Browse
Submit Data
Databases
API
Help

Dataset Information

22 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Surface Engineering and Design Strategy for Surface-Amorphized TiO₂@Graphene Hybrids for High Power Li-Ion Battery Electrodes.

ABSTRACT: Surface amorphization provides unprecedented opportunities for altering and tuning material properties. Surface-amorphized TiO₂@graphene synthesized using a designed low temperature-phase transformation technique exhibits significantly improved rate capability compared to well-crystallized TiO₂@graphene and bare TiO₂ electrodes. These improvements facilitates lithium-ion transport in both insertion and extraction processes and enhance electrolyte absorption capability.

SUBMITTER: Zhou T

PROVIDER: S-EPMC5115387 | biostudies-literature | 2015 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Surface Engineering and Design Strategy for Surface-Amorphized TiO2@Graphene Hybrids for High Power Li-Ion Battery Electrodes.

Zhou Tengfei T Zheng Yang Y Gao Hong H Min Shudi S Li Sean S Liu Hua Kun HK Guo Zaiping Z

Advanced science (Weinheim, Baden-Wurttemberg, Germany) 20150526 9

Surface amorphization provides unprecedented opportunities for altering and tuning material properties. Surface-amorphized TiO2@graphene synthesized using a designed low temperature-phase transformation technique exhibits significantly improved rate capability compared to well-crystallized TiO2@graphene and bare TiO2 electrodes. These improvements facilitates lithium-ion transport in both insertion and extraction processes and enhance electrolyte absorptio ...[more]

PMID: 27980970

Similar Datasets

In Situ Studies of 30% Li-Doped Bi25FeO40 Conversion Type Lithium Battery Electrodes.

Project description:One of the important discharge mechanisms for lithium batteries is the conversion reaction mechanism, where a metal oxide (fluoride) can decompose into metallic nanoparticles embedded in a Li2O (LiF) matrix. Here, 30% Li-doped Bi25FeO40 is successfully synthesized and displays an electrochemical discharge capacity of ∼300 mAh/g above 1.5 V (vs Li/Li+). During the electrochemical cycling process, 30% Li-doped Bi25FeO40 is decomposed into metallic Bi. During the subsequent charging process, the metallic bismuth can be first converted into an amorphous bismuth oxide phase, which contributed to the electrochemical discharge activities observed between 2 and 2.5 V. At a higher charging voltage between 3.5 and 5 V, metallic Bi can be oxidized to BiO x 2-O3-2x -, which contributes to the discharge activities observed above 2.5 V. Using graphite as current collectors can prevent the corrosion from O- species and the discharge capacity is greatly enhanced at the voltage region between 1.5 and 2.5 V. This work provides a deeper understanding over the role of oxygen ions during the conversion reaction process and is beneficial for the future design of battery systems based on the conversion reaction.

| S-EPMC6648275 | biostudies-literature

Surface-Engineered Li4Ti5O12 Nanostructures for High-Power Li-Ion Batteries.

Project description:Materials with high-power charge-discharge capabilities are of interest to overcome the power limitations of conventional Li-ion batteries. In this study, a unique solvothermal synthesis of Li4Ti5O12 nanoparticles is proposed by using an off-stoichiometric precursor ratio. A Li-deficient off-stoichiometry leads to the coexistence of phase-separated crystalline nanoparticles of Li4Ti5O12 and TiO2 exhibiting reasonable high-rate performances. However, after the solvothermal process, an extended aging of the hydrolyzed solution leads to the formation of a Li4Ti5O12 nanoplate-like structure with a self-assembled disordered surface layer without crystalline TiO2. The Li4Ti5O12 nanoplates with the disordered surface layer deliver ultrahigh-rate performances for both charging and discharging in the range of 50-300C and reversible capacities of 156 and 113 mAh g-1 at these two rates, respectively. Furthermore, the electrode exhibits an ultrahigh-charging-rate capability up to 1200C (60 mAh g-1; discharge limited to 100C). Unlike previously reported high-rate half cells, we demonstrate a high-power Li-ion battery by coupling Li4Ti5O12 with a high-rate LiMn2O4 cathode. The full cell exhibits ultrafast charging/discharging for 140 and 12 s while retaining 97 and 66% of the anode theoretical capacity, respectively. Room- (25 °C), low- (- 10 °C), and high- (55 °C) temperature cycling data show the wide temperature operation range of the cell at a high rate of 100C.

| S-EPMC7770703 | biostudies-literature

Three-dimensional MoS2/Graphene Aerogel as Binder-free Electrode for Li-ion Battery.

Project description:Hybrid MoS2/reduced graphene aerogels with rich micro-pore are fabricated through a hydrothermal method, followed by freeze-drying and annealing treatment. The porous structure could act as an electrode directly, free of binder and conductive agent, which promotes an improved electron transfer, and provides a 3D network for an enhanced ion transport, thus leading to an increased capacity and stable long cycle stability performance. Notably, the specific capacity of MoS2/reduced graphene aerogel is 1041 mA h g-1 at 100 mA g-1. Moreover, reversible capacities of 667 mA h g-1 with 58.6% capacity retention are kept after 100 cycles. The outstanding performance is beneficial from the synergistic effect of the MoS2 nanostructure and graphene conductive network, as well as the binder-free design. These results provide a route to integrate transition-metal-dichalcogenides with graphene to fabricate composites with rich micro-pores and a three-dimensional network for energy storage devices.

| S-EPMC6408559 | biostudies-literature

Evolution of Reduced Graphene Oxide-SnS2 Hybrid Nanoparticle Electrodes in Li-Ion Batteries.

Project description:Hybrid nanomaterials where active battery nanoparticles are synthesized directly onto conductive additives such as graphene hold the promise of improving the cyclability and energy density of conversion and alloying type Li-ion battery electrodes. Here we investigate the evolution of hybrid reduced graphene oxide-tin sulfide (rGO-SnS2) electrodes during battery cycling. These hybrid nanoparticles are synthesized by a one-step solvothermal microwave reaction which allows for simultaneous synthesis of the SnS2 nanocrystals and reduction of GO. Despite the hybrid architecture of these electrodes, electrochemical impedance spectroscopy shows that the impedance doubles in about 25 cycles and subsequently gradually increases, which may be caused by an irreversible surface passivation of rGO by sulfur enriched conversion products. This surface passivation is further confirmed by post-mortem Raman spectroscopy of the electrodes, which no longer detects rGO peaks after 100 cycles. Moreover, galvanostatic intermittent titration analysis during the 1st and 100th cycles shows a drop in Li-ion diffusion coefficient of over an order of magnitude. Despite reports of excellent cycling performance of hybrid nanomaterials, our work indicates that in certain electrode systems, it is still critical to further address passivation and charge transport issues between the active phase and the conductive additive in order to retain high energy density and cycling performance.

| S-EPMC5547442 | biostudies-literature

Graphene-TiO2 hybrids for photocatalytic aided removal of VOCs and nitrogen oxides from outdoor environment.

Project description:Outdoor and indoor air pollution has become a global concern in modern society. Although many policies and regulations on air quality have been promulgated worldwide over the past decades, airborne pollution still negatively affects health and therefore the life-style of human beings. One of the strategies to challenge this problem might be reducing the amount of airborne pollutant by mineralising them via photoinduced reactions. Photocatalytic oxidation of gaseous pollutants via titanium dioxide is one of the most promising solar photochemical reactions. In this research work, by means of a green sol-gel procedure, we have coupled titania to graphene (0.5 and 1.0 wt%) aiming to increase the solar photocatalytic activity of the produced hybrid materials. Transient paramagnetic species formed upon UV-A irradiation were detected by means of EPR spectroscopy. The photocatalytic reactions were assessed by monitoring the removal of nitrogen oxides and two different volatile organic compounds (benzene and isopropanol), which has never been assessed before. Our results highlight the exceptional characteristics of the TiO2/graphene hybrid material synthesised with 1.0 wt% graphene, and its excellent suitability for multi-purpose applications in the field of environmental remediation. Compared to unmodified titania, it shows a clear enhancement in the photocatalytic removal of those hazardous pollutants, having a photocatalytic degradation rate twice higher. In addition, the same material is highly stable and shows fully recyclability over repeated tests. Hybrid titania-graphene materials could thus be exploited to grant safer outdoor and indoor environments, having thus a beneficial impact on public health and on the quality of our lives.

| S-EPMC7425720 | biostudies-literature

Advanced Electrodes for High Power Li-ion Batteries.

Project description:While little success has been obtained over the past few years in attempts to increase the capacity of Li-ion batteries, significant improvement in the power density has been achieved, opening the route to new applications, from hybrid electric vehicles to high-power electronics and regulation of the intermittency problem of electric energy supply on smart grids. This success has been achieved not only by decreasing the size of the active particles of the electrodes to few tens of nanometers, but also by surface modification and the synthesis of new multi-composite particles. It is the aim of this work to review the different approaches that have been successful to obtain Li-ion batteries with improved high-rate performance and to discuss how these results prefigure further improvement in the near future.

| S-EPMC5512962 | biostudies-other

Monodispersed Ru Nanoparticles Functionalized Graphene Nanosheets as Efficient Cathode Catalysts for O2-Assisted Li-CO2 Battery.

Project description:In Li-CO2 battery, due to the highly insulating nature of the discharge product of Li2CO3, the battery needs to be charged at a high charge overpotential, leading to severe cathode and electrolyte instability and hence poor battery cycle performance. Developing efficient cathode catalysts to effectively reduce the charge overpotential represents one of key challenges to realize practical Li-CO2 batteries. Here, we report the use of monodispersed Ru nanoparticles functionalized graphene nanosheets as cathode catalysts in Li-CO2 battery to significantly lower the charge overpotential for the electrochemical decomposition of Li2CO3. In our battery, a low charge voltage of 4.02 V, a high Coulomb efficiency of 89.2%, and a good cycle stability (67 cycles at a 500 mA h/g limited capacity) are achieved. It is also found that O2 plays an essential role in the discharge process of the rechargeable Li-CO2 battery. Under the pure CO2 environment, Li-CO2 battery exhibits negligible discharge capacity; however, after introducing 2% O2 (volume ratio) into CO2, the O2-assisted Li-CO2 battery can deliver a high capacity of 4742 mA h/g. Through an in situ quantitative differential electrochemical mass spectrometry investigation, the final discharge product Li2CO3 is proposed to form via the reaction 4Li+ + 2CO2 + O2 + 4e- → 2Li2CO3. Our results validate the essential role of O2 and can help deepen the understanding of the discharge and charge reaction mechanisms of the Li-CO2 battery.

| S-EPMC6645591 | biostudies-literature

Temperature-Controlled Synthesis of Li- and Mn-Rich Li1.2Mn0.54Ni0.13Co0.13O2 Hollow Nano/Sub-Microsphere Electrodes for High-Performance Lithium-Ion Battery.

Project description:The calcination temperature plays a significant role in the structural, textural, and energy-storage performance of metal oxide nanomaterials in Li-ion battery application. Here, we report the formation of well-crystallized homogeneously dispersed Li1.2Mn0.54Ni0.13Co0.13O2 hollow nano/sub-microsphere architectures through a simple cost-effective coprecipitation and chemical mixing route without surface modification for improving the efficiency of energy storage devices. The synthesized Li1.2Mn0.54Ni0.13Co0.13O2 hollow nano/sub-microsphere cathode materials are calcined at 800, 900, 950, and 1000 °C. Among them, Li1.2Mn0.54Ni0.13Co0.13O2 calcined at 950 °C exhibits a high discharge capacity (277 mAh g-1 at 0.1C rate) and excellent capacity retention (88%) after 50 cycles and also delivers an excellent discharge capacity of >172 mAh g-1 at 5C rate. Good electrochemical performance of Li1.2Mn0.54Ni0.13Co0.13O2-950 is directly related to the optimized size of its primary particles (85 nm) (which constitute the spherical secondary particle, ∼720 nm) and homogeneous cation mixing. Higher calcination temperature (≥950 °C) leads to an increase of the primary particle size, poor cycling stability, and inferior rate capacity of Li1.2Mn0.54Ni0.13Co0.13O2 due to smashing of quasi-hollow spheres upon repeated lithium ion intercalations/deintercalations. Therefore, Li1.2Mn0.54Ni0.13Co0.13O2-950 is a promising electrode for the next-generation high-voltage and high-capacity Li-ion battery application.

| S-EPMC6893958 | biostudies-literature

An Ultrahigh Capacity Graphite/Li2S Battery with Holey-Li2S Nanoarchitectures.

Project description:The pairing of high-capacity Li2S cathode (1166 mAh g-1) and lithium-free anode (LFA) provides an unparalleled potential in developing safe and energy-dense next-generation secondary batteries. However, the low utilization of the Li2S cathode and the lack of electrolytes compatible to both electrodes are impeding the development. Here, a novel graphite/Li2S battery system, which features a self-assembled, holey-Li2S nanoarchitecture and a stable solid electrolyte interface (SEI) on the graphite electrode, is reported. The holey structure on Li2S is beneficial in decomposing Li2S at the first charging process due to the enhanced Li ion extraction and transfer from the Li2S to the electrolyte. In addition, the concentrated dioxolane (DOL)-rich electrolyte designed lowers the irreversible capacity loss for SEI formation. By using the combined strategies, the graphite/holey-Li2S battery delivers an ultrahigh discharge capacity of 810 mAh g-1 at 0.1 C (based on the mass of Li2S) and of 714 mAh g-1 at 0.2 C. Moreover, it exhibits a reversible capacity of 300 mAh g-1 after a record lifecycle of 600 cycles at 1 C. These results suggest the great potential of the designed LFA/holey-Li2S batteries for practical use.

| S-EPMC6051237 | biostudies-literature

Etched colloidal LiFePO4 nanoplatelets toward high-rate capable Li-ion battery electrodes.

Project description:LiFePO4 has been intensively investigated as a cathode material in Li-ion batteries, as it can in principle enable the development of high power electrodes. LiFePO4, on the other hand, is inherently "plagued" by poor electronic and ionic conductivity. While the problems with low electron conductivity are partially solved by carbon coating and further by doping or by downsizing the active particles to nanoscale dimensions, poor ionic conductivity is still an issue. To develop colloidally synthesized LiFePO4 nanocrystals (NCs) optimized for high rate applications, we propose here a surface treatment of the NCs. The particles as delivered from the synthesis have a surface passivated with long chain organic surfactants, and therefore can be dispersed only in aprotic solvents such as chloroform or toluene. Glucose that is commonly used as carbon source for carbon-coating procedure is not soluble in these solvents, but it can be dissolved in water. In order to make the NCs hydrophilic, we treated them with lithium hexafluorophosphate (LiPF6), which removes the surfactant ligand shell while preserving the structural and morphological properties of the NCs. Only a roughening of the edges of NCs was observed due to a partial etching of their surface. Electrodes prepared from these platelet NCs (after carbon coating) delivered a capacity of ? 155 mAh/g, ? 135 mAh/g, and ? 125 mAh/g, at 1 C, 5 C, and 10 C, respectively, with significant capacity retention and remarkable rate capability. For example, at 61 C (10.3 A/g), a capacity of ? 70 mAh/g was obtained, and at 122 C (20.7 A/g), the capacity was ? 30 mAh/g. The rate capability and the ease of scalability in the preparation of these surface-treated nanoplatelets make them highly suitable as electrodes in Li-ion batteries.

| S-EPMC4264480 | biostudies-literature