Advanced Lithium-ion Batteries Research Articles

Solar irradiated construction of coordinatively unsaturated Znx+ (0

Biomass-derived carbon is regarded as a potential replacement for commercial graphite carbon for the anode of powerful lithium-ion batteries (LIBs), because of its abundance and ecological advantage. In this research, biomass-derived carbon is prepared from natural Carex meyeriana Kunth, and the biomass-derived carbon electrode with coordinatively unsaturated Znx+(0 < x < 2) sites is synthesized by solar irradiation. The Znx+(0 < x < 2) electrode is used as the LIBs anode. It provides a highly specific capacity of 638.6 mAh g−1 at 200 mA g−1 after 900 cycles and an outstanding cycling capacity of 614.9 mAh g−1 at 1000 mA g−1 after 1000 cycles. The capacity of the electrode exceeds the majority of reported carbonaceous anodes. This study presents a practical strategy to prepare novel and low-cost carbonaceous anode. The resulting anode has promising potential for use in advanced LIBs and other energy storage devices due to its excellent Li+ storage capability.

In-situ construction of Ti3C2TX/Ni-HHTP heterostructure as anode for lithium-ion batteries

Pursuing anode materials with high specific capacity and long cycle stability is critical for advanced lithium-ion batteries (LIBs). Metal-organic frameworks (MOFs) with high specific surface area, regular pore channels, and multiple active sites are promising anode materials for LIBs. However, the poor electronic conductivity limits their application in LIBs. Thus, introducing some conducting materials is necessary. MXene, known for its excellent electronic conductivity in electrochemical energy storage systems, is an ideal candidate. Herein, a heterostructure composite material (Ti3C2TX/Ni-HHTP) that combines the advantages of both MOFs and MXene has been synthesized via an in-situ growth method, the composite exhibits regular pore channels, enhanced electronic conductivity, and excellent stability. When it is used as an anode material in LIBs, the composite presents satisfying rate performance and cycling stability. The initial discharge capacity of the Ti3C2TX/Ni-HHTP electrode exhibits 424.4 mA h g−1 at 0.5 A g−1 and remains at 390.2 mA h g−1 after 800 cycles with a capacity retention rate of 92.0%. This design strategy provides valuable insights into constructing MOF hybrid materials with enhanced electronic conductivity for various electrochemical applications.

Crystallization-induced formation of two-dimensional carbon nanosheets derived from sodium lignosulfonate for fast lithium storage

Sodium lignosulfonate, an abundant natural resource, is regarded as an ideal precursor for the synthesis of hard carbon. The development of high-performance, low-cost and sustainable anode materials is a significant challenge facing lithium-ion batteries (LIBs). The modulation of morphology and defect structure during thermal transformation is crucial to improve Li+ storage behavior. Synthesized using sodium lignosulfonate as a precursor, two-dimensional carbon nanosheets with a high density of defects were produced. The synergistic influence of ice templates and KCl was leveraged, where the ice prevented clumping of potassium chloride during drying, and the latter served as a skeletal support during pyrolysis. This resulted in the formation of an interconnected two-dimensional nanosheet structure through the combined action of both templates. The optimized sample has a charging capacity of 712.4 mA h g−1 at 0.1 A g−1, which is contributed by the slope region. After 200 cycles at 0.2 A g−1, the specific charge capacity remains 514.4 mA h g−1, and a high specific charge capacity of 333.8 mA h g−1 after 800 cycles at 2 A g−1. The proposed investigation offers a promising approach for developing high-performance, low-cost carbon-based anode materials that could be used in advanced lithium-ion batteries.

Formulating Electron Beam-Induced Covalent Linkages for Stable and High-Energy-Density Silicon Microparticle Anode.

High-capacity silicon (Si) materials hold a position at the forefront of advanced lithium-ion batteries. The inherent potential offers considerable advantages for substantially increasing the energy density in batteries, capable of maximizing the benefit by changing the paradigm from nano- to micron-sized Si particles. Nevertheless, intrinsic structural instability remains a significant barrier to its practical application, especially for larger Si particles. Here, a covalently interconnected system is reported employing Si microparticles (5 µm) and a highly elastic gel polymer electrolyte (GPE) through electron beam irradiation. The integrated system mitigates the substantial volumetric expansion of pure Si, enhancing overall stability, while accelerating charge carrier kinetics due to the high ionic conductivity. Through the cost-effective but practical approach of electron beam technology, the resulting 500 mAh-pouch cell showed exceptional stability and high gravimetric/volumetric energy densities of 413 Wh kg-1, 1022 Wh L-1, highlighting the feasibility even in current battery production lines.

Active balancing circuit for advanced lithium-ion batteries used in photovoltaic application

An approach to the analysis and design of a bidirectional DC power converter for the cell voltage balancing control of a series connected lithium-ion battery string is presented in this paper. The proposed Cell Balancing Circuit (CBC) is designed to transfer the energy from the fully charged battery cell to the weakest one using a switch mode power converter operation. This operation maintains cell batteries at the same State-Of-Charge (SOC) and voltage range. Unlike previous battery balancing circuits, the balancing method uses only one magnetic component, resulting small size system. Simulation and experimental results show that the proposed cell balancing method can not only enhance the bidirectional battery equalization performance, but can also reduce the switching loss during the equalization period. Experiment results are provided to verify the operating principle of the proposed balancing method. Specific conditions of experiments are used to reproduce photovoltaic operations

Plasma enhanced reduction method for synthesis of reduced graphene oxide fiber/Si anode with improved performance

Silicon (Si) is considered as one of the most promising anode materials for advanced lithium-ion batteries due to its high theoretical capacity, environmental friendliness, and widespread availability. However, great challenges such as volumetric expansion, limited ionic/electronic conductivity properties and complex manufacturing processes hinder its practical applications. Herein, a novel plasma-enhanced reduced graphene oxide fibers/Si (PrGOFs/Si) composite anode is first proposed by using wet-spinning technology followed by plasma-enhanced reduction method. The PrGOFs provide large space to accommodate the volume expansion of Si nanoparticles (SiNPs) by forming a flexible 3D conductive network. Compared to the conventional thermally reduced graphene oxide fibers/Si (TrGOFs/Si) sample, the PrGOFs/Si anodes demonstrate higher conductivity, specific surface area, and superior fabrication efficiency. Accordingly, the PrGOFs/Si anodes exhibit a reversible capacity of 698.3 mAh/g, and maintain a specific capacity of 602.5 mAh/g at a current density of 200 mA/g after 100 cycles, superior to conventional TrGOFs/Si counterparts. This research presents a novel strategy for the preparation of high-performance Si/carbon anodes for energy storage applications.

Intimately mixed copper, cobalt, and iron fluorides resulting from the insertion of fluorine into a LDH template.

The advancement of lithium-ion batteries (LIBs) with high performance is crucial across various sectors, notably in space exploration. This advancement hinges on the development of innovative cathode materials. Our research is dedicated to pioneering a new category of cathodes using fluorinated multimetallic materials, with a specific focus on diverging from the traditional Ni, Co, and Mn-based NMC chemistries by substituting nickel and manganese with copper and iron which are more sustainable elements. Our goal is also to enhance the robustness of cathodes upon cycling by substituting oxygen with fluorine as the metal-ligand. To achieve this, an intimate composite blend of CuF2 and FeF3, through the multi-metallic template fluorination (MMTF) methodology using a layered double hydroxide (LDH) as a precursor has been designed. Each of these components was carefully selected for its distinct attributes, including high redox potential, elevated energy density, substantial theoretical capacity, and improved cyclability. The composition denoted as (Cu1.5Co0.5)2+(Fe0.75Al0.25)3+ has been selected for fluorination because it maximizes Fe3+ and Cu2+ amount in the screened LDHs. Subsequently, this particular LDH was fluorinated through solid-gas fluorination at different temperatures (200, 350, and 500 °C) using gaseous molecular fluorine (F2). A comprehensive characterization of these materials using various techniques, including X-ray diffraction (XRD), 57Fe Mössbauer spectrometry, scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX), and inductively coupled plasma analyses (ICP-AES) was conducted, and the evolution of LDH upon fluorination has revealed an intermediate porous texture particularly sensitive to hydration. Two original crystallographic phases are else obtained by fluorination: one formed by the hydration of the amorphous intermediate compound: Cu3Fe1.5Al0.5F12(H2O)12 an anti-perovskite structure and another stabilized through the combination of solid gas fluorination and LDH precursor yielding an original CoFeF5-type phase. Raman operando during cyclic voltammetry measurement applied on a sample fluorinated at 500 °C and used as a cathode in front of lithium metal was finally conducted to validate redox activity and mechanism.

Achievements, challenges, and perspectives in the design of polymer binders for advanced lithium-ion batteries

The design of binders for lithium-ion batteries is highlighted, with an emphasis on key parameters affecting device performance and failure mechanisms. These issues are discussed in detail using the example of a silicon anode and a sulfur cathode.

Fast-charging anodes for lithium ion batteries: progress and challenges.

Slow charging speed has been a serious constraint to the promotion of electric vehicles (EVs), and therefore the development of advanced lithium-ion batteries (LIBs) with fast-charging capability has become an urgent task. Thanks to its low price and excellent overall electrochemical performance, graphite has dominated the anode market for the past 30 years. However, it is difficult to meet the development needs of fast-charging batteries using graphite anodes due to their fast capacity degradation and safety hazards under high-current charging processes. This feature article describes the failure mechanism of graphite anodes under fast charging, and then summarizes the basic principles, current research progress, advanced strategies and challenges of fast-charging anodes represented by graphite, lithium titanate (Li4Ti5O12) and niobium-based oxides. Moreover, we look forward to the development prospects of fast-charging anodes and provide some guidance for future research in the field of fast-charging batteries.

Tuning wettability of gallium-based liquid metal anode for lithium-ion battery via a metal mixing strategy

Exploring highly stable alloy-type anodes for rechargeable lithium batteries is urgent with the ever-increasing demands for high energy density batteries. The liquid metal (LM)-based anodes demonstrate great potential in advanced lithium-ion batteries due to their high energy densities and self-healing performance. However, its high surface tension leads to poor wettability towards the current collector and higher interfacial contact resistance. In this study, we developed a new free-standing LM-based anode LM-W10/Cu foil with good wettability and machinability by mixing high-melting-point tungsten (W) nanoparticles. It greatly improves the inherent defects of poor interfacial contact and lithium diffusion kinetics between the LM and current collectors, reduces the tedious and costly electrode manufacturing process, and regulates lithium deposition behaviors. And this metal mixing strategy has a negligible effect on the self-healing nature of LM. Symmetric cells of LM-W10/Cu foil anodes displayed a low overpotential (~13 mV) and cycled stably for more than 8,000 h (4,000 cycles) at 0.5 or 1 mA/cm2; full cells coupled with LiFePO4 cathode showed a high capacity retention of 95.15% after 150 cycles.

One-dimensional van der Waals transition metal chalcogenide as an anode material for advanced lithium-ion batteries

1D vdW Nb2Se9 is a promising advanced anode material for LIBs due to superior electrochemical performance originating from its unique structural properties, which allow swift transport of Li ions and buffer the volume changes during Li-ion storage.

Hierarchical flower-like N-doped Nb2O5@N-doped carbon composites as superior anodes for advanced lithium-ion batteries

Hierarchical flower-like N-doped Nb2O5@N-doped carbon composites as superior anodes for advanced lithium-ion batteries

Laser-Induced Printing of Next Generation Silicon-Graphite Anodes for the Development of Advanced Lithium-Ion Batteries

The expansion of renewable causing a rising demand for affordable and improved energy storage systems. Lithium-ion batteries (LIB) are one of the most promising technologies for this achievement, with further improvements to be made in terms of new materials and an advanced electrode architecture. As a new generation electrode material to be included in LIB, silicon is in the focus of the today’s investigations. Silicon offers one order of magnitude higher theoretical specific capacity (3579 mAh/g) compared to the state-of-the-art material graphite (372 mAh/g). However, during lithiation of silicon a volume expansion of up to 300 % takes place. Due to the huge volume expansion tremendous mechanical degradation of the anode occurs, resulting in a drop in capacity and a shorten lifetime.Laser induced forward transfer (LIFT) is applied in this study as printing technology to develop enhanced silicon-graphite electrode compositions and electrode architectures. LIFT was performed using a pulsed nanosecond UV-laser with a maximum power of 10 W and repetitions rate of up to 30 kHz. For the LIFT process of anodes, polyacrylic acid (PAA) is used as binder, in contrast to the polyvinylidene fluoride (PVDF) binder commonly used for LIFT assisted printing of electrodes. PAA is a more appropriate binder for silicon-containing anodes than PVDF. In addition, also a customized architecture using subtractive and additive laser process techniques is introduced for an increase in lifetime of batteries containing silicon-based electrodes. For this purpose, graphite electrodes were structured with an ultrashort pulse laser with pattern widths of 100 µm. Subsequently, silicon rich slurry was printed into the patterns to increase the areal capacity. The as-prepared electrodes have spatially separated graphite and silicon regions. The respective electrodes were electrochemically cycled in half-cells and charged at different C-rates up to 5C to investigate their lithiation capability. After the rate capability analysis, the cells were cycled at C/2 to investigate the long-term degradation. The cells with the printed electrodes were cycled for more than 450 cycles with a capacity fade of 5 %. At their end-of-life, the cells were analyzed post-mortem. Finally, full-cells were assembled with cathodes containing NMC 622 as the active cathode material. Subsequently to the cell priming a lifetime analysis was performed at a C-rate of C/2 and cycle stability as well as lithium loss during cycling were evaluated.

Non-Newtonian Dynamics in Water-in-Salt Electrolytes.

Water-in-salt electrolytes have attracted considerable interest in the past decade for advanced lithium-ion batteries, possessing important advantages over the non-aqueous electrolytes currently in use. A battery with a LiTFSI-water electrolyte was demonstrated in which an operating window of 3 V is made possible by a solid-electrolyte interface. Viscosity is an important property for such electrolytes, because high viscosity is normally associated with low ionic conductivity. Here, we investigate shear and longitudinal viscosities using shear stress and compressional longitudinal stress measurements as functions of frequency and concentration. We find that both viscosities are frequency-dependent and exhibit almost identical frequency and concentration dependences in the high-concentration region. A comparison to quasielastic neutron scattering experiments suggests that both are governed by structural relaxation of the TFSI- network. Thus, LiFTSI-water electrolytes appear to be an unusual case of a non-Newtonian fluid, where shear and longitudinal viscosities are determined by the same relaxation mechanism.

Development of Moisture Absorbent Ceramic-Coated Separators for Advanced Lithium-Ion Batteries

In the present human life, various electric devices and machines are worked by lithium-ion batteries (LIBs). The batteries have still remained challenges such as, the low cycling stability due to side reactions during charge-discharge cycling and the weak thermal stability at high temperatures. Accordingly, research on improving resistance to high temperatures and impregnability by coating ceramic particles and polymer binders on the surface of the separator is being conducted. The ceramic coating separator is manufactured by connecting small-sized inorganic particles to each other using a small amount of binder. The inorganic particles have high hydrophilicity and high specific surface area, so the ceramic separator has excellent wettability to the electrolyte. As a ceramic coating, alumina is currently commercialized, and a slurry is prepared by mixing a binder, etc., and then coated on a separator and then dried. LG Energy Solutions has commercialized a ceramic composite separator called SRS (Safety-reinforcing separator) and is applying it to batteries. By introducing a ceramic layer on the surface of a polyolefin-based separator, the heat resistance and mechanical strength of the separator have been greatly improved, and it has been widely used in high-capacity and large-sized batteries. when the temperature of the LIBs rises and the separator shrinks or ruptures, a large amount of lithium ions may move, making control difficult and creating a risk of explosion. Therefore, shutdown occurs, but a separator with good shape retention at high temperature is required. Accordingly, research on improving resistance to high temperatures by coating ceramic particles and a polymer binder on the surface of the separator is being conducted. In this work, Ceramic-coated separator membrane film was fabricated using aluminum fluoride (AlF3) materials for a powerful moisture (H2O) scavenger. Accordingly, research on improving high temperature resistance and impregnation property by coating ceramic particles and a polymer binder on the surface of the separator is in progress. First of all, a-AlF₃ nanorods with an average length of 1.882 μm and a diameter of 320 nm were synthesized under low supersaturation conditions. Then, PVdF-HFP [Poly(vinylidene fluoride-co-hexafluoropropylene)]-acetone solution was mixed and coated on a polypropylene membrane. The AlF₃-coated separator exhibited thermal shrinkage of 4%, 8%, and 18% at 130, 140, and 150°C, respectively, confirming that thermal stability was improved. In addition, as a result of the impregnation test, it was confirmed that the impregnation property of the coated separator was improved compared to the existing polypropylene separator. In addition, it was confirmed that the full cell manufactured using the a-AlF₃-coated membrane film has improved cycle stability and high-speed, high-capacity compared to the full cell manufactured using the existing non-coated separator.

(Invited) Impact of Binder Selection in Advanced Lithium Battery Electrode Fabrication and Performance

Polymer based binder plays an important role in electrode structures for varies energy storage systems such as battery and capacitor. In conventional wet coating process for battery electrode fabrication process, the polymer binders are mixed with the active material and conductive additives to form the slurry for the coating. The binders provide both physical and chemical supporting to the overall electrode structure, in addition to the basic “gluing” function. In recent years, a lot of aqueous soluble polymers were introduced in lithium-ion battery study working as alternative of traditional PVDF binder. The application of aqueous based polymer binder covers graphite, silicon, metal oxide, and even sulfur electrode fabrication. In this talk we will present some of our recent study on selected polymer binders in certain chemistry, such as Li-S system. We will reveal the difference in both physical and chemical properties of the selected binders, as well as the impact on the overall electrochemical performance. We will also discuss the binder selection and challenges from manufacturing point of view.

Fluorinated polymer coated cyanoethyl-chitin nanofiber composite separators for high performance lithium ion batteries

Natural polymer nanofiber-based separators with excellent thermal stability, mechanical strength, and electrolyte wettability have shown great potentials for advanced lithium ion batteries. However, there are two crucial issues to block their practical applications, including high moisture absorption and interfacial instability toward electrodes. Here, a surface coating strategy to overcome these disadvantages and promote natural polymer nanofiber-based separator performance is demonstrated. A hydrophobic polymer, poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), is adopted to coating on the surface of cyanoethyl-chitin nanofiber (CCN) separators. The as-fabricated CCN/PVDF-HFP composite separators not only exhibit much lower moisture absorption and higher interfacial instability but also retain high mechanical strength and ionic conductivity in comparison to CCN separators. The LiFePO4/Li cells using CCN/PVDF-HFP separators exhibit much better electrochemical cycle performance and enhanced capacity retention than that using CCN separators.

Reduced Graphene Oxide Coating LiFePO4 Composite Cathodes for Advanced Lithium-Ion Battery Applications.

Recently, the application of LiFePO4 (LFP) batteries in electric vehicles has attracted extensive attention from researchers. This work presents a composite of LFP particles trapped in reduced graphene oxide (rGO) nanosheets obtained through the high-temperature reduction strategy. The obtained LiFePO4/rGO composites indicate spherical morphology and uniform particles. As to the structure mode of the composite, LFP distributes in the interlayer structure of rGO, and the rGO evenly covers the surface of the particles. The LFP/rGO cathodes demonstrate a reversible specific capacity of 165 mA h g-1 and high coulombic efficiency at 0.2 C, excellent rate capacity (up to 10 C), outstanding long-term cycling stability (98%) after 1000 cycles at 5 C. The combined high electron conductivity of the layered rGO coating and uniform LFP particles contribute to the remarkable electrochemical performance of the LFP/rGO composite. The unique LFP/rGO cathode provides a potential application in high-power lithium-ion batteries.

Double-walled carbon nanotubes as effective conducting agents for lithium iron phosphate cathodes

The aim of this study was to compare the effectiveness of carbon black, single-walled carbon nanotubes (SWCNTs), and double-walled carbon nanotubes (DWCNTs) as conducting agents for lithium iron phosphate (LFP) cathodes. A water-based slurry system was employed by incorporating SWCNTs and DWCNTs with polyvinylpyrrolidone (PVP) as a dispersing agent and binder. Both SWCNTs and DWCNTs exhibited remarkable wrapping ability on the surface of LFP particles, affecting the electrical conductivity and physical properties (including adhesion and cohesion strengths) of the electrode, and then influencing the electrochemical performance of the cathode. Notably, the DWCNTs outperformed the SWCNTs as conducting agents, demonstrating higher electrical conductivity and adhesion/cohesion strengths, as well as improved rate performances. This can be attributed to the higher aspect ratio, better crystallinity, and superior mechanical strength of the DWCNTs. In situ Raman measurements conducted during the charge–discharge process showed significant changes in the Raman peaks. SWCNTs exhibited complete suppression of Raman signals upon lithiation, while DWCNTs displayed the unique ability of retaining the Raman peaks originating from the inner nanotubes, indicating the protective function of the outer tubes. These findings highlight the promising potential of the incorporation of SWCNTs and DWCNTs into cathodes, as their exceptional wrapping ability distinguishes them from multi-walled carbon nanotubes and carbon black. In particular, owing to their high aspect ratio and superior wrapping capabilities, the DWCNTs are expected to serve as effective conducting agents for advanced lithium-ion batteries.

G–C3N4–assisted synthesis of ultrafine Mn2O3 nanoparticles embedded into N–doped carbon for advanced lithium–ion battery anode

The construction of advanced transition metal oxide (TMO)/carbon anodes to substitute graphite is always being an enormous challenge for the evolution of lithium–ion batteries (LIBs). Herein, a g–C3N4–assisted pyrolysis strategy is exploited to produce Mn2O3 nanoparticles embedded into N–doped carbon (Mn2O3@NC) hybrids. The results confirm that g–C3N4 plays three critical roles (dispersing agent, pore–forming agent and doping agent) in producing Mn2O3@NC hybrids. In the meantime, it is verified that the feed of Mn source greatly affects the synthesis of Mn2O3@NC hybrids. As a consequence, the resultant Mn2O3@NC–M (M means medium loading of Mn source) reaches a balanced proportion of Mn2O3 and NC, and contemporaneously displays a series of intriguing features, including ultrafine Mn2O3 nanoparticles, large specific surface area, rich mesopores and much high N doping amount. Benefitting from these advantages, the obtained Mn2O3@NC–M shows much enhanced cycling stability and rate performance when engaged as an battery anode.