High-performance Anode Materials For Lithium-ion Batteries Research Articles

Simple hydrothermal synthesis of HCNFs@CoNiO2 composite material for high-performance anode of lithium-ion batteries

In this study, a novel helical carbon nanofibers@CoNiO2 (HCNFs@CoNiO2) composite was first successfully synthesized by the simple hydrothermal method and utilized as anode materials of lithium-ion batteries (LIBs). CoNiO2 nanoparticles with a particle size of about 6 nm were distributed on the surface of HCNFs matrix. The HCNFs@CoNiO2 anode shows the excellent reversible specific capacity of 808.5 mAh/g after 100 cycles at 200 mA/g, which is about four and twenty times larger than that of HCNFs (193.5 mAh/g) and CoNiO2 (35.4 mAh/g), respectively. The electrochemical performance of HCNFs@CoNiO2 was improved due to the synergistic contribution of HCNFs and CoNiO2. In particular, HCNFs with the unique three-dimensional helical structure improve the conductivity and also provide a strong supporting network space during the volume expansion of CoNiO2 nanoparticles. The present study provides a useful reference for the development of the novel high-performance anode material for LIBs.

MOF-Derived Bimetallic Selenide CoNiSe2 Nanododecahedrons Encapsulated in Porous Carbon Matrix as Advanced Anodes for Lithium-Ion Batteries.

Transition metal selenides have received considerable attention as promising candidates for lithium-ion battery (LIB) anode materials due to their high theoretical capacity and safety characteristics. However, their commercial viability is hampered by insufficient conductivity and volumetric fluctuations during cycling. To address these issues, we have utilized bimetallic metal-organic frameworks to fabricate CoNiSe2/C nanodecahedral composites with a high specific surface area, abundant pore structures, and a surface-coated layer of the carbon-based matrix. The optimized material, CoNiSe2/C-700, exhibited impressive Li+ storage performance with an initial discharge specific capacity of 2125.5 mA h g-1 at 0.1 A g-1 and a Coulombic efficiency of 98% over cycles. Even after 1000 cycles at 1.0 A g-1, a reversible discharge specific capacity of 549.9 mA h g-1 was achieved. The research highlights the synergistic effect of bimetallic selenides, well-defined nanodecahedral structures, stable carbon networks, and the formation of smaller particles during initial cycling, all of which contribute to improved electronic performance, reduced volume change, increased Li+ storage active sites, and shorter Li+ diffusion paths. In addition, the pseudocapacitance behavior contributes significantly to the high energy storage of Li+. These features facilitate rapid charge transfer and help maintain a stable solid-electrolyte interphase layer, which ultimately leads to an excellent electrochemical performance. This work provides a viable approach for fabricating bimetallic selenides as anode materials for high-performance LIBs through architectural engineering and compositional tailoring.

Effects of Secondary Phase on Electrochemical Performance of Co-Free High Entropy Spinel Oxide Anodes for Lithium-Ion Batteries

High entropy oxide (HEO) anode materials have recently gained significant attention in lithium-ion batteries (LIBs) due to their exceptional cycling stability, high specific capacity, and unique adjustable properties. The exclusive feature of HEO allows the use of endless element combinations to create new electrode materials with exciting and unexplored properties. In the context of Li-ion battery anode materials, unlike conventional thinking, where a single-phase high entropy oxide (HEO) is considered sufficient and necessary for delivering good electrochemical performance, we report here that this is not a necessary condition. This study demonstrates the advantages of a secondary phase in HEO. Two types of Co-free high entropy spinel oxide (HESO) are synthesized using solvothermal and hydrothermal methods, resulting in single-phase cubic HESO (HESO (C)) and binary-phase (cubic + tetragonal) HESO (HESO (C+T)), respectively. The secondary tetragonal spinel phase introduces phase boundaries and defects/oxygen vacancies in HESO (C+T), which can improve the redox kinetics and reversibility during electrode lithiation/delithiation. The minor tetragonal phase in the HESO (C+T) anode sustains after cycling, largely reducing the morphology deterioration due to improved reversibility, thus contributing to enhanced cyclability. Density functional theory calculation is performed to assess the phase stability of cubic spinel, tetragonal spinel, and rock-salt structures, and validate the cycling stability of the HEO electrodes upon lithiation/delithiation. This is the first time that the effects of a secondary phase in HEO on the electrochemical properties have been reported. A HESO (C+T)||LiNi0.8Co0.1Mn0.1O2 full cell delivers an energy density of ~610 Wh kg−1, demonstrating a great potential of the HESO (C+T) for use in LIBs. The results provide useful guidelines for designing new high-performance anode materials for LIBs.

Surface-wave-sustained plasma synthesis of graphene@Fe–Si nanoparticles for lithium-ion battery anodes

Silicon encapsulated in conductive layers has proven to be an excellent method for retaining the high capacity of silicon in lithium-ion batteries (LIBs) throughout cycling. This study presents an ultra-fast, single-step, and scalable method for synthesizing graphene@Fe–Si nanoparticles via an atmospheric pressure surface-wave-sustained plasma. The verification of the synthesized nanoparticles, encompassing graphene cladding and silicon nanoparticles encapsulated in iron, was conducted through energy-dispersive x-ray spectroscopy mapping, line scanning in the transmission electron microscopy mode, and high-resolution transmission electron microscopy. Additionally, Raman spectroscopy corroborated the identity of the cladding as graphene. This study provides a viable strategy for the industrial production of anode materials for high-performance LIBs.

N/O/P ternary-doped coal-based hierarchical porous carbon networks for high lithium-ion storage performance

Constructing porous structure and surface modification are effective ways to enhance the Li-ion storage performance of commercial graphite anode for lithium-ion batteries (LIBs). Herein, nitrogen, oxygen and phosphorus ternary-doped coal-based hierarchical porous carbon networks (N/O/P-CCNs) were prepared through liquid oxidation combined with self-assembly method. The N/O/P-CCNs have a three-dimensional porous carbon network structure formed by cross-linking carbon nanosheets with an appropriate specific surface area (321 m2 g−1) and distribution of micro-, meso- and macropore, while the surfaces of carbon nanosheets are doped with nitrogen, oxygen and phosphorus. Due to unique hierarchical porous structure and the synergistic effect of ternary doping, the N/O/P-CCNs anode exhibits excellent Li-ion storage properties with initial reversible capacity of 1079 mAh g−1, which is much higher than that of coal-based graphite anode (382 mAh g−1). Besides, the N/O/P-CCNs anode also has superior rate capability (336 and 275 mAh g−1 at 1.0 and 2.0 A g−1) and cycle stability with a high capacity retention (near 100 % after 100 cycles). The excellent electrochemical performance is not only related to the hierarchical pore structure that can provide efficient channels for lithium-ion transport, but also to the ternary-doping of nitrogen, oxygen and phosphorus that can provide more active sites for lithium-ion storage and enhance conductivity. This work provides a novel and effective design strategy for developing high-performance anode materials for LIBs.

Preparation and electrochemical properties of two novel high entropy spinel oxides (MgTiZnNiFe)3O4 and (CoTiZnNiFe)3O4 by solid state reaction

High entropy oxides (HEOs), a novel class of single-phase inorganic materials with high specific capacity, excellent cycling performance, high structural stability, and super-electronic conductivity, exhibit a wide range of useful properties. It is believed that there is one of the most promising anode materials for lithium-ion batteries (LIBs). Being able to create new electrode materials using an infinite number of elemental combinations thanks to the HEO's distinctive adjustable chemical composition characteristics is advantageous. Herein, two varieties of high entropy spinel oxides, (MgTiZnNiFe)3O4 and (CoTiZnNiFe)3O4 by solid state sintering method, and their material characterization and electrochemical properties were investigated respectively. The outcomes of the experiment demonstrate that the particle size distribution of the two samples is uniform. In the electrochemical test, the capacity is unaffected after 800 cycles at the current density of 1000 mA·g−1, and the two powders exhibit excellent cycle stability and magnification performance. Due to the abundant oxygen vacancies, quick three-dimensional Li+ transport path, and entropy stabilization effect of the spinel structure, all HESOs exhibit exceptional cycle stability and rate capability when serving as the anode of LIBs. The next generation of high-performance lithium-ion battery anode materials may gain from the logical design of high-entropy oxides with a variety of electrochemically active elements and novel structures, according to this research, which proposes a novel method for producing high-entropy energy storage materials.

Mixed-valent Nb boosted the electrochemical performance of K3Nb6P4O26@C anode material for lithium-ion batteries

Niobium-based anode materials have good prospects for application in lithium-ion batteries (LIBs) due to the advantages of high specific capacity and high safety. However, the low electronic conductivity poses the main obstacle that limits its performance at present. Here, a mixed-valent niobium based phosphate, K3Nb6P4O26@C (KNPO@C), was designed and prepared as the anode material for LIBs. The mixed-valent Nb in KNPO provides multi-electron electrochemical reactions and presents an electronic conductivity higher than that of a sole Nb5+-based material. In addition, the three-dimensional (3D) channels in the crystal structure of KNPO facilitate the rapid transport of lithium-ions. KNPO@C anode delivers a high specific capacity of 250 mA h g–1 at 0.1 C and an excellent cycling stability was measured with a capacity retention of 60.7 % after 1000 cycles at 2 C. The charge/discharge mechanism of KNPO@C was systematically investigated by ex-situ XRD and ex-situ XPS. The kinetic information obtained from the cyclic voltammetry (CV) suggests that the pseudocapacitance effect also play an important role in the specific capacity. These results demonstrate the potential of KNPO@C as a practical anode material for high-performance LIBs.

Two-dimensional CrP2 with high specific capacity and fast charge rate for lithium-ion battery

The electrode material is regarded as one of the key factors that determine the performance of lithium-ion batteries (LIBs). However, it is still a challenge to search for an anode material with large capacity, low diffusion barrier, and good stability. In the present work, two new CrP2 monolayers (Pmmn-CrP2 and Pmma-CrP2) are predicted by means of first principles swarm structure search. Our study shows that both the two CrP2 monolayers have high dynamical and thermal stability, as well as excellent electron conductivity. Additionally, Pmmn-CrP2 exhibits a remarkably high storage capacity of 705 mA⋅h⋅g−1 for Li, meanwhile the diffusion energy barrier of Li on the surface of this monolayer is 0.21 eV, ensuring it as a high-performance anode material for LIBs. We hope that our study will inspire researchers to search for new-type two-dimensional (2D) transition metal phosphides for the electrode materials of LIBs.

CoSe nanoparticles in-situ grown in 3D honeycomb carbon for high-performance lithium storage

Although transition metal selenides are considered to be extremely promising anode materials for lithium-ion batteries (LIBs), severe volume changes and low electronic conductivity are their huge and unavoidable challenges. To solve these problems, CoSe nanoparticles in-situ grown on the inner surface of every macropore of 3D honeycomb C is successfully synthesized by three simple steps: dense assembling of polystyrene spheres, calcination and gaseous selenylation. The sizes of CoSe and honeycomb pores are 10–15 nm and 190 nm, respectively. The content of CoSe is 72 wt%. This unique architecture guarantees high electrochemical activity, rapid reaction kinetics and excellent structural stability of CoSe, as identified by cycling and rate performance measurements, various electrochemical kinetics analyses and ex-situ characterization of the cycled electrode material. As a result, the CoSe@honeycomb C anode exhibits extraordinary cycling performance (823.5 mAh g−1 after 200 cycles at 0.5 A g−1, 610.1 mAh g−1 after 250 cycles at 2 A g−1, 247 mAh g−1 after 1500 cycles at 5 A g−1) and exceptional rate capability (261.9 mAh g−1 at 10 A g−1, 1491.4 mAh g−1 at 0.1 A g−1), demonstrating that it is a potential anode material for high-performance LIBs.

Molten salt-assisted valorization of waste PET plastics into nanostructured SnO2@terephthalic acid with excellent Li-ion storage performance

Polyethylene terephthalate (PET) is one of the most widely used plastic materials, and therefore, its clean, efficient and low-cost valorization into high-value materials is of substantial economic and environmental interest. Here, for the first time, the utilization of molten salts for the facile, scalable and fast depolymerization of PET into terephthalic acid (C8H6O4) is reported. It is asserted that the simple heat-treatment of PET in molten KCl-LiCl containing SnCl2 in air leads to the green preparation of nanocrystalline terephthalic acid embedded with SnO2 nanocrystals, with an excellent performance as the anode of lithium ion batteries (LIBs). The structural, morphological, thermal, surface, electrical and electrochemical characteristics of plastic-derived nanocomposites are evaluated by various techniques. The sample prepared at 500 °C (PDN-500) contains 28.3 wt% SnO2, and exhibits an enhanced bulk electrical conductivity of 447.3 S m−1, and an excellent Li-ion storage capacity of 498 mAh g-1 after 500 cycles, corresponding to 1657 mAh per gram of SnO2. This performance is accompanied by an enhanced lithium ions diffusion coefficient of 8.51 × 10−10 cm2 s−1 recorded after 300 cycles, and a capacitive storage contribution of above 42 %. The sustainability of the presented molten salt approach is discussed from two complementary points of view, in terms of the clean conversion of waste plastics into high-performance anode materials for LIBs, as well as the facile and scalable depolymerization of PET, reducing the waste plastics in our environment. This article proposes an efficient and green strategy for the valorization of waste plastics into nanostructured SnO2@terephthalic acid for energy storage applications.

Ordered sandwich silicon quantum dot/Fe3O4/reduced graphene oxide architectures for high-performance lithium-ion batteries

Iron-based oxides are one of the most promising anode materials for lithium-ion batteries (LIBs) because of their high theoretical capacity, low cost, and eco-friendliness. However, its poor cycle stability and low-rate performance limit its wide application. In this work, a novel ordered sandwich-structured nanocomposite consisting of Fe3O4, silicon quantum dots (Si-QDs), and reduced graphene oxide (rGO) is synthesized via a self-assembly approach combined with subsequent annealing. Si-QDs are vital to guide the uniform formation and homogeneous distribution of nano-sized Fe3O4 on the rGO nanosheets. The resultant Si-QDs/Fe3O4/rGO composite possesses a unique ordered sandwich structure, in which Si-QDs and Fe3O4 particles are evenly anchored on rGO nanosheets. Si-QDs/Fe3O4/rGO delivers high specific capacity, outstanding cycling stability, and rate capability. At a current density of 100 mA·g−1, it displays an initial discharge-specific capacity of 1489.6 mAh·g−1 and maintained a specific capacity of 1367.1 mAh·g−1 after 80 cycles. The crucial effect of Si-QDs on the composite's morphology, structure, and electrochemical performances is deeply investigated by corresponding characterizations. The preparation strategy may be introduced in other metal-oxide-based nanocomposites with ordered sandwich structures and points out an ingenious way to design anode materials for high-performance LIBs.

Organic Anode Materials for Lithium-Ion Batteries: Recent Progress and Challenges.

In the search for novel anode materials for lithium-ion batteries (LIBs), organic electrode materials have recently attracted substantial attention and seem to be the next preferred candidates for use as high-performance anode materials in rechargeable LIBs due to their low cost, high theoretical capacity, structural diversity, environmental friendliness, and facile synthesis. Up to now, the electrochemical properties of numerous organic compounds with different functional groups (carbonyl, azo, sulfur, imine, etc.) have been thoroughly explored as anode materials for LIBs, dividing organic anode materials into four main classes: organic carbonyl compounds, covalent organic frameworks (COFs), metal-organic frameworks (MOFs), and organic compounds with nitrogen-containing groups. In this review, an overview of the recent progress in organic anodes is provided. The electrochemical performances of different organic anode materials are compared, revealing the advantages and disadvantages of each class of organic materials in both research and commercial applications. Afterward, the practical applications of some organic anode materials in full cells of LIBs are provided. Finally, some techniques to address significant issues, such as poor electronic conductivity, low discharge voltage, and undesired dissolution of active organic anode material into typical organic electrolytes, are discussed. This paper will guide the study of more efficient organic compounds that can be employed as high-performance anode materials in LIBs.

Synthesis of Co3O4/VG/CNT Composite Microspheres with Excellent Lithium Storage Performance

In order to improve the conductivity of Co3O4, Co3O4/VG/CNT composite microspheres were prepared by facile spray drying method and subsequently plasma-enhanced chemical vapor deposition method. A three-dimensional conductivity network was constructed by vertical graphenes and CNTs distributed throughout the microspheres, the transmission of electrons was greatly promoted, excellent rate performance was realized, and the high average reversible specific capacity of 526 mA h g–1 was still retained at 1000 mA g–1. Besides, thanks to the abundant pores distributed in the whole microspheres, the stress could be greatly released during the repeated charging/discharging processes, long cycling stability could be achieved, and the reversible specific capacity as high as 396 mA h g–1 was retained after 1000 cycles at 800 mA g–1. The preparation of Co3O4/VG/CNT composite microspheres can provide a new idea for high-performance lithium-ion battery anode materials.

SiO–Sn2Fe@C composites with uniformly distributed Sn2Fe nanoparticles as fast-charging anodes for lithium-ion batteries

SiO-based materials represent a promising class of anodes for lithium-ion batteries (LIBs), with a high theoretical capacity and appropriate and safe Li-insertion potential. However, SiO experiences a large volume change during the electrochemical reaction, low Li diffusivity, and low electron conductivity, resulting in degradation and low rate capability for LIBs. Here, we report on the rapid crafting of SiO–Sn2Fe@C composites via a one-step plasma milling process, leading to an alloy of Sn and Fe and in turn refining SiO and Sn2Fe into nanoparticles that are well dispersed in a nanosized, few-layer graphene matrix. The Sn and Fe nanoparticles generated during the first Li-insertion process form a stable network to improve Li diffusivity and electron conductivity. As an anode material, the SiO–Sn2Fe@C composite manifests high reversible capacities, superior cycling stability, and excellent rate capability. The capacity retention is found to be as high as 95% and 84% at the 100th and 300th cycles under 0.3 ​C. During rate capability testing at 3, 6, and 11 ​C, the capacity retentions are 71%, 60%, and 50%, respectively. This study highlights that this simple, one-step plasma milling strategy can further improve SiO-based anode materials for high-performance LIBs.

Graphene supported double-layer carbon encapsulated silicon for high-performance lithium-ion battery anode materials

Carbon coating has been an effective procedure to tackle the severe structural degradation and poor conductivity during cycling of silicon-based anodes in lithium-ion batteries (LIBs). However, the traditional coated carbon usually is tight and thus limit the fast-charging rate and high specific capacity. Herein, through in-situ formation of metal-organic frameworks on the surface, silicon particles were firstly coated by an inside carbon layer. Followed by a solvothermal reaction with the mixture of sucrose and graphene oxide, the second carbon layer outside the silicon particles was deposited, and simultaneously a highly conductive graphene network was formed. After a high temperature pyrolysis process, a graphene matrix supported silicon material with inward multi-channel carbon and outward tight activated carbon was prepared. This unique core/double-layer carbon structure, combined with the highly conductive graphene frameworks, render the material to demonstrate excellent electrochemical performance as anode materials for LIBs in terms of both lithium storage capacity and cycling stability. Thus, the electrode materials deliver a high specific capacity of 1528.1 mA h g−1 at the current density of 0.1 A g−1 and rate capacity retention of 45.5% at 1 A g−1 to 0.1 A g−1. Simultaneously, a highly stable reversible capacity of 1182 mAh g−1 with 89.5% retention over 240 cycles at a current density of 0.2 A g−1 and 484 mAh g−1 with 76.8% retention after 450 cycles at 1.0 A g−1 were obtained. This work can offer an alternative approach for high-energy and low-cost silicon-based anodes for LIBs.

In-situ construction of nano-sized Ni-NiO-MoO2 heterostructures on holey reduced graphene oxide nanosheets as high-capacity lithium-ion battery anodes

Transition metal oxide anodes for lithium-ion batteries (LIBs) have evoked widespread concern by reason of their high theoretical capacity, abundance, and diversity. Nevertheless, they suffer from severe volume expansion/contraction and slow reaction kinetics during cycling, resulting in poor electrochemical lithium storage performance. Herein, we ingeniously design a unique multi-component composite with Ni-NiO-MoO2 heterostructure nanoparticles in-situ dispersed on holey reduced graphene oxide (rGO) nanosheets using a facile self-sacrificed MOFs template method. The integration of Ni-NiO-MoO2 heterostructure nanoparticles and well-conductive rGO nanosheets with unique nanoholes can collaborate the inherent properties of each component to improve the reaction kinetics and synergistically enhance the lithium storage property. Thereby, the Ni-NiO-MoO2/rGO composite as a LIB anode exhibits outstanding cycling performance with a high reversible capacity (910 mAh g−1 after 220 cycles at 500 mA g−1) as well as excellent rate capability maintaining the great capacity retention of 534 mAh g−1 at 3000 mA g−1. This research offers a vital inspiration for designing and fabricating multi-component metal oxide-based composite anode materials for high-performance LIBs.

Encapsulating ultrafine cobalt sulfides into multichannel carbon nanofibers for superior Li-ion energy storage

Developing high-capacity anode materials based on metal sulfides is of great importance for building advanced lithium-ion batteries (LIBs). Herein, we demonstrate rational encapsulation of cobalt sulfide (CoSx) nanoparticles into multichannel carbon nanofibers (CoSx/MCF) with substantially improved Li+ reactivity and durability. The unique multichannel and conductive carbon scaffold not only affords boosted electron/Li + transportation pathways for fast redox reaction with CoSx, but also stabilizes the electrode structure by buffering the volume change of CoSx. Impressively, the CoSx/MCF composite could serve as flexible anodes to deliver a high reversible capacity of 737 mAh g−1 at 0.2 A g−1 after 100 cycles, superior rate capacity of 374 mAh g−1 at 5 A g−1, and excellent operating stability over 1000 cycles. Practical feasibility is also demonstrated by a full cell based on the high-capacity CoSx/MCF anode and Li[Ni0.8Co0.1Mn0.1]O2 cathode. The present study may provide insights for the facile synthesis of advanced anode materials for high-performance LIBs.

Construction of three-dimensional carbon framework-loaded silicon nanoparticles anchored by carbon film for high-performance lithium-ion battery anode materials

Construction of three-dimensional carbon framework-loaded silicon nanoparticles anchored by carbon film for high-performance lithium-ion battery anode materials

One-pot synthesis of MnO-loaded mildly expanded graphite composites as high-performance lithium-ion battery anode materials

Improving the properties of conventional graphite anode materials has been an important research topic for enhancing the performances of lithium-ion batteries (LIBs). Herein, we develop a facile one-pot approach to mildly expand graphite (MEG) and simultaneously load MnO onto the as-prepared MEG to synthesize MnO@MEG composites as high-performance anode materials for LIBs. With the improved porous structure and electrical conduction network, both the MEG and MnO components of the composite exhibit well-defined electrochemical properties and alleviated volume changes upon charge/discharge, synergistically enhancing the electrochemical performances for our composites. With a high active material content and high mass loading for the testing electrode, the optimized MnO@MEG composite shows a high capacity (437.77 mAh g−1 at 0.1 C), a high rate capability (capacity retains 71.93% at 1 C vs. 0.1 C), and a high cycling stability (capacity retains 73.17% and 68.13% after charge/discharge at 0.5 C and 1 C, respectively, for 50 cycles), significantly outperforming its pristine graphite counterpart and previously reported similar MnO composites with other carbon materials, thereby standing for a practically promising anode material for LIBs. Broadly, the one-pot approach developed in the present work can be extended for producing other graphite-based composites for other energy-related technologies.

In situ measurement and mechanism analysis of the lithium storage behavior of graphene electrodes

Graphene has attracted widespread attention for development of high-performance lithium-ion battery anode materials. In this paper, the lithium storage mechanisms of multilayer graphene, few-layer graphene, and reduced graphene oxide electrodes are investigated, and the influences of layers and defects in the microstructure are analyzed. The evolution of microstructure deformation of different graphene electrodes, combined with the diffusivity and distribution of lithium, is systemically investigated by in-situ Raman spectroscopy during lithiation and delithiation. The results show that graphene electrodes with different structures exhibit different mechanical behaviors and thus different lithium storage capacities. Mechanical analysis indicates that although the surfaces and defects are active, interlayer lithium insertion contributes the most lithium storage capacity. As the number of graphene layers increases and/or defects decrease, more interlayer spaces would be provided. Thus, the lithium storage capacity of multilayer graphene is significantly higher than those of few-layer graphene and reduced graphene oxide. An in-depth understanding of the effect of the microstructure on the lithium storage behavior of graphene electrodes will provide an experimental basis for development of high-performance graphene electrodes.