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Vanadate is expected to be a promising anode material for lithium-ion batteries (LIBs). Herein, a series of Ni doped Zn3V2O8 continuous solid solution has been synthesized through a simple sol–gel method. The effects of Ni-doping on the microstructure of Zn3V2O8 is systematically investigated. The results show that Ni-doping has almost no influence on the crystalline phase structure and morphology, but has influences on the grain size of the samples. With the increase of Ni-doping amount, the grain size of Ni doped Zn3V2O8 gradually increases. Moreover, the conductivity of Ni doped Zn3V2O8 is also improved. Ni doped Zn3V2O8 has exhibited better electrochemical performance than that of Zn3V2O8. In particular, the sample Zn2.4Ni0.6V2O8 can deliver a capacity of 452.3 mAh g−1 at a current density of 1 A g−1 after 600 cycles. This should be attributed to the decrease of band gap, leading to the improvement of conductivity, which is more conducive to the transport of lithium ions and electrons. [ABSTRACT FROM AUTHOR]

The nitrogen-doped graphene (C3N) had special physical and chemical properties, thus it was widely used in various fields, especially as a lithium-ion batteries (LIBs) anode material. However, the electric field was one of the important factors affecting the performance of C3N as an anode electrode material for LIBs. Consequently, in this work, first-principal calculations were adopted to investigate the adsorption and migration properties of lithium ions on C3N surface by electric field. Calculation results show that the C3N monolayer exhibited a narrower band gap (0.0191 eV) and lower diffusion barrier (0.107 eV) under the application of the electric field, and the negative value of the adsorption energy increased by degrees with the increase of the electric field. Bader charge analysis and charge density difference calculations also provided forceful evidence for the ability of C3N to adsorb lithium ions. As a result, our theoretical results demonstrated that C3N should be a new type of anode material for LIBs. [ABSTRACT FROM AUTHOR]

Herein, a novel hollow rod-like composite was obtained by doping nitrogen-doped carbon quantum dots (NCDs) into covalent organic frameworks (COFs) (NCDs@COFBTH-TT) by a one-pot hydrothermal method. Such a hollow structure not only facilitates the transport of Li+ but also exposes a large number of active sites. The doped NCDs improve the electrical conductivity of NCDs@COFBTH-TT. When NCDs@COFBTH-TT was applied as the anode materials of lithium-ion batteries (LIBs), it showed excellent Li-storage performance. At a current density of 0.2 A g−1, the NCDs@COFBTH-TT exhibited an initial capacity of 336.8 mAh g−1 and then stabilized at 210.7 mAh g−1 after 226 charge/discharge cycles. This work combines zero-dimensional NCDs with two-dimensional COFs to improve the electrical conductivity and π-π stacking interaction of COFs, which is of great significance for the construction of COF-based LIBs with high storage capacity and ultra-long cycle life. [ABSTRACT FROM AUTHOR]

This research tried to estimate diffusion coefficient for lithium ions through the surface of the spinel LiNiMnO by spin-polarized total energy calculation. In addition, calculated result by this ab initio model was compared with a semi-empirical model. Both of these models predicted diffusion coefficient for lithium ions at the interface of the spinel LiNiMnO/electrolyte as 10 cm s which is 3 orders of magnitude higher than the diffusion coefficient of lithium ions in LiNiMnO. Details of these two models have been explained in this paper along with calculated results for surface diffusion coefficient of LiNiMnO cathode material. [ABSTRACT FROM AUTHOR]

In this paper, three-dimensional feather-like Co3O4/ZnCo2O4/NF is synthesized by one-dimensional Co3O4 nanorods and ZnCo2O4 nanowires on nickel foam. The special feather-like structure significantly improves the electrochemical performance of Co3O4/ZnCo2O4/NF. As anode for lithium-ion batteries, its initial capacity is 1480 mAh g−1 and keeps at 934 mAh g−1 after 200 cycles. After sequentially charge/discharge cycles with high current density, the discharge capacity returns to 942 mAh g−1 when the current density returns to 0.2 A g−1, showing excellent rate performance. In addition, a unique feather-like structure reduces the transport distance of lithium ions and accelerates the gather and release of lithium ions, making the battery have a large capacitance contribution ratio and exhibit significant pseudocapacitance characteristics. Besides, the excellent electrochemical performance of Co3O4/ZnCo2O4/NF is also attributed to its unique feather-like structure, synergistic effect, and good electrical conductivity. [ABSTRACT FROM AUTHOR]

Small lithium-ion (Li-ion) batteries are often used in smart devices. Due to its low battery capacity, the lifespan of the headset needs to be improved by reducing the decay of the Li-ion battery capacity. Here, an electrochemical-thermal coupling model and a capacity fade model based on the pseudo-two-dimensional (P2D) model are established by COMSOL multi-physics field simulation software. The aging behavior of the Li-ion battery during cycling and the effects of different factors on the battery capacity are investigated; the condition of the battery is further predicted. The simulation parameters include charge–discharge rate, initial concentration of lithium ions in the liquid phase, and radius of the anode particles. The results show that the electrolyte diffusion coefficient increases with the increase of temperature in the range of 1000–1600 mol/m3 concentration. However, the initial concentration of 1600 mol/m3 leads to a higher concentration increment (421 mol/m3) during 3000 cycles; it aggravates the concentration polarization. The larger particle radius forms a thicker SEI film. When the radius rises from 2 to 12.5 μm, the thickness and resistance of the SEI film increase to 1136.51 nm and 6.685 m Ω ∙m2, respectively. It consumes more lithium ions and increases the cycle time under the same current. [ABSTRACT FROM AUTHOR]

Solid-state lithium batteries (SSBs) have attracted attention as the next-generation high-safety lithium batteries due to their high energy density, excellent security, and electrochemical stability. Currently, polyvinylidene fluoride (PVDF) is considered one of the most crucial materials in solid polymer electrolytes because of its flexibility and workability. However, PVDF-based solid electrolytes encounter challenges such as low electrical conductivity and high internal resistance. The electrochemical properties of these solid electrolytes can be effectively enhanced through composite design and molecular structure modification. This review specifically focuses on the impact of nano-fillers with different structures (zero-dimensional nanoparticles, one-dimensional nanofibers, two-dimensional nanosheets, and three-dimensional nanoskeleton structures) on the key properties of PVDF-based solid electrolytes. The specific focus is on optimizing ion conductivity, improving lithium-ion migration efficiency, expanding the electrochemical stability window, extending battery life, enhancing electrical performance stability, and increasing battery capacity. The goal is to explore innovative filler design and modification technology application strategies in order to effectively enhance the performance of PVDF-based solid electrolytes in the field of solid lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Herein, a ZnO@carbon composite with a porous nanocage structure was synthesized via direct pyrolysis oxidation using a zeolite imidazolate framework (ZIF-8) as a precursor. Owing to the in situ and confined reactions of Zn in ZIF-8, the generated ultrasmall ZnO nanocrystalline active units (< 10 nm) were highly dispersed and embedded in the carbon nanocage framework. This considerably reduced the transport distance of lithium ions and effectively prevented them from coalescing during cycling. In addition, the porous nanocage structure could buffer the volume expansion of ZnO nanoparticles and accommodate the mechanical stress of the entire electrode, resulting in enhanced electrochemical reaction kinetics and mechanical stability of the electrode material. Benefiting from the tailor-fit nanostructured features, the ZnO@carbon composite used as the anode material for lithium-ion batteries showed high specific capacity and long-term cycling performance. In particular, its reversible specific capacity reached 519.3 mAh·g−1 after 200 cycles at a current density of 200 mA·g−1. [ABSTRACT FROM AUTHOR]

Lithium dendrites produced during the process of lithium metal cycling lead to poor cycle stability and safety problems, seriously hindering the practical application and commercialization of lithium metal. In this work, a facile method is used to coat lithium titanate (LTO) onto polypropylene (PP), resulting in the formation of a lithium titanate diaphragm (LTO@PP). The characteristic properties such as morphology, EIS, and electrochemical performance of the LTO@PP diaphragm are systematically investigated. The results indicate that during the first discharge cycle, Li4Ti5O12 can undergo lithiation, facilitating the transfer of Li+ ions and thereby accelerating the migration kinetics of lithium ions within the LTO@PP diaphragm. The LTO@PP-based cell can stably cycle for more than 4800 h in a Li symmetrical battery at a high current density of 3 mA cm−2, with an overvoltage as low as 6 mV. The Li | Cu battery can stably cycle for more than 380 cycles under a deposition rate of 1 mAh/cm2. Additionally, the LTO@PP diaphragm-based LFP cell displays a high capacity retention rate and excellent rate performance. Compared with current diaphragm modification methods, this work provides a promising prospect for the simple and rapid preparation of modified diaphragms. [ABSTRACT FROM AUTHOR]

Lithium titanate (Li4Ti5O12, LTO) anode materials doped with Zr, Cr, and Co were prepared by a simple solution freeze-drying (SFD) strategy. Doping with Zr, Cr, and Co metal ions can reduce the charge transfer resistance and enhance the diffusion rate and conductivity of lithium ions. Among the prepared samples, LTO-0.1Zr shows the best electrochemical performance with the reversible capacities of 286.8, 258.5, 235.4, 196.2, 151.5, and 119.6 mAh g−1 at 0.5, 1, 2, 5, 10, and 20 C, respectively. After 500 cycles at 10 C, a high retention rate of 94.6% for LTO-0.1Zr capacity can still be achieved. As a result, this study provides a simple and effective way to improve the electrochemical performance of LTO as anode material for high rate lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Ti2Nb10O29 (TNO) has garnered significant research attention due to its high specific capacity and excellent safety features, positioning it as a promising anode material for lithium-ion batteries (LIBs). Nevertheless, its rate capability is significantly hampered by poor electronic and ionic conductivity. In this paper, Ni2+ doping has been first applied to address these issues. A series of Ni2+ doped TNO (Nix-TNO (x = 0.03, 0.05, 0.07) electrode materials have been prepared to unveil the effects of Ni2+ content. The experimental results unveil that Ni2+ doping maintains the Wadsley-Roth shear structure of TNO while augmenting the single-cell volume and introducing additional oxygen vacancies in TNO. This generates a wider diffusion path and more active sites for lithium ions (Li+). Besides, the introduction of Ni2+ can alter the conductive field distribution of TNO, giving rise to a much higher electronic conductivity of Nix-TNO. Among the synthesized Nix-TNO, Ni0.05-TNO shows the best electrochemical performance, demonstrating a reversible capacity of 306 mAh g−1 with a Coulombic efficiency of 91.46% in the first cycle at 0.1 C and 146.19 mAh g−1 at 10 C after 500 cycles. [ABSTRACT FROM AUTHOR]

Separators have directly affected the safety and electrochemical performance of lithium-ion batteries. In this study, an alkali etched enhanced polyimide (PI)/polyacrylonitrile (PAN)@ cellulose acetate (CA)/PI three-layer composite separator is prepared using electrospinning, non-solvent phase separation, and alkali etching methods. The effects of alkali etching on the mechanical strength, thermal stability, and electrochemical performance of the PI/PAN@CA/PI separator are explored. The obtained separator has two different pore structures, and the surface of the alkali etched separator has abundant polar groups, further enhancing the migration rate of lithium-ions. The mechanical strength and thermal performance decrease with the prolongation of alkali etching time. When the alkali etching time is 3 min, the PI/PAN@CA/PI separator has the best comprehensive performance, with a mechanical strength of 17.8 MPa, ion conductivity of 1.22 mS cm−1, and interface impedance of 152 Ω. After 100 cycles of charging and discharging at a current density of 1 C, the capacity retention rate is 95.3%. At a current density of 5 C, the specific capacity of charging and discharging can reach 114 mAh g−1, which is better than the 87.3 mAh g−1 of the initial PI/PAN@CA/PI separator. [ABSTRACT FROM AUTHOR]

The effect of doping with aluminum compounds on the crystal structure, morphology, and electrochemical properties of LiFePO4 has been investigated with aluminum stearate, alumina, aluminum sulfate, and aluminum phosphate as dopants. The contraction of unit cell observed by XRD analysis and reduced lattice spacing determined by HRTEM of the doped crystals indicate that Al3+ ions, which occupy smaller space than lithium ions, are successfully doped into the lattice of LiFePO4. Lattice doping of aluminum ions enlarges Li+ transport channels; 1%-AlP-LFP has the slowest attenuation of discharge specific capacity. After 30 cycles of charge and discharge curve test at 0.5C, the retention rate of the sample is 97.43%. Owing to the substitution of S for O sites, and SO42− has a breaking effect on the carbon layer, this accelerates the capacity decay of 1%-AlS-LFP. The discharge capacity of 1%-AlS-LFP is 132.9 mAh/g, which is lower than 139.8mAh/g of LFP. The electrochemical impedance spectroscopy (EIS) results show that the resistance of 1%-AlP-LFP is 147.1 Ω, the resistance of LFP is 138.9Ω, and the resistance of LFP is 183.9Ω. The Li+ diffusion coefficient of 1%-AlP-LFP is partially increased; the double substitution of Al3+ and S2− slows the migration rate of Li+. [ABSTRACT FROM AUTHOR]

Zn3Mo2O9 with various morphologies were constructed using hydrothermal, solvothermal, and high-temperature solid-phase strategies and used as negative electrodes of lithium-ion batteries firstly. The Zn3Mo2O9 obtained by high-temperature solid-state method (ZMO-t) is constructed by lots of small nanosheets, which has relatively uniform size and small particles among three samples. The unique morphology is beneficial for electrolyte permeation and further promotes the migration rate of lithium ions. At various current densities, test results can illustrate that the ZMO-t exhibited the best electrochemical performance than those of Zn3Mo2O9 obtained by solvothermal method (ZMO-s) and hydrothermal way (ZMO-h) materials at the same rates. Based on these results, the Zn3Mo2O9 synthesized via high-temperature solid-state strategy has the potential to become a novel negative electrode for Li-ion batteries going forward. [ABSTRACT FROM AUTHOR]

Combining iron oxide with carbon materials such as graphene oxide is an effective measure to solve the issues of terrible electronic conductivity and serious volume effect of iron oxides. Fe2O3/reduced graphene oxide nanocomposite was synthesized via simple hydrothermal method with cubic iron oxide of a uniform particle size distribution (~ 50 nm), which were encapsulated between reduced graphene oxide layers. Construction of nanostructure cubic iron oxide facilitates the transportation of lithium ions and electrons. Furthermore, the introduction of reduced graphene oxide promotes the conductivity and structural integrity of the nanocomposites, while avoids the agglomeration and crushing of iron oxide particles during the lithiation/de-lithiation, facilitating the storage of lithium ions. Fe2O3-rGO-c0.2 as an anode material exhibits superior electrochemical performance, with initial discharge capacity of 1580.6 mAh g−1 and reversible capacity of 1145.4 mAh g−1 after 100 cycles at the current density of 200 mA g−1. Moreover, it has a good rate performance of 479.1 mAh g−1 at a current density of 5000 mA g−1. [ABSTRACT FROM AUTHOR]

The main challenge that hinders lithium-ion batteries in space applications is their poor performance at subzero temperatures. Such poor performance is primarily due to the low ionic conductivity and freezing of the electrolyte, leading to the loss of battery capacity. This research investigates the behavior of lithium-ion batteries at low temperatures by employing electrochemical and material characterization techniques. Based on the electrochemical behavior of the battery cells, lithium-ion batteries' performance declined rapidly at − 30 °C. The major findings indicate that charging at low-temperature conditions increases the impedance, which slows down the reaction kinetics affecting the intercalation of lithium ions. According to the results obtained from the ex situ material characterization analysis, the main factor that induces this behavior is the freezing and the decomposition of the electrolyte at the cathode-electrolyte interphase and the mechanical degradation of the active materials of the cathode. These changes lead to interfacial instability and considerable development of resistance to the flow of charges. The findings in this study contribute to the development of lithium-ion batteries for low temperature and space applications by understanding the behavior of lithium-ion batteries in subzero temperature environments. [ABSTRACT FROM AUTHOR]

Here, we have prepared carbon-coated cadmium sulfide nanowires with sulfur defect (Vs-CdS NWs@C) anode by a polyvinylpyrrolidone (PVP)-assisted solvothermal method. Vs-CdS NWs@C anode not only increases the wettability of the electrode material and the electrolyte but also exposes more active sites, which can effectively alleviate the volume expansion during the charging and discharging process, accelerate the reaction kinetics, and maintain the stability of the electrode structure. At the same time, the surface defects engineered to construct unsaturated active sites on the surface contribute to the conductivity and introduce active sites for binding lithium ions. Finally, the conductivity of the carbon layer can effectively improve the electrode conductivity. Therefore, the synergistic regulation strategy of nanostructures, sulfur defect engineering, and carbon coating is expected to construct new and efficient anode materials for LIBs. [ABSTRACT FROM AUTHOR]

Silicon(Si) is one of the anode materials to replace graphite electrodes due to large specific capacity. However, the volume expansion of silicon anode material and instability of solid electrolyte interphase (SEI) layer greatly limits their practical applications. Herein, we demonstrate a novel sandwich network structure silicon-carbon anode composites and explored as electrode material for lithium-ion batteries (LIBs). The CBC/Si/NC composites were synthesized by using bacterial cellulose (BC) as the structural template and retains the three-dimensional network structure of BC and has a high specific surface area which ease the volume expansion of silicon during the charge-discharge process. Meanwhile, silicon nanoparticles covered with dopamine, the outer carbon, uniformly attached to the cellulose surface. The internal and external carbon layers improve the conductivity of the composite and can accelerate the diffusion and electronic transmission of lithium ions. The sandwich network structure composite anode demonstrates excellent cycle stability and a high reversible specific capacity of 889mAh·g−1 after 200 cycles at a current density of 0.5 A·g−1. [ABSTRACT FROM AUTHOR]

The LATP solid electrolyte is the most promising material for high Li-ion and electronic conductivity compared to other fast ionic conductors. Herein, we intend to develop a three-dimensional Li1+xAlxTi2−x(PO4)3 solid electrolyte to facilitate the migration of lithium ions from substituting Al3+ for Ti4+ through a simple, effective sol–gel technique. Thermal treatment over ceramic pellet at 1123 K resembles the NASICON-type Rhombohedral structure by X-ray and Raman analysis. A study of dielectric relaxation and ionic behaviour of conducting materials was carried out due to their potential application in electronic devices. Analogous to the ion conduction mechanism, pelletised LATP was achieved with excellent ionic conductivity σ = 1.919 × 10−4 S/cm at room temperature. Similarly, the temperature-dependent ion conduction mechanism was carried out at various temperatures, and the activation energy was determined to be 0.10 eV. In addition, the LiCoO2/LATP/AC device is constructed by sandwiching the composite electrolyte LATP between activated carbon (AC) and LiCoO2. Such a solid-state device achieved a remarkable energy density of 2.10 Wh/kg and a power density of 141.17 W/kg. This exhibits enhanced rate capability and cycling performance of 93% over 10,000 cycles. This analysis may provide a promising strategy for designing high-performance energy storage systems. [ABSTRACT FROM AUTHOR]

The employment of functional interlayers could efficiently inhibit the polysulfide migration for high-performance lithium-sulfur batteries. In this study, functional interlayers consisting of ceric dioxide particle–incorporated carbon nanofibers (CO@CNF) were successfully prepared. These CO@CNF interlayers could not only work as physical barrier for the soluble polysulfide; the presence of CO also provide chemical adsorption for the polysulfide. When the CO particles were incorporated to the carbon nanofibers, 3D channels for the transport of lithium ions and electrons could be formed, which are beneficial for the rapid transport of the lithium ions and electrons. Owing to these superior advantages, the Li–S batteries with CO@CNF interlayer deliver high discharge specific capacity of 1086 mAh g−1 at 0.1 C. It also delivers good rate performance and rate capability. [ABSTRACT FROM AUTHOR]

Laminated metal sulfide is a unique material with a graphite-like structure and good storage capacity for both lithium and sodium ions. However, the inherent low electrical conductivity and severe volume expansion of SnS2 lead to poor electrochemical properties, further limiting practical applications. In this work, a nitrogen-doped carbon (NC) and reduced graphene oxide (rGO) co-decorated SnS2 nanoplatelets (SnS2/NC-rGO) using dopamine (PDA) and graphene oxide (GO) as carbon sources are cleverly designed. SnS2/NC wrapped with rGO is synthesized via hydrothermal followed by calcination. This design not only increases the electrical conductivity of the composite but also provides more pathways for ions/electrons. Furthermore, the larger specific surface area of the composite allows better contact between the electrolyte and the electrode, which further enhances the redox dynamics of lithium ions/sodium ions. Thanks to this structure, the charge/discharge specific capacity of the SnS2/NC-rGO composite electrode is 1215.8/1220.7 mAh g−1 after 200 cycles at 0.1 A g−1. The superior sodium storage performance has also been demonstrated in sodium-ion batteries, where a high specific capacity of 501.6 mAh g−1 can be achieved after 80 cycles at a current density of 0.1 A g−1. [ABSTRACT FROM AUTHOR]

The mechanism of magnesium compounds on the crystal structure, morphology, and electrochemical properties of LiFePO4 has been investigated using magnesium oxide, magnesium sulfate, and magnesium hydrogen phosphate as dopants. The shrinkage of crystal cell and lattice spacing implies that Mg2+ is successfully doped into the lattice of LiFePO4, since magnesium ions occupy less space than ferrous ions or lithium ions. Meanwhile, the primary particle size of LiFePO4 tends to reduce when high-content magnesium is doped, which is ascribed to cell shrinkage as well as the reduction of surface energy. In addition, agglomeration of crystal fine particles is observed in the SEM images. The discharge capacity of 1%MgHPO4-LFP increases as the proceeding of the charging/discharging cycle; i.e., the retention rate of this sample exceeds 100% (100.96%) at 0.5 C after 30 cycles. Owing to the substitution of S for O sites, the diffusion channel of Li+ expands while the total number of Fe-Li reverse site defects decreases, which lowers the capacity attenuation of 10%MgSO4-LFP under high-rate conditions (compared to 10%MgO-LFP). The discharge capacity of 10%MgSO4-LFP is 88.7 mAh/g, which is higher than 10%MgO-LFP (75.06 mAh/g). [ABSTRACT FROM AUTHOR]

The use of sintering additives with low melting point, high ionic conductivity, and high wettability can reduce the grain boundary impedance of the ceramic electrolyte. As a commonly used sintering auxiliary for inorganic ceramic electrolytes, Li2O-B2O3-SiO2 has a role in reducing the sintering temperature of ceramic electrolyte and improving sintering density and ionic conductivity. The low ionic conductivity affects its breadth of applications. Improving its performance is conducive to adjusting the grain boundary impedance of ceramic electrolytes. In this work, the (0.75-3x) Li2O-0.125B2O3-0.125SiO2-xLa2O3 ceramic solid electrolyte sintering additives prepared by ultra-fast melting method are mainly studied, and the effects of different amounts of La2O3 doping on their structure and ionic conductivity are explored. La2O3 doping modulates the electrolyte structure by influencing [BO3]3- and [BO4]5- content, Si-O recombination. And reduce the binding force of groups to lithium ions in the system, increase its ionic conductivity, and reduce the activation energy. At x = 0.02, the room temperature ionic conductivity of 0.69Li2O-0.125B2O3-0.125SiO2-0.02La2O3 is 4.70×10-6 S/cm-1, and the activation energy is 0.30 eV, which is a higher improvement than that of undoped. Experiments show that it reduces the grain boundary impedance of LiTa2PO8 and improves the room temperature ionic conductivity and density. [ABSTRACT FROM AUTHOR]

Fe3O4 and Fe3O4/NiO heterostructures were successfully prepared by a simple one-step solvothermal method. The morphology of Fe3O4/NiO heterostructures is flower-like spheres composed of nanosheets with a thickness of 10–20 nm. As anode material for lithium-ion batteries (LIBs), the electrochemical performance of the Fe3O4 and Fe3O4/NiO heterostructures are comparatively investigated. At current density of 100 mA g−1, the Fe3O4/NiO heterostructures can maintain 1021 mAh g−1 after 100 cycles. The discharge capacity can still maintain at 500 mAh g−1 and the coulomb efficiency is always stable at 99.6% after 1000 cycles at 1 A g−1. The Fe3O4/NiO heterostructures also have lower impedance and better rate capability, compared with the bare Fe3O4 electrode. Moreover, the electrochemical properties of the Fe3O4/NiO heterostructures can be further improved when the new binder CMC-Li is used. At 100 mA g−1, it can still maintain 1544 mAh g−1 after 100 cycles. These loose-layered nanosheets can effectively alleviate the volume expansion of materials in the process of charge and discharge. Meanwhile, the large surface area can provide more reaction sites. The ultra-thin nanosheet can also reduce the diffusion distance of lithium ions, so that the Fe3O4/NiO heterostructures have excellent performance in lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Li2FeSiO4, as a cathode material for lithium-ion batteries (LIBs), has attracted much attention owing to its high theoretical capacity, environmental benignity, and low cost. However, low electronic conductivity and slow diffusion of lithium ions preclude its application. To solve the aforementioned issues, Li2FeSiO4/C/CePO4 composite is designed and synthesized by a sol–gel method, in which the surface-coated carbon layer and CePO4 improve the electronic and ionic conductance of Li2FeSiO4, respectively. Benefiting from synergistic contributions from C and CePO4, 6 wt.% CePO4-modified Li2FeSiO4/C exhibits high rate performance (144, 132, 118, 104, and 74 mAh g−1 at 1, 2, 5, 10, and 20 C) and good cycling stability (112 and 87 mAh g−1 after 500 and 800 cycles at 5 and 10 C, respectively). This work allows the potential applications of Li2FeSiO4/C/CePO4 cathode in LIBs with low-cost and high performance. [ABSTRACT FROM AUTHOR]

The objective of this study is to find out the factor that accounts for the capacity fading and to predict the cycle life of lithium-ion batteries by the driving cycle test. A new method, incremental polarization resistance, is elected to analyze the gradation mechanism based on incremental capacity analysis. It is summarized that the two major factors, the loss of lithium ions and the cathode fading, make the capacity loss in different stages. In the first stage, the loss of lithium ions, caused by the solid electrolyte interface (SEI) lay reaction, is the main reason for battery degradation. In the second stage, the cathode starts to decay and make the capacity loss, because of the less intercalation in cathode. In the third stage, the cathode degradation gradually outpaces the loss of Li and becomes the limit factor for the battery recession. Finally, a cycle life model was established to predict the capacity loss with cycle numbers. [ABSTRACT FROM AUTHOR]

This review paper presents a comprehensive analysis of the electrode materials used for Li-ion batteries. Key electrode materials for Li-ion batteries have been explored and the associated challenges and advancements have been discussed. Through an extensive literature review, the current state of research and future developments related to Li-ion battery electrodes were identified. The study also covers a wide range of subtopics, including the theoretical aspects of the basic functioning of lithium-ion batteries and the crystal structures of different electrode materials. Additionally, emerging trends and future directions in the development of high-performance commercial battery electrodes have been revealed, providing insights into promising avenues for further research. By synthesizing existing knowledge and analyzing the latest research, this review aims to provide a valuable resource for researchers, practitioners, and stakeholders interested in developing state-of-the-art high-performance Li-ion batteries. The findings and perspectives presented in this paper contribute to a deeper understanding of electrode materials for Li-ion batteries and their advantages and disadvantages, ultimately fostering advancements and innovations in commercial lithium-ion battery (LiB) electrode technology. [ABSTRACT FROM AUTHOR]

In order to improve the diffusion kinetics of lithium ions in polycrystalline LNMO cathode materials, LNMO cathode materials with grain radial growth microstructure were prepared by high-temperature solid-phase method after adjusting the microstructure of MnCO3 precursor, and the effect of this unique microstructure on the electrochemical performance was studied. The excellent rate performance of R-LNMO electrode proves that the microstructure of grain radial growth provides a rapid diffusion path for Li+ from the inside to the surface of the particle, which is conducive to efficient transmission. In addition, the directional arrangement of grains helps the electrolyte to enter and reduce the polarization effect, thus endowing LNMO with excellent rate performance. Compared with the traditional polycrystalline LNMO, the R-LNMO electrode can still provide a high specific discharge capacity of 101.5 mAh g−1 at a high current density of 10 C, and the retention rate of 10 C/0.2 C is 86.9%. Even after 1000 cycles at 10 C high current, the capacity retention rate can reach 77.2%, which shows excellent cycle stability. This strategy of controlling precursor structure provides a new idea for the fast charging and discharging of polycrystalline cathode materials. [ABSTRACT FROM AUTHOR]

The composite separator PP-CPE was created by coating the polypropylene (PP) separator with the composite polymer electrolyte (CPE), which is made up of Li6.4La3Zr1.4Ta0.6O12 (LLZTO) and polyvinylidene fluoride hexafluoropropylene (PVDF-HFP). To compensate for the inequalities in Li+ flux movement caused by the conventional PP separator, this new separator features several rapid Li+ channels along on the PVDF-HFP, LLZTO, and PVDF-HFP/LLZTO interfaces. To ensure that lithium ions are uniformly deposited on the anode, CPE layers can be utilized to immobilize anions and control their movement. The Cu/Li battery with modified separator PP-CPE circulates 300 times at 1 mA cm−2, and the Coulombic efficiency is more than 98.1%. The Li symmetrical battery can cycle stably for more than 600 h and maintain a stable overpotential. The capacity of the LFP/Li battery loaded with 10 mg cm−2 decreased to 126 mAh g−1 when 300 cycles were performed at 1C, and the Coulombic efficiency over 99.3%. This effective and simple separator modification strategy can reduce the formation and growth of lithium dendrites, which leads to higher coulombic efficiency and better cycle stability. [ABSTRACT FROM AUTHOR]

Considering its relatively large specific capacity along with low cost advantages, manganese sulfide (MnS) emerges as a competitive lithium-ion host material. However, some excruciating issues such as inevitable volume expansion and inherent insufficient conductivity always result in a low specific capacity, limited cycling life and poor rate capability. Rational morphology and structure design is vital to achieve superior Li-storage performance. Herein, a heterostructured composite with small MnS embedded on glycine-derived N, S-doped amorphous carbon sheets (MnS@NSC) has been synthesized through an annealing and sulfuration route. MnS nanoparticles are well confined by carbon matrix, which is conductive to an effective suppression on volume change and reservation of integrated structure. Meanwhile, porous carbon framework supplies desirable expressway for fast electron delivery and reduces the distance for lithium ions diffusion. Consequently, the MnS@NSC anode delivers a remarkably elevated lithium-storage performance. [ABSTRACT FROM AUTHOR]

Increasing the intrinsic conductivity of LiFePO4 can improve its electrochemical performance. Solving this problem can be achieved by P-site doping of LiFePO4 powder. Here, B-Mg co-doped LiFePO4 is successfully synthesized by solvothermal methods. The physical and electrochemical properties of all samples are systematically characterized with various characterization methods. In particular, proper B ion doping is determined to be beneficial to electronic conductivity, which induces the rearrangement of the PO43+ electron cloud. Also, doping with Mg can balance the problems of oxygen vacancies caused by doping B, thereby smoothing the transmission path of lithium ions, resulting in enhanced electrochemical performance. Moreover, XRD and SEM results illustrated that co-doping B and Mg do not change the LiFePO4 structure but promote the formation of a uniform and small particle. Compared with other samples, LiFeMg0.02P0.98B0.02O4 demonstrates superior electrochemical performance, which showed a specific discharge capacity of 147.4 mAh g−1 at 1 C and a corresponding capacity retention rate of 98.6% after 100 cycles. Even at 10 C, the discharge capacity still maintains 114.9 mAh g−1. The results of this work indicate that enhancing electronic conductivity and balancing oxygen vacancy are attributed to high electrochemical performance. [ABSTRACT FROM AUTHOR]

In this work, cycling-induced aging occurring in 18650-type LiFePO4/graphite full cells at different C-rates is studied extensively. The mechanism of performance degradation is investigated using a combination of electrochemical and microstructural analyses. Half-cell studies are carried out after dismantling the full cells, using fresh and cycled LiFePO4 cathode and graphite anode to independently study them. The results show that the capacity of LiFePO4 electrodes is significantly recovered. The rate of capacity fading in the discharge state considered as irreversible capacity in the graphite is higher than LiFePO4 half cells, indicating a greater degradation in the performance of this electrode. At relatively high current rates, this phenomenon is mainly attributed to the instability of the electrode/electrolyte interface and the solid electrolyte interphase (SEI) layer, causing the formation of active lithium ion-impermeable covering layer on the anode surface that strongly influences the cyclic aging. As a result, significant consumption of inventory active lithium ions occurred at relatively high current rates measured by half-cell studies. Forming thick covering layer and subsequently separation between active materials, which lead to the loss of electrical contact among them, result in electrode deactivation. To confirm this claim, various morphological, structural, and electrochemical analyses are employed. [ABSTRACT FROM AUTHOR]

The polymer separator is part of the gel polymer electrolyte (GPE) and plays a crucial role in battery. In this study, a novel PES-based separator for lithium-oxygen batteries was prepared using non-solvent-induced phase separation (NIPS) technique firstly and modified by doping Al2O3 nanoparticles. It is proved that the properties of the PES/Al2O3 separator are affected by the presence of Al2O3 nanoparticles. The results show that the PES/Al2O3 separator with Al2O3 content of 2 wt% and 4 wt% has lower crystallinity, higher electrolyte uptake, and better mechanical properties and thermal stability than PES-based separator without Al2O3. The resulting PES/Al2O3 separator containing 4 wt% Al2O3 has higher ionic conductivity (0.49 mS cm−1) and lithium ions transference number (0.28). Consequently, the assembled batteries with the PES/Al2O3 separator containing 4 wt% Al2O3 exhibit excellent cycling performance (75 cycles, 1000 mAh g−1 at 0.05 mA cm−2). Therefore, PES/Al2O3 separator has a significance meaning in the research of high-safety and long-cycle lithium-oxygen battery. [ABSTRACT FROM AUTHOR]

The nickel-rich cathode material NCM (LiNi1-x-yCoxMnyO2) has aroused widespread interests among researchers due to its high specific capacity and better cycle performance. Nevertheless, high nickel component also brings adverse influences such as Li+/Ni2+ disordering aggravating and surface NiO content increasing, which aggravate the phase transitions and impede lithium-ions diffusion. Herein, the NASICON-type fast ionic conductor LiTi2(PO4)3 is adopted to form a functional coating layer on the surface of Ni-rich material. The results indicate that the modified Ni-rich material achieves an initial specific capacity of 187.1 mAh/g at 1 C and remains 91.7% capacity after 100 cycles. Furthermore, it still exhibits a discharge specific capacity of 165.2 mAh/g at 5 C. It was also found that the modified Ni-rich material possesses a more stable working voltage platform and minor impedance than pristine cathode. Above better performance of modified cathode can be attributed to its better electrochemical kinetics and smaller polarization. [ABSTRACT FROM AUTHOR]

Using diatomite and lithium carbonate as raw materials, a porous Li4SiO4 ceramic separator is prepared by sintering. The separator has an abundant and uniform three-dimensional pore structure, excellent electrolyte wettability, and thermal stability. Lithium ions are migrated through the electrolyte and uniformly distributed in the three-dimensional pores of the separator. The sintering temperature has an important influence on the composition of the ceramic separator. When the sintering temperature reaches 650 °C, pure Li4SiO4 is synthesized. The large porosity and excellent electrolyte affinity provide a maximum ionic conductivity of 1.18 mS cm-1 for the LSCS650 ceramic separator. After 120 charge-discharge cycles, the lithium iron phosphate battery assembled with the LSCS650 separator has a discharge specific capacity of 128.4 mA h g-1 and a capacity retention rate of nearly 100% at a current density of 1 C. Meanwhile, at a high current density of 10 C, the cell still has a discharge capacity of 71.4 mA h g-1. Therefore, the Li4SiO4 ceramic separator has a good application prospect in high-power lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Cobalt manganese oxide (CMO) has been confirmed to be a potential anode material for lithium-ion storage. This contribution adopted a colloid dispersion system combustion combination with NaOH etching strategy to prepare hierarchical mesoporous CMO with enough cavities. The prepared mesoporous CMO's specific surface area could attain 194.5 m2 g−1 with abundant hierarchical mesopores. The hierarchical mesoporous architecture with enough cavities is conducive to boosting the lithium ions storage ability. The mesoporous CMO could afford the 1st discharge capacity of 1346.1 mAh g−1 at 1 A g−1 and deliver 1109.3 mAh g−1 after 450 cycles. The hierarchical mesoporous CMO with rich cavities can offer abundant electroactive sites, which is helpful to enhance the Li-ion storage ability. Moreover, plentiful cavities can relieve the structural stress resulting from charge/discharge processes. This contribution not only proposed a novel strategy to synthesize hierarchical mesoporous CMO but also revealed its potential application in Li-ion storage. [ABSTRACT FROM AUTHOR]

Due to the high energy density and low cost, LiNi1/3Co1/3Mn1/3O2 is wildly explored as a promising cathode material for lithium-ion batteries. However, this material suffers from the destruction of surface structure in the electrolyte and the reacting of electrode with the electrolyte during cycles in highly voltage. Herein, we rationally designed core-shell nanostructure LiNi1/3Mn1/3Co1/3O2@ ultrathin δ-MnO2 nanoflakes cathode material with excellent capacity retention and rate capacity by a liquid-phase precipitation method. The unique ultrathin δ-MnO2 nanoflakes shell nanostructure plays a key role in effectively improving rate performance and cycle life of LiNi1/3Co1/3Mn1/3O2. The electrode with the coating amount of 3 wt% exhibits excellent cycle performance and superior rate capacity compared with bare electrode. The δ-MnO2 nanoflakes-coated layer can react with Li+ during cycling and convert to spinel phase, resulting in a reversibly de/lithiation coating layer to improve its specific capacity compared with other inactive coating layer, and the spinel phase can also provide a three-dimensional lithium ions diffusion channels and thus promote lithium ions diffusion. Judging from the discussion, it can be concluded that the role of δ-MnO2-nanoflakes coating layer not only acts as a protective layer to impede the electrode directly contact with electrolyte but also accelerates lithium ions diffusion and improve its specific capacity. [ABSTRACT FROM AUTHOR]

Ga-doped V6O13 is successfully synthesized by solvothermal method. Ga doping can make V6O13 nanocrystallization, and this structure is conducive to the de-intercalation and intercalation of lithium ions. Ga3+ can be doped into V6O13 lattice and replaces the partial position of V. The Ga0.05V5.95O13 has a structure of nanowires with the width of about 80–100 nm. It exhibits good electrochemical performance. The initial discharge specific capacity is 406.51 mAh g−1 at a rate of 0.1 C, and the capacity retention is 66.95% after 100 cycles. Compared with the pure phase, the discharge capacity and capacity retention rate are increased by 45.5% and 29%, respectively. Compared with other Ga-doped V6O13, Ga0.05V5.95O13 has a higher lithium ion diffusion rate, which is also related to its structure of nanowires. The improvement of electrochemical performance indicates that Ga doping is favorable, and Ga-doped V6O13 cathode material has potential application value in lithium-ion batteries. [ABSTRACT FROM AUTHOR]

V6O13 is synthesized by hydrothermal and solvothermal, respectively. The methods are compared to seek a simpler method for V6O13 synthesis. The results show that the best reaction time of hydrothermal-V6O13 is 3.5 h and the phase is pure. Compare with the solvothermal, the hydrothermal-V6O13 has smaller structure unit of about 100-200 nm, and there are also many pores, which is conducive to the transportation and storage of lithium ions. The results of charge-discharge test show that the electrochemical performance of hydrothermal-V6O13 is better than solvothermal-V6O13. The initial discharge capacity of hydrothermal-V6O13 is 319.2 mAh/g, and the retention rate is 50.5% after 100 cycles, which are 39.9 mAh/g and 12.6% higher than solvothermal-V6O13, respectively. The results of CV and EIS also confirm that hydrothermal-V6O13 has better electrochemical performance as lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Composite solid electrolyte (CSE), especially the composite room temperature solid electrolyte (CRTSE), is emerging as the promising electrolyte for all-solid-state lithium batteries (ASSLB) due to their ability to combine the desirable properties of ceramic and polymer-based electrolytes and the room temperature operation condition. In this paper, the CRTSE with polyethylene oxide (PEO), bis(fluorosulfonyl)imide (LiTFSI), succinonitrile (SN), LLZTO inorganic fillers, and cross-linked ethoxylated trimethylolpropane triacrylate (ETPTA) was proposed. With the help of lithium dendrite suppression via cross-linked microscopic pore structure, enhancement of the ionic conductivity via LLZTO fillers, and wide electrochemical window via SN, the obtained LCSE showed high ionic conductivity (2.12 × 10−4 S cm−1), high Li+ transfer number (tLi+ = 0.55), and stable electrochemical window (5.0 V vs Li/Li+) at room temperature. The Li symmetrical cell with LCSE can cycle over 500 h stably with current density of 0.1 mA cm−2 and 0.5 mA cm−2 at room temperature. The full solid-state LiFePO4 cell can successfully work over 200 cycles with capacity retention ratio of about 70% at room temperature. [ABSTRACT FROM AUTHOR]

Li7La3Zr2O12 (LLZO) has shown excellent electrochemical performance and chemical stability. In this work, Li6.4Ga0.2La3-xYbxZr2O12 (0 ≤ x ≤ 0.1) has been synthesized by solid-state reaction method. The effect of Ga and Yb co-doping on the crystal structure, morphology, densification, and electrical performance was investigated. The doping with Ga3+ stabilized the cubic phase while the doping with Yb3+ optimized Li+ transport channel size and accelerated the densification of the ceramics. Li6.4Ga0.2La2.95Yb0.05Zr2O12 (relative density 94.8%) exhibited the highest total conductivity (8.96 × 10−4 S·cm−1 at 30 °C) and the lowest activation energy of 0.28 eV. Meanwhile, Li6.4Ga0.2La2.95Yb0.05Zr2O12 showed high mobility (1.36 × 10−6 cm2 V−1 s−1), diffusion coefficient (3.18 × 10−8 cm2 s−1) and high hopping rate of lithium ions (5.0 × 106 rad s−1) at 0 °C. The high discharge capacity and capacity retention of LiFePO4/Li6.4Ga0.2La2.95Yb0.05Zr2O12/Li solid-state batteries indicate that Ga and Yb co-doped Li7La3Zr2O12 ceramic should be a promising electrolyte. [ABSTRACT FROM AUTHOR]

In the new energy vehicle field, the lithium ion batteries (LIBs) are widely used as energy storage devices. In this paper, the decay characteristics and thermal stability of LIBs' negative electrode with capacity retention rate (CRR) 60–100% were studied. The lithium content and polarization impedance of the negative electrode were analyzed by constant current charge/discharge test, the inductively coupled plasma–optical emission spectrometer test and impedance test. The result reveals that the capacity loss caused by the active lithium loss mainly occurs before 80% CRR, and the deterioration of kinetic performance is the main reason for capacity loss of negative electrode with 80–60% CRR. Surface composition, structure changes, and thermal stability of the negative electrode were analyzed by scanning electron microscope, X-ray photoelectron spectroscopy, X-ray diffraction, and differential scanning calorimetry. The results show that the SEI film becomes more inorganic and its conductivity of lithium ions decreases as the capacity retention rate declines, which have an important effect on the kinetic performance of negative electrode. The thermal stability of the negative electrode also decreased significantly because of the loose secondary SEI film formation at elevated temperature. [ABSTRACT FROM AUTHOR]

Transition metal chalcogenides (TMCs) are considered to be promising as anode materials for lithium-ion batteries (LIBs) due to their unique physical and chemical properties and high theoretical specific capacity. Nevertheless, the poor rate performance and fast capacity decay seriously affect its practical application in LIBs. In the present study, porous yolk-shell CoS2@FeS2@NC hollow microspheres have been successfully prepared through a simple step-by-step strategy. In addition to shortening the transport length of lithium ions, this unique structure can also successfully alleviate the volume change during charging/discharging. Importantly, the coating of the nitrogen-doped carbon (NC) layer effectively enhances the electrical conductivity of the material and prevents exfoliation of metal particles. The yolk-shell CoS2@FeS2@NC hollow microspheres show high specific capacity (1162.6 mAh g−1) and excellent cycle stability (614 mAh g−1 at 1 A g−1 after 100 cycles) when used as anode material for LIBs. These fascinating electrochemical performances strongly demonstrate that the as-obtained yolk-shell CoS2@FeS2@NC hollow microspheres can be highly applicable in the field of high-performance LIBs electrode materials. [ABSTRACT FROM AUTHOR]

A good electrode interface film is the guarantee for the efficient migration of lithium-ions (Li-ions) between the cathode and anode and is also the basis for achieving a stable cycle of high-specific energy secondary batteries. However, the cathode electrolyte interface (CEI) and solid electrolyte interface (SEI) formed on the surface of the cathode and anode via the commonly used electrolyte do not have good interface stability and excellent performance. Pouch cells with NCM523/graphite cycle with conventional electrolytes fell below 20% capacity retention in under 150 cycles. Herein, we employ a bicomponent lithium difluorophosphate (LiPO2F2) and ethylene sulfate (DTD) electrolyte additive to enhance the stability of the interface film. According to theoretical calculation results, LiPO2F2 is easier to oxidize and decompose on the surface of the cathode and DTD is more likely to undergo reductive decomposition on the anode surface than other solvents. When matched with a 5000mAh NCM523/graphite pouch cell, the new electrolyte additive can effectively improve the electrode interface stability and the cycling performance (almost 100% capacity retention after 200 cycles) under severe cycling conditions. Overall, this work offers new fundamental insights into the interface optimization and provides direction for the design of new electrolyte additive to better stabilize the lithium-ion batteries (LIBs). [ABSTRACT FROM AUTHOR]