High-rate Lithium-ion Battery Anodes Research Articles

Fluffy carbon-coated red phosphorus as a highly stable and high-rate anode for lithium-ion batteries

Using fluffy carbon prepared from expanded rice, carbon-coated red phosphorus composites with a stable structure were synthesized via a simple ball milling route, which exhibited ultra-long cycle stability and excellent rate capability as anode for lithium-ion batteries.

Uniform distribution of siloxane-grafted SiOx nanoparticles in micron hard-carbon matrix for high-rate composite anode in Li-ion batteries

Uniform distribution of siloxane-grafted SiO0.26 hydrophobic nanoparticles in porous micron hard-carbon matrix was in situ made by a simple mixing in the organic medium of N-methylpyrrolidinone during the slurry preparation of composite anode for a fast-charge of lithium-ion batteries, whose characteristics are advantageous for a good electronic conductivity and the accommodation of volume change of silicon during charge-discharge cycling. The composite anode enables fast charge in 6 min at the rate of 10 C and high cycling stability, delivering the discharge capacities of 648–538 mAh g−1, coulombic efficiencies of 99%, and high capacity retention of 98% at the 100th cycle. Surface and structural analysis results reveal that the formation of relatively thinner solid electrolyte interphase (SEI) layer at 10 C and higher structural maintenance than at low rate (0.2 C) are correlated to lowered interfacial resistances at 10 C and a good high-rate cycling stability. The data give an insight into material design principles and the SEI property of anode for high-rate lithium-ion batteries.

Superlithiated Polydopamine Derivative for High-Capacity and High-Rate Anode for Lithium-Ion Batteries.

Organic electrode materials, with low-cost synthesis and environmental friendliness, have gained significant research interest in lithium-ion batteries (LIBs). Polydopamine (PDA), as a bioderived organic electrode material, exhibits a low capacity of ∼100 mAh g-1, greatly limiting the practical application in LIBs. In this work, we find that a simple heat treatment at 300 °C can endow PDA-derived material (PDA300) with superior electrochemical performance. The obtained PDA300 electrode exhibits an ultrahigh capacity of 977 mAh g-1 at 50 mA g-1. Further combining the PDA300 with highly conductive Ti3C2T x MXene, the obtained PDA300/Ti3C2T x composite is demonstrated by high capacity (1190 mAh g-1, 50 mA g-1), excellent rate capability (remaining 552 mAh g-1 at 5 A g-1), and good cycling stability (82% retaining after 1000 cycles). The outstanding lithium storage performance is highly associated with the superlithiation process of the unsaturated carbon-carbon bonds in the PDA derivative and the introduction of the highly conductive Ti3C2T x substrate with a unique two-dimensional nanostructure. This work will provide new opportunities for the expansion of high-performance organic anodes for LIBs.

Rice-panicle-like γ-Fe2O3@C nanofibers as high-rate anodes for superior lithium-ion batteries

We synthesized nanoarchitectures comprising γ-Fe2O3@C nanofibers with one-dimensional rice-panicle-like morphologies via a facile electrospinning and annealing process for use as anodes in lithium-ion batteries (LIBs). A thin carbon layer grown on the surface of γ-Fe2O3 provides a synergistic effect to relieve the stress and alleviate the volume expansion occurring during the lithium-ion insertion/extraction process. The unique structure not only offers good electron transport routes, but also enhances the lithium-ion conductive channels, resulting in excellent electrochemical activity and electrical conductivity of the LIB anode material. A high reversible specific capacity of 1252 mAh g−1 was achieved after 200 cycles even at the current density of 10 A g−1. When examined at the scan rate of 5 mV s−1, a high capacitive contribution ratio of 88.5% was achieved. The short lithium-ion diffusion pathways avoid structural damage to the active material and provide excellent rate capacities. This work suggests a new method to improve the electrochemical performance of LIBs through the synergistic design of uniquely structured metal oxides.

Facile and Cost Effective Directly Electrosprayed Graphene/Silicon Nanocomposites for High-Rate Lithium-Ion Battery Anodes

Silicon is in the research spotlight for the next generation of Li-ion battery anodes due to its high specific capacity of 4200 mAh/g for lithium storage at room temperature. However, it has a few serious shortcomings that prevent its commercialization. In the present work, we explored a facile and environmentally friendly process based on electrospraying to directly deposit active material on the current collector and remedy silicon problems in one step. Instead of graphene-oxide or other derivatives, direct employment of a graphene suspension in the deposition process which does not require heat treatment to increase its conductivity enables usage of a polymeric binder in the system. As a result, the sprayed composite layer has a uniform morphology with an excellent dispersion of nanoparticles between graphene layers and an electrode density above 0.7 g/cc was prepared. Graphene sheets provide conductivity and keep the silicon nanoparticles in place during constant volume expansion/contraction. Nevertheless, existence of polymeric binder greatly increases the life of the electrodes with minimal capacity fading of about 15% after 300 cycles with a specific capacity of 2100 mAh/g. In addition, electrodes prepared with this technique have a noticeably high first cycle columbic efficiency up to 92%, which makes them desirable for full cell fabrication. These electrodes also have a great electrochemical performance at high rates (1200 mAh/g at 2C and 1000 at 5C), due to the highly conductive network of dispersed graphene sheets. In this presentation, the innovative and facile electrode preparation technique will be introduced and underlying phenomena responsible for the outstanding electrochemical performance of the fabricated electrodes will be discussed.

Rational synthesis of graphene-encapsulated uniform MnMoO4 hollow spheres as long-life and high-rate anodes for lithium-ion batteries

In this manuscript, the graphene-encapsulated MnMoO4 hollow spheres (MnMoO4@G) synthesized by an effective strategy were reported. Benefiting from the intriguing hybrid architecture of hollow structure and conductive graphene network, the MnMoO4@G composite displays superior electrochemical performance with high specific capacity of 1142 mA h g−1, high reversible cycling stability of 921 mA h g−1 at a current density of 100 mA g-1 after 70 cycles, and stable rate performance (around 513 mA h g−1 at a current density of 4.0 A g−1). The remarkable battery performance can be attributed to the rational design of the architecture, which not only ensures the fast transport of electrons and lithium ions within the electrode material, but also effectively relax the stress induced by the insertion/extraction of lithium ions. This facile synthetic method can extend to other transition metal oxides with large volume excursions and poor electric conductivity and promotes the development of transition metal oxides as high-performance LIB anode material.

Investigation of carbon coating approach on electrochemical performance of Li4Ti5O12/C composite anodes for high-rate lithium-ion batteries

Submicron-sized Li4Ti5O12/C (LTO/C) composites were successfully synthesized by using one-step and two-step route, in which sucrose was used as carbon precursor, and employed as anode materials for lithium-ion batteries (LIBs). The structure, surface morphology, and chemical compositions were characterized by X-ray diffraction, Raman spectroscopy, scanning, and transmission electron microscopy techniques. The electrochemical properties of the carbon-coated samples were examined by using the charge/discharge tests, cyclic voltammetry, and electrochemical impedance spectroscopy. It was found that the LTO/C synthesized by one-step method (designated as LTO/C-O) possessed smaller LTO/C particle size, more cohesive particle distribution, and more uniform conductive carbon layer on LTO surface compared with that synthesized by two-step method (LTO/C-T). As a result, the LTO/C-O electrode illustrated a high discharge capacity of 173.6 mAh g−1 at a charge/discharge rate of 0.1 C. Moreover, the discharge capacity retention of the LTO/C-O electrode can effectively deliver to 95.9, 90.9, 87.9, and 80.9%, whereas the LTO/C-T electrode exhibited 94.0, 79.9, 68.0, and 50.1% at 1, 5, 10, and 20 C, respectively. Therefore, the LTO/C-O can be considered as one of the promising anode materials for high-rate LIBs.

A bottom-up synthetic hierarchical buffer structure of copper silicon nanowire hybrids as ultra-stable and high-rate lithium-ion battery anodes

Silicon (Si) is a promising anode material for next-generation high-energy lithium-ion batteries (LIBs).

Graphene oxide hydrogel as a restricted-area nanoreactor for synthesis of 3D graphene-supported ultrafine TiO2 nanorod nanocomposites for high-rate lithium-ion battery anodes

Three-dimensional graphene-supported TiO2 nanorod nanocomposites (3D GS-TNR) are prepared using graphene oxide hydrogel as a restricted-area nanoreactor in the hydrothermal process, in which well-distributed TiO2 nanorods with a width of approximately 5 nm and length of 30 nm are conformally embedded in the 3D interconnected graphene network. The 3D graphene oxide not only works as a restricted-area nanoreactor to constrain the size, distribution and morphology of the TiO2; it also work as a highly interconnected conducting network to facilitate electrochemical reactions and maintain good structural integration when the nanocomposites are used as anode materials in lithium-ion batteries. Benefiting from the nanostructure, the 3D GS-TNR nanocomposites show high capacity and excellent long-term cycling capability at high current rates. The 3D GS-TNR composites deliver a high initial charge capacity of 280 mAh g−1 at 0.2 C and maintain a reversible capacity of 115 mAh g−1, with a capacity retention of 83% at 20 C after 1000 cycles. Meanwhile, compared with that of previously reported TiO2-based materials, the 3D GS-TNR nanocomposites show much better performance, including higher capacity, better rate capability and long-term cycling stability.

Polystyrene-template-assisted synthesis of Li3VO4/C/rGO ternary composite with honeycomb-like structure for durable high-rate lithium ion battery anode materials

Li3VO4/C/rGO (HC-LVO/C/G) ternary composite with honeycomb-like structure is successfully prepared through a simple spray drying method with polystyrene (PS) microspheres as soft template. In this characteristic structure, carbon-coated Li3VO4 nanoparticles are well wrapped by rGO sheets and uniformly distributed within the honeycomb-like micrometer-sized clusters. The double coating layers of amorphous carbon and rGO can avoid the direct exposure of Li3VO4 nanoparticles to the electrolyte and enhance the electronic conductivity. Meanwhile, the honeycomb-like structure can shorten the diffusion paths of Li+ ions and favors the relaxation of the strain/stress during cycling. The resultant HC-LVO/C/G composite exhibits significantly improved high-rate performance and long cycle-life (the high reversible capacity of 312mAhg−1 can be maintained after 1000 cycles at 10 C) compared with the contrastive Li3VO4/C composite synthesized by a typical solid-state reaction method.

Highly efficient solid-state synthesis of carbon-encapsulated ultrafine MoO2 nanocrystals as high rate lithium-ion battery anode

A simple and highly efficient method is developed for the one-step in situ preparation of carbon-encapsulated MoO2 nanocrystals (MoO2@C) with core-shell structure for high-performance lithium-ion battery anode. The synthesis is depending on the solid-state reaction of cyclopentadienylmolybdenum tricarbonyl dimer with ammonium persulfate in an autoclave at 200 °C for 30 min. The large amount of heat generated during the explosive reaction cleaves the cyclopentadiene ligands into small carbon fragments, which form carbon shell after oxidative dehydrogenation coating on the MoO2 nanocrystals, resulting in the formation of core-shell structure. The MoO2 nanocrystals have an equiaxial morphology with an ultrafine diameter of 2–8 nm, and the median size is 4.9 nm. Hundreds of MoO2 nanocrystals are encapsulated together by the worm-like carbon shell, which is amorphous and about 3–5 nm in thickness. The content of MoO2 nanocrystals in the nanocomposite is about 69.3 wt.%. The MoO2@C anode shows stable cyclability and retains a high reversible capacity of 443 mAh g−1 after 50 cycles at a current density of 3 A g−1, owing to the effective protection of carbon shell.

Electrospun dual phase Li4Ti5O12-TiO2/C nanocomposites as anodes for high-rate lithium-ion batteries

ABSTRACTDual phase Li4Ti5O12-TiO2/C nanocomposites have been one-step synthesized by the method of electrospinning. When the Li4Ti5O12-TiO2/C nanocomposites are used as anode material for lithium-ion batteries, it exhibits excellent capacity of 186.5 mAh/g at 4000 mA/g with a good cycling performance. Simultaneously, it owns remarkable rate capability and reversible capability. The introduction of TiO2 enhances both the electric conductivity and the lithium ion diffusivity in Li4Ti5O12. And then it has good electrochemical performance.

Tailoring the Electrode Interface with Enhanced Electron Transfer for High-Rate Lithium-Ion Battery Anodes

Contact interface between the active materials and the current collector is essential for electron transfer rate and the mechanical properties of an electrode. In this study, various types of contacts between the active material (graphene sheets) and the metal current collector are created through different fabrication methods, and their impacts to the electrochemical performance are investigated. Intimate “sheet contact” is observed between graphene sheets and Ni foam after KOH in situ activation, which is believed to facilitate the electron transfer. The anode that is tailored to have “sheet contact” delivers a reversible capacity of 1457 mAh g–1 at 0.1 C, which is higher than the electrode obtained by a commercial drop-casting method and comparable to most of the high-end graphene-based anodes. In addition, the anode delivers a high capacity of 173 mAh g–1 with a short charging time of 56 s, indicating its promising use as a high-rate LIB anode.

A chemically modified graphene oxide wrapped porous hematite nano-architecture as a high rate lithium-ion battery anode material

Chemically modified graphene oxide wrapped porous hematite nanorods: an interconnected hollow network for excellent lithium storage in lithium ion batteries.

Designed construction and validation of carbon-free porous MnO spheres with hybrid architecture as anodes for lithium-ion batteries

Porous micro/nanostructures of earth abundant and ecobenign metals are emerging as advanced green materials for use in electrochemical energy storage devices. We present here the custom designed construction of a hybrid architecture containing porous MnO microspheres, formed out of hierarchically assembled nanoparticles using a template-free co-precipitation method, wherein the sacrificial template growth of porous spheres has been obtained by a solution mediated and time dependent oxidation strategy. The nanoporous channels in the MnO microspheres and the nanosized primary particles of MnO anodes in synergy increase the electrolyte percolation, resulting in a discharge capacity of 1200 mA h g(-1) at a current density of 50 mA g(-1) and a capacity as high as 450 mA h g(-1) under the 1000 mA g(-1) condition. The study assumes importance based on the fact that engineering of electrode materials is typically challenging, wherein design, preparation and fabrication of tailor-made electrodes with a desirable micro/nanocrystalline assembly play a critical role, especially when recommended for high capacity and high-rate applications in electrochemical energy storage devices. Further, this communication elaborates the designed construction and validation of porous MnO microspheres engineered through a time dependent process protocol as economically viable and environmentally benign anodes for lithium-ion batteries.

A universal strategy to prepare porous graphene films: binder-free anodes for high-rate lithium-ion and sodium-ion batteries

A porous graphene film with controllable pore size is developed for high-rate lithium-ion and sodium-ion batteries.

NiSi(x)/a-Si Nanowires with Interfacial a-Ge as Anodes for High-Rate Lithium-Ion Batteries.

Conductive metal nanowire is a promising current collector for the Si-based anode material in high-rate lithium-ion batteries. However, to harness this remarkable potential for high power density energy storage, one has to address the interfacial potential barrier that hinders the electron injection from the metal side. Herein, we present that, solely by inserting ultrathin amorphous germanium (a-Ge) (∼5 nm) at the interface of NiSix/amorphous Si (a-Si), the rate capacity was substantially enhanced, 477 mAh g(-1) even at a high rate of 40 A g(-1). In addition, batteries containing the NiSix/Ge+Si anodes cycled over 1000 times at 10 A g(-1) while the capacity retaining more than 877 mAh g(-1), which is among the highest reported. The excellent electrochemical performance is directly correlated with the significantly improved electrical conductivity and mechanical stability throughout the entire electrode. The potential barrier between the NiSix and a-Si was modulated by a-Ge, which constructs an electron highway. Besides, the a-Ge interlayer enhances the interfacial adhesion by reducing void fraction and the inhomogeneous strain of the Li-Ge and Li-Si stacking structure was accommodated through the bending and twist of relatively thin NiSix, thus ensures a more stable high-rate cycling performance. Our work shows an effective way to fabricate metal/a-Si nanowires for high-rate lithium-ion battery anodes.

TiO2 mesoporous single crystals with controllable architectures and TiO2/graphene oxide nanocomposites for high-performance lithium ion battery anodes

TiO2 mesoporous single crystals (MSCs) with diverse constructions in a controllable fashion are successfully fabricated by a new template-free method for the first time, using oxalic acid (OA) as the pore-forming agent and morphological controller. Unlike the seeding-template based growth mechanism, the TiO2 MSCs in the present work may involve a process of oriented aggregation and crystallographic fusion of primary nanocrystals. The structural control of TiO2 MSCs can be easily realized by tailoring growth conditions, such as Ti-source concentration and OA dosages. Moreover, the TiO2 MSCs shows substantial improvement in lithium specific capacity from 0.2C to 10C in comparison to the reference TiO2 nanoparticle. The high-rate performance was further improved by fabricating MSCs/graphene oxide nanocomposites, and specific capacity of the composite at the rate of 20C is as high as 90mAhg−1. This new template-free strategy may open up new and exciting opportunities for the preparation of other MSCs, and makes important applicatory significance for the structure design of high-rate lithium ion battery anodes.

Candle Soot derived Fractal-like Carbon Nanoparticles Network as High-Rate Lithium Ion Battery Anode Material

In this article, we report a facile and inexpensive approach to synthesize fractal-like interconnected network of carbon nanoparticles from candle soot and its direct application as anode material for high-rate lithium ion batteries used for electric vehicles. At low charge/discharge rate (0.5C), an initial discharge capacity was found to be 1997mAh/g with moderate 30% coulombic efficiency that increased to 91% after 10 cycles. More importantly, at very high charge/discharge rate (10C), reversible capacity was stabilized at 170mAh/g even after 1000 cycles. This remarkable electrochemical performance may be ascribed to unique morphology of these hard carbon nanoparticles that reduces the diffusion length and also allows fast adsorption/desorption of Li ions on their surface.

Porous Carbon Spheres Doped with Fe3C as an Anode for High-Rate Lithium-ion Batteries

The search of advanced anodes has been an important way to satisfy the ever-growing demands on high rate performance lithium-ion batteries (LIBs). It was observed that the capacity of Fe3C as an anode is larger than its theoretical one, which might be attributed to the pseudocapacity on the interface between the carbide and electrolyte. In this work, a novel carbon sphere doped with Fe3C nanoparticles was fabricated and tested as the anode in LIBs. In the first place, iron precursors were embedded in the cross-link polymer resorcinol-formaldehyde (RF) spheres via a facile hydrothermal reaction, in which RF served as the carbon source and ethanol as a dispersant agent. Consequently, the hydrothermal products were carbonized successively at 700°C under inert atmosphere to obtain porous carbon spheres doped with Fe3C. When the composite severed as an anode in LIBs, its discharge capacity increased to the largest during the first 250-400 cycles, then dropped down to a similar level of that after 1000 cycles at different current rates. The discharge capacity of the composite increased from ∼300mAhg−1 to ∼540mAhg−1 at the current of 100mAg−1 during the initial hundreds cycles, and even a discharge capacity of ∼230mAhg−1 at the current of 2000mAg−1. Moreover, it was observed that a discharge plateau gradually appeared between 0.7∼1.1V during the first hundreds of cycles. The electrochemical behaviors of the anode before 1000 discharge/charge cycles were compared with that after 1000 discharge/charge cycles by cyclic voltammetry and electrochemical impedance spectroscopy to find out the differences between their features. The high rate performance of LIBs might result from the decomposition of electrolyte and the pseudocapacity behavior presented on the interfacial (surface) lithium storage of the active materials.