海藻酸钠粘结剂用于钠离子电池红磷-碳负极

通过球磨法制备了红磷-碳(P-C)复合材料,并考察了海藻酸钠(SA)粘结剂用于钠离子电池P-C负极的电化学性能。结果表明,相对于聚偏氟乙烯(PVDF)粘结剂,SA粘结剂使P-C电极展示了较高的可逆容量(在0.1 A·g~(-1)的电流密度下循环20圈后的容量为2 126 m Ah·g~(-1))。使用SA作粘接剂的P-C复合材料优越的电化学性能,归因于SA粘结剂与活性物质之间可能存在的化学作用力,有效缓解了红磷脱嵌钠过程中的体积变化,保持了电极的稳定性。     

Multiple Active Sites: Lithium Storage Mechanism of Cu‐TCNQ as an Anode Material for Lithium‐Ion Batteries

Recently, carboxylate metal‐organic framework (MOF) materials were reported to perform well as anode materials for lithium‐ion batteries (LIBs); however, the presumed lithium storage mechanism of MOFs is controversial. To gain insight into the mechanism of MOFs as anode materials for LIBs, a self‐supported Cu‐TCNQ (TCNQ: 7,7,8,8‐tetracyanoquinodimethane) film was fabricated via an in situ redox routine, and directly used as electrode for LIBs. The first discharge and charge specific capacities of the self‐supported Cu‐TCNQ electrode are 373.4 and 219.4 mAh g^?1, respectively. After 500 cycles, the reversible specific capacity of Cu‐TCNQ reaches 280.9 mAh g^?1 at a current density of 100 mA g^?1. Mutually validated data reveal that the high capacity is ascribed to the multiple‐electron redox conversion of both metal ions and ligands, as well as the reversible insertion and desertion of Li⁺ ions into the benzene rings of ligands. This work raises the expectation for MOFs as electrode materials of LIBs by utilizing multiple active sites and provides new clues for designing improved electrode materials for LIBs.     

High‐Loading Nano‐SnO2 Encapsulated in situ in Three‐Dimensional Rigid Porous Carbon for Superior Lithium‐Ion Batteries

Tin oxide nanoparticles (SnO₂ NPs) have been encapsulated in situ in a three‐dimensional ordered space structure. Within this composite, ordered mesoporous carbon (OMC) acts as a carbon framework showing a desirable ordered mesoporous structure with an average pore size (≈6 nm) and a high surface area (470.3 m² g^?1), and the SnO₂ NPs (≈10 nm) are highly loaded (up to 80 wt %) and homogeneously distributed within the OMC matrix. As an anode material for lithium‐ion batteries, a SnO₂@OMC composite material can deliver an initial charge capacity of 943 mAh g^?1 and retain 68.9 % of the initial capacity after 50 cycles at a current density of 50 mA g^?1, even exhibit a capacity of 503 mA h g^?1 after 100 cycles at 160 mA g^?1. In situ encapsulation of the SnO₂ NPs within an OMC framework contributes to a higher capacity and a better cycling stability and rate capability in comparison with bare OMC and OMC ex situ loaded with SnO₂ particles (SnO₂/OMC). The significantly improved electrochemical performance of the SnO₂@OMC composite can be attributed to the multifunctional OMC matrix, which can facilitate electrolyte infiltration, accelerate charge transfer, and lithium‐ion diffusion, and act as a favorable buffer to release reaction strains for lithiation/delithiation of the SnO₂ NPs.     

A 3D Organically Synthesized Porous Carbon Material for Lithium‐Ion Batteries

We report the first organically synthesized sp–sp³ hybridized porous carbon, OSPC‐1. This new carbon shows electron conductivity, high porosity, the highest uptake of lithium ions of any carbon material to‐date, and the ability to inhibit dangerous lithium dendrite formation. The new carbon exhibits exceptional potential as anode material for lithium‐ion batteries (LIBs) with high capacity, excellent rate capability, long cycle life, and potential for improved safety performance.     

Carbon and Carbon Hybrid Materials as Anodes for Sodium‐Ion Batteries

Sodium‐ion batteries (SIBs) have attracted much attention for application in large‐scale grid energy storage owing to the abundance and low cost of sodium sources. However, low energy density and poor cycling life hinder practical application of SIBs. Recently, substantial efforts have been made to develop electrode materials to push forward large‐scale practical applications. Carbon materials can be directly used as anode materials, and they show excellent sodium storage performance. Additionally, designing and constructing carbon hybrid materials is an effective strategy to obtain high‐performance anodes for SIBs. In this review, we summarize recent research progress on carbon and carbon hybrid materials as anodes for SIBs. Nanostructural design to enhance the sodium storage performance of anode materials is discussed, and we offer some insight into the potential directions of and future high‐performance anode materials for SIBs.     

High‐Capacity Anode Materials for Sodium‐Ion Batteries

Na‐ion batteries are an attractive alternative to Li‐ion batteries for large‐scale energy storage systems because of their low cost and the abundant Na resources. This Review provides a comprehensive overview of selected anode materials with high reversible capacities that can increase the energy density of Na‐ion batteries. Moreover, we discuss the reaction and failure mechanisms of those anode materials with a view to suggesting promising strategies for improving their electrochemical performance.     

二氧化锡/碳气凝胶的制备与电化学性能研究

应用真空浸渍法制备二氧化锡/碳气凝胶的复合材料. XRD、BET、SEM及TEM等测试结果显示,二氧化锡纳米颗粒（5~10 nm）均匀地填充在碳气凝胶的孔道内部. 在100 mA/g的电流密度下经过100周次充放电测试,该材料的容量保持率为首次循环的61.9%.     

锂离子电池硅纳米线负极材料研究

采用涂膜法和直接生长成膜法分别制备两种硅纳米线电极.XRD、SEM和充放电曲线表征、观察和测定材料嵌锂状态过程的结构、形貌及电化学性能.与涂膜法相比,直接生长成膜法制备的硅纳米线电极具有较高的比容量、良好的循环寿命及较好的倍率性能;直接生长成膜法制备的硅纳米线电极,其嵌锂过程硅由晶态逐渐转变为非晶态,且其纳米线直径逐渐增大,但线状结构仍保持完好,进而防止了电极粉化和脱落.     

A Hierarchical Tin/Carbon Composite as an Anode for Lithium‐Ion Batteries with a Long Cycle Life

Tin is a promising anode candidate for next‐generation lithium‐ion batteries with a high energy density, but suffers from the huge volume change (ca. 260 %) upon lithiation. To address this issue, here we report a new hierarchical tin/carbon composite in which some of the nanosized Sn particles are anchored on the tips of carbon nanotubes (CNTs) that are rooted on the exterior surfaces of micro‐sized hollow carbon cubes while other Sn nanoparticles are encapsulated in hollow carbon cubes. Such a hierarchical structure possesses a robust framework with rich voids, which allows Sn to alleviate its mechanical strain without forming cracks and pulverization upon lithiation/de‐lithiation. As a result, the Sn/C composite exhibits an excellent cyclic performance, namely, retaining a capacity of 537 mAh g^?1 for around 1000 cycles without obvious decay at a high current density of 3000 mA g^?1.     

CoO填充多壁碳纳米管作为锂离子电池负极材料

碳纳米管自1990年被日本科学家Iijima发现以来[1],由于其独特的结构组成而具有良好的强度和弹性模量、高比表面积、良好的耐腐蚀性和导电性等特点受到了广泛的关注,并已在催化剂载体、纳米电子器件、储能材料、复合功能材料等诸多领域得到应用。多壁碳纳米管(MWCNT)是由多层石墨卷绕而成的同心圆筒,石墨层间距约为0.034nm,管径一般为几十纳米,管长可达数微米,因此多壁碳纳米管具有较高的长径比,可以被看作一维纳米线。由于多壁碳纳米管在管壁之间和管腔之中存在大量空间,为锂离子的嵌入提供了可能,因此近年来关于多壁碳纳米管储锂的研究…     

CoS2/N-Doped Hollow Spheres as an Anode Material for High-Performance Sodium-Ion Batteries

In this work, we first synthesized polyacrylic acid (PAA) spheres and then used PAA as a template to load Co(OH)₂ particles onto its surface. The product of CoS₂ nanoparticles dispersed in N-doped hollow spheres (N-HCS) was prepared through sulfurization treatment (CoS₂/S@N-HCS). During the sulfuration process, sulfur penetrates into the PAA, embedding into the graphite layer along with the carbonization process. It was found that during the charging and discharging process, the sulfur in the carbon layer will gradually dissolve out, thereby forming new ion diffusion channels in the carbon spheres and exposing more CoS₂ active sites. The CoS₂/S@N-HCS composite exhibits a specific capacity of 729.6 mAh g⁻¹ after 500 cycles at a current density of 1 A g⁻¹. The sodium-storage mechanism and reaction kinetics of the materials were further measured by in-situ electrochemical impedance spectroscopy, ex-situ X-ray diffraction, capacitance performance evaluation, and galvanostatic intermittent titration technique. The excellent cycling performance and rate capability demonstrated that the CoS₂/S@N-HCS is a potential and prospective anode material for sodium-ion batteries.     

From Lithium‐Ion to Sodium‐Ion Batteries: Advantages,Challenges, and Surprises

Mobile and stationary energy storage by rechargeable batteries is a topic of broad societal and economical relevance. Lithium‐ion battery (LIB) technology is at the forefront of the development, but a massively growing market will likely put severe pressure on resources and supply chains. Recently, sodium‐ion batteries (SIBs) have been reconsidered with the aim of providing a lower‐cost alternative that is less susceptible to resource and supply risks. On paper, the replacement of lithium by sodium in a battery seems straightforward at first, but unpredictable surprises are often found in practice. What happens when replacing lithium by sodium in electrode reactions? This review provides a state‐of‐the art overview on the redox behavior of materials when used as electrodes in lithium‐ion and sodium‐ion batteries, respectively. Advantages and challenges related to the use of sodium instead of lithium are discussed.     

Ascorbic Acid‐Assisted Synthesis of Mesoporous Sodium Vanadium Phosphate Nanoparticles with Highly sp2‐Coordinated Carbon Coatings as Efficient Cathode Materials for Rechargeable Sodium‐Ion Batteries

Herein, mesoporous sodium vanadium phosphate nanoparticles with highly sp²‐coordinated carbon coatings (meso‐Na₃V₂(PO₄)₃/C) were successfully synthesized as efficient cathode material for rechargeable sodium‐ion batteries by using ascorbic acid as both the reductant and carbon source, followed by calcination at 750 °C in an argon atmosphere. Their crystalline structure, morphology, surface area, chemical composition, carbon nature and amount were systematically explored. Following electrochemical measurements, the resultant meso‐Na₃V₂(PO₄)₃/C not only delivered good reversible capacity (98 mAh g^?1 at 0.1 A g^?1) and superior rate capability (63 mAh g^?1 at 1 A g^?1) but also exhibited comparable cycling performance (capacity retention: ≈74 % at 450 cycles at 0.4 A g^?1). Moreover, the symmetrical sodium‐ion full cell with excellent reversibility and cycling stability was also achieved (capacity retention: 92.2 % at 0.1 A g^?1 with 99.5 % coulombic efficiency after 100 cycles). These attributes are ascribed to the distinctive mesostructure for facile sodium‐ion insertion/extraction and their continuous sp²‐coordinated carbon coatings, which facilitate electronic conduction.     

h‐BN Nanosheets as 2D Substrates to Load 0D Fe3O4 Nanoparticles: A Hybrid Anode Material for Lithium‐Ion Batteries

h‐BN, as an isoelectronic analogue of graphene, has improved thermal mechanical properties. Moreover, the liquid‐phase production of h‐BN is greener since harmful oxidants/reductants are unnecessary. Here we report a novel hybrid architecture by employing h‐BN nanosheets as 2D substrates to load 0D Fe₃O₄ nanoparticles, followed by phenol/formol carbonization to form a carbon coating. The resulting carbon‐encapsulated h‐BN@Fe₃O₄ hybrid architecture exhibits synergistic interactions: 1) The h‐BN nanosheets act as flexible 2D substrates to accommodate the volume change of the Fe₃O₄ nanoparticles; 2) The Fe₃O₄ nanoparticles serve as active materials to contribute to a high specific capacity; and 3) The carbon coating not only protects the hybrid architecture from deformation but also keeps the whole electrode highly conductive. The synergistic interactions translate into significantly enhanced electrochemical performances, laying a basis for the development of superior hybrid anode materials.     

Cobalt‐Doped FeS2 Nanospheres with Complete Solid Solubility as a High‐Performance Anode Material for Sodium‐Ion Batteries

Considering that the high capacity, long‐term cycle life, and high‐rate capability of anode materials for sodium‐ion batteries (SIBs) is a bottleneck currently, a series of Co‐doped FeS₂ solid solutions with different Co contents were prepared by a facile solvothermal method, and for the first time their Na‐storage properties were investigated. The optimized Co_0.5Fe_0.5S₂ (Fe0.5) has discharge capacities of 0.220 Ah g^?1 after 5000 cycles at 2 A g^?1 and 0.172 Ah g^?1 even at 20 A g^?1 with compatible ether‐based electrolyte in a voltage window of 0.8–2.9 V. The Fe0.5 sample transforms to layered Na_xCo_0.5Fe_0.5S₂ by initial activation, and the layered structure is maintained during following cycles. The redox reactions of Na_xCo_0.5Fe_0.5S₂ are dominated by pseudocapacitive behavior, leading to fast Na⁺ insertion/extraction and durable cycle life. A Na₃V₂(PO₄)₃/Fe0.5 full cell was assembled, delivering an initial capacity of 0.340 Ah g^?1.     

Few-Layer MoS2 Nanosheets Encapsulated in N-Doped Carbon Hollow Spheres as Long-Life Anode Materials for Lithium-Ion Batteries

Two-dimensional molybdenum disulfide (MoS₂) has been recognized as a promising anode material for lithium-ion batteries (LIBs) due to its high theoretical capacity, but its rapid capacity decay owing to poor conductivity, structure pulverization, and polysulfide dissolution presents significant challenges in practical applications. Herein, triple-layered hollow spheres in which MoS₂ nanosheets are fully encapsulated between inner carbon and outer nitrogen-doped carbon (NC) were fabricated. Such an architecture provides high conductivity and efficient lithium-ion transfer. Moreover, the NC shell prevents aggregation and exfoliation of MoS₂ nanosheets and thus maintains the integrity of the nanostructure during the charge/discharge process. As anode materials for LIBs, the C@MoS₂@NC hollow spheres deliver a high reversible capacity (747 mA h g⁻¹ after 100 cycles at 100 mA g⁻¹) and excellent long-cycle performance (650 mA h g⁻¹ after 1000 cycles at 1.0 A g⁻¹), which confirm its potential for high-performance LIBs.     

Hierarchical Mesoporous SnO Microspheres as High Capacity Anode Materials for Sodium‐Ion Batteries

Mesoporous SnO microspheres were synthesised by a hydrothermal method using NaSO₄ as the morphology directing agent. Field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and high‐resolution transmission electron microscopy (HRTEM) analyses showed that SnO microspheres consist of nanosheets with a thickness of about 20 nm. Each nanosheet contains a mesoporous structure with a pore size of approximately 5 nm. When applied as anode materials in Na‐ion batteries, SnO microspheres exhibited high reversible sodium storage capacity, good cyclability and a satisfactory high rate performance. Through ex situ XRD analysis, it was found that Na⁺ ions first insert themselves into SnO crystals, and then react with SnO to generate crystalline Sn, followed by Na–Sn alloying with the formation of crystalline NaSn₂ phase. During the charge process, there are two slopes corresponding to the de‐alloying of Na–Sn compounds and oxidisation of Sn, respectively. The high sodium storage capacity and good electrochemical performance could be ascribed to the unique hierarchical mesoporous architecture of SnO microspheres.     

锂离子电池硅基复合物负极材料*

作为颇有前途的锂离子电池负极材料,硅基材料的研究日益受到重视。硅基负极材料在充放电循环中体积变化过大导致的循环性能差、首次库仑效率低等始终是阻碍其商业化的主要问题。纳米化、合金化和碳包覆是有效的解决措施。本文详细论述了TiB2、TiN、TiC作为基质的硅-化合物复合物,Fe-Si、Cu-Si、Ni-Si体系的硅-金属复合物和硅-碳复合物的研究进展。在硅-碳复合物的研究上,综述了分别采用热解法、球磨法、球磨-热解法、化学聚合法合成,以聚吡咯、聚氯乙烯、聚丙烯腈、间苯二酚-甲醛、柠檬酸、环氧树脂等为碳源的研究进展,同时也综述了Si/碳纳米管复合电极材料的研究情况。     

MoS2‐on‐MXene Heterostructures as Highly Reversible Anode Materials for Lithium‐Ion Batteries

Two‐dimensional (2D) heterostructured materials, combining the collective advantages of individual building blocks and synergistic properties, have spurred great interest as a new paradigm in materials science. The family of 2D transition‐metal carbides and nitrides, MXenes, has emerged as an attractive platform to construct functional materials with enhanced performance for diverse applications. Here, we synthesized 2D MoS₂‐on‐MXene heterostructures through in situ sulfidation of Mo₂TiC₂T_x MXene. The computational results show that MoS₂‐on‐MXene heterostructures have metallic properties. Moreover, the presence of MXene leads to enhanced Li and Li₂S adsorption during the intercalation and conversion reactions. These characteristics render the as‐prepared MoS₂‐on‐MXene heterostructures stable Li‐ion storage performance. This work paves the way to use MXene to construct 2D heterostructures for energy storage applications.