High-performance Lithium Storage Material Research Articles

Highly graphitized coal tar pitch-derived porous carbon as high-performance lithium storage materials.

Because of its high specific capacity and superior rate performance, porous carbon is regarded as a potential anode material for lithium-ion batteries (LIBs). However, porous carbon materials with wide pore diameter distributions suffer from low structural stability and low electrical conductivity during the application process. During this study, the calcium carbonate nanoparticle template method is used to prepare coal tar pitch-derived porous carbon (CTP-X). The coal tar pitch-derived porous carbon has a well-developed macroporous-mesoporous-microporous hierarchical porous network structure, which provides abundant active sites for Li+ storage, significantly reduces polarization and charge transfer resistance, shortens the diffusion path and promotes the rapid transport of Li+. More specifically, the CTP-2 anode shows high charge capacity (496.9 mAh g-1 at 50 mA g-1), excellent rate performance (413.6 mAh g-1 even at 500 mA g-1), and high cycling stability (capacity retention rate of about 100% after 1,000 cycles at 2 A g-1). The clean and eco-friendly large-scale utilization of coal tar pitch will facilitate the development of high-performance anodes in the field of LIBs.

Approaching high-performance lithium storage materials by constructing Li2ZnTi3O8@LiAlO2 composites

Approaching high-performance lithium storage materials by constructing Li2ZnTi3O8@LiAlO2 composites

Approaching high-performance lithium storage materials of CoNiO2 microspheres wrapped coal tar pitch-derived porous carbon.

Ternary transition metal oxides (TMOs) are deemed as promising anode materials of Li-ion batteries (LIBs) owing to their large theoretical capacity and rich redox reaction. Nevertheless, the inherent semiconductor characteristic and enormous volume variation of TMOs during cycling bring about sluggish reaction kinetics, fast capacity fading, and poor rate capability. In this study, three-dimensional (3D) porous CoNiO2@CTP architectures, i.e., CoNiO2 microspheres combined with coal tar pitch-derived porous carbon, were designed and synthesized through a one-step hydrothermal method followed by a heat treatment process for the first time. The microsphere morphology increases the contact area between the anode and electrolyte, shortens the transport distance of Li+ ions, and reduces the agglomeration. The existence of the CTP layer provides rich charge transmission paths, improves the electronic conductivity of CoNiO2 and provides abundant active sites for Li+ storage. Owing to the synergistic effect of porous carbon and microsphere morphology of CoNiO2, the CoNiO2@CTP (10.0 wt%) anode shows remarkable electrochemical performance with a high charge capacity (1437.5 mA h g-1 at 500 mA g-1), good rate performance (839.76 mA h g-1 even at 1 A g-1), and remarkable cycle durability (741.4 mA h g-1 after 1000 cycles at 1 A g-1), which is significantly better than pristine CoNiO2. This study not only provides a simple strategy for high-value utilization of CTP but also offers cost-effective CoNiO2@CTP architectures for high-performance LIBs.

Li2ZnTi3O8@α-Fe2O3 composite anode material for Li-ion batteries

Li2ZnTi3O8@α-Fe2O3 composites have been successfully prepared by a facile hydrothermal process. Li2ZnTi3O8/α-Fe2O3 composites show similar irregular spherical morphologies like Li2ZnTi3O8 and relatively smaller particle sizes than pristine Li2ZnTi3O8. Among all Li2ZnTi3O8/α-Fe2O3 composites, Li2ZnTi3O8/α-Fe2O3 composite (5 wt%) exhibits the best electrochemical properties. Li2ZnTi3O8/α-Fe2O3 composite (5 wt%) delivers a reversible charge capacity of 184.8 mAh g−1 even at 1000 mA g−1 after 500 cycles, while pristine Li2ZnTi3O8 only delivers a reversible charge capacity of 110.7 mAh g−1. The strong covalent bonds between Li2ZnTi3O8 and α-Fe2O3 will be formed, which is beneficial for the reduction of interfacial energy and thus helpful for the stabilization of the composite. Because of the special synergistic effect of the multi-phase interface, Li2ZnTi3O8/α-Fe2O3 composites not only possess the advantages of single components but also show novel and attractive performances, such as the enhanced ionic conductivity, reduced interfacial charge transfer impedance, improved migration rate of lithium ions, and the enhancement of the rate performance and reversible capacity. The as-prepared Li2ZnTi3O8/α-Fe2O3 composites reveal important potentials as anode materials for next-generation rechargeable Li-ion batteries, and this work also offers an effective strategy to design high performance lithium storage materials for advanced lithium-ion batteries.

Bimetal-organic frameworks derived ternary metal sulphide nanoparticles embedded in porous carbon spheres/carbon nanotubes as high-performance lithium storage materials

Designing advanced structures to ameliorate the deficiencies of conversion anodes in terms of poor conductivity and sever volume change over cycling is still the attracting area for fundamental research but challenging, toward which more efforts are needed. Here, we demonstrate the synthesis of a hierarchical composite of CoNi2S4 from sulfurizing the elaborately designed Co/Ni bimetal-organic frameworks (MOF-74) precursors with well-defined sphere morphology. In this composite, the CoNi2S4 nanoparticles are evenly embedded in the carbon nanosheets which are in situ carbonized from organic ligand and self-assembled into porous carbon spheres with short carbon nanotubes (CNTs) deeply rooted in the surface (CoNi2S4@PCS/CNTs). The porous structure provides favourable paths for electrolyte penetration and spaces for volume changing upon cycling, while the outwardly grew short CNTs and the carbon skeleton of the spheres guarantee fast electron transfer. Beneficial from the robust structure plus the synergetic effect from two different metal elements, the obtained CoNi2S4@PCS/CNTs demonstrates excellent lithium storage performance in terms of reversible capacity (1250 mAh g−1 at 500 mA g−1), cycle stability (843 mAh g−1 at 1 A g−1 after 600 cycles) and rate capability (608 mAh g−1 at 4 A g−1). The kinetic analysis reveals that the CoNi2S4@PCS/CNTs is benefit from capacitive contribution to the reversible lithium storage capacity under a faradaic surface pseudocapacitive mechanism, especially at high current densities. This work demonstrates an effective strategy that combines the synergetic effect from two metals upon lithium insertion and advantages from structure design to enhance the lithium storage performance of conversion materials.

Biphasic silicon oxide nanocomposites as high-performance lithium storage materials

By synergetic effect with unique microstructure and chemical composition, the biphasic Si/SiOx–SiO composites showed high performance Li storage characteristics.

Bottom-up self-assembly of nano-netting cluster microspheres as high-performance lithium storage materials

Cluster microspheres are prepared by self-assembly process, where two dissimilar metal oxide materials are inversely placed.

Converting biomass waste into microporous carbon with simultaneously high surface area and carbon purity as advanced electrochemical energy storage materials

Developing carbon materials featuring both high accessible surface area and high structure stability are desirable to boost the performance of constructed electrochemical electrodes and devices. Herein, we report a new type of microporous carbon (MPC) derived from biomass waste based on a simple high-temperature chemical activation procedure. The optimized MPC-900 possesses microporous structure, high surface area, partially graphitic structure, and particularly low impurity content, which are critical features for enhancing carbon-based electrochemical process. The constructed MPC-900 symmetric supercapacitor exhibits high performances in commercial organic electrolyte such as widened voltage window up to 3V and thereby high energy/power densities (50.95Whkg−1 at 0.44kWkg−1; 25.3Whkg−1 at 21.5kWkg−1). Furthermore, a simple melt infiltration method has been employed to enclose SnO2 nanocrystals onto the carbon matrix of MPC-900 as a high-performance lithium storage material. The obtained SnO2-MPC composite with ultrafine SnO2 nanocrystals delivers high capacities (1115mAhg−1 at 0.2A g−1; 402mAhg−1 at 10Ag−1) and high-rate cycling lifespan of over 2000 cycles. This work not only develops a microporous carbon with high carbon purity and high surface area, but also provides a general platform for combining electrochemically active materials.

Encapsulation of SnO2 nanocrystals into hierarchically porous carbon by melt infiltration for high-performance lithium storage

A melt infiltration method is developed to encapsulate SnO2 nanocrystals into porous carbon as a high-performance lithium storage material.

First Observation of the Pore Dynamics in Ordered Mesoporous Electrode Materials By in Operando Small Angle X-Ray Scattering

To monitor dynamic volume changes of electrode materials during electrochemical lithium storage and removal process is of utmost importance for developing high performance lithium storage materials. We herein report an in operando probing of mesoscopic structural changes in ordered mesoporous electrode materials during cycling with synchrotron-based small angle X-ray scattering (SAXS) technique. In operando SAXS studies combined with electrochemical and other physical characterizations straightforwardly show how porous electrode materials underwent volume changes during the whole process of charge and discharge, with respect to their own reaction mechanism with lithium. This comprehensive information on the pore dynamics as well as volume changes of the electrode materials will not only be critical in further understanding of lithium ion storage reaction mechanism of materials, but also enable the innovative design of high performance nanostructured materials for next generation batteries.

In Operando Monitoring of the Pore Dynamics in Ordered Mesoporous Electrode Materials by Small Angle X-ray Scattering.

To monitor dynamic volume changes of electrode materials during electrochemical lithium storage and removal process is of utmost importance for developing high performance lithium storage materials. We herein report an in operando probing of mesoscopic structural changes in ordered mesoporous electrode materials during cycling with synchrotron-based small angel X-ray scattering (SAXS) technique. In operando SAXS studies combined with electrochemical and other physical characterizations straightforwardly show how porous electrode materials underwent volume changes during the whole process of charge and discharge, with respect to their own reaction mechanism with lithium. This comprehensive information on the pore dynamics as well as volume changes of the electrode materials will not only be critical in further understanding of lithium ion storage reaction mechanism of materials, but also enable the innovative design of high performance nanostructured materials for next generation batteries.

Nano/micro structure ammonium cerium nitrate tetrahydrate/carbon nanotube as high performance lithium storage material

Using carbon nanotube (CNT) as conductive additive, (NH4)2Ce(NO3)5·4H2O/CNT is prepared from (NH4)2Ce(NO3)6 by a facile solution method and used as high capacity anode material for the first time. Morphology and structure investigation shows that (NH4)2Ce(NO3)5·4H2O/CNT exhibits high purity phase with particle size of 0.1–1.0 μm. In the composite, CNT provides a three-dimensional conductive network for electron transportation and can maintain the whole structure upon electrochemical cycles. For comparison, (NH4)2Ce(NO3)5·4H2O and (NH4)2Ce(NO3)5·4H2O/carbon black ((NH4)2Ce(NO3)5·4H2O/CB) are also prepared by the same method. Impurity phase of (NH4)3Ce2(NO3)9 can be detected in both (NH4)2Ce(NO3)5·4H2O and (NH4)2Ce(NO3)5·4H2O/CB. Electrochemical testing results reveals that (NH4)2Ce(NO3)5·4H2O/CNT shows lower initial discharge capacity (1683.6 mAh g−1) than (NH4)2Ce(NO3)5·4H2O (1972.8 mAh g−1) in the first cycle. However, (NH4)2Ce(NO3)5·4H2O/CNT shows the highest reversible capacity among all the three samples. After 30 cycles, it can deliver a reversible capacity of 818.5 mAh g−1, which is much higher than that of (NH4)2Ce(NO3)5·4H2O (50.6 mAh g−1) and (NH4)2Ce(NO3)5·4H2O/CB (208.8 mAh g−1). It suggests that the enhanced electrochemical properties are attributed to the introduction of CNT, which improves the electronic conductivity and structural stability during repeated cycles.

In situ growth of coiled carbon nanotubes on LiFePO4 as high performance lithium storage material

In this paper, LiFePO4@CNTs is fabricated by in situ growth of CNTs on the surface of LiFePO4 particles. The use of Ni–P alloy as catalyst results in the formation of coiled CNTs. The crosslinked CNTs provide good electronic conductive pathways interconnecting LiFePO4 particles. By using as cathode material for lithium ion battery, LiFePO4@CNTs shows higher electronic conductivity and charge transfer rate than those of the pristine LiFePO4 before coating. As a result, LiFePO4@CNTs displays outstanding lithium storage capacity and rate property. Electrochemical results reveal that LiFePO4@CNTs can deliver the reversible capacities of 161.3mAhg−1 at 0.2C and 108.0mAhg−1 at 10C. For comparison, bare LiFePO4 only reveals reversible capacities of 144.1mAhg−1 at 0.2C and 90.9mAhg−1 at 10C.

Polythiophene coordination complexes as high performance lithium storage materials

Polythiophene (PTh)-based coordination complexes, polythiophene–iron (PTh–Fe) and polythiophene–iron–oxygen (PTh–Fe–O) were synthesized by chemical method and proved to be novel high-performance organometallic lithium-storage materials. Extended X-ray absorption fine structural (EXAFS) spectroscopy and density functional theory (DFT) calculations indicate that these complexes have layered structures. It is believed that the strong and stable Fe–S coordination creates sites of lithium storage and ensures the high specific capacity and outstanding cycle performance of the PTh-based complexes.

Polypyrrole-Transition Metal-Oxygen Coordination Complexes as High Performance Lithium Storage Material

Polypyrrole-Transition Metal-Oxygen Coordination Complexes as High Performance Lithium Storage Material

Polypyrrole–NiO composite as high-performance lithium storage material

Organic electrode materials have long been proposed but their electrochemical performances are far from satisfactory in, for example, specific capacity and cycling stability, for secondary batteries. This article reports the electrochemical performance of a composite of polypyrrole (PPy) and nickel oxide (NiO), in which another lithium storage material, polypyrrole–nickel–oxygen (PPy–Ni–O) coordination complex, was fabricated during initial galvanostatically discharging. Extended X-ray absorption fine structure (EXAFS) spectroscopy and density functional theory (DFT) calculations indicate the process of the electrochemical formation of a PPy–Ni–O coordination and determine its multilayer structure. The strong and electrochemically stable coordination between the nickel and nitrogen atoms ensures the excellent electrochemical performances of the complex. These findings pave new ways to construct a new type of high-performance organic anode material for lithium ion batteries.

Polypyrrole-iron-oxygen coordination complex as high performance lithium storage material

Current lithium ion battery (LIB) technologies are all based on inorganic electrodes though organic materials have been hyped as electrodes for years. Disadvantages such as low specific capacity and poor rate performance hinder their applications. Here we report a novel high-performance organometallic lithium-storage material, a polypyrrole-iron-oxygen (PPy-Fe-O) coordination complex. Extended X-ray absorption fine structure (EXAFS) spectroscopy and density functional theory (DFT) calculations indicate that this complex has a multilayer structure. The strong and stable intralayer Fe–N coordination permits the material to possess high specific capacity, the high reversibility of its interlayer Fe–O–Fe interaction during cycling ensures its high cycling stability and the conducting PPy matrix endows it with outstanding rate performance. These findings pave the way to constructing a new type of high-performance organic anode materials for LIBs.