Hexagonal FeNi2Se4@C Nanoflakes as High Performance Anode Materials for Sodium-ion Batteries

Metal selenides have drawn significant attention as promising anode materials for sodium-ion batteries(SIBs)owing to their high electronic conductivity and reversible capacity.Herein,hexagonal FeNi2Se4@C nanoflakes were synthesized via a facile one-step hydrothermal method.They deliver a reversible capacity of 480.7 mA·h/g at 500 mA/g and a high initial Coulombic efficiency of 87.8%.Furthermore,a discharge capacity of 444.8 mA·h/g can be achieved at 1000 mA/g after 180 cycles.The sodium storage mechanism of FeNi2Se4@C is uncovered.In the discharge process,Fe and Ni nanoparticles are generated and distributed in Na2Se matrix homogeneously.In the charge process,FeNi2Se4 phase is formed reversibly.The reversible phase conversion of FeNi2Se4@C during cycling is responsible for the excellent electrochemical performance and enables FeNi2Se4@C nanoflakes promising anode materials for SIBs.     

碳包覆纳米SnSb合金作为高性能钠离子电池负极材料

采用喷雾热解法合成了碳包覆的SnSb/C合金复合材料,利用X射线粉末衍射仪(XRD)、场发射扫描电子显微镜(FESEM)、透射电子显微镜(TEM)等方法对产物的物相和形貌进行了表征,其中SnSb/C颗粒为10 nm左右的复合材料(10-SnSb/C)作为钠离子电池负极时,表现出优异的循环和倍率性能。首圈放电达到722.1m Ah·g~(-1),首圈库仑效率86.3%,在100、1000、3000 m A·g~(-1)下比容量分别为607.7、645.4、452.2 m Ah·g~(-1),在1000 m A·g~(-1)电流下循环200周后可逆容量达到623 m Ah·g~(-1),容量保持率为95%。SnSb/C复合材料出色的储钠性能源于其完全被碳包裹的纳米结构,该结构可以有效提高活性物质的利用率,促进电子、离子的传导,并且抑制纳米粒子在长循环过程中的粉化和团聚。     

基于水凝胶衍生的硅/碳纳米管/石墨烯纳米复合材料及储锂性能

通过氧化石墨烯(GO)和壳聚糖(Cs)之间的氢键以及静电作用形成GO水凝胶,从而将纳米硅颗粒和碳纳米管(CNT)原位包封于其中,再经冷冻干燥及随后的热处理制得三维硅/碳纳米管/石墨烯(Si-CNT@G)纳米复合材料。采用X射线衍射(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)、热重分析(TGA)等技术对制得样品的物相、结构和微观形貌等进行了表征。结果表明,所得复合材料在CNT纵横交织的石墨烯网络中,均匀地分布着纳米硅颗粒。当作为锂离子电池的负极材料时,在两种碳介质的协同作用下,有效缓冲硅材料在充放电过程中脱/嵌锂引起的体积变化,缩短了锂离子和电子传输的距离,Si-CNT@G复合材料表现出较好的循环稳定性以及倍率性能。在500 m A·g~(-1)的充放电电流密度下,经过200圈循环后,其放电比容量仍高达673.7 m Ah·g~(-1),容量保持率高达97%;即使将充放电电流密度升至2000 m A·g~(-1)时,该复合材料仍保持有566.9 m Ah·g~(-1)的高可逆放电比容量。独特的制备方法和优越的储锂性能,使得Si-CNT@G纳米复合材料成为理想的高性能锂离子电池负极材料的候选.     

Nitrogen-doped Carbon Coated Na3V2(PO4)3 with Superior Sodium Storage Capability

Cathodes with high cycling stability and rate capability are required for ambient temperature sodium ion batteries in renewable energy storage application. Na₃V₂(PO₄)₃ is an attractive cathode material with excellent electrochemical stability and fast ion diffusion coefficient within the 3D NASICON structure. Nevertheless, the practical application of Na₃V₂(PO₄)₃ is seriously hindered by its intrinsically poor electronic conductivity. Herein, solvent evaporation method is presented to obtain the nitrogen-doped carbon coated Na₃V₂(PO₄)₃ cathode material, delivering enhanced electrochemical performances. N-Doped carbon layer coating serves as a highly conducting pathway, and creates numerous extrinsic defects and active sites, which can facilitate the storage and diffusion of Na⁺. Moreover, the N-doped carbon layer can provide a stable framework to accommodate the agglomeration of the electrode upon electrode cycling. N-Doped carbon coated Na₃V₂(PO₄)₃(NC-NVP) exhibits excellent long cycling life and superior rate performances than bare Na₃V₂(PO₄)₃ without carbon coating. NC-NVP delivers a stable capacity of 95.9 mA·h/g after 500 cycles at 1 C rate, which corresponds to high capacity retention(94.6%) with respect to the initial capacity(101.4 mA·h/g). Over 91.3% of the initial capacity is retained after 500 cycles at 5 C, and the capacity can reach 85 mA·h/g at 30 C rate.     

Ni3S2@碳纳米管复合材料的制备及其储钠性能

采用一步固相煅烧工艺制备了碳纳米管原位封装Ni₃S₂纳米颗粒（Ni₃S₂@CNT）,并研究了其作为钠离子电池（SIBs）负极材料的电化学性能. 通过X射线衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、循环伏安测试、恒流充放电以及交流阻抗等研究了Ni₃S₂@CNT的物相结构、形貌特征以及电化学性能. 电化学测试表明,材料在100 mA·g ^-1电流密度下,放电容量可以达到541.6 mAh·g ^-1,甚至在2000 mA·g ^-1的大电流密度下其放电比容量也可以维持在274.5 mAh·g ^-1. 另外,材料在100 mA·g ^-1电流密度下,经过120周充放电循环后其放电和充电比容量仍然可以保持在374.5 mAh·g ^-1和359.3 mAh·g ^-1,说明其具有良好倍率性能和循环稳定性能. 良好的电化学性能归因于这种独特的碳纳米管原位封装Ni₃S₂纳米颗粒结构. 碳纳米管不但可以提高复合材料的导电性,也可以缓冲Ni₃S₂纳米颗粒在反复充放电过程中产生的体积膨胀效应,明显改善了Ni₃S₂@CNT负极复合材料的电化学性能.     

利用原位氟化保护层改善三维锡锂合金/碳纸负极贫电解液下性能

金属锂具有最高的理论比容量(3860 mAh·g^?1)和最低的还原电势(?3.04 V),是新型高能量密度电池负极材料的最佳选择之一。然而由于金属锂负极表面自发生成的固态电解质界面(SEI)十分不稳定,导致锂枝晶的产生和电池容量快速衰减,严重限制了锂金属电池的商业化应用。因此,本工作利用碳酸双(2,2,2-三氟乙基)酯(DTFEC)添加剂在三维锡锂合金/碳纸负极(SnLi/Cp)表面原位构筑了高机械强度和离子穿透性的含氟化物(LiF和SnF2)保护层,有效地改善了锂负极的倍率性能和循环稳定性。结果显示,SnLi/Cp对称电池在8 mA·cm^?2的电流密度下经过100次循环后过电位仅为90 mV。当将电解液降低到12μL(1.5μL·(mAh)?1)时,在5 mA·cm^?2的电流密度下对称电池仍具有优异的稳定性;SnLi/Cp||NMC811电池在1C(1.5 mA·cm^?2)条件下能稳定循环300圈以上,库伦效率高达98.1%。这种方法能够显著改善锂金属负极的循环稳定性,有助于实现高能量密度锂金属电池的实际应用。     

碳布负载的缺氧型Na2Ti3O7纳米带阵列作为高性能柔性钠离子电池负极材料

作为锂离子电池的理想替代品,钠离子电池因具有能源储备丰富、成本低廉等优点而受到人们的广泛关注。柔性便携式电子产品的发展亟需柔性储能器件的研制。因此,发展一种廉价、高性能的柔性钠离子电池负极材料成了科研工作者的共同目标。在此项工作中,我们通过简单的水热合成和热还原法发展了一种以柔性碳布为基底,与缺氧型的Na₂Ti₃O₇纳米带(NTO)构成三维阵列结构的新型柔性钠离子电池负极材料。复合材料(R-NTO/CC)的导电性和活性位点得到提高,电化学性能也大幅提升,在200 mA·cm^-2的电流密度下,实现100 mAh·cm^-2的面积比容量,且经过200次循环后仍保留最初电容值的80%。此外,这种电极还具有优良的倍率性能,当电流密度提高到400 mA·cm^-2时,仍保持69.7 mAh·cm^-2的面积比容量,是未引入氧空位材料的三倍之多。这种三维缺氧的电极材料可有效提高载流子浓度,缩短离子传输通道,从而大幅提升电极的电化学性能。此工作为设计合成高储钠性能的新型的负极材料提供了一种实用有效的策略。     

Novel Biomass-derived Hollow Carbons as Anode Materials for Lithium-ion Batteries

A novel hollow carbon derived from biomass lotus-root has been prepared by a one-step carbonization method. The carbon anode obtained at 900 ℃ showed the best electrochemical performance, corresponding to a high specific capacity of 445 mA∙h/g at 0.1 C, as well as excellent cycling stability after 500 cycles. Further investigation exhibits that the lithium storage of hollow carbon involves Li⁺ adsorption in the defect sites and Li⁺ insertion. The results showed that the intrinsic structure of lotus root can inspire us to prepare biomass carbon with a hollow structure as an excellent anode for lithium-ion batteries.     

Bimetallic Sulfide/Sulfur Doped T3C2Tx MXene Nanocomposites as High-performance Anode Materials for Sodium-ion Batteries

The application of transition metal dichalcogenides(TMDs) as anode materials in sodium-ion batteries (SIBs) has been hindered by low conductivity and poor cyclability. Herein, we report the synthesis of Co_xFe_1-xS₂ bimetallic sulfide/sulfur-doped Ti₃C₂ MXene nanocomposites(Co_xFe_1-xS₂@S-Ti₃C₂) by a facile co-precipitation process and thermal-sulfurization reaction. The interconnected 3D frameworks consisting of MXene nanosheets can effectively buffer the volume change and enhance the charge transfer. In particular, sulfur-doped MXene nanosheets provide rich active sites for sodium storage and restrain sulfur loss during charging/discharging processes, leading the increase of specific capacity and cycling the stability of anode materials. As a result, Co_xFe_1-xS₂@S-Ti₃C₂ anodes exhibited high capacity, high rate capability and long cycle life(399 mA·h/g at 5 A/g with an 94% capacity retention after 600 cycles).     

钠离子电池炭基负极材料研究进展

钠离子电池是目前新兴的低成本储能技术,因在大规模电化学储能中具有较好的应用前景而受到了国内外学者广泛的关注与研究。作为钠离子电池的关键电极材料之一,非石墨的炭质材料因具有储钠活性高、成本低廉、无毒无害等诸多优点,而被认为是钠离子电池实际应用时负极的最佳选择。本文详细综述了目前钠离子电池炭基负极材料的研究进展,重点介绍了炭质材料的储钠机理与特性,分析了炭材料结构与电化学性能之间的关系,探讨了其存在的问题,为钠离子电池炭基负极材料的发展提供有益的认识。     

Improved Initial Charging Capacity of Na-poor Na0.44MnO2 via Chemical Presodiation Strategy for Low-cost Sodium-ion Batteries

Sodium-ion batteries(SIBs)are promising for grid-scale energy storage applications due to the natural abundance and low cost of sodium.Among various Na insertion cathode materials,Na0.44MnO2 has attracted the most attention because of its cost effectiveness and structural stability.However,the low initial charge capacity for Na-poor Na0.44MnO2 hinders its practical applications.Herein,we developed a facile chemical presodiated method using sodiated biphenly to transform Na-poor Na0.44MnO2 into Na-rich Na0.66MnO2.After presodiation,the initial charge capacity of Na0.44MnO2 is greatly enhanced from 56.5 mA·h/g to 115.7 mA·h/g at 0.1 C(1 C=121 mA/g)and the excellent cycling stability(the capacity retention of 94.1%over 200 cycles at 2 C)is achieved.This presodiation strategy would open a new avenue for promoting the practical applications of Na-poor cathode materials in sodium-ion batteries.     

高性能混合相钠离子层状负极材料Na_(0.65)Li_(0.13)Mg_(0.13)Ti_(0.74)O_2

钛基层状氧化物因具有较低的成本、较好的空气稳定性和循环稳定性,以及较高的安全性等优点,被认为是一种具有潜在应用价值的室温钠离子电池负极材料。本文使用固相法首次设计并合成了一种新型P2相Na_(0.65)Li_(0.13)Mg_(0.13)Ti_(0.74)O_2电极材料。通过延长烧结时间,可以制得混有正交相的样品,进一步研究发现该混合相样品具有更加优异的储钠性能。混合相样品首周可逆容量为96.3 m Ah·g~(-1),而纯P2相仅为85.1 m Ah·g~(-1);在1C倍率下循环400周的容量保持率为89.7%,高于P2相的84.4%,并且倍率性能显著提升(混合相样品56.6 m Ah·g~(-1)/5C vs.纯P2相样品47.1m Ah·g~(-1)/2C)。该研究发现共生的两种结构能够提高材料的离子、电子传导,进而可以改善材料充放电过程中离子、电荷分布的均一性,从而提升材料的循环性能。该研究成果有助于拓展其他层状氧化物材料的研究思路,为提高钠离子电池的能量密度和循环性能提供了可行方法。     

Synthesis and Electrochemical Investigation of O3-Type High-nickel NCM Cathodes for Sodium-ion Batteries

Sodium ion batteries(SIBs)are promising energy storage devices for smart grid applications due to their low cost and the high abundance of sodium,but few cathode materials of SIBs with high energy density are available for practical applications.Herein,a series of NaNCM ternary materials(NCM=nickel-cobalt-manganese)is obtained by solid-phase reaction with well-regulated temperature and other reaction conditions.XRD results show that impure NiO phase is more likely to occur under high nickel content.The cross-section SEM indicates that the primary particles in the electrode materials are radially distributed along the radial direction,and the internal porous structure is conducive to the infiltration of electrolyte.The initial specific capacities of Na[Ni0.68Co0.10Mn0.22]O2(NaNCM712),Na[Ni0.6Co0.2Mn0.2]O2(NaNCM622)and Na[Ni0.4Co0.3Mn0.3]O2(NaNCM433)at 0.2 C are 165.5,153.1 and 146.8 mA·h/g,and the corresponding capacity retention rates are 63.2%,78.5%and 71.7%after 100 cycles.NaNCM712 possesses the highest initial specific capacity,and NaNCM433 delivers the best rate capability.The rate capabilities of high-nickel and low-cobalt NaNCM cathodes need to be further improved.Moreover,ex-situ XRD pattern reveals the structure evolution(from O3 type to P2 type)during a long cycling charge and discharge process.     

石墨炔-有机共轭分子复合材料的制备及其储锂性能

发展了基于超分子化学的新方法实现了对石墨炔的原位氮掺杂,通过利用石墨炔与有机共轭分子间强的π–π作用,原位制备了石墨炔/卟吩复合材料薄膜,并用作锂离子电池的负极材料,其比容量增加到了1000 mAh∙g⁻¹,该复合材料表现出优良的倍率性能和循环稳定性,为可控制备掺氮石墨炔复合材料提供了新的思路。     

还原氧化石墨烯包覆MOF衍生In2Se3用于钠离子电池负极(英文)

MOF衍生金属硒化物由于其有序的碳骨架结构和高导电性,被认为是钠离子电池极具前景的负极材料。它们具有快速的电子/离子输运通道,有利于钠离子的嵌入和脱出。然而,循环过程中的大量体积膨胀会导致结构坍塌。为了解决这个问题,通过表面改性在MOF衍生金属硒化物表面引入了一个二维的还原氧化石墨烯网络,既可以缓解体积变化,又能加速电子转移。实验证实这种策略是有效的,在1 A·g^-1下500次循环后,包覆了还原氧化石墨烯的复合材料电极容量保持率提高到了95.2%。相比之下,不含还原氧化石墨烯的容量保留率仅为74.2%。此外,由于还原氧化石墨烯网络和MOF衍生In₂Se₃协同作用,在0.1 A·g^-1下显示出了468 m Ah·g^-1的优越容量。而在相同的电流密度下,未包覆还原氧化石墨烯的只产生393 m Ah·g^-1的比容量。采用循环伏安法(CV)研究了In₂Se₃@C/rGO电极的电化学过程,结果表明其具有良好的电化学反应活性...     

Se-decorated SnO2/rGO composite spheres and their sodium storage performances

SnO₂ is considered a promising anode material for sodium-ion batteries due to its high theoretical capacity and low cost.However,the poor electrical conductivity and dramatic volume variation during cha rge/discharge cycling is a major limitation in its practical applicability.Here we propose a simple onepot spray pyrolysis process to construct unique pomegranate-like SnO₂/rGO/Se spheres.The ideal structural configuration of these architectures was effective in alleviating the large volume variation of SnO₂,besides facilitating rapid electron transfer,allowing the devised anode to exhibit superior sodium sto rage performances in terms of capacity(506.7 mAh/g at 30 mA/g),cycle performance(397 mAh/g after100 cycles at 50 mA/g) and rate capability(188.9 mAh/g at an ultrahigh current density of 10 A/g).The experimental evidence confirms the practical workability of p-SnO₂/rGO/Se spheres in SIBs.     

Facile Route to Constructing Ternary Nanoalloy Bifunctional Oxyegn Cathode for Metal-Air Batteries

Highly stable and efficient bifunctional air cathode catalyst is crucial to rechargeable metal-air batteries. Herein, a ternary nanoalloy layer composed of noble and base metal coated on a three-dimensional porous Ni sponge as the bifunctional cathode is synthesized through in-situ anchoring strategy, which can effectively keep the multi-metal nanoparticles from agglomeration and improve the density of active sites and catalytic activity. The prepared catalyst displays an excellent catalytic performance with lower overpotential and long-term stability. The Zn-air batteries with the as-prepared cathodes possess a large power density of 170 mW/cm², long cycling stability up to 230 cycles, and a high specific capacity of 771 mA·h/g. Furthermore, the corresponding Li-air batteries deliver a discharge capacity of 22429 mA·h/g. These superior properties of the metal-air batteries can be attributed to the combined influence of design and composition of electrode, which is of great significance to improve the electrochemical catalytic activity, providing great potential of wide application in expanded rechargeable energy systems.     

钠离子电池用高性能锑基负极材料的调控策略研究进展

Na-ion batteries (SIBs) are promising alternatives for Li-ion batteries owing to the natural abundance of sodium resources and similar energy storage mechanisms. Although significant progress has been achieved in research on SIBs, there remain several challenges to be addressed. One of the major challenges in the construction of high-performance SIBs is the development of suitable anode materials with a large reversible capacity, high cycling stability, and good rate performance. Alloying anode materials mainly composed of elements from Groups IVA and VA, as well as their alloys, have attracted widespread attention because of their low working voltage, high cost-effectiveness, and large theoretical capacity. Alloying-type anode materials can be alloyed with metallic Na to achieve large reversible capacities, ensuring a high energy density. Antimony is a promising anode material for SIBs owing to its high theoretical specific capacity (660 mAh·g⁻¹, corresponding to the full sodiation Na₃Sb alloy), small degree of electrode polarization (~0.25 V), appropriate Na⁺ deintercalation potential (0.5–0.75 V), low price, and environmental friendliness. However, an important challenge for using Sb-based anode materials is that the high specific capacity is accompanied by large volume changes during cycling. Such changes lead to the pulverization of the active materials and their falling off from the collector, which significantly limit their large-scale application in the field of sodium-ion batteries. Therefore, mitigating the volume expansion issue of Sb-based anode materials in the charge-discharge process is very important for the design of high-performance SIBs. In recent years, researchers have attempted to address this issue by designing special structures to prepare various composites, and substantial progress has been achieved in improving the electrochemical performance of SIBs. In this review, the relationship between the structure and properties of Sb-based materials and their applications in SIBs are presented and discussed in detail. The latest research progress on using Sb-based anode materials for SIBs in redox reaction mechanisms along with their morphology design, structure-performance relationship, etc. have been reviewed. The main objective of this review is to explore the determining factors of the performance of Sb-based anode materials to propose suitable modification strategies for improving their reversible capacity and cycle stability. Finally, future developments, challenges, and prospects of Sb-based anode materials for SIBs are discussed. Despite several challenges, Sb-based materials are very promising anode materials for SIBs with alloying reaction mechanisms. To further improve the large-scale application of Sb-based anode materials, it is necessary to optimize the binder, electrode structure, and electrolyte composition. The combination of in-depth studies on the electrochemical reaction mechanisms and advanced characterization technologies is important for the development and construction of advanced Sb-based anode materials for SIBs. Finally, to achieve extensive large-scale applications, it is necessary to further explore environmentally friendly, low-cost, and controllable synthetic technologies to prepare high-performance Sb-based anode materials. This review provides specific perspectives for the construction and optimization of Sb-based anode materials and suggests scope for future work on Sb-based anode materials, thereby promoting the rapid development and practical application of SIBs.      

Na2Ti3O7纳米片原位制备与钠离子电池负极材料应用

报道了Na₂Ti₃O₇纳米片的原位生长和钠离子电池负极材料的应用。通过简单的腐蚀市售的钛片制备出相互连接的微纳结构的Na₂Ti₃O₇纳米片。此外,腐蚀后的钛片在不用添加导电剂或粘结剂的情况下,可以直接作为电极材料使用。这种电极材料表现出优越的电化学性能,在50 mA·g^–1的电流密度下具有175 mAh·g^–1的可逆容量,在2000 mA·g^–1的电流密度下循环3000周后,其容量仍保持120 mAh·g^–1,容量保持率为96.5%。Na₂Ti₃O₇纳米片电极的优越电化学性能归因于二维结构具有较短的离子/电子扩散路径以及无粘结剂结构能有效的增加电极的电子传导能力。结果表明,这种微纳结构能够有效地克服Na₂Ti₃O₇作为电极材料离子/电子导电性差的缺点。因此,这种无粘结剂结构的Na₂Ti₃O₇纳米片负极材料是一种很有潜力的钠离子负极材料。     

尖晶石型高熵氧化物的制备和电化学性能

采用溶液燃烧法制备了化学组成均一的尖晶石型（Cr_0.2Fe_0.2Mn_0.2Ni_0.2M_0.2）₃O₄（M=Co,Zn,Mg）高熵氧化物（HEOs）纳米晶粉体,并将3种高熵氧化物用作锂离子电池负极材料,研究了活性过渡金属Co和Zn阳离子与非活性Mg阳离子对电化学性能的影响.结果表明,由于具有高构型熵稳定的晶体结构,3种高熵氧化物均表现出优异的循环稳定性,其中含有非活性Mg离子的高熵氧化物（Cr_0.2Fe_0.2Mn_0.2Ni_0.2Mg_0.2）₃O₄不仅具有更高的初始比容量（1300 mA·h/g）和倍率性能（在3 A/g电流密度下比容量约为450 mA·h/g）,且在循环500次后Li⁺的扩散系数为其它2种高熵氧化物的3倍以上.（Cr_0.2Fe_0.2Mn_0.2Ni_0.2Mg_0.2）₃O₄电化学性能提高的原因是非活性Mg离子不仅避免了锂化过程中活性物质的团聚,还提高了锂离子的扩散系数.