Carbon-coated ZnO Nanocomposite Microspheres as Anode Materials for Lithium-ion Batteries

The carbon-coated ZnO nanospheres materials have been synthesized via a simple hydrothermal method.The effect of carbon content on the microstructure,morphology and electrochemical performance of the materials was investigated by XRD,Raman spectroscopy,transmission electron microscopy,scanning electron microscopy and electrochemical techniques.Research results show that the spherical ZnO/C material with a carbon cladding content of 10%is very homogeneous and approximately 200 nm in size.The electrochemical performances of the ZnO/C nanospheres as an anode materials are examines.The ZnO/C exhibits better stability than pure ZnO,excellent lithium storage properties as well as improved circulation performance.The Coulomb efficiency of the ZnO/C with 10%carbon coated content reaches 98%.The improvement of electrochemical performance can be attributed to the carbon layer on the ZnO surface.The large volume change of ZnO during the charge-discharge process can be effectively relieved.

Hierarchical Zn_(3)V_(2)O_(8)microspheres interconnected via conductive carbon nanotubes as promising anode materials for lithium-ion battery applications

Zn_(3)V_(2)O_(8) was considered as a promising anode material for lithium-ion battery(LIB),because of its high theoretical specific capacity,environmental friendliness,and ease of availability.However,the large volume change and low electronic conductivity of Zn_(3)V_(2)O_(8)in repeated charge/discharge cycles have severely limited its applications.To solve the above issues,hierarchical Zn_(3)V_(2)O_(8) microspheres assembled by two-dimensional(2D)nanosheets were successfully synthesized,and carbon nanotubes(CNTs)were further introduced to cross-link the Zn_(3)V_(2)O_(8) microspheres.The interconnected nature of the three-dimensional(3D)conducting network and the special hierarchical morphology were beneficial for improving the stability and conductivity of the composite,leading to the reduction of the impedance and a significant improvement of the electrochemical performance.The reversible capacity of the as-prepared composite can achieve 1049.5mAh·g^(-1)at a current density of 0.2 A·g^(-1)with a capacity retention of~81%after 100 cycles.It is suggested that morphology modulation coupled with interconnecting CNT network is an effective method to boost the electrochemical performance of the anode materials for lithium-ion batteries.

Interconnected sandwich structure carbon/Si-SiO_2/carbon nanospheres composite as high performance anode material for lithium-ion batteries

In the present work,an interconnected sandwich carbon/Si-SiO2/carbon nanospheres composite was prepared by template method and carbon thermal vapor deposition（TVD）.The carbon conductive layer can not only efficiently improve the electronic conductivity of Si-based anode,but also play a key role in alleviating the negative effect from huge volume expansion over discharge/charge of Si-based anode.The resulting material delivered a reversible capacity of 1094 mAh/g,and exhibited excellent cycling stability.It kept a reversible capacity of 1050 mAh/g over 200 cycles with a capacity retention of 96%.

Bi nanoparticles in situ encapsulated by carbon film as high-performance anode materials for Li-ion batteries

Bismuth (Bi) has indeed inspired great interests in lithium-ion batteries (LIBs) due to the high capacity,but was still limited by the low electrical conductivity and large volume variation.Herein,a composite material based on Bi nanoparticles in situ encapsulated by carbon film (Bi@CF) is prepared successfully through a facile metal–organic framework (MOF)-engaged approach.As anode materials for LIBs,the Bi@CF composites achieved high reversible capacities of 705 and 538 mAh g^(-1)at 0.2 and 0.5 A g^(-1) after200 cycles,and long cycling performance with a stable capacity of 306 mAh g^(-1)at 1.0 A g^(-1) even after 900 cycles.In situ X-ray diffraction (XRD) measurements clearly revealed the conversion between Bi and Li_(3)Bi during the alloying/dealloying process,confirming the good electrochemical reversibility of Bi@CF for Li-storage.The reaction kinetics of this Bi@CF composite was further studied by galvanostatic intermittent titration technique (GITT).This work may provide an inspiration for the elaborate design and facile preparation of alloy-type anode materials for high-performance rechargeable batteries.

Modified disordered carbon prepared from 3,4,9,10-perylenetetracarboxylic dianhydride as an anode material for Li-ion batteries

To prepare an anode material for Li-ion batteries with high discharge capacity and good cycling stability, disordered carbon （DC） formed by calcinations of 3,4,9,10-perylenetetracarboxylic dianhydride was modified via an acid treatment using a mixture of HNO3 and H2SO4. The modified disordered carbon （MDC） was characterized by Fourier-transform infrared （FTIR） spectroscopy, X-ray diffraction （XRD） analysis, Brtmaner-Emmett-Teller （BET） analysis, and scanning electron microscopy （SEM）. FTIR spectra confirm the successful introduction of carbonyl groups onto the DC surface. Some pores appear in the columnar structure of MDC, as observed in SEM micro- graphs. Li＋ ions intercalation/deintercalation is facilitated by the modified morphology. Electrochemical tests show that the MDC exhibits a significant improvement in discharge capacity and cycling stability. These results indicate that the MDC has strong potential for use as an anode material in Li-ion batteries.

Effects of carbon sources on electrochemical performance of Li_4Ti_5O_(12)/C composite anode materials

Li4Ti5O12/C composite materials were synthesized by two-step solid state reaction method with glucose, sucrose, and starch as carbon sources, respectively. The effects of carbon sources on the structure, morphology, and electrochemical performance of Li4Ti5O12/C composite materials were investigated by SEM, XRD and electrochemical tests. The results indicate that carbon sources have almost no effect on the structure of Li4Ti5O12/C composite materials. The initial discharge capacities of the Li4Ti1O12/C composite materials are slightly lower than those of as-synthesized Li4Ti5O12. However, Li4Ti5O12/C composite materials show better electrochemical rate performance than the as-synthesized Li4Ti5O12. The capacity retention （79%） of the Li4Ti5O12/C composite materials with starch as carbon source, is higher than that of Li4Ti5O12/C composite materials with glucose and sucrose as carbon source at current rate of 2.0C.

Fabrication of Silicon/Carbon Composite Material with Silicon Waste and Carbon Nanofiber Applied in Lithium-Ion Battery

Silicon (Si) is regarded as a promising material for lithium-ion battery anode because of high theoretical capacity. Nevertheless, Si faces particle pulverization and rapid capacity fading due to serious volume change during the lithiation and the delithiation process. In this work, a silicon/carbon composite constituted to Si powder and carbon nanofiber (CNF) is produced to solve the above issues as a new design structure of anode material. The Si powder was recycled from the silicon slicing waste in photovoltaic industry and the CNF was from dry rice straws. By mixing the purified Si powder with CNF, the composite was synthesized by the freeze-drying method and calcination. In the cyclic test, Si adding with 1 wt% CNF showed 3091 mAh/g capacity in the first cycle and 1079 mAh/g capacity after 100 cycles at the current density of 0.5 A/g, which were both better than pristine Si. SEM images also show the composite structure can eliminate cracks on the surface of the electrode during cycling. CNF attaching on Si particles can increase specific surface area, so binder can easily combine the active materials and the conductive materials together. This strategy enhances the structure stability and prevents the electrode from delamination.

Influence of carbon coating on the electrochemical performance of SiO@C/graphite composite anode materials

Silicon monoxide(SiO) has been considered as one of the most promising anode materials for next generation highenergy-density Li-ion batteries(LiBs) thanks to its high theoretical capacity. However, the poor intrinsic electronic conductivity and large volume change during lithium intercalation/de-intercalation restrict its practical applications. Fabrication of SiO/C composites is an effective way to overcome these problems. Herein, a series of micro-sized SiO@C/graphite(Si0@C/G) composite anode materials, with designed capacity of 600 mAh·g-1, are successfully prepared through a pitch pyrolysis reaction method. The electrochemical performance of SiO@C/G composite anodes with different carbon coating contents of 5 wt%, 10 wt%, 15 wt%, and 35 wt% is investigated. The results show that the SiO@C/G composite with15-wt% carbon coating content exhibits the best cycle performance, with a high capacity retention of 90.7% at 25℃ and90.1% at 45 0 C after 100 cycles in full cells with LiNi0.5Co0.2Mn0.3O2 as cathodes. The scanning electron microscope(SEM) and electrochemistry impedance spectroscopy(EIS) results suggest that a moderate carbon coating layer can promote the formation of stable SEI film, which is favorable for maintaining good interfacial conductivity and thus enhancing the cycling stability of SiO electrode.

One-dimensional Li_(3)VO_(4)/carbon fiber composites for enhanced electrochemical performance as an anode material for lithium-ion batteries

Lithium vanadium oxide(Li_(3)VO_(4))has gained attention as an alternative anode material because of its higher theoretical capacity(592 mAh g^(−1)),moderate ionic conductivity(∼10^(−4)S cm^(−1)),and lower working voltage range(∼0.5–1.0 V vs.Li/Li^(+))in comparison to other metal oxides.However,there are disadvantages to using Li_(3)VO_(4)as an anode material,such as low initial Coulombic efficiency and poor rate performance that is attributed to its low electronic conductivity(<10^(−1)0 S cm^(−1)).In the present study,the synthesis of one-dimensional Li_(3)VO_(4)electrode was performed via a facile method by using oxidized vapor grown carbon fiber as a template and the formation of the outer shells of conductive carbon via chemical vapor deposition technique.In a half-cell configuration,the prepared Li_(3)VO_(4)composites exhib-ited an enhanced electrochemical performance with a reversible capacity of 516.2 mAh g^(−1)after 100 cycles at a rate of 0.5 C within the voltage range of 0.01–3.0 V.At a high rate of 5 C,a large reversible capacity of 322.6 mAh g^(−1)was also observed after 500 cycles.The full cell(LVO/VGCF16-C||LiCoO_(2))using LiCoO_(2)as the cathode showed competitive electrochemical performance,which demonstrates its high potential in commercial applications.

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.

Preparation of biomass-derived carbon loaded with MnO_(2) as lithium-ion battery anode for improving its reversible capacity and cycling performance

Biomass-derived carbon materials for lithiumion batteries emerge as one of the most promising anodes from sustainable perspective.However,improving the reversible capacity and cycling performance remains a long-standing challenge.By combining the benefits of K2CO_(3) activation and KMnO_(4) hydrothermal treatment,this work proposes a two-step activation method to load MnO_(2) charge transfer onto biomass-derived carbon(KAC@MnO_(2)).Comprehensive analysis reveals that KAC@MnO_(2) has a micro-mesoporous coexistence structure and uniform surface distribution of MnO_(2),thus providing an improved electrochemical performance.Specifically,KAC@MnO_(2) exhibits an initial chargedischarge capacity of 847.3/1813.2 mAh·g^(-1) at 0.2 A·g^(-1),which is significantly higher than that of direct pyrolysis carbon and K2CO_(3) activated carbon,respectively.Furthermore,the KAC@MnO_(2) maintains a reversible capacity of 652.6 mAh·g^(-1) after 100 cycles.Even at a high current density of 1.0 A·g^(-1),KAC@MnO_(2) still exhibits excellent long-term cycling stability and maintains a stable reversible capacity of 306.7 mAh·g^(-1) after 500 cycles.Compared with reported biochar anode materials,the KAC@MnO_(2) prepared in this work shows superior reversible capacity and cycling performance.Additionally,the Li+insertion and de-insertion mechanisms are verified by ex situ X-ray diffraction analysis during the chargedischarge process,helping us better understand the energy storage mechanism of KAC@MnO_(2).

Fe_(2)O_(3)-MWNTs Composite with Reinforced Concrete Structure as High-performance Anode Material for Lithium-ion Batteries

A Fe_(2)O_(3)-MWNTs(multi-walled carbon nanotubes)composite with a reinforced concrete structure was fabricated employing a two-step method which involves a sol-gel process followed by high-temperature in situ sintering.This Fe_(2)O_(3)-MWNTs composite,intended to be used as an anode material for lithium-ion batteries,maintained a reversible capacity as high as 896.3 mA·h/g after 100 cycles at a current density of 100 mA/g and the initial coulombic efficiency reached 75.5%.The rate capabilities of the Fe_(2)O_(3)-MWNTs composite,evaluated using the ratios of capacity at 100,200,500,1000,2000 and 100 mA/g after every 10 cycles,were determined to be 904.7,852.1,759.0,653.8,566.8 and 866.3 mA·h/g,respectively.Such a superior electrochemical performance of the Fe_(2)O_(3)-MWNTs composite is mainly attributed to the reinforced concrete construction,in which the MWNTs function as the skeleton and conductive network.Such a structure contributes to shortening the transport pathways for both Li+and electrons,enhancing conductivity and accommodating volume expansion during prolonged cycling.This Fe_(2)O_(3)-MWNTs composite with the designed structure is a promising anode material for high-performance lithium-ion batteries.

High-performance SiO/C as anode materials for lithium-ion batteries using commercial SiO and glucose as raw materials

Silicon monoxide(SiO)is considered as a promising anode material for lithium-ion batteries(LIBs)due to its higher capacity and longer cycle life than those of graphite and silicon,respectively.In this study,glucose was developed as a suitable and inexpensive carbon source to synthesize SiO/C composite with a high performance.In addition,the effects of the calcination temperature and the amount of c arbon source on the electrochemical performance of the SiO/C composite were investigated.The addition of 5 wt%glucose and a calcination temperature of 800℃ demonstrated the optimum conditions for SiO/C synthesis.The resultant SiO/C showed an initial charge capacity of 1259 mAh·g^(-1) and a high initial coulombic efficiency of 71.9%.A charge capacity of 850 mAh·g^(-1) after 100 cycles at 200 mA·g^(-1) was achieved,demonstrating the best value of the SiO/C-based materials.The composition changes of SiO under the calcination temperature played a significant role in the electrochemical performance.Overall,the obtained SiO/C material with a high capacity and good stability is suitable for LIB applications as an anode material.

Aromatic Carbon Coated Tin Composites as Anode Materials for Lithium Ion Batteries

Aromatic carbon coated tin composites（A/Sn） have been prepared by thermal decomposition of the stannous 1,8-naphthalenedicarboxylate precursors,which is a reformative preparation method.Sugar carbon coated tin composites（S/Sn） also are prepared as a contrast with the A/Sn composites.The morphology and composition of the products were characterized by Scanning Electricity Microscopy（SEM） and X-Ray Diffraction（XRD）.Their electrochemical performance as anode materials for lithium ion batteries were investigated;the results indicated that these materials exhibited good performance,and the cycle stability of A/Sn composites is especially superior to the S/Sn composites due to its special carbon resource.

Carbon-coated Li_4Ti_5O_(12) Anode Materials Synthesized Using H_2TiO_3 as Ti Source

Two low-cost synthesis routes have been developed to fabricate carbon-coated Li4Ti5O12 by using H2TiO3 instead of anatase TiO2 as Ti source through solid-state reaction process. One route is a direct solid mixture of H2TiO3, Li2CO3 and pitch followed by high-temperature solid-state reaction. The other includes mixture of H2TiO3 and Li2CO3 with pitch dissolved in furanidine under vacuum and the same solid-state reaction procedure is followed after the mixture is totally dried. Microstructural investigations indicate that H2TiO3 exhibits secondary aggregates morphology with primary particle sizes of 10-20 nm. Carbon-coating layers with thickness of 2-3 nm have been observed on Li4Ti5O12 synthesized by the two routes. Cyclic performance, rate capability and electrochemical impedance spectrum of the two Li4Ti5O12/C composites have been performed, which indicate that Li4Ti5O12/C obtained by furanidine-assisted mixture exhibits better electrochemical performance than Li4Ti5O12/C synthesized by direct solid mixture. The possible reasons have been discussed. The low-cost synthesis routes of Li4Ti5O12/C using H2TiO3 as Ti source are expected to be more competitive than the traditional one for practical applications.

Three-dimensional structural Cu^(6)Sn_(5)/carbon nanotubes alloy thin-film electrodes fabricated by in situ electrodeposition from the leaching solution of waste-printed circuit boards

Tin-based materials are very attractive anodes because of their high theoretical capacity,but their rapid capacity fading from volume expansions limits their practical applications during alloying and dealloying processes.Herein,the improved binder-free tin-copper intermetallic/carbon nanotubes(Cu6Sn5/CNTs)alloy thin-film electrodes are directly fabricated through efficient in situ electrodeposition from the leaching solution of treated waste-printed circuit boards(WPCBs).The characterization results show that the easily agglomerated Cu6Sn5 alloy nanoparticles are uniformly dispersed across the three-dimensional network when the CNTs concentration in the electrodeposition solution is maintained at 0.2 g·L−1.Moreover,the optimal Cu6Sn5/CNTs-0.2 alloy thin-film electrode can not only provide a decent discharge specific capacity of 458.35 mAh·g^(−1)after 50 cycles at 100 mA·g^(−1)within capacity retention of 82.58%but also deliver a relatively high reversible specific capacity of 518.24,445.52,418.18,345.33,and 278.05 mAh·g^(−1)at step-increased current density of 0.1,0.2,0.5,1.0,and 2.0 A·g^(−1),respectively.Therefore,the preparation process of the Cu6Sn5/CNTs-0.2 alloy thin-film electrode with improved electrochemical performance may provide a cost-effective strategy for the resource utilization of WPCBs to fabricate anode materials for lithium-ion batteries.

Micrometer-sized ferrosilicon composites wrapped with multi-layered carbon nanosheets as industrialized anodes for high energy lithium-ion batteries

Various nanostructured architectures have been demonstrated to be effective to address the issues of high capacity Si anodes. However, the scale-up of these nano-Si materials is still a critical obstacle for commercialization. Herein, we use industrial ferrosilicon as low-cost Si source and introduce a facile and scalable method to fabricate a micrometer-sized ferrosilicon/C composite anode, in which ferrosilicon microparticles are wrapped with multi-layered carbon nanosheets. The multi-layered carbon nanosheets could effectively buffer the volume variation of Si as well as create an abundant and reliable conductivity framework, ensuring fast transport of electrons. As a result, the micrometer-sized ferrosilicon/C anode achieves a stable cycling with 805.9 m Ah g-1 over 200 cycles at 500 mA g-1 and a good rate capability of455.6 mAh g-1 at 10 A g-1. Therefore, our approach based on ferrosilicon provides a new opportunity in fabricating cost-effective, pollution-free, and large-scale Si electrode materials for high energy lithium-ion batteries.

Recent progress on three-dimensional nanoarchitecture anode materials for lithium/sodium storage

High-performance batteries with high density and low cost are needed for the development of largescale energy storage fields such as electric vehicles and renewable energy systems.The anode with threedimensional(3D)nanoarchitecture is one of the most attractive candidates for high-performance lithiumion batteries(LIBs)and sodium-ion batteries(SIBs)due to its efficient electron/ion transport and high active material mass loading.Although some important breakthroughs have been made in 3D nanoarchitecture anode materials,more improvements are still needed for high cycling stability and high energy density.Herein,the latest research progress of 3D nanoarchitecture anode materials for LIBs and SIBs is reviewed,including nanoporous metal,nanoporous graphene,and their derived foams.Specifically,the storage properties of Li/Na ions,the kinetics of ion/electron transport,and specific chemical interactions are discussed based on the structure design.In addition,the research strategies and structural characteristics of 3D nanoarchitecture anode materials are summarized,providing a reference for the further development of LIBs and SIBs.Meanwhile,the future research directions of LIBs and SIBs have also prospected.

Annihilating the Formation of Silicon Carbide:Molten Salt Electrolysis of Carbon-Silica Composite to Prepare the Carbon-Silicon Hybrid for Lithium-lon Battery Anode

Silicon(Si)and carbon(C)composites hold the promise for replacing the commercial graphite anode,thus increasing the energy density of lithium-ion batteries(LIBs).To mitigate the formation of SiC,this paper reports a molten salt electrolysis approach to prepare C-Si composite by the electrolysis of C-SiO2 composites.Unlike the conventional way of making a C coating on Si,C-SiO2 composites were prepared by pyrolyzing the low-cost sucrose and silica.The electrochemical deoxidation of the C-SiO2 composites not only produces nanostructured Si inside the C matrix but also introduces voids between the C and Si owing to the volume shrinkage from converting SiO2 to Si.More importantly,the use of Mg ion-containing molten salts precludes the generation of SiC,and the electrolytic Si@C composite anode delivers a capacity of about 1500 mAh g-1 after 100 cycles at a current density of 500 mA g-1.Further,the Si@C‖LiNi0.6Co0.2Mn0.2O2 full cell delivers a high energy density of 608 Wh kg-1.Overall,the molten salt approach provides a one-step electrochemical way to convert oxides@C to metals@C functional materials.

The application of carbon materials in nonaqueous Na‐O2 batteries

Na‐O2 batteries are advantageous as the candidates of next‐generation electric vehicles due to their ultrahigh theoretical energy density and have attracted enormous attention recently.Tremendous efforts have been devoted to improve the Na‐O2 battery performance by designing advanced electrodes with various carbonbased materials.Carbon materials used in Na‐O2 batteries not only function as the air electrode to provide active sites and accommodate discharge products but also as Na anode protectors against dendrite growth and chemical/electrochemical corrosion.In this review,we mainly focus on the application of various carbonbased materials in Na‐O2 batteries and highlight their advances.The scientific understanding on the fundamental design of the material microstructure and chemistry in relation to the battery performance are summarized.Finally,perspectives on enhancing the overall battery performance based on the optimization and rational design of carbon‐based cell components are also briefly anticipated.