High Lithium-ion Storage Capacity Research Articles

Carbon nanotubes anchored SiOx composite anode for high cyclic stability lithium-ion batteries

Silicon suboxide (SiOx, 0 < x < 2) is one of the most promising anode materials because of its high lithium-ion storage capacity. However, the poor intrinsic conductivity and large volume change during cycling limits its practical application as lithium-ion battery anode materials. Herein, we propose a novel strategy to introduce carbon nanotubes (CNTs) on the SiOx particles, forming a conductive network and relieving the volume expansion effect, which possess improved reversible capacity and robust structure for long cycling stability. The SiOx/CNT composite anode delivers reversible capacity of 1533.8 mAh g−1 at the first cycle and maintains 599.6 mAh g−1 after 500 cycles with a high coulombic efficiency of 99.7 %. In this paper, SiOx composite anchored by CNTs was prepared, which is a simple and effective strategy to improve the conductivity of SiOx, relieve the volume effect and further promote its electrochemical performance benefit from the high conductivity and structural stability of CNTs. This research provides a significant reference for constructing the delicate structure of SiOx-based composites to enhance cyclic performance.

Mn-based MXene with high lithium-ion storage capacity

Mn-based MXene with high lithium-ion storage capacity

Superior lithium storage performance in MoO3 by synergistic effects: Oxygen vacancies and nanostructures

The process of oxygen vacancy generation in MoO 3 using electron-proton co-doping strategy is investigated by DFT calculation. On the one hand, oxygen vacancies intrinsically improve the semiconductor properties of MoO 3 . On the other hand, the nanostructure externally improves the massive expansion of MoO 3 during the lithiation process. Dual synergistic effects ensure high capacity and long cycle stability. • DFT is used to calculate the products of electron-proton co-doping. • The dual synergistic effect of intrinsic and extrinsic standpoints is considered. • Minerals are used directly as electrode materials. • Methods to improve the electrochemical performance of TMOs is provided. Molybdenum trioxide (MoO 3 ) has recently attracted wide attention as a typical conversion-type anode of Li-ion batteries (LIBs). Nevertheless, the inferior intrinsic conductivity and rapid capacity fading during charge/discharge process seriously limit large-scale commercial application of MoO 3 . Herein, the density function theory (DFT) calculations show that electron-proton co-doping preferentially bonds symmetric oxygen to form unstable H x MoO 3 . When the -OH- group in H x MoO 3 is released into the solution in the form of H 2 O, it is going to form MoO 3− x with lower binding energy. By the means of both electron-proton co-doping and high-energy nanosizing, oxygen vacancies and nanoflower structure are introduced into MoO 3 to accelerate the ion and electronic diffusion/transport kinetics. Benefitting from the promotion of ion diffusion kinetics related to nanostructures, as well as both the augmentation of active sites and the improvement of electrical conductivity induced by oxygen vacancies, the MoO 3− x /nanoflower structures show excellent lithium-ion storage performance. The prepared specimen has a high lithium-ion storage capacity of 1261 mA h g −1 at 0.1 A g −1 and cyclic stability (450 cycle), remarkably higher than those of previously reported MoO 3 -based anode materials.

Rational design of a C3N/C3B p-n heterostructure as a promising anode material in Li-ion batteries.

It is urgent to develop high-performance anode materials for lithium-ion batteries. In this work, a C3N/C3B p-n heterostructure was systematically investigated by first-principles calculations. The bonding strength of Li in C3N is relatively low (-0.53 eV), whereas the C3N/C3B heterostructure (-1.64 eV to -2.84 eV) can greatly improve the bonding strength without compromising the Li migration capability. The good bonding strength and Li mobility in the C3N/C3B heterostructure are mainly caused by the synergy effect and internal electric field of the p-n heterostructure. Moreover, the electronic structures indicate that the C3N/C3B heterostructure has good conductivity with a tiny bandgap of 0.09 eV. Compared to pristine C3N, the stiffness of the C3N/C3B heterostructure improved significantly (549.35 N m-1). Besides, the C3N/C3B heterostructure presents a high lithium-ion storage capacity (986.61 mA h g-1). The ultrahigh stiffness, good conductivities of electrons and ions, high bonding strength of Li, and high capacity show that the C3N/C3B heterostructure is a prospective anode material for lithium-ion batteries.

Fan-shape Mn-doped CoO/C microspheres for high lithium-ion storage capacity

Cobalt monoxide (CoO) has received considerable attention because of promising applications in lithium-ion batteries (LIBs). However, nanostructured CoO anode materials still suffer from the poor conductivity and large volume change. By optimizing the morphology and introducing the proper dopants, some of the obstacles can be overcome. In this work, a fan-shape Mn-doped CoO/C microsphere (Mn-CoO/C) composite is synthesized by a one-step hydrothermal process and the electrochemical properties are evaluated systematically. The Mn-CoO composite has a flabellum structure with a length of 5–10 µm assembled on nanosheets with a size of 20–50 nm. The interlayer spacing is 30–100 nm and the Co to Mn ratio is 8:1. The Mn-CoO/C electrode shows a high specific capacity of 741.2 mAhg−1 at 0.1 C as well as good cycling stability. To demonstrate the practicality of the electrode materials, the lithium-ion battery shows a capacity of 726.4 mAhg−1 after 200 cycles. The large specific surface area and short ion/electron transfer paths lead to the excellent electrochemical performance and our results reveal a simple and practical strategy to improve the lithium storage capacity of LIBs.

Constructing N-doping biomass-derived carbon with hierarchically porous architecture to boost fast reaction kinetics for high-performance lithium storage

Active biomass-derived carbons are brought into focus on boosting high-performance lithium storage. However, their low electric conductivity and poor ion diffusion kinetics during the lithium storage reactions remain confusing topics. This study demonstrates a novel and effective strategy of dual system activation process to construct the nitrogen-doped biomass-derived carbon with hierarchically porous architecture (HNBC), which is composed of the three-dimensional porous networks connected by carbon nanorods and the flake-like edges constructed by carbon nanosheets. A large amount of nitrogen doping can improve the conductivity and facilitate the charge transfer during charging/discharging, while the hierarchically porous structure can decrease the diffusion path for lithium-ion transport, enabling fast diffusion and charge-transfer dynamics. The HNBC electrode displays a high lithium-ion storage capacity of above 1392 mAh g−1 at 0.1 A g−1 and superior stability. Moreover, the assembled asymmetric lithium-ion capacitor exhibits excellent cycling stability and delivers a high power density of 225 W kg−1 with an energy density of 186.31 W h kg−1. This dual system activation strategy may inspire the reasonable design of new-generation progressive carbon-based electrodes for high-performance lithium storage devices.

Intercalation and delamination of Ti2SnC with high lithium ion storage capacity.

Li-ion batteries attract great attention due to the rapidly increasing and urgent demand for high energy storage devices. MAX phase compounds, layered ternary transition metal carbides and/or nitrides show promise as candidate materials of electrodes for Li-ion batteries. However, the highest specific capacity reported up to now is relatively low (180 mA h g-1), preventing them from use in real applications. Exploring more MAX phase compounds with delaminated two-dimensional structure is an effective solution to increase the specific capacity. Herein, we report the reversible electrochemical intercalation of Li+ into Ti2SnC (MAX phase) nanosheets. Owing to the synergistic effects of intercalation and dimethyl sulfoxide (DMSO)-assisted exfoliation, Ti2SnC nanosheets are successfully obtained via sonication in DMSO. Moreover, when using as an anode of a Li-ion battery, Ti2SnC nanosheets exhibited an increasing specific capacity with cycling due to the exfoliation of Ti2SnC nanosheets via reversible Li-ion intercalation. After 1000 charge-discharge cycles, Ti2SnC nanosheets delivered a high specific capacity of 735 mA h g-1 at a current density of 50 mA g-1, which is far better than other MAX phases, such as Ti2SC, Ti3SiC2 and Nb2SnC. The current work demonstrates the Li-ion storage potential and indicates a novel strategy for further intercalation and delamination of MAX phases.

Nanophase MnV2O4 particles as anode materials for lithium-ion batteries

Developing electrode materials with high energy and power densities holds the key for satisfying the urgent demand for energy storage. Addressing at this issue, we herein report a nanophase MnV2O4 material as a novel anode material for lithium-ion batteries. Nanoscale V2O3 precursor was employed as raw material and successfully limited the diameter of the MnV2O4 particles. Nanoscale MnV2O4 with carbon coating behaves an ideal electrochemical performance, and its initial capacity and Coulombic efficiency are 736.9 mAh g−1 under 50 mA g−1 and of 83.17%, respectively. Besides, the MnV2O4 also shows the high lithium-ion storage capacity and excellent cycling stability under high current density, indicating potential application in energy storage devices.

Hierarchically Porous N,S-Codoped Carbon-Embedded Dual Phase MnO/MnS Nanoparticles for Efficient Lithium Ion Storage.

An intriguingly nanostructured composite comprising of MnO/MnS nanoparticles embedded in an N,S-codoped carbon frame (MnO/MnS@C) is designed here and employed as a promising Li-ion storage electrode material to address the challenge of inferior conductivity and large volume change toward manganese chalcogenide-based anode. Combining with the merits of coherent MnO/MnS, elaborately hierarchical-porous architecture and N,S-codoped carbon frame, this composite exhibits high lithium-ion storage capacity (591 mAh g-1 at 0.1 A g-1) and remarkable cyclic performance (628 mAh g-1 at 1 A g-1 over 330 cycles). It is revealed via quantitative analysis that capacitive effect is also responsible for Li+ storage except ordinary diffusion-controlled mechanism, which consists of faradaic surface pseudocapacitance rooting from further oxidation of Mn2+ and nonfaradaic interfacial double-layer capacitance stemming from the charge separation at the MnO/MnS phase boundary. As a dynamic equilibrium for diffusion-controlled lithium storage, such capacitive contribution leads to ever-increasing Li-ion storage. The delicate construction endows an improved ion/electron transport kinetics, increased electrode/electrolyte contact area and plentifully heterogeneous interface, accounting for the high capacity and long-cycle stability.

Ternary tin-based chalcogenide nanoplates as a promising anode material for lithium-ion batteries

As an advanced anode material for lithium-ion batteries, tin-chalcogenides receive substantial attention due to their high lithium-ion storage capacity. Here, tin chalcogenide (SnSe0.5S0.5) nanoplates are synthesized using a facile and quick polyol-method, followed by heating at different temperatures. Results show that the as-prepared of SnSe0.5S0.5 heated at temperature of 180 °C exhibits the best electrochemical performance with an outstanding discharge specific capacity of 1144 mA h g−1 at 0.1 A g−1 after 100 cycles and 682 mA h g−1 at 0.5 A g−1 after 200 cycles with a high coulombic efficiency (CE) of 98.7%. Even at a high current density of 5 A g−1, this anode material delivers a specific capacity of 473 mA h g−1. The high electrochemical performance of SnSe0.5S0.5 is shown by in-situ XRD analysis to originate from an enhanced Li+ intercalation and an alloy conversion process.

Tailored silicon hollow spheres with Micrococcus for Li ion battery electrodes

The porous Si hollow spheres (p-Si HSs), which feature interconnected Si nanostructures decorated with spherical-type Micrococcus bacteria, were synthesized by a combination of magnesiothermic reduction and byproduct removal and were subsequently studied as an anode material for lithium-ion batteries (LIBs). The p-Si HSs offer a high lithium-ion storage capacity because of their numerous active sites and large electrolyte contact area stemming from their large specific surface area (∼313.7m2g−1); in addition, their large pore volume (∼0.927cm3g−1) buffers large volume changes during the lithiation/delithiation processes, which is important for improving the cycle stability of anode materials. Furthermore, carbon coating resulted in the formation of a stable solid electrolyte interface through minimization of the Si/electrolyte contact area and also offered an efficient electronic conduction pathway, corresponding with improved lithium reactivity of the active Si materials. The lithium-ion diffusion coefficient of the non-clogging carbon-coated p-Si HSs was approximately five times greater than that of the p-Si HSs. As a result, the designed composite nanostructured electrodes demonstrated excellent cycle stability and superior rate capability.

Metal–Organic Framework Derived Iron Sulfide–Carbon Core–Shell Nanorods as a Conversion-Type Battery Material

We report the design and nanoengineering of carbon-film-coated iron sulfide nanorods (C@Fe7S8) as an advanced conversion-type lithium-ion storage material. The structural advantages of the iron-based metal–organic framework (MIL-88-Fe) as both a sacrificed template and a precursor are explored to prepare carbon-encapsulated ploy iron sulfide through solid-state chemical sulfurizing. The resulting core–shell nanorods consisting of approximately 13% carbon and 87% Fe7S8 have a hierarchically porous structure and a very high specific surface area of 277 m2 g–1. When tested for use in fabrication of a redox conversion-type lithium-ion battery, this composite material has demonstrated high lithium-ion storage capacity at 1148 mA h g–1 under the current rate of 500 mA g–1 for 170 cycles and an impressive rate-retention capability at 657 mA h g–1 with a current density of 2000 mA g–1. On the basis of systematic structural analysis and microscopic mapping, we discuss the charge–discharge mechanisms and the crucia...

Heterostructure of SnO2/TiO2 Nanotubes with Precise Wall Thickness Control As Anodes for Lithium Ion Battery

Devices of energy storage and conversion draw much attention recently, among the devices, secondary lithium-ion batteries for energy storage will play an increasingly important role. SnO2 as anode materials have attracted a lot of attention and are regarded as one of the most promising candidates for lithium-ion battery, with the theoretical reversible capacity of 782 mAhg- 1 and low enough discharge potential of 0.01V. Like to other alloy-type anode materials, its practical application has been impeded by the poor cycling performance owing to the pulverization and subsequent electrical disconnection of the electrode caused by extremely large volume change (about 300%) during the insertion and extraction processes of lithium ions. Li2O phases, produced by the reaction of SnO2 and lithium ions, are electrochemically inactive, which is the main reason for the large initial irreversible capacity. To overcome this problem, feasible strategy is to design the nanostructure. 1-dimensional nanotubular structures exhibit enhanced cyclability due to the short diffusion path of lithium ions within the wall of nanotubes and the local empty space in the core of tubular structures can accommodate its volume expansion. SnO2 and TiO2 nanotubes as well as their heterostructures were synthesized by anodic aluminum oxide (AAO) template-directed ALD (Atomic Layer Deposition) process. Nanotubes and their heterostructures were characterized by thermogravimetric/differential thermal analysis (TG/DTA), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and X-ray diffraction (XRD). The wall thickness of nonotubes can be easily controlled by the number of cycles during ALD processes. The porous nanotubes and their heterostructures exhibit high lithium ion storage capacity, fairly high rate performance, and high cyclability when evaluated as anode materials. As expected, the nanotubes of SnO2 with the wall thickness of about 10 nm show the initial capacity of 900 mAhg-1 and reduces down to 300 mAhg-1 after 50 cycle. The conversion reaction of SnO2 to Sn and further Li and Sn alloys were clealy observed by ex sity TEM. Composite heterostructures of TiO2/SnO2 show much improved cycle performance without any degradation during Li insertion and di-insertion. Advantages of using heterostructure of TiO2/SnO2 nanotubes as anode materials will be further discussed. Figure 1

Microwave-assisted hydrothermal synthesis of porous SnO2 nanotubes and their lithium ion storage properties

Porous SnO2 nanotubes have been synthesized by a rapid microwave-assisted hydrothermal process followed by annealing in air. The detailed morphological and structural studies indicate that the SnO2 tubes typically have diameters from 200 to 400nm, lengths from 0.5 to 1.5μm and wall thicknesses from 50 to 100nm. The SnO2 nanotubes are self-assembled by interconnected nanocrystals with sizes ∼8nm resulting in a specific surface area of ∼54m2g−1. The pristine SnO2 nanotubes are used to fabricate lithium half cells to evaluate their lithium ion storage properties. The porous SnO2 nanotubes are characteristic with high lithium ion storage capacity, that is found to be 1258, 951, 757, 603, 458, and 288mAhg−1, at 0.1, 0.2, 0.5, 1, 2, and 4C, respectively. The enhanced electrochemical properties of the SnO2 nanotubes can be ascribed to their unique geometry and porous structures.

Template-free synthesis of hollow core–shell MoO2 microspheres with high lithium-ion storage capacity

Hollow core–shell MoO2 microspheres were successfully synthesized via a simple one-pot template-free approach for the first time. The crystalline structure of the products was characterized by Powder X-ray diffraction (XRD), the morphology and particle size of the products were analyzed by Transmission Electron Microscope (TEM). The microsphere formation mechanism was discussed, and an Ostwald ripening accompanied by self-assembly process was proposed for the formation of the core–shell and hollow structures. When used as an anode material for lithium ion battery, this unique MoO2 structure could store large amount of Li+, and cycled well. The electrochemical performance of core–shell MoO2 microspheres was much better than that of bulk MoO2.