Heterogeneous isomorphism hollow SiGe nanospheres with porous carbon reinforcing for superior electrochemical lithium storage

Silicon is emerging as a promising next-generation lithium-ion battery anode because of its high theoretical capacity and low cost. However, the poor cyclability and inferior rate performance hinder its largescale applications. Here, hollow silicon/germanium(H-SiGe) nanospheres with a binary-active component and heterogeneous structure combined with porous carbon(pC) reinforcing are synthesized as lithium-ion battery anodes. Experimental studies demonstrate that the H-SiGe/pC anodes possess tiny...     

Highly elastic cobweb-like SiO/CNF composites with reconstructed heterostructure for high-efficient lithium storage

The silicon-based materials are promising candidates for lithium-ion batteries owing to their high energy density. However, achieving long lifespan under realistic conditions remains a challenge because of the volume expansion and low conductivity. In this work, the highly elastic cobweb-like composite materials consisted by SiO and nanofibers are designed and fabricated for high-efficient lithium storage by ball-milling & electrostatic spinning method. The reconstructed heterostructure and highly elastic nanofibers can simultaneously increase the conductivity and inhibit the “expansion effect” of silicon-based materials. The constructed electrode of n-SiO/CNF delivers an initial capacity of 1700 mAh/g, and maintains the capacities over 1000 mAh/g after 100 cycles at the current density of 500 mA/g. Meanwhile, this electrode can give an initial coulombic efficiency over 85% and maintains at 98% in the following charge/discharge processes. Furthermore, it exhibits efficient long-term electrochemical performance, maintaining the capacity at about 1000 mAh/g at a high current density of 1000 mA/g after 1000 cycles. This work could provide a promising strategy for enhancing the performance of silicon-based composite materials for practical application in lithium-ion batteries.     

金属改性与碳包覆的多孔硅微球复合材料的制备及其电化学储锂性能

以工业级SiAl合金微球为前驱物,采用多步刻蚀-热处理策略,制备了金属(Sb-Sn)改性与碳包覆的多孔硅微球复合材料(pSi/Sb-Sn@C)。pSi/Sb-Sn@C具有以 Sb-Sn改性的多孔硅微球(pSi/Sb-Sn)为核、碳包覆层为壳的三维结构。碳外壳可以提高多孔硅微球的电子导电性和机械稳定性,有利于获得稳定的固体电解质界面(SEI)膜;而三维多孔核可以促进锂离子的扩散,增加嵌/脱锂活性位,缓冲嵌锂过程中的体积膨胀。此外,活性金属(Sb-Sn)的引入能够提高复合材料的导电性,并可以贡献一定的储锂容量。由于其特殊的组成和独特的微观结构,pSi/Sb-Sn@C复合材料在1.0 A·g^-1电流密度下充放电300次后的可逆容量为1 247.4 mAh·g^-1,显示了良好的高速率储锂性能和优异的电化学嵌/脱锂循环稳定性。     

Microwave-induced synthesis of porous single-crystal-like TiO2 with excellent lithium storage properties

Porous anatase TiO(2) single crystal architectures with large specific surface area and remarkable crystalline phase-stability were fabricated via a green microwave-assisted process. Ionic liquid was chosen as both an essential structure-directing agent for the formation of the {001} facets exposed TiO(2) and an etching agent source for selective erosion of the exposed {001} facets, leading to robust porous framework with exposed {101} facets. These porous anatase single crystals were thermally stable up to 800 °C, indicating excellent structure stability. The product showed stable cyclability at high current rate, better reversibility, and high Coulumbic efficiency of 100% for lithium storage.     

Bimetallic selenide heterostructure with directional built-in electricfield confined in N-doped carbon nanofibers for superior sodium storage with ultralong lifespan

Constructing heterostructure is considered as an effective strategy to address the sluggish electronic and ionic kinetics of anode materials for sodium ion batteries(SIBs).However,realizing the orientated growth and uniform distribution of the heterostructure is still a great challenge.Herein,the regulated novel CoSe2/NiSe2 heterostructure confined in N-doped carbon nanofibers(CoSe₂/NiSe₂@N-C) are prepared by using Co/Ni-ZIF template,in which,the CoSe₂/NiSe_2...     

3D porous V_2O_5 architectures for high-rate lithium storage

The discovery of novel electrode materials promises to unleash a number of technological advances in lithium-ion batteries. V_2O_5 is recognized as a high-performance cathode that capitalizes on the rich redox chemistry of vanadium to store lithium. To unlock the full potential of V_2O_5, nanotechnology solution and rational electrode design are used to imbue V_2O_5 with high energy and power density by addressing some of their intrinsic disadvantages in macroscopic crystal form. Here, we demonstrate a facile and environmental-friendly method to prepare nanorods-constructed 3D porous V_2O_5 architectures(3 D-V_2O_5)in large-scale. The 3D porous architecture is found to be responsible for the enhanced charge transfer kinetics and Li-ion diffusion rate of the 3D-V_2O_5 electrode. As the result, the 3D-V_2O_5 surpasses the conventional bulk V_2O_5 by showing enhanced discharge capacity and rate capability(delivering 154 and127 m Ah g~(-1) at 15 and 20 C, respectively).     

Hierarchical porous carbon derived from rice straw for lithium ion batteries with high-rate performance

Porous carbons with a high surface area have been prepared from rice straw. The hierarchical porous network with large macroporous channels and micropores within the channel walls enable the porous carbons to provide the pathways for easy accessibility of electrolytes and fast transportation of lithium ions. These porous carbons which show a particular large reversible capacity are proved to be promising anode materials for high-rate and high-capacity lithium ion batteries.     

MOF-derived ZnO/ZnFe2O4@RGO nanocomposites with high lithium storage performance

ZnO/ZnFe₂O₄@reduced graphene oxide (RGO) nanocomposites have been successfully synthesized through annealing treatment of Zn/Fe MOF-5@GO composites. The ZnO/ZnFe₂O₄ nanoparticles with a diameter of 12–15 nm are evenly distributed on the surface of RGO. The ZnO/ZnFe₂O₄@RGO nanocomposites show superior rate capacity and cyclic stability of 655 mAh/g after 200 cycles at 0.2 A/g for lithium ion battery (LIB) anode. The superior electrochemical property benefits from the unique structure of ZnO/ZnFe₂O₄@RGO nanocomposites, which can provide a buffer space for volume expansion, and enhance conductivity in the charge/discharge cycle.

     

A lithiated gel polymer electrolyte with superior interfacial performance for safe and long-life lithium metal battery

Rechargeable lithium metal batteries(LMBs)have gained much attention recently.However,the short lifespan and safety issues restrict their commercial applications.Here we report a novel gel polymer electrolyte(GPE)based on lithiated poly(vinyl chloride-r-acrylic acid)(PVCAALi)to realize dendritesuppressing and long-term stable lithium metal cycling.PVC chains ensure the quick gelation process and high electrolyte uptake,and lithiated PAA segments enable the increase of mechanical strength,acceleration of lithium-ion transmission and improvement of interfacial compatibility.PVCAALi GPE showed much higher mechanical strength compared with other free-standing GPEs in previous works.It displays a superior ionic conductivity of 1.50 m S cm^-1 and a high lithium-ion transference number of 0.59 at room temperature.Besides,the lithiated GPE exhibits excellent interfacial compatibility with lithium metal anodes.Lithium symmetrical cells with PVCAALi GPE yield low hysteresis of 50 m V over1000 h at 1.0 m A cm^-2.And the possible mechanism of the lithiated GPE with improved lithium-ion transfer and interfacial property was discussed.Accordingly,both the Li4Ti5O12/Li and lithium-sulfur(Li-S)cells assembled with PVCAALi GPE show outstanding electrochemical performance,retaining high discharge capacities of 133.8 m Ah g^-1 and 603.8 m Ah g^-1 over 200 cycles,respectively.This work proves excellent application potential of the highly effective and low-cost PVCAALi GPE in safe and long-life LMBs.     

双金属(Sn/Ni)掺杂多孔硅微球的液相合成与电化学储锂性能

使用廉价的硅铝合金前驱体,通过简单的化学沉积方法制备了新型双金属(Sn/Ni)掺杂多孔硅微球(pSi@SnNi)。pSi@SnNi复合材料的三维多孔结构可以缓冲硅在锂化过程中的巨大体积膨胀,增加储锂活性位点。双金属(Sn/Ni)的掺杂可以提高硅的电子导电性,改进pSi的结构稳定性。由于其独特的组成和微观结构,具有适当Sn/Ni含量的pSi@SnNi复合材料显示了较大的可逆储锂容量(0.1 A·g^-1下为2 651.7 mAh·g^-1)、较高的电化学循环稳定性(1 A·g^-1下400次循环后为1 139 mAh·g^-1)和优异的倍率性能(2.5 A·g^-1下为1 235.8 mAh·g^-1)。     

MoS2 nanosheet arrays supported on hierarchical porous carbon with enhanced lithium storage properties

MoS₂ nanosheet arrays supported on hierarchical nitrogen-doped porous carbon(MoS₂@C)have been synthesized by a facile hydrothermal approach combined with high-temperature calcination.The hierarchical nitrogen-doped porous carbon can serve as three-dimensional conductive frameworks to improve the electronic transport of semiconducting MoS₂.When evaluated as anode material for lithium-ion batteries,the MoS₂@C exhibit enhanced electrochemical performances compared with pure MoS₂ nanosheets,including high capacity(1305.5 mA h g^-1 at 100 mA g^-1),excellent rate capability (438.4 mA h g^-1 at 1000 mA g^-1).The reasons for the improved electrochemical performances are explored in terms of the high electronic conductivity and the facilitation of lithium ion transport arising from the hierarchical structures of MoS₂@C.     

双金属(Sn/Ni)掺杂多孔硅微球的液相合成与电化学储锂性能

使用廉价的硅铝合金前驱体,通过简单的化学沉积方法制备了新型双金属(Sn/Ni)掺杂多孔硅微球(pSi@SnNi)。pSi@SnNi复合材料的三维多孔结构可以缓冲硅在锂化过程中的巨大体积膨胀,增加储锂活性位点。双金属(Sn/Ni)的掺杂可以提高硅的电子导电性,改进pSi的结构稳定性。由于其独特的组成和微观结构,具有适当Sn/Ni含量的pSi@SnNi复合材料显示了较大的可逆储锂容量(0.1 A·g^-1下为2 651.7 mAh·g^-1)、较高的电化学循环稳定性(1 A·g^-1下400次循环后为1 139 mAh·g^-1)和优异的倍率性能(2.5 A·g^-1下为1 235.8 mAh·g^-1)。     

Chain engineering-tailored microstructures and lithium storage performance of hydrothermally-synthesized linear polyimides

Polyimides with high capacity, fast kinetics, abundant resource, and structural diversity offer an exhilarating opportunity for developing sustainable rechargeable batteries. Herein, a series of 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA)-based polyimides were successfully crafted through a facile and eco-friendly hydrothermal synthesis route. The microstructure and lithium storage performance of polyimides were tailored by regulating diamine linkers between NTCDA units. Interestingly, the moderate increased length of flexible diamine units with ethylenediamine and diaminobutane can stabilize the polymer skeleton. This leads to the formation of honeycomb-like porous structures with a sufficient exposure of active carbonyl groups, thereby achieving a large capacity and high rate capability. Therefore, polyimides derived from ethylenediamine and diaminobutane show larger reversible capacities (123 and 113.5 mA h/g at 50 mA/g, respectively) and better rate capabilities with capacity retentions of up to 50% when the current increased from 50 to 2000 mA/g. This work would provide new insights into macromolecular engineering of polymers for advanced electrode materials.     

Porous SnO2/layered titanate nanohybrid with enhanced electrochemical performance for reversible lithium storage

A porous hybrid of titanate nanosheets with SnO(2) nanoparticles has been realized by an exfoliation and reassembling route. The present nanohybrid shows a large reversible capacity of 860 mA h g(-1) with a good capacity retention (about 60% retention of the initial capacity after 50 cycles).     

Hydrothermal carbon spheres containing silicon nanoparticles: synthesis and lithium storage performance

Spherically shaped carbon/silicon nanocomposites have been obtained in a one-step procedure using hydrothermal carbonization of glucose in the presence of commercially available silicon nanoparticles and have been tested electrochemically as an anode material for lithium-ion batteries.     

Preparation and performance of porous titania with a trimodal pore system as anode of lithium ion battery

A porous titania has been prepared by using polystyrene spheres and tri-block copolymer ((EO)₂₀–(PO)₇₀–(EO)₂₀, P123) as templates, and its structure, composition, and performance as anode of lithium ion battery are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction, and galvanostatic charge/discharge test. The results from SEM and TEM indicate that the prepared porous titania has a trimodal pore system, in which the pores are in ordered arrangement and interconnected with the same pore diameter and uniform wall thickness. The charge/discharge tests show that the battery using the prepared porous titania as anode exhibits good rate capacity and cycle stability.     

Improved lithium storage performance of sulfur loaded by CMK-3 with a tailored hierarchical pore structure

Porous carbon materials such as CMK-3 are proved as effective hosts for loading sulfur in the design of the positive electrode for lithium-sulfur batteries. In this work, CMK-3 with a tailored hierarchical pore structure (CMK-3 M) is prepared by using SBA-15 and Sn nanoparticles as the sacrificial templates. Compared to CMK-3, CMK-3 M possesses higher surface area and larger pore size, which are conducive to the transfer of electron and Li⁺ ions. The large contact area with sulfur also enhances the interaction of CMK-3 M and sulfur. Moreover, the generated micropores of CMK-3 M can contain smaller sulfur molecules, which avoids the formation of soluble polysulfides and suppresses the shuttle effect of lithium polysulfides. Therefore, compared to sulfur-loaded CMK-3, sulfur-loaded CMK-3 M exhibits superior electrochemical performance. Besides, the performance of sulfur-loaded CMK-3 M can be further improved by coating with polyethylene glycol. This suggests that polymer protection is still an effective way to inhibit the polypyl sulfide shuttle.

     

Application of porous phosphate heterostructure materials for gas separation

In this study, the adsorbents Cu+-3SiPPH723 and Cu2+-3SiPPH723 were prepared starting from a silica-expanded zirconium phosphate heterostructure, 3SiPPH(0.2), which was subjected to an ion exchange with Cu(I) and Cu(II). These materials were characterized using powder X-ray diffraction, X-ray photoelectron spectroscopy, ammonia thermally programmed desorption, hydrogen temperature-programmed reduction, and N2 adsorption (77 K). The equilibria and kinetics of adsorption of pure propylene (C3H6) and propane (C3H8) were studied using a conventional glass high-vacuum volumetric device, equipped with grease-free valves, in the temperature range of 273-393 K. The starting material, 3SiPPH(0.2), presented a high acidity and irreversible chemisorption of the olefin, which increases with temperature. Unlike the support, the irreversible adsorption of the olefin on the Cu+-3SiPPH723 and Cu2+-3SiPPH723 samples decreases with increasing temperature and disappears at 393 K, showing a very high selectivity toward propylene. The C3H8 adsorption in all the samples was always reversible. On the basis of the results of this study, both Cu+-3SiPPH723 and Cu2+-3SiPPH723 samples can be efficiently applied in the separation of a C3H6/C3H8 mixture at 393 K. Cu+-3SiPPH723 would have the highest efficiency, because its capacity for C3H6 adsorption was higher than that for the Cu2+-3SiPPH723 sample.     

Fabrication based on the Kirkendall effect of Co3O4 porous nanocages with extraordinarily high capacity for lithium storage

Herein we report a novel facile strategy for the fabrication of Co(3)O(4) porous nanocages based on the Kirkendall effect, which involves the thermal decomposition of Prussian blue analogue (PBA) Co(3)[Co(CN)(6)](2) truncated nanocubes at 400?°C. Owing to the volume loss and release of internally generated CO(2) and N(x) O(y) in the process of interdiffusion, Co(3)O(4) nanocages with porous shells and containing nanoparticles were finally obtained. When evaluated as electrode materials for lithium-ion batteries, the as-prepared Co(3)O(4) porous nanocages displayed superior battery performance. Most importantly, capacities of up to 1465?mA?h?g(-1) are attained after 50 cycles at a current density of 300?mA?g(-1). Moreover, this simple synthetic strategy is potentially competitive for scaling-up industrial production.