1 at 8.0 A g−1), and robust cycling stability (1000 cycles without obvious capacity fading even at 5 A g−1). The proposed concept of oxygen vacancies and long-range disordered character of MoO2-δ in lithium storage could be extended to develop other high-performance energy storage materials.

Fast Li-ion conductor additive toward high-rate lithium storage capacity for Li2ZnTi3O8 in lithium-ion batteries

Fast Li-ion conductor additive toward high-rate lithium storage capacity for Li2ZnTi3O8 in lithium-ion batteries

Scalable synthesis of few-layered MoS2/C sandwiched nanocomposites via ionic crystal (NH4)2MoS4 assisted ball-milling method and their enhanced high-rate lithium storage property

Ball milling has been proven to be an efficient method for exfoliating and reassembling heterogeneous layered nanocomposites on a large scale. This study explores the use of ammonium tetrathiomolybdate (NH4)2MoS4, an ion crystal with an octahedral structure, as both a precursor of layered molybdenum disulfide (MoS2) and an intermediate during ball milling to assist in the exfoliation and fragilization of expandable graphite (EG). Due to its ion crystal structure and high hardness, (NH4)2MoS4 can efficiently transfer and magnify the impacting and shearing forces generated during the ball milling process, accelerating the exfoliation and fragmentation efficiency of EG. Moreover, (NH4)2MoS4 is nano-crystallized by the ball milling forces and uniformly distributed on the carbon nanosheets. Electrochemical performance tests indicate that the resulting nanocomposites, with a satisfactory heterogeneous structure, exhibit excellent Li-storage capacity, achieving 529 mA h g−1 after 150 cycles at a high current density of 500 mA g−1. The relationship between the microstructure and improved electrochemical performance, as well as the formation mechanism of the product, is discussed in detail. This study provides a new approach for conveniently constructing nanocomposites using two types of layered materials that offer satisfactory rate capability and cyclability, making them potentially suitable for application in Li-ion batteries.

High-rate lithium storage performance of TiNb2O7 anode due to single-crystal structure coupling with Cr3+-doping

High-rate lithium storage performance of TiNb2O7 anode due to single-crystal structure coupling with Cr3+-doping

Controlled Isotropic Canalization of Microsized Silicon Enabling Stable High-Rate and High-Loading Lithium Storage.

Silicon is attractive for lithium-ion batteries and beyond but suffers large volume change upon cycling. Hierarchical tactics show promise yet lack control over the unit construction and arrangement, limiting stability improvement at the practical level. Here, a protocol is developed as controlled isotropic canalization of microsized silicon. Distinct from the existing strategies, it involves isotropic canalization by honeycomb-like radial arrangement of silicon nanosheets, and canal consolidation by controlled dual bonding of silicon with carbon. The proof-of-concept nitrogen-doped carbon dual-bonded silicon honeycomb-like microparticles, specifically with a medium density of CNSi and COSi bonds, exhibit stable cycling impressively at high rates and industrial-scale loadings. Two key issues involve isotropic canalization facilitating ion transport in all directions of individual granules and controlled consolidation conferring selective ion permeation and securing charge transport. The study highlights the configurational isotropy and interfacial bonding density, and provides insight into rational design and manufacture of silicon and others with industry-viable features.