High lithium storage performance of Ni0.5Fe0.5O1−xNx thin film with NiO-type crystal structure

The large voltage hysteresis of the NiO anode, which owes much to the intermediate product Li₂NiO₂, is one of the main obstacles to its practical application in lithium-ion batteries. In this work, we show that the incorporation of Fe- and N-ions in the NiO lattice can suppress the formation of intermediate product Li₂NiO₂ and thus greatly reduces the voltage hysteresis of the NiO anode from ~1.2 to ~0.9 V. In comparison with the pure NiO electrode, the Ni_0.5Fe_0.5O_1−xN_x anode exhibits significantly enhanced reversible specific capacity (959 mAh·g⁻¹ at 0.3 A·g⁻¹), cycling stability (capacity retention of 96.1% at 100th cycle relative to the second cycle) and rate capability (442 at 10 A·g⁻¹). These results provide a practical method to enhance the lithium storage performance of the NiO anode and more importantly a new solution to the large voltage hysteresis of conversion-type anodes.     

Bimetallic sulfide FeS2@SnS2 as high-performance anodes for sodium-ion batteries

A novel hierarchical structure of bimetal sulfide FeS₂@SnS₂ with the 1D/2D heterostructure was developed for high-performance sodium-ion batteries (SIBs). The FeS₂@SnS₂ was synthesized through a hydrothermal reaction and a sulphuration process. The exquisite 1D/2D heterostructure is featured with 2D SnS₂ nanoflakes anchoring on the 1D FeS₂ nanorod. This well-designed FeS₂@SnS₂ provides shortened ion diffusion pathway and adequate surface area, which facilitates the Na⁺ transport and capacitive Na⁺ storage. Besides, the FeS₂@SnS₂ integrates the 1D/2D synthetic structural advantages and synthetic hybrid active material. Consequently, the FeS₂@SnS₂ anode exhibits high initial specific capacity of 765.5 mAh·g⁻¹ at 1 A·g⁻¹ and outstanding reversibility (506.0 mAh·g⁻¹ at 1 A·g⁻¹ after 200 cycles, 262.5 mAh·g⁻¹ at 5 A·g⁻¹ after 1400 cycles). Moreover, the kinetic analysis reveals that the FeS₂@SnS₂ anode displays significant capacitive behavior which boosts the rate capacity.     

Conducting polymer PEDOT:PSS coated Co3O4 nanoparticles as the anode for sodium-ion battery applications

Metal oxides are considered as potential anodes for sodium-ion batteries (SIBs). Nevertheless, they suffer from poor cycling and rate capability. Here, we investigate conductive polymer coating on Co₃O₄ nanoparticles varying with different percentages. X-ray diffraction, electron microscopy and surface chemical analysis were adopted to analyze coated and uncoated Co₃O₄ nanoparticles. Conducting polymer, poly(3,4-ethylene dioxythiophene) polystyrene sulfonate (PEDOT:PSS), has been utilized for coating. Improved specific capacity and rate capability for an optimal coating of 0.5 wt.% were observed. The 0.5 wt.% coated sample outperformed the uncoated one in terms of capacity, rate capability and coulombic efficiency. It delivered a reversible capacity of 561 mAh·g⁻¹ at 100 mA·g⁻¹ and maintained a capacity of 318 mAh·g⁻¹ at a high rate of 1 A·g⁻¹. Increasing the PEDOT:PSS coating percentage led to lower performance due to the thicker coating induced kinetic issues. Ex-situ analysis of the 0.5 wt.% coated sample after 100 cycles at 1 A·g⁻¹ was characterized for performance correlation. Such a simple, cost-effective and wet-chemical approach has not been employed before for Co₃O₄ as the SIB anode.     

高性能自支撑CuS/SnS2锂电池负极材料

过渡金属硫化物作为锂电池负极材料具有极高比容量,但其制备的电极普遍存在导电性差、体积变化大等问题,本研究设计了一种新型的自支撑CuS/SnS₂镂空片状锂电池负极材料,以导电碳布作为基底,生长包覆CuS/SnS₂镂空纳米片,具备特殊的纳米包覆结构及双金属协同效应,使其在保持较高比容量的同时具备良好的循环稳定性,整体电化学性能优异。研究不同Cu/Sn含量对CuS/SnS₂负极材料电化学性能的影响,最佳配比的CuS/SnS₂负极材料在0.2 A·g?1电流密度下循环50次后比容量为1480 mAh·g?1,库伦效率稳定在99.5%,在2 A·g?1电流密度下循环200次后比容量仍能保持在697 mAh·g?1,库伦效率为99.8%。      

Bi/3DPG composite structure optimization realizes high specific capacity and rapid sodium-ion storage

As an anode material for sodium-ion batteries (SIBs), bismuth (Bi) has attracted widespread attention due to its suitable voltage platform and high volumetric energy density. However, the severe volume expansion of Bi during charging and discharging leads to a rapid decline in battery capacity. Loading Bi on the graphene can relieve volume expansion and improve electrochemical performance. However, excessive loading of Bi on graphene will cause the porosity of the composite material to decrease, which leads to a decrease of the Na⁺ transmission rate. Herein, the Bi/three-dimensional porous graphene (Bi/3DPG) composite material was prepared and the pore structure was optimized to obtain the medium-load Bi/3DPG (Bi/3DPG-M) with better electrochemical performance. Bi/3DPG-M exhibited a fast kinetic process while maintaining a high specific capacity. The specific capacity still remained at 270 mA·h·g⁻¹ (93.3%) after 500 cycles at a current density of 0.1 A·g⁻¹. Even at 5 A·g⁻¹, the specific capacity of Bi/3DPG-M could still reach 266.1 mA·h·g⁻¹. This work can provide a reference for research on the use of alloy–graphene composite in the anode of SIBs.     

源于溪木贼的高性能锂离子电池三维多孔生物质硅/碳复合负极材料

锂离子电池硅基负极材料的理论比容量比传统石墨材料高10倍,是最有前途的锂离子电池负极材料之一.然而硅基纳米材料的制备工艺复杂、成本高昂,严重限制了锂离子电池硅负极的商业应用.本工作采用溪木贼为原料,通过深度还原、浅度氧化和碳包覆工艺制备了三维多孔生物质硅/碳复合材料(多孔3D-bio-Si/C).三维多孔结构不仅有利于...     

Interface-modulated fabrication of hierarchical yolk–shell Co<Subscript>3</Subscript>O<Subscript>4</Subscript>/C dodecahedrons as stable anodes for lithium and sodium storage

Transition-metal oxides (TMOs) have gradually attracted attention from researchers as anode materials for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) because of their high theoretical capacity.However,their poor cycling stability and inferior rate capability resulting from the large volume variation during the lithiation/sodiation process and their low intrinsic electronic conductivity limit their applications.To solve the problems of TMOs,carbon-based metal-oxide composites with complex structures derived from metal-organic frameworks (MOFs) have emerged as promising electrode materials for LIBs and SIBs.In this study,we adopted a facile interface-modulated method to synthesize yolk-shell carbon-based Co3O4 dodecahedrons derived from ZIF-67 zeolitic imidazolate frameworks.This strategy is based on the interface separation between the ZIF-67 core and the carbon-based shell during the pyrolysis process.The unique yolk-shell structure effectively accommodates the volume expansion during lithiation or sodiation,and the carbon matrix improves the electrical conductivity of the electrode.As an anode for LIBs,the yolk-shell Co3O4/C dodecahedrons exhibit a high specific capacity and excellent cycling stability (1,100 mAh·g-1 after 120 cycles at 200 mA·g-1).As an anode for SIBs,the composites exhibit an outstanding rate capability (307 mAh·g-1 at 1,000 mA·g-1 and 269 mAh·g-1 at 2,000 mA·g-1).Detailed electrochemical kinetic analysis indicates that the energy storage for Li+ and Na+ in yolk-shell Co3O4/C dodecahedrons shows a dominant capacitive behavior.This work introduces an effective approach for fabricating carbonbased metal-oxide composites by using MOFs as ideal precursors and as electrode materials to enhance the electrochemical performance of LIBs and SIBs.     

NH4+扩层MoS2的制备及其储锌性能研究

二硫化钼(Mo S₂)作为水系锌离子电池的正极材料,受到锌离子(Zn²⁺)与主体框架之间的强静电相互作用表现出缓慢的反应动力学。并且Mo S₂的层间距较窄难以嵌入大尺寸水合Zn²⁺,导致Mo S₂电极呈现出较低的放电比容量。本研究通过一种简单的氨水辅助水热法制备了NH₄⁺扩层的二硫化钼(Mo S₂-N)电极,氨水分解产生的氨气在促进硫代乙酰胺水解和提供还原性S^2–的同时,还会产生大量NH₄⁺作为插层离子,将Mo S₂的层间距由0.62 nm扩展至0.92 nm,进而大大降低了Zn²⁺嵌入能垒(改性电极的电荷转移电阻R_ct低至35?)。当电流密度为0.1 A·g^–1时,Mo S₂-N电极的初始放电比容量相比未扩层的Mo S₂     

四氧化三钴/碳纳米管薄膜的水热合成及其储锂性能

以5-磺基水杨酸和戊二酸为螯合和氧化试剂,在水热条件下将硫酸钴氧化成纳米级Co₃O₄。以碳纳米管薄膜为载体将Co₃O₄颗粒紧密地附着在碳纳米管上使其填充入碳纳米管薄膜的空隙生成Co₃O₄/碳纳米管复合材料薄膜(Co₃O₄@CNTs),并研究其储锂性能。电化学测试结果表明,Co₃O₄@CNTs薄膜具有较高的放电比容量和优异的倍率性能,在0.2C倍率下初始放电比容量高达1712.5 mAh·g^-1,100圈循环后放电比容量为1128.9 mAh·g^-1的;在1C倍率下100圈循环后放电比容量仍然保持527.8 mAh·g^-1。Co₃O₄@CNTs薄膜优异的性能源于Co₃O₄与CNTs的协同作用。高分散性的Co₃O₄增大了活性材料与电解液之间的接触面积,CNTs有助于形成良好的导电网络提高电子电导率,进而提高了Co₃O₄负极材料的循环性能和倍率性能。     

Fe2O3纳米纤维锂离子电池负极材料的制备及其电化学性能研究

Fe₂O₃具有理论比容量高和价格低廉等特点, 已成为锂离子电池负极材料的研究热点之一。实验以不同质量比PVP/FeCl₃溶液为前驱体, 静电纺丝技术制备PVP/FeCl₃纳米纤维并热处理, 得到不同直径的Fe₂O₃纳米纤维负极材料, 并以水热合成法制备了Fe₂O₃纳米颗粒。利用X射线衍射、热重、红外光谱、扫描电镜、透射电镜和恒流充放电等测试手段对材料的物相、微观形貌和电化学性能进行表征。结果表明, Fe₂O₃纳米纤维比Fe₂O₃纳米颗粒表现出更优的电化学性能, 直径为160 nm的Fe₂O₃纳米纤维负极材料的倍率性能和循环性能最佳, 材料在0.1 A/g电流密度下的可逆容量为827.3 mAh/g;在2 A/g电流密度下70次循环放电比容量有439.1 mAh/g。     

Template-mediated strategy to regulate hierarchically nitrogen--sulfur co-doped porous carbon as superior anode material for lithium capacity

Considering its rapid lithiation/delithiation process and robust capacitive energy storage, hierarchical porous carbon is regarded as a promising candidate for lithium-ion batteries (LIBs). However, it remains a great challenge to construct a porous structure and prevent structure stacking for carbon-based materials. Herein, a template-mediated approach is developed to synthesize hierarchical nitrogen–sulfur co-doped porous carbon (NSPC) using low-cost asphalt precursors. The strategy for synthesis uses g-C₃N₄ and NaHCO₃ as gaseous templates and NaCl as a solid template, which causes the formation of hierarchical porous carbon with a high specific surface area. The resultant porous structure and nitrogen-doping process can prevent the aggregation of nanosheets, maintain the structural stability upon cycling, and achieve rate-capable lithium storage. Serving as a LIBs anode, reversible specific capacities of the NSPC24 electrode reach 788 and 280 mAh·g^–1 at 0.1 and 1 A·g^–1, respectively. Furthermore, its specific capacity remains at 830 mAh·g^–1 after 115 cycles at 0.1 A·g^–1. Even after 500 cycles, high specific capacities of 727 mAh·g^–1 at 0.5 A·g^–1 and 624 mAh·g^–1 at 1 A·g^–1 are achieved, demonstrating excellent cycling performance. The gas–solid bifunctional template-mediated approach can guide the design of porous materials very well, meanwhile realizing the high value-added utilization of asphalt.     

TiO2/C复合材料用于钠离子电池负极的性能研究

近年来,TiO₂作为钠离子电池(NIB)负极材料,因其低成本和高稳定性等优势受到广泛关注。但受TiO₂本征电子导电性的固有限制,使得TiO₂作为NIB负极材料导电性较差,导致其容量和倍率等性能不理想。利用海藻酸钠与金属离子自主交联反应的特性,将反应产物在最佳温度下进行简单碳化,制备了具有分级多孔结构的TiO₂/C复合材料,其中TiO₂纳米颗粒均匀地分布在多孔互连的碳基体中,该结构提升了复合材料导电性的同时扩展了钠离子反应的附着位点。将TiO₂/C复合材料用于NIB负极材料,在100 mA·g^-1的电流密度下循环300圈后,电池可逆比容量维持在180.4 mAh·g^-1;进一步,在更高的1000 mA·g^-1电流密度下经过1000次循环后,电池可逆比容量维持在102.3 mAh·g^-1,充分显示出TiO₂/C复合材料作为NIB负极材料的应用潜能。     

高性能自支撑不锈钢网@MoS2锂离子电池负极材料

为了提高MoS₂作为Li离子电池负极材料整体的导电性和稳定性,将纳米化的MoS₂与其它导电性好的材料进行复合,通过水热法在导电基底不锈钢网(Stainless steel net, SS)上原位合成了一层MoS₂纳米花,制备了无粘结剂的自支撑结构的SS@MoS₂负极材料。纳米花状的MoS₂和导电性优异的SS提高了电子和Li离子的扩散速率,同时改善了电极的反应动力学。当作为Li离子电池负极材料时,SS@MoS₂电极表现出优异的储Li性能,特别是具有显著的大倍率充放电性能,即在1 000 mA/g的大电流密度下循环600次,比容量仍保持在862.1 mA·h/g。      

Ultrafine Sn nanocrystals in a hierarchically porous N-doped carbon for lithium ion batteries

We report a simple method of preparing a high performance,Sn-based anode material for lithium ion batteries (LIBs).Adding H2O2 to an aqueous solution containing Sn2+ and aniline results in simultaneous polymerization of aniline and oxidation of Sn2+ to SnO2,leading to a homogeneous composite of polyaniline and SnO2.Hydrogen thermal reduction of the above composite yields N-doped carbon with hierarchical porosity and homogeneously distributed,ultrafine Sn particles.The nanocomposite exhibits excellent performance as an anode material for lithium ion batteries,showing a high reversible specific capacity of 788 mAh·g-1 at a current density of 100 mA·g-1 after 300 cycles and very good stability up to 5,000 mA·g-1.The simple preparation method combined with the good electrochemical performance is highly promising to promote the application of Sn based anode materials.     

竹基碳纤维/MoS2锂离子电池负极材料

随着电子产品、电动汽车以及智能电网的快速发展,不仅需要锂离子电池(LIBs)具有优异的储锂性能,而且要求电极材料成本低廉、资源丰富和绿色环保。基于碳负极材料的优点,将废弃的一次性竹筷,在碱性溶液中经过可控的热处理,利用竹子中丰富的天然纤维素,从而获得尺寸均匀的碳纤维(CFs)材料。相比于石墨电极,竹基CFs作为LIBs的负极材料时表现出优异的电化学性能。为进一步提高其储锂性能,以CFs为骨架,通过水热法在其表面制备了一层二硫化钼(MoS₂)纳米花,形成核壳结构的CFs/MoS₂复合电极材料。电化学测试结果表明,CFs电极在200 mA/g的电流密度下循环500次,放电比容量仍有381.1 mA·h/g;CFs/MoS₂复合材料在1 000 mA/g的大电流密度下经过1 000次循环,仍保持有843 mA·h/g的放电比容量。     

A diluent protective organic additive electrolyte of hydrophilic hyperbranched polyester for long-life reversible aqueous zinc manganese oxide batteries

A hydrophilic hyperbranched polyester (poly (tetramethylol acetylenediurea (TA)-CO-succinyl chloride) (PTS)) was proposed to be used as an organic additive in aqueous ZnSO₄ electrolyte to achieve a highly reversible zinc/manganese oxide battery. It is found that the zinc symmetric battery based on the 2.0 wt.% PTS/ZnSO₄ electrolyte showed a long cycle stability of more than 2400 h at 1.0 mA·cm⁻², which is much longer than that including the blank ZnSO₄ electrolyte (140 h). Furthermore, the capacity retention of the Zn||MnO₂ full cells employing the 2.0 wt.% PTS/ZnSO₄ electrolyte remained 85% after 100 cycles at 0.2 A·g⁻¹, which is much higher than 20% capacity retention of the cell containing the blank ZnSO₄ electrolyte, and also greater than 59.6% capacity retention of the cell including the 10.0 wt.% TA/ZnSO₄ electrolyte. By using 2.0 wt.% PTS/ZnSO₄ electrolytes, the capacity retention of the Zn||MnO₂ full cells even reached 65% after 2000 cycles at a higher current density of 1.0 A·g⁻¹. It is further demonstrated that the PTS was firmly adsorbed on the zinc anode surface to form a protective layer.     

碗状C@FeS2@NC复合材料的制备及其电化学性能

在二氧化硅微球表面包覆一层酚醛树脂并在高温下将其转化为碳壳,然后进行溶剂热反应、多巴胺包覆、高温硫化以及氢氧化钠刻蚀,制备出碗状C@FeS₂@NC(氮掺杂碳层)复合材料。这种复合材料具有开放性三维碗状结构,能释放体积变化产生的应力,其较大的比表面积(70.67 m²·g^-1)有很多的活性点位。内外双层碳壳提高了这种复合材料的导电性并提供了稳定的机械结构,外层NC具有很好的保护作用。将这种复合材料用作锂离子电池负极,在0.2 A·g^-1电流密度下首圈放电比容量和充电比容量分别为954.3 mAh·g^-1和847.2 mAh·g^-1,对应的首圈库伦效率为88.78%。循环100圈后,其放电比容量稳定在793.8 mAh·g^-1。     

中空海胆状结构的碳包覆Fe2O3用作锂离子电池的高性能负极材料

Fe2O3由于成本低廉,储量丰富和理论比容量高(1007 mA hg^-1)等特点,在锂离子电池负极材料的应用中极具发展前景.然而一些问题仍然存在,如:充放电过程中比容量的迅速衰减,不可逆的体积膨胀以及较短的循环寿命等.这些问题严重制约了Fe2O3在锂离子电池中的实际应用.为了突破这些局限,本文以金属-有机骨架(MOF...     

Superior performance for lithium storage from an integrated composite anode consisting of SiO-based active material and current collector

Silicon-based material is considered to be one of the most promising anodes for the next-generation lithium-ion batteries (LIBs) due to its rich sources, non-toxicity, low cost and high theoretical specific capacity. However, it cannot maintain a stable electrode structure during repeated charge/discharge cycles, and therefore long cycling life is difficult to be achieved. To address this problem, herein a simple and efficient method is developed for the fabrication of an integrated composite anode consisting of SiO-based active material and current collector, which exhibits a core–shell structure with nitrogen-doped carbon coating on SiO/P micro-particles. Without binder and conductive agent, the volume expansion of SiO active material in the integrated composite anode is suppressed to prevent its pulverization. At a current density of 500 mA·g⁻¹, this integrated composite anode exhibits a reversible specific capacity of 458 mA·h·g⁻¹ after 200 cycles. Furthermore, superior rate performance and cycling stability are also achieved. This work illustrates a potential method for the fabrication of integrated composite anodes with superior electrochemical properties for high-performance LIBs.     

Nanoscale Borate Coating Network Stabilized Iron Oxide Anode for High-Energy-Density Bipolar Lithium-Ion Batteries

High-capacity metal oxides based on non-toxic earth-abundant elements offer unique opportunities as advanced anodes for lithium-ion batteries (LIBs). But they often suffer from large volumetric expansion, particle pulverization, extensive side reactions, and fast degradations during cycling. Here, an easy synthesis method is reported to construct amorphous borate coating network, which stabilizes conversion-type iron oxide anode for the high-energy-density semi-solid-state bipolar LIBs. The nano-borate coated iron oxide anode has high tap density (1.6 g cm⁻³), high capacity (710 mAh g⁻¹ between 0.5 – 3.0 V, vs Li/Li⁺), good rate performance (200 mAh g⁻¹ at 50 C), and excellent cycling stability (≈100% capacity resention over 1,000 cycles at 5 A g⁻¹). When paired with high-voltage cathode LiCoO₂, it enables Cu current collector-free pouch-type classic and bipolar full cells with high voltage (7.6 V with two stack layers), achieving high energy density (≈350 Wh kg⁻¹), outstanding power density (≈6,700 W kg⁻¹), and extended cycle life (75% capacity retention after 2,000 cycles at 2 C), superior to the state-of-the-art high-power LIBs using Li₄Ti₅O₁₂ anode. The design and methodology of the nanoscale polyanion-like coating can be applied to other metal oxides electrode materials, as well as other electrochemical materials and devices.