A comprehensive review of various carbonaceous materials for anodes in lithium-ion batteries.

With the advent of lithium-ion batteries (LIBs), the selection and application of electrode materials have been the subject of much discussion and study. Among them, graphite has been widely investigated for use as electrode materials in LIBs due to its abundant resources, low cost, safety and electrochemical diversity. While it is commonly recognized that conventional graphite materials utilized for commercial purposes have a limited theoretical capacity, there has been a steady emergence of new and improved carbonaceous materials for use as anodes in light of the progressive development of LIBs. In this paper, the latest research progress of various carbon materials in LIBs is systematically and comprehensively reviewed. Firstly, the rocking chair charging and discharging mechanism of LIBs is briefly introduced in this paper, using graphite anodes as an example. After that, the general categories of carbonaceous materials are highlighted, and the recent research on the recent progress of various carbonaceous materials (graphite-based, amorphous carbon-based, and nanocarbon-based) used in LIB anodes is presented separately based on the classification of the structural morphology, emphasizing the influence of the morphology and structure of carbon-based materials on the electrochemical performance of the batteries. Finally, the current challenges of carbonaceous materials in LIB applications and the future development of other novel carbonaceous materials are envisioned.

Metal Phosphide Anodes in Sodium-Ion Batteries: Latest Applications and Progress.

Sodium-ion batteries (SIBs), as the next-generation high-performance electrochemical energy storage devices, have attracted widespread attention due to their cost-effectiveness and wide geographical distribution of sodium. As a crucial component of the structure of SIBs, the anode material plays a crucial role in determining its electrochemical performance. Significantly, metal phosphide exhibits remarkable application prospects as an anode material for SIBs because of its low redox potential and high theoretical capacity. However, due to volume expansion limitations and other factors, the rate and cycling performance of metal phosphides have gradually declined. To address these challenges, various viable solutions have been explored. In this paper, the recent research progress of metal phosphide materials for SIBs is systematically reviewed, including the synthesis strategy of metal phosphide, the storage mechanism of sodium ions, and the application of metal phosphide in electrochemical aspects. In addition, future challenges and opportunities based on current developments are presented.

Strategies to mitigate the shuttle effect in room temperature sodium-sulfur batteries: improving cathode materials.

Room-temperature sodium-sulfur batteries (RT-Na/S batteries) with high reversible capacity (1675 mA h g-1) and excellent energy density (1274 W h kg-1) based on abundant resources of the metal Na have become a research hotspot recently. However, the intermediate product sodium polysulfides (NaPSs) generated during the charge-discharge process are easily dissolved in the ether electrolyte and transferred from the sulfur cathode to the metallic sodium surface, resulting in rapid capacity decay (shuttle effect), which seriously affects the practical application of RT-Na/S batteries. Herein, the mechanism and recent research progress in suppressing the shuttle effect of the sulfur cathode in RT-Na/S batteries are summarized. Strategies such as carbon-based materials physically fixing NaPSs, polar materials absorbing NaPSs to reduce their dissolution, and catalytic materials accelerating the transformation of NaPSs into final products are provided. Challenges and insights into high-performance sulfur electrodes for optimizing RT-Na/S batteries are discussed.

Review of metal oxides as anode materials for lithium-ion batteries.

Lithium-ion batteries with a stable circulation capacity, high energy density and good safety are widely used in automobiles, mobile phones, manufacturing and other fields. MOs due to their large theoretical capacity, simple processing and abundant reserves, and used as anode materials for LIBs, have attracted much attention. Three electrochemical mechanisms of MOs are reviewed in this paper. In addition, research progress of MOs and prospects for their further applications in LIBs are summarized.

MoP2/C@rGO synthesised by phosphating the molybdenum-based metal organic framework and GO coating with excellent lithium ion storage performance.

With a high specific capacity, MoP2 has been identified as an ideal electrode material for LIBs. However, the specific capacity is negatively affected due to its poor conductivity and severe volume expansion during insertion and extraction of Li+. In this paper, MoP2-C synthesized by using a Mo-MOF as a precursor, with the generation of C, can effectively solve the agglomeration problem in the synthesis process and alleviate serious volume changes during cycling. Due to the lack of carbon sources provided by a Mo-MOF, the conductivity of MoP2-C cannot be greatly improved. Therefore, rGO and PPy are added to improve the conductivity of MoP2 and further increase the stability of the structure. Compared with MoP2/C and MoP2/C@PPy, MoP2/C@rGO exhibits the highest initial discharge specific capacity of 1208 mA h g-1 at a current density of 100 mA g-1 and rate performances of 830, 750, 630, 550, and 430 mA h g-1 with the current density increasing from 100 mA g-1 to 2000 mA g-1. Notably, the specific capacity remains at 640 mA h g-1 at a current density of 100 mA g-1 after 100 cycles. Followed by 200 cycles at a current density of 2000 mA h g-1, the specific capacity remains at 395 mA h g-1 with a capacity retention rate of 80%.

Layered Niobium Oxide Hydrate Anode with Excellent Performance for Lithium-Ion Batteries.

Benefiting from the advantages of cost-effectiveness and sustainability, lithium-ion batteries (LIBs) are recognized as a next-generation energy technology with great development potential. Herein, niobium oxide hydrate (H3ONb3O8) synthesized by a facile and inexpensive solvothermal method is proposed as the anode of LIBs. It is a layered two-dimensional material composed of negatively charged two-dimensional lamellae and positively charged interlayer hydronium ions. The former consist of NbO6 octahedral units connected by bridging oxygen. Because of the mutual effect of hydronium ions and niobium oxide quantum dots, niobium oxide hydrate exhibits excellent electrochemical activity when used as an anode material. This compound is first applied to lithium-ion batteries, obtaining a high specific capacity (1232 mAh g-1) at 100 mA g-1 and maintaining an outstanding performance after 200 cycles. Therefore, this work not only proposes a simple preparation method of niobium oxide hydrate but also expands the variety of high-performance anode materials.

Superior lithium-storage properties derived from a g-C3N4-embedded honeycomb-shaped meso@mesoporous carbon nanofiber anode loaded with Fe2O3 for Li-ion batteries.

In this work, a honeycomb-shaped meso@mesoporous carbon nanofiber material incorporating homogeneously dispersed ultra-fine Fe2O3 nanoparticles (denoted as Fe2O3@g-C3N4@H-MMCN) is synthesised through a pyrolysis process. The honeycomb-shaped configuration of the meso@mesoporous carbon nanofiber material derived from a natural bio-carbon source (crab shell) acts as a support for an anode material for Li-ion batteries. Graphitic carbon nitride (g-C3N4) is produced via the one-step pyrolysis of urea at high temperature under an N2 atmosphere without the assistance of additives. The resulting favorable electrochemical performance, with superior rate capabilities (1067 mA h g-1 at 1000 mA g-1), a remarkable specific capacity (1510 mA h g-1 at 100 mA g-1), and steady cycling performance (782.9 mA h g-1 after 500 cycles at 2000 mA g-1), benefitted from the advantages of both the host material and the Fe2O3 nanoparticles, which play an important role due to their ultra-fine particle size of 5 nm. The excellent cycle life and high capacity demonstrate that this strategy of strong synergistic effects represents a new pathway for pursuing high-electrochemical-performance materials for lithium-ion batteries.

Several carbon-coated Ga2O3 anodes: efficient coating of reduced graphene oxide enhanced the electrochemical performance of lithium ion batteries.

Gallium oxide as a novel electrode material has attracted attention because of its high stability and conductivity. In addition, Ga2O3 will be converted to Ga during the charge and discharge process, and the self-healing behavior of Ga can improve the cycling stability. In this paper, we synthesized Ga2O3 nanoparticles with a size of about 4 nm via a facile sol-gel method. Meanwhile, we employed three types of carbon materials (reduced graphene oxide, mesoporous carbon nanofiber arrays, and carbon nanotubes) to avoid the aggregation of Ga2O3 nanoparticles and improve the conductivity of Ga2O3 during the discharge/charge process as well. Among the three samples, the deactivating defective sites and special carbon matrix of reduced graphene oxide can provide more attachment points for Ga ions, so the Ga2O3 nanoparticles can be more closely and uniformly distributed on rGO. Benefitting from the perfect combination of reduced graphene oxide sheets and Ga2O3 nanoparticles, a stable capacity of the Ga2O3/rGO electrode can be maintained at 411 mA h g-1 at a current density of 1000 mA g-1 after 600 cycles. We believe that this work provides a novel and efficient way to improve the electrochemical stability of Li-ion batteries.

Flocculent Cu Caused by the Jahn-Teller Effect Improved the Performance of Mg-MOF-74 as an Anode Material for Lithium-Ion Batteries.

Mg-MOF-74/Cu was synthesized by a one-step method and then using the product as a lithium-ion anode material. The flocculent Cu caused by the Jahn-Teller effect conspicuously improves the electrochemical performance of Mg-MOF-74 by enhancing the conductivity of electrode materials. The as-prepared materials exhibited superior rate performance (298.3 mAh g-1 at a current density of 2000 mA g-1) and remarkable cyclability (a specific capacity of 534.5 mAh g-1 is obtained after 300 cycles at 500 mA g-1, which remains at 89.1%). In addition, an electrochemical test of coating an anode material on a stainless steel sheet has also been carried out, and the performance is comparable to that of traditional coating on copper foil (a reversible capacity of 531.7 mAh g-1 is collected, which retains 88.7% of initial capacity). The superior performance, facile one-step synthesis, and low cost of Mg-MOF-74/Cu show promise for practical applications.

One-step synthesis of MOF-derived Ga/Ga2O3@C dodecahedra as an anode material for high-performance lithium-ion batteries.

A Ga/Ga2O3@C dodecahedron composite with a high specific capacity of about 542 mA h g-1 after 200 cycles at the current density of 1000 mA g-1 was synthesized by one-step hydrogen reduction. This hierarchical homogeneous structure combined the Ga, Ga2O3 and carbon frameworks (from Ga-MOF) to exhibit excellent electrochemical performance.

A novel Zr-MOF-based and polyaniline-coated UIO-67@Se@PANI composite cathode for lithium-selenium batteries.

In this work, we synthesized a novel UIO-67@Se@PANI composite cathode material for Li-Se battery applications. Zr-MOFs (metal organic frameworks) were used as a support and a PANI (polyaniline) layer was employed as the coating. UIO-67@Se@PANI was expected to be one of the candidates for Li-Se batteries, with a high specific capacity of 248.3 mA h g-1 at 1C (1C = 675 mA g-1) after 100 cycles. In particular, stable capacities of 203.1 and 167.6 mA h g-1 were received after 100 cycles at high rates of 2C and 5C, respectively. To explain such a good electrochemistry performance of the composite cathode material, multiple characterization methods were carried out. And that can be attributed to the sandwich-like structure of the UIO-67@Se@PANI composite and the fact that UIO-67 can provide unsaturated sites to tether the selenium effectively and the PANI layer can improve the electronic conductivity of the whole electrode significantly.

Bi2S3/C nanorods as efficient anode materials for lithium-ion batteries.

Bi2S3 is a promising negative electrode material for lithium storage owing to its high theoretical capacity. Nevertheless, the capacity of Bi2S3 decays very rapidly upon Li cycling. Here, Bi2S3 and Bi2S3/C were successfully synthesized by a novel route. Sulfur powder as a kind of sulfur source reacted with a metal organic framework based on bismuth and trimesinic acid-Bi(BTC)(DMF)·DMF·(CH3OH)2 (denoted as Bi-BTC). Trimesic acid further acted as a new type of carbon source to synthesize the Bi2S3/C composite. The particle sizes of the composite were smaller than those of pure Bi2S3, showing the suppression of Bi2S3 aggregation. Charge-discharge performance and cyclability for both the Bi2S3 and Bi2S3/C composites in lithium-ion batteries were measured. Specifically, the specific capacities of Bi2S3/C and Bi2S3 reached 765 and 603 mA h g-1, respectively, at 100 mA g-1 after 100 cycles. Because of its high capacity and excellent cycle life, Bi2S3/C is a promising energy storage material.

Realizing uniform dispersion of MnO2 with the post-synthetic modification of metal-organic frameworks (MOFs) for advanced lithium ion battery anodes.

MnO2 nanoparticles were uniformly loaded on the surface of zeolitic imidazolate frameworks (ZIF-67 and ZIF-8) with ligand modification via a facile method with no other impurities introduced, with an average diameter of less than 10 nm. The MnO2/ZIF-COOH composites with stable structures can effectively alleviate expansion tension and provide a fast ion transport channel during electrochemical performance tests. The introduction of carboxyl (-COOH) increases the specific capacity due to Li insertion, enhances the conductivity with ionization, and improves stability through the formation of H-bonds. When used as an anode for lithium ion batteries, the MnO2/ZIF-67-COOH composite exhibits an excellent rate performance (1208 mA h g-1 at 50 mA g-1, 931 mA h g-1 at 100 mA g-1, 828 mA h g-1 at 200 mA g-1, 684 mA h g-1 at 500 mA g-1, 566 mA h g-1 at 1000 mA g-1, 431 mA h g-1 at 2000 mA g-1, and 242 mA h g-1 at 5000 mA g-1) and high cycle stability even at high rates (a high capacity of 664 mA h g-1 is achieved at 1000 mA g-1 and is maintained at approximately 100% after 100 cycles).

Synthesis and Electrochemical Performance of SnOx Quantum Dots@ UiO-66 Hybrid for Lithium Ion Battery Applications.

A novel method that combines the dehydration of inorganic clusters in metal-organic frameworks (MOFs) with nonaqueous sol-gel chemistry and pyrolysis processes is developed to synthesize SnOx quantum dots@Zr-MOFs (UIO-66) composites. The size of as-prepared SnOx nanoparticles is approximately 4 nm. Moreover, SnOx nanoparticles are uniformly anchored on the surface of the Zr-MOFs, which serves as a matrix to alleviate the agglomeration of SnOx grains. This structure provides an accessible surrounding space to accommodate the volume change of SnOx during the charge/discharge process. Cyclic voltammetry and galvanostatic charge/discharge were employed to examine the electrochemical properties of the ultrafine SnOx@Zr-MOF (UIO-66) material. Benefiting from the advantages of the smaller size of SnOx nanoparticles and the synergistic effect between SnOx nanoparticles and the Zr-MOFs, the SnOx@Zr-MOF composite exhibits enhanced electrochemical performance when compared to that of its SnOx bulk counterpart. Specifically, the discharge-specific capacity of the SnOx@Zr-MOF electrode can still remain at 994 mA h g-1 at 50 mA g-1 after 100 cycles. The columbic efficiencies can reach 99%.

Mechanism of electrochemical lithiation of a metal-organic framework without redox-active nodes.

Metal-organic frameworks (MOFs) have many potential uses for separations, storage, and catalysis, but their use as intercalation hosts for batteries has been scarce. In this article, we examine the mechanism of Li insertion in a MOF to provide guidance to future design efforts in this area. As a model system, we choose UiO-66, a MOF with the formula (Zr6O4(OH)4)4(1,4-benzenedicarboxylate)6, as an electrode material for lithium-ion batteries; this MOF is of special interest because the zirconium is not redox active. We report both quantum mechanical characterization of the mechanism and experimental studies in which the material is synthesized as nanoparticles to reduce diffusion lengths for lithium ions and increase the contact area with a conductive carbon phase. The calculated changes in the IR spectra of UiO-66 and lithiated UiO-66 are consistent with the experimental FTIR results. We found experimentally that this MOF can maintain a specific discharge capacity of at least 118 mAh/g for 30 lithiation and delithiation cycles at a rate of C/5, exhibiting good cyclability. Density functional electronic structure calculations show that the charge transfer during lithiation is mainly from Li to node oxygens and carboxylate oxygens, that is, it involves anions rather than cations or aromatic rings, and they provide a mechanistic understanding of the potential for increased Li capacity because the theoretical capacity of UiO-66 with Li at the oxygens in the metal oxide nodes and the carboxylate linkers is more than 400 mAh/g. The lithiation process greatly decreases the bandgap of UiO-66, which is expected to increase its electronic conductivity. The electrode material was also characterized by X-ray diffraction and scanning electron microscopy, which were consistent in confirming that smaller particle sizes were obtained in lower-temperature syntheses.