High-rate Lithium-ion Batteries Research Articles

Gel Polymer Electrolyte Enables Low-Temperature and High-Rate Lithium-Ion Batteries via Bionic Interface Design.

Traditional ethylene carbonate (EC)-based electrolytes constrain the applications of silicon carbon (Si-C) anodes under fast-charging and low-temperature conditions due to sluggish Li+ migration kinetics and unstable solid electrolyte interphase (SEI). Herein, inspired by the efficient water purification and soil stabilization of aquatic plants, a stable SEI with a 3D desolvation interface is designed with gel polymer electrolyte (GPE), accelerating Li+ desolvation and migration at the interface and within stable SEI. As demonstrated by theoretical simulations and experiment results, the resulting poly(1,3-dioxolane) (PDOL), prepared by in situ ring-opening polymerization of 1,3-dioxolane (DOL), creates a 3D desolvation area, improving the Li+ desolvation at the interface and yielding an amorphous GPE with a high Li+ ionic conductivity (5.73 mS cm-1). Furthermore, more anions participate in the solvated structure, forming an anion-derived stable SEI and improving Li+ transport through SEI. Consequently, the Si-C anode achieves excellent rate performance with GPE at room temperature (RT) and low temperature (-40°C). The pouch full cell coupled with LiFePO4 cathode obtains 97.42 mAh g-1 after 500 cycles at 5 C/5 C. This innovatively designed 3D desolvation interface and SEI represent significant breakthroughs for developing fast-charging and low-temperature batteries.

Metal alkoxides: A new type of reversible anode materials for stable and high-rate lithium-ion batteries

Metal-organic compounds have attracted significant attention for lithium-ion battery (LIB) anodes. However, their practical application is severely hindered by the poor structural stability and sluggish Li+ reaction kinetics. Herein, we proposed a new type of metal–organic compound, metal alkoxides, for high-performance LIBs. A series of metal-alkoxide/graphene composites with different transition metal centers and alkoxide anions are prepared to investigate the structural stability, Li-storage ability, and Li+ diffusion kinetics. The results reveal that the metal centers and alkoxide anions have significant influence on the structural stability, molar mass, and electronic structures, which are highly related to the Li-storage performance. Among them, Co-EG/rGO (EG represents the ethylene glycol anion) delivers the best performance involving high specific capacity (975 mAh g−1 at 0.2 A g−1), excellent rate capability (400.8 mAh g−1 at 10 A g−1), and stable cycling performance (86.8 % capacity retention after 600 cycles) due to its stable structure, smaller molar mass, and favorable electronic structure. Moreover, the Li-storage mechanism and solid electrolyte interphase (SEI) evolution of the Co-EG/rGO electrode are studied in detail through multiple ex-situ/in-situ characterizations. This work provides a new type of metal alkoxide anode material for high-rate and long-life LIBs toward practical energy applications.

A highly stable insertion type V1-xTixP solid solution as an anode material for high-rate lithium-ion batteries

As electric vehicles (EVs) grow in popularity, the demand for lithium-ion batteries (LIBs) simultaneously grows, and the fast-charging capability is becoming increasingly important. However, it is generally believed that graphite anode still suffers from a poor rate capability for fast-charging applications, and other insertion-type oxide anodes with a high rate capability exhibit too high Li+-ion insertion/extraction potential, which cannot meet a requirement for high energy density anodes. In this work, the hexagonal structure of V1-xTixP (x = 0.0, 0.25, and 1.0) phases were introduced as insertion-type anode materials for LIBs with a low reaction potential of Li+-ion insertion/extraction. The crystal structure and the corresponding electrochemical reaction mechanism of insertion-type anodes of TiP, VP, and MoP were compared. A facile strategy forming a substitutional solid solution is suggested to improve the electrochemical properties of anode materials by combining the end members among insertion-type VP, TiP, and MoP as forming V1-xTixP and V1-xMoxP compounds. V1-xTixP (x = 0.25) electrode, substituting V atoms with Ti atoms in VP structure, shows excellent long-term cycle stability at 1 A/g with a cycle retention of 87.7 % during 2500 cycles, delivering a two times higher capacity of 211.1 mAh g−1 compared to that of the commercial graphite electrode.

Synthesis and Electrochemical Performance of Na and F Elements Co-Doped LiFePO4/C as a Cathode Material for High-Rate Lithium-Ion Batteries and the Mechanism of Modification

Synthesis and Electrochemical Performance of Na and F Elements Co-Doped LiFePO4/C as a Cathode Material for High-Rate Lithium-Ion Batteries and the Mechanism of Modification

Spontaneous Electrochemical Reconstruction of NiNb2O6@C for High-Rate Lithium-Ion Batteries

Niobium oxides are widely active in the arena of lithium-ion batteries due to their distinctive structure and rapid charging capability, nevertheless facing the serious challenge from their inherently low electrical conductivity. Herein, a molten salt method is proposed to prepare nickel niobate (NiNb2O6) anode materials for lithium-ion batteries, and a carbon coating derived from mesophase pitch is fabricated to construct NiNb2O6@C composites. Importantly, NiNb2O6@C undergoes spontaneous electrochemical reconstruction to generate metallic Ni and amorphous Nb2O5 during the initial charge/discharge cycle. The presence of the outer carbon layer not only serves as a uniform conductive coating to improve the conductivity and thereby deliver superior rate performance, but also effectively inhibits the stripping of Ni0 to guarantee a great cycling stability. The synergistic effects of the dual conductive interfaces, consisting of the carbon layer and the Mott-Schottky heterojunction between amorphous Nb2O5 and metallic Ni, culminate in exceptional electrochemical performance. Specifically, NiNb2O6@C-10% delivers impressive specific capacity of 436.3 mAh g−1 at 0.5C and conspicuous cycling stability, maintaining 86.3% capacity retention after 800 cycles at 10C. This work underscores the substantial potential of nickel niobate anode materials in advancing the development of next-generation lithium-ion batteries.

Melamine Polymerization Promotes Compact Phosphorus/Carbon Composite for High-Performance and Safe Lithium Storage.

Phosphorus is regarded as a promising material for high-performance lithium-ion batteries (LIBs) due to its high theoretical capacity, appropriate lithiation potential, and low lithium-ion diffusion barrier. Phosphorus/carbon composites (PC) are engineered to serve as high-capacity high-rate anodes; the interaction between phosphorus and carbon, long-term capacity retention, and safety problems are important issues that must be well addressed simultaneously. Herein, an in situ polymerization approach to fabricate a poly-melamine-hybridized (pMA) phosphorus/carbon composite (pMA-PC) is employed. The pMA hybridization enhances the density and electrical conductivity of the PC, improves the structural integrity, and facilitates stable electron transfer within the pMA-PC composite. Moreover, the pMA-PC composite exhibits efficient adsorption of lithium polysulfides, enabling stable transport of Li+ ions. Therefore, the pMA-PC anode demonstrates a high specific charging capacity of 1,381mAhg-1 at 10Ag-1, and a great capacity retention of 86.7% at 1Ag-1 over 500 cycles. The synergistic effect of phosphorus and nitrogen further confers excellent flame retardant properties to the pMA-PC anode, including self-extinguishing in 2.5s, and a much lower combustion temperature than PC. The enhanced capacity and safety performance of pMA-PC show potential in future high-capacity and high-rate LIBs.

High-rate lithium-ion battery performance of a ternary sea urchin-shaped CoNiO2@NiP6Mo18/CNTs composites

Bimetallic oxides are attractive anode materials for lithium-ion batteries (LIBs) due to their large theoretical capacity. However, the low conductivity, short cycle life, and poor rate capability are the bottlenecks for their further applications. To overcome above issues, the basket-like polymolybdate (NiP6Mo18) and carbon nanotubes (CNTs) were uniformly embedded on the urchin-shaped CoNiO2 nanospheres to yield a ternary composites CoNiO2@NiP6Mo18/CNTs via electrostatic adsorption. The multi-level morphology of urchin spinules accelerates the diffusion rate of Li+; CNT improves the conductivity and enhances cycle stability of the material; and heteropoly acid contributes more redox activity centres. Thus, CoNiO2@NiP6Mo18/CNTs as an anode of LIBs exhibits a high initial capacity (1396.7 mA h g−1 at 0.1 A g−1), long-term cycling stability (750.2 mA h g−1 after 300 cycles), and rate performance (450.3 mA h g−1 at 2 A g−1), which are superior to reported metallic oxides anode of LIBs. The density functional theory (DFT) and kinetic mechanism suggest that CoNiO2@NiP6Mo18/CNTs delivers an outstanding pseudocapacitance and rapid Li+ diffusion behaviors, which is due to the rich surface area of the urchin-like CoNiO2 with the uniform embeddedness of NiP6Mo18 and CNTs. This study provides a new idea for optimizing the performance of bimetallic oxides and developing high-rate lithium-ion battery composites.

Boehmite-PVDF-CTFE/F-PI composite separator irradiated by electron beam for high-rate lithium-ion batteries

As an important part of the fields such as renewable energy and electric vehicles, electrochemical energy storage technology faces significant challenges in improving energy density, extending battery life and improving safety. We successfully prepared a composite battery separator of polyvinylidene fluoride-chlorotrifluorinylene (PVDF-CTFE) and fluorinated polyimide (F-PI) -based materials, mixed it with different contents of boehmite nanoparticles, and then modified it by different doses of electron beam irradiation to improve the performance, especially to overcome the problem of maintaining capacity decline in high-speed charging environment. The results showed that the prepared battery separators exhibited outstanding thermal stability, electrochemical properties and ionic conductivity with 12 % boehmite nanoparticles. After 1000 high-speed charge and discharge cycles in current density of 10C, the battery based on the modified separator still maintained a capacity retention rate of 84.4 %, with the initial discharge specific capacity of 111.9 mAhg−1. This means that irradiated separators not only maintain a high energy density in a high-speed charging environment, but also overcome the problem of maintaining capacity decline. Electron beam irradiation further improved the comprehensive performance of the separator. After 1000 and 1500 cycles at the current density of 10C and 15C, the specific discharge capacity of the battery can still retain more than 90 % and 80 % of the initial specific discharge capacity, which provides a longer life in practical applications.

Free-standing ultra-thin carbon nanofiber films with controllable thickness for lithium ion batteries

Thin and porous anode materials enable short ion migration distances and high-rate performance. However, the current freestanding anode materials are too thick (typically around 100 μm) for high-rate lithium ion batteries (LIBs). Here, we have developed a facile and scalable process to synthesize ultra-thin (<400 nm) freestanding films. In comparison to other chemical and physical deposition methods that yield thin films (<500 nm), our freestanding films do not require the substrate material, achieving a 100 % loading of active material. Our ultra-thin carbon nanofiber films exhibit an exceptional specific capacity of 599 mAh/g even after 10,000 cycles at a current density of 10 A/g. Compared to thick carbon nanofiber films, the utilization of ultra-thin carbon nanofiber films as anode materials exhibits a remarkable enhancement of more than tenfold in cycling performance

High-Rate Performance of a Designed Si Nanoparticle–Graphite Nanosheet Composite as the Anode for Lithium-Ion Batteries

A silicon nanoparticle–graphite nanosheet composite was prepared via a facile ball milling process for use as the anode for high-rate lithium-ion batteries. The size effect of Si nanoparticles on the structure and on the lithium-ion battery performance of the composite is evaluated. SEM and TEM analyses show a structural alteration of the composites from Si nanoparticle-surrounded graphite nanosheets to Si nanoparticle-embedded graphite nanosheets by decreasing the size of Si nanoparticles from 250 nm to 40 nm. The composites with finer Si nanoparticles provide an effective nanostructure containing encapsulated Si and free space. This structure facilitates the indirect exposure of Si to electrolyte and Si expansion during cycling, which leads to a stable solid–electrolyte interphase and elevated conductivity. An enhanced rate capability was obtained for the 40 nm Si nanoparticle–graphite nanosheet composite, delivering a specific capacity of 276 mAh g−1 at a current density of 1 C after 1000 cycles and a rate capacity of 205 mAh g−1 at 8 C.

Three-dimensional porous polyimide anode for high-rate lithium ion batteries

Polymeric electrode materials are widely used in many applications but still suffer from poor electrical conductivity and slow transport kinetics, especially poor performance at high current densities. Herein, a polyimide electrode structure with 3D-ordered interconnected gradient pores was developed to improve the lithium-ion transport efficiency. The homogeneous mixed PMTA-PMMA composite was prepared by a simple one-pot method, followed by removal of PMMA (polymethyl methacrylate) spherical porogenic agent during the synthesis of polyimide material at high temperatures to form a low curvature gradient-pore structure. The large pores in the electrode enhanced the ion transport ability and improved the electrolyte infiltration rate, while the small pores improved the active specific surface area and guided the deposition of lithium ions. As a result, a high specific capacity reaching 907 mAh/g was maintained even after 1000 cycles at 5 A/g, a value about 3-fold that of un-pored electrode materials. The experimental studies and DFT calculations were used to develop a 24Li storage mechanism of PMTA, and the active electrode material was fully electrochemically activated by the constructed three-dimensional porous electrode structure. Overall, the proposed porous material with a high active area and porosity looks potential for use as an ultra-fast charging and discharging electrode of lithium-ion batteries with high specific capacity and excellent cycling performance.

Cation mixing regulation of cobalt-free high-nickel layered cathodes enables stable and high-rate lithium-ion batteries

The cobalt-free high-nickel layered oxide possesses high capacity and controllable cost, positioning it as a prospective option for cathode materials in the future lithium-ion batteries (LIBs). However, the charge compensation effect and high nickel content usually cause serious cation mixing, resulting in poor capacity stability, and hindering its practical application. Here, three types of LiNi0.9Mn0.1O2 microspheres with varying levels of cation mixing are constructed by simply adjusting the calcination temperatures, and the impacts of cation mixing on the electrochemical performance in LIBs are systematically investigated. By using XRD and cross-section STEM to characterize the levels of cation mixing, the resulting LiNi0.9Mn0.1O2 after treated at 780 °C (denoted as NM91–780) shows a lower degree of cation mixing compared to other samples (NM91–720 and NM91–840). As a proof-of-concept application in LIBs, the NM91–780 exhibits remarkable cycling stability with 92.4% capacity retention after 100 cycles, along with excellent rate capability of 132.5 mAh g−1 at 10 C. In situ XRD analysis shows that the low cation mixing of NM91–780 inhibits harmful volumetric strain during the electrochemical process, providing structural and chemical stability for its long-term cycling. This investigation contributes to the advancement of commercializing cobalt-free high-nickel layered oxide LiNi0.9Mn0.1O2 for use in LIBs.

Surface surgery on TiNb2O7 electrode via N2/Air atmospheric pressure plasma jet for high-rate lithium-ion battery anode

TiNb2O7 (TNO) is regarded as a potential anode material for its high capacity compared to Li4Ti5O12 and high safety due to its adequate Fermi level in lithium-ion batteries. This work represents a promising method of modifying the electrode, which includes polyvinylidene fluoride (PVDF), conductive carbon, and TiNb2O7, using an atmospheric pressure plasma jet (APPj) treatment. Our results reveal that atmospheric pressure plasma jet improves the electrochemical performance by N-doped decoration on conductive carbon, electrolyte wettability enhancement on polyvinylidene fluoride binder, and defects manufacturing in TiNb2O7 anode materials. Good wettability of surface free energy to 44.6 mJ/m2 in the APPj-treated (APP-10) sample contributes to improved cycling performance. Both N-doped carbon and modified TiNb2O7 promote the high-rate capability. The C-rate performance of APP-10 improves by over 200 % at 10C compared to the non-treated sample (APP-0). APP-10 sample also shows 81.9 % retention after 300 cycles at 1C. The formation of Li3N or LiNxOy after cycling due to the nitro-group in the electrode with atmospheric pressure plasma jet offers good protection and high ionic-conductivity interface. This work demonstrates a potential solution to achieve a roll-to-roll modification without any complex synthesis processes, which is a promising technology for the affordable manufacturing of lithium-ion battery.

Ultrafine VN quantum nanodots anchored in three-dimensional porous N-doped carbon with excellent pseudocapacitive behaviour for high rate lithium-ion batteries

Vanadium nitride (VN) is an attractive anode material for lithium-ion batteries (LIBs) owing to its large theoretical capacity and excellent electrical conductivity; however, its low rate performance and poor cycle...

Failure mechanisms of the Li(Ni0.6Co0.2Mn0.2)O2-Li4Ti5O12 lithium-ion batteries in long-time high-rate cycle.

With the ever-growing widespread use of lithium-ion batteries in heavy machinery and daily life, the demand for improved longevity and high-rate performance is escalating. While Li4Ti5O12 (LTO) batteries excel in safety and cycling performance, their full potential for long-term, high-rate cycling still yet remains unrealized. In this paper, we present an analysis of a pouch battery with an LTO anode system that was cycled for an extended period at high rates. We compared the performance changes and internal component properties between fresh and cycled batteries. Our results reveal that, after tens of thousands of high-rate cycles, microcracks emerged on the cathode electrode material (NCM622) particles of the battery, whereas the LTO remained largely unchanged. Additionally, we observed significant electrolyte reduction, characterized the separator surface, and measured its properties. Our findings indicate that the electrolyte reactions are the primary cause of battery failure, leading to capacity fading and impedance increase. This research provides valuable insights into the failure mechanisms of lithium-ion batteries at high rates, thus contributing to the improvement of high-rate lithium-ion batteries.

Expanded graphite incorporated with Li4Ti5O12 nanoparticles as a high-rate lithium-ion battery anode.

Due to their small interlayer spacing and a low lithiation potential close to Li+ deposition, current graphite anodes suffer from weak kinetics, and lithium deposition in a fast-charging process, hindering their practical application in high-power lithium-ion batteries (LIBs). In this work, expanded graphite incorporated with Li4Ti5O12 nanoparticles (EG/LTO) was synthesized via moderate oxidization of artificial graphite following a solution coating process. The EG/LTO has sufficient porosity for fast Li+ diffusion and a dense Li4Ti5O12 layer for decreased interface reaction resistance, resulting in excellent fast-charging properties. EG/LTO presented a high reversible capacity of 272.8 mA h g-1 at 3.74 A g-1 (10C), much higher than that of the original commercial graphite (50.1 mA h g-1 at 10C) and even superior to that of hard carbon. In addition, EG/LTO exhibited capacity retention rate of 98.4% after 500 cycles at 10C, demonstrating high structural stability during a long cycling process. This study provides a protocol for a solution chemistry method to prepare fast-charging graphite anode materials with high stability for high-power LIBs.

Melt-Spinning Mesophase Pitch-Based Graphite Fibers as Anode Materials for High-Rate Lithium-Ion Batteries

Lithium-ion batteries have rapidly become the most widely used energy storage devices in mobile electronic equipment, electric vehicles, power grid energy storage devices and other applications. Due to their outstanding stability and high conductivity, carbon materials are among the most preferred anode materials for lithium-ion batteries. In this study, mesophase pitch-based graphite fibers (GFs) were successfully prepared through melt-spinning, thermo-oxidative stabilization, carbonization and graphitization and used as anode materials. The radial fiber structure can lower the activation energy and minimize the distance of the Li+ diffusion, while the highly conductive cross-linked network within the fibers benefits the speed up charge transmission. Thus, the as-synthesized graphite fibers demonstrate superior rate capability and cycle stability. GFs exhibit a capacity retention rate of 97.94% and reversible capacity of 327.8 mA h g−1 after 100 cycles at 0.1 C, which is higher than that of natural graphite anode materials (85.66% and 289.7 mA h g−1, respectively). Moreover, the as-synthesized graphite fibers deliver a capacity retention of 64.7% at a high rate of 5 C, which is considerably higher than that of natural graphite (19.7%).

Glucose promoted synthesis of homogeneously embedded black phosphorus carbon composite with enhanced lithium storage performance

Black phosphorus (BP) has attracted extensive attention in high-rate lithium-ion batteries due to its high theoretical capacity and moderate lithiation potential. However, the large volume expansion and the low conductivity of BP nanostructures in the electrochemical cycle have inhibited the rate performance and long-term cycle stability. In this paper, by combining the glucose-assisted ball-milling and carbonization method, a black-phosphorus/carbon (BP@C) composite anodic material is developed, in which the nano-sized BP nanoparticles are homogeneously embedded in the amorphous carbon matrix. Both the phosphorus-oxygen-carbon bonds and the phosphorus-carbon bonds improve the cross-link between BP and the surface-coated carbon matrix. The unique well-embedded structure promotes the cycling stability and the rate performance of BP@C. The composite shows a high discharge specific capacity of about 1881 mAh g−1 at 0.1 A g−1, the specific capacity at 4 A g−1 is about 63% of the low current capacity, and the discharge specific capacity retains 1130 mAh g−1 after 300 charge-discharge cycles at 0.5 A g−1. Moreover, the significant role of the active unsaturated groups for building the well-embedded composite is further revealed. These results indicate that dual regulation of surface coating and structure optimization offers great potential for further optimizing phosphorus-based anode materials.

A long service life silicon-doped laser-etched polyimide anode materials for high-rate lithium-ion battery

Silicon (Si)-based materials emerge as promising anode materials owing to their theoretical capacity as high as 4200 mAh g−1. However, when Si-based materials are assembled into battery anode sheets, they face the dilemmas of severe volume expansion and poor electric conductivity. In this study, three-dimensional (3D) layered porous Si‑carbon (C) composites are designed and fabricated from a polyimide (PI) precursor through cyclization polymerization and laser etching. SiC particles are dispersed in the porous network structure, which reduces the volume expansion of the anode during charging and discharging, so that the electrode has good cycle life and specific capacity. The laser-etched Si-doped polyimide (L-Si-PI) anode achieves 1332 mAh g−1 capacity in the first discharge and a high capacity of 1057 mAh g−1 after 1500 cycles at 0.2 A g−1 for half lithium-ion batteries (LIBs). When the L-Si-PI is employed for full LIBs, it exhibits a specific capacity of 142 mAh g−1 at 0.1C with 800 cycles working life. And kinetic analysis reveals a diffusion-controlled lithium storage mechanism in the composite. In a word, such rational nanostructure design and multi-component synergic interaction system has a good application prospect in the field of LIB research.

Oxygen Defect and Cl--Doped Modulated TiNb2O7 Compound with High Rate Performance in Lithium-Ion Batteries.

TiNb2O7 has attracted extensive attention from lithium-ion battery researchers due to its superior specific capacity and safety. However, its poor ion conductivity and electron conductivity hinder its further development. To improve the ion/electron transport of TiNb2O7, we report that chlorine doping and oxygen vacancy engineering regulate the energy band and crystal structure simultaneously through a simple solid-phase method. NH4Cl was used to realize Cl- doping and oxygen vacancy production. A Rietveld refinement demonstrates an effective substitution of Cl in the O sites of Nb-O octahedra, with an enlarged crystal plane spacing. The oxygen vacancies provide more active sites for lithium intercalation. The diffusion coefficient of Li+ is inceased from 2.39 × 10-14 to 1.50 × 10-13 cm2 s-1, which reveals the positive influence of Cl- doping and oxygen vacancies on the promoted Li+ transport behavior. Charge compensation is introduced by the doping of Cl- and the generation of oxygen vacancies, leading to the formation of Ti3+ and Nb4+ and the adjustment of the electronic structure. DFT calculations reveal that TiNb2O7 with Cl- doping and an O vacancy shows a metallic property with a finite value at the Fermi level, which is conducive to electron transfer in the electrode material. Benefiting from these advantages, the modified TiNb2O7 presents superior rate performance with a commendable capacity of 172.82 mAh g-1 at 50 C. This work provides guidance to design high-performance anode materials for high-rate lithium-ion batteries.