SnSe2 nanoplate-graphene composites as anode materials for lithium ion batteries

Through a solution approach, SnSe(2) nanoplate-graphene composites were prepared and applied as anode materials in lithium ion batteries, showing promising storage performance superior to SnSe(2) nanoplates or graphene alone.     

Electrospun porous SnO2 nanotubes as high capacity anode materials for lithium ion batteries

Porous SnO₂ nanotubes were prepared via electrospinning followed by calcination in air. As anode materials for lithium ion batteries, the porous nanotubes delivered a high discharge capacity of 807 mAh g^? 1 after 50 cycles. Even after cycled at high rates, the electrode still retained a high fraction of its theoretical capacity. Such excellent performances of porous SnO₂ nanotubes could be attributed to the porous and hollow structure which facilitated liquid electrolyte diffusion into the bulk materials and buffered large volume changes during lithium ions insertion/extraction. Furthermore, the nanoparticles of nanotubes provided the shorter diffusion length for lithium ions insertion which benefited in retaining the structural stability and good rate performance. Our results demonstrated that this simple method could be extended for the synthesis of porous metal oxide nanotubes with high performances in the applications of lithium ion batteries and other fields.     

Si–AB5 composites as anode materials for lithium ion batteries

The Si–AB₅ (MmNi_3.6Co_0.7Al_0.3Mn_0.4 alloy) composites with a high tap density as anode materials for lithium-ion batteries were synthesized by ball-milling. Si nanoparticles are distributed homogeneously on the surface of the AB₅ matrix. The electrochemical performance of the Si–AB₅ composites as a function of Si content was investigated. It is demonstrated that the Si–AB₅ composite delivers a larger reversible capacity and better cycle ability because the inactive AB₅ alloy can accommodate the large volume changes of Si nanoparticles distributed on the surface of the Si–AB₅ composite during cycling. In particular, the Si–AB₅ composite containing 20 wt% Si with the high tap density of 2.8 g/cm³ obtained after ball-milling for 11 h exhibits an initial and maximum reversible (charge) capacity of 370 and 385 mAh/g. The high capacity retention can be achieved after 50 cycles in the potential range from 0.02 to 1.5 V.     

Dispersing SnO2 nanocrystals in amorphous carbon as a cyclic durable anode material for lithium ion batteries

We demonstrate a facile route for the massive production of SnCb/carbon nanocomposite used as high-capacity anode materials of nextgeneration lithium-ion batteries.The nanocomposite had a unique structure of ultrafine SnO2 nanocrystals（5 nm,80 wt%） homogeneously dispersed in amorphous carbon matrix.This structure design can well accommodate the volume change of Li＋ insertion/desertion in SnO2,and prevent the aggregation of the nanosized active materials during cycling,leading to superior cycle performance with stable reversible capacity of 400 mAh/g at a high current rate of 3.3 A/g.     

Co3O4@graphene composites as anode materials for high-performance lithium ion batteries

This paper reports on the synthesis of Co(3)O(4)@graphene composites (CGC) and their applications as anode materials in lithium ion batteries (LIBs). Through a chemical deposition method, Co(3)O(4) nanoparticles (NPs) with sizes in the range of 10-30 nm were homogeneously dispersed onto graphene sheets. Due to their high electrical conductivity, the graphene sheets in the CGC improved the electrical conductivity and the structure stability of CGC. CGC displayed a superior performance in LIBs with a large reversible capacity value of 941 mA hg(-1) in the initial cycle with a large current density and an excellent cyclic performance of 740 mA hg(-1) after 60 cycles, corresponding to 88.3% of the theoretical value of CGC, owing to the interactions between graphene sheets and Co(3)O(4) NPs anchored on the graphene sheets. This synthesis approach may find its application in the design and synthesis of novel electrode materials used in LIBs.     

Synthesis of phosphorus-doped soft carbon as anode materials for lithium and sodium ion batteries

Phosphorus-doped soft carbon was synthesized by a facile phosphoric acid-assisted route. It is found that the phosphorus-doped soft carbon used as lithium ion battery anode exhibits a high reversible capacity of 333.6 mA h g^–1 with the first cycle coulombic efficiency of 87.0% at the current density of 30 mA g^–1. When used as sodium ion battery anode, it also shows great storage performance, with a reversible capacity of 121.3 mA h g^–1 with an initial coulombic efficiency of 65.0% at the current density of 10 mA g^–1. Besides, good rate capability and stable cycling performance are also observed for both lithium and sodium ion batteries, indicating potential of their application in large-scale storage devices.

     

Silver-coated TiO2 nanostructured anode materials for lithium ion batteries

Anatase TiO₂ nanoribbons/nanotubes (TiO₂-NRTs) have been synthesised successfully via a reflux method followed by drying in a vacuum oven, and then, silver-coated TiO₂ NRTs (Ag/TiO₂-NRTs) were prepared by coating silver particles onto the TiO₂-NRTs surface by the traditional silver mirror reaction. The physical properties of the synthesised products were examined in detail using X-ray diffraction, field emission gun scanning electron microscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy, respectively. The results indicated that the Ag nanoparticles were uniformly deposited on the surface of the TiO₂ nanoribbons/nanotubes. The electrochemical properties were investigated by a variety of techniques. The rate capability and cycle durability for the Ag/TiO₂-NRTs were improved compared with TiO₂-NRTs. It is speculated that the Ag-coated TiO₂ nanoribbons/nanotubes are an effective anode candidate for lithium ion batteries.     

High capacity silicon/carbon composite anode materials for lithium ion batteries

Silicon/carbon composite materials are prepared by pyrolysis of pitch embedded with graphite and silicon powders. As anode for lithium ion batteries, its initial reversible capacity is 800–900 mAh/g at 0.25 mA/cm² in a voltage range of 0.02/1.5 V vs. Li. The material modification by adding a small amount of CaCO₃ into precursor improves the initial reversibility (η₁=84%) and suppresses the capacity fade upon cycling. A little higher insertion voltage of the composites than commercial CMS anode material improves the cell safety in the high rate charging process.     

Tea-derived carbon materials as anode for high-performance sodium ion batteries

Sodium-ion batteries (SIB) have attracted widespread attention in large-scale energy storage fields owing to the abundant reserve in the earth and similar properties of sodium to lithium. Biomass-based carbon materials with low-cost, controllable structure, simple processing technology, and environmental friendliness tick almost all the right boxes as one of the promising anode materials for SIB. Herein, we present a simple novel strategy involving tea tomenta biomass-derived carbon anode with enhanced interlayer carbon distance (0.44 nm) and high performance, which is constructed by N,P co-doped hard carbon (Tea-1100-NP) derived from tea tomenta. The prepared Tea-1100-NP composite could deliver a high reversible capacity (326.1 mAh/g at 28 mA/g), high initial coulombic efficiency (ICE = 90% at 28 mA/g), stable cycle life (262.4 mAh/g at 280 mA/g for 100 cycles), and superior rate performance (224.5 mAh/g at 1400 mA/g). Experimental results show that the excellent electrochemical performance of Tea-1100-NP due to the high number of active N,P-containing groups, and disordered amorphous structures provide ample active sites and increase the conductivity, meanwhile, large amounts of microporous shorten the Na⁺ diffusion distance as well as quicken ion transport. This work provides a new type of N,P co-doped high-performance tomenta-derived carbon, which may also greatly promote the commercial application of SIB.     

Porous Si coated with S-doped carbon as anode material for lithium ion batteries

A novel porous Si/S-doped carbon composite was prepared by a magnesiothermic reaction of mesoporous SiO₂, subsequently coating with a sulfur-containing polymer-poly(3,4-ethylene dioxythiophene), and a post-carbonization process. The as-prepared Si composite was homogeneously coated with disordered S-doped carbon with 2.6 wt.%?S in the composite and retained a high surface area of 58.8 m²?g^?1. The Si/S-doped carbon composite exhibited superior electrochemical performance and long cycle life as an anode material in lithium ion cells, showing a stable reversible capacity of 450 mAh g^?1 even at a high current rate of 6,000 mA?g^?1.     

Fabrication of Ti-doped SnO2/RGO composites as anode materials with high stability for lithium-ion batteries

Research on Chemical Intermediates - The electrochemical performance of lithium-ion batteries are affected by the anode materials. SnO2 is an important anode material due to its high theoretical...     

Carbon anode materials from polysiloxanes for lithium ion batteries

Three kinds of silicon-containing disordered carbons have been prepared by pyrolysis of polysiloxanes with different amounts of phenyl side groups. X-ray powder diffraction, X-ray photoelectron spectroscopy and electrochemical capacity measurements were performed to study their behaviors. Graphite crystallites, micropores, and silicon species affect their electrochemical performances. All of them present high reversible capacities, >372 mAh/g. Since the graphite crystallites are very small, they contribute very little to reversible capacity. The number of micropores produced by gas emission during the heat-treatment process decides whether they exhibit reversible capacity. Si mainly exists in the form C–Si–O and influences the irreversible capacity. There is no evident capacity fading in the first ten cycles, indicating promising properties for these disordered carbons.     

Polyaniline(PANI) coated Zn2SnO4 cube as anode materials for lithium batteries

Zn₂SnO₄@PANI composites were synthesized via a micro emulsion polymerization method. The outer surfaces of monodispersed cubes are covered with amorphous aggregated PANI. The addition of PANI can create a buffering structure for Zn₂SnO₄ cubes. Compared with Zn₂SnO₄ cubes, Zn₂SnO₄@PANI composites show an improved electrochemical performance (491.0 mAh g^?1 at a current density of 600 mAg^?1 after 50 cycles). It is believed that PANI coating is a simple and effective way to improve the cycling performance for lithium batteries.     

Polyaniline encapsulated silicon nanocomposite as high-performance anode materials for lithium ion batteries

Polyaniline encapsulated silicon (Si/PANI) nanocomposite as anode materials for high-capacity lithium ion batteries has been prepared by an in situ chemical polymerization of aniline monomer in the suspension of Si nanoparticles. The obtained Si/PANI nanocomposite demonstrates a reversible specific capacity of 840 mAh g^?1 after 100 cycles at a rate of 100 mA g^?1 and excellent cycling stability. The enhanced electrochemical performance can be due to that the polyaniline (PANI) matrix offers a continuous electrically conductive network as well as enhances the compatibility of electrode materials and electrolyte as a result of suppressing volume stress of Si during cycles and preventing the agglomeration of Si nanoparticles.     

Sn-Al合金作为锂电池负极材料的第一性原理研究

采用基于密度泛函理论的第一性原理平面波赝势方法计算了不同Al含量的固溶体Sn-Al合金的总能量与电子结构,得到Sn0.7Al0.3合金比例最适合用于锂离子电池Sn基合金材料,并对Sn0.7Al0.3合金嵌锂后的各种物理性质和电化学性质进行了理论计算,发现该固溶体合金相具有较稳定的电化学嵌锂电位和良好的充放电循环性能.同时采用磁控溅射制备了该合金薄膜材料,测试结果与理论计算具有较好的一致性.     

Silicon nanowires with and without carbon coating as anode materials for lithium-ion batteries

Silicon nanowires (Si NWs) with and without carbon coating were successfully prepared by combination of chemical vapor deposition and thermal evaporation method. The morphologies, structures, and compositions of these nanomaterials were characterized in detail. Furthermore, the electrochemical performances of uncoated and carbon-coated Si NWs as anode materials were also studied. It shows that the carbon-coated Si NWs electrode has higher capacity, better cycle stability, and rate capability than the uncoated materials. For example, it delivers 3,702 and 3,082 mAh g⁻¹ in the initial charge and discharge processes. When cycled between 0.02 and 2.0 V at a current density of 210 mA g⁻¹, it yields a high coulombic efficiency of 83.2%. The discharge capacity still remains around 2,150 mAh g⁻¹ after 30 cycles.     

Electrochemical reduction of nano-SiO2 in hard carbon as anode material for lithium ion batteries

A composite of silica (SiO₂) and hard carbon was prepared by hydrothermal reaction. Special attention was paid to the characterization of the possible electrochemical reduction of nano-SiO₂ in the composite. Evidence by solid-state nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) and high lithium storage capacity of the composite prove the electrochemical reduction of nano-SiO₂ and the formation of Li₄SiO₄ and Li₂O as well as Si in the first-discharge. The reversible lithium storage capacity of the nano-SiO₂ is as high as 1675 mAh/g.