Binder-free Anode For Lithium-ion Batteries Research Articles

Morphology-Tuned Synthesis of NiCo2O4-Coated 3D Graphene Architectures As Binder-Free Electrode for Lithium Ion Battery

Nanostructured NiCo2O4 is directly grown on the surface of three-dimensional graphene-coated nickel foam (3D-GNF) by a facile electrodeposition technique and subsequent annealing. The resulting NiCo2O4 possesses a distinct flower or sheet morphology tuned by potential or current variation electrodeposition, which is used as a binder-free lithium ion battery anode for the first time. Both samples exhibit high lithium storage capacity profiting from unique binder-free electrode structures. The flower-type NiCo2O4 demonstrates high reversible discharge capacity (1459 mAh g–1 at 200 mA g–1) and excellent cyclability with around 71% retention of the reversible capacity after 60 cycles, which are superior to sheet-type NiCo2O4. Such superb performance can be attributed to high volume utilization efficiency with unique morphological character, a well-preserved connection of active materials to the current collector, a short lithium ion diffusion path, and fast electrolyte transfer in binder-free NiCo2O4-coated 3D graphene structure. The simple preparation process and easily controllable morphology make binder-free NiCo2O4/3D-GNF hybrid a potential material for commercial application.

Flexible free-standing porous graphene/Ni film electrode with enhanced rate capability for lithium-ion batteries

Flexible, lightweight and reliable lithium-ion batteries have attracted tremendous attention and research interest to meet the requirements of portable and bendable devices. Here, flexible, free-standing and porous graphene/Ni film with vertical nano-channels inside is prepared by metal etching of graphene film. Compared with dense graphene film, the porous graphene/Ni film employed as a binder-free anode in lithium-ion batteries exhibits higher capacity and much better rate capability, due to its unique interior channel architecture which is favorable for fast ion transport. At a high current density of 2Ag−1, it can reach a specific capacity of 117mAhg−1. The porous film also shows low charge transfer resistance and good cycling stability. After 300 cycles at 1Ag−1, its specific capacity still remains at 147mAhg−1, with high Coulombic efficiency of nearly 100%. Furthermore, the strategy developed here is very simple and of great importance to rational design of porous graphene film or graphene-based hybrids with various applications.

Synthesis of porous nickel networks supported metal oxide nanowire arrays as binder-free anode for lithium-ion batteries

Directional design/preparation of porous metal/metal oxides composite arrays is critical for construction of advanced optical-electrochemical devices. Herein we report three-dimensional (3D) porous Ni networks supported cobalt oxide nanowire arrays (Ni-Co3O4 NWs) by combining electro-deposition and hydrothermal process. 3D Ni networks with porous branches and interconnected pores are well formed and used as the skeleton for the growth of cobalt oxide nanowire arrays. High porosity and integrated growth are combined in the composite electrode. Due to the unique composite architecture, the Ni-Co3O4 NWs electrode exhibits higher discharge capacities, better cycling stability (714 mAh g−1 at 0.5 A g−1 after 100 cycles), and enhanced rate capability, as compared to the Ni networks supported dense Co3O4 film (Ni-Co3O4 dense film). The proposed method is useful for construction of other porous metal/metal oxide composite films for application in electrochemical catalysis, energy storage and sensing.

Graphite-coated ZnO nanosheets as high-capacity, highly stable, and binder-free anodes for lithium-ion batteries

ZnO is one of the materials of choice as anode for lithium batteries, due to its high theoretical capacity, natural abundance, low toxicity, and low cost. At present, however, its industrial exploitation is impeded by massive capacity fading, and by cycling instability due to the drastic volume expansions during the electrochemical lithiation/delithiation process. Herein, we present a novel graphite coated-ZnO anode for LiBs based on films of nanosheets, coated with graphite. The electrode is obtained by a simple and inexpensive solution hydrothermal synthesis, whereas the graphite is deposited by thermal evaporation, which is easier to perform than a wet chemistry technique. Our approach leads to a substantial increase of the permanent specific capacity, obtaining values of 600 mAhg−1 after 100 cycles at a high specific current of 1 Ag−1. This represents the best performance for long-cycled, ZnO-based anodes obtained so far. Such result derives from the peculiar porous structure of the nanosheets film (pore diameter < 1 nm), as well as by the graphite coating that works as a dimensional buffer and preserves its morphology during cycling. This appears a very promising strategy for designing more stable ZnO-based anodes for Li batteries and microbatteries.

Flexible NiO-Graphene-Carbon Fiber Mats Containing Multifunctional Graphene for High Stability and High Specific Capacity Lithium-Ion Storage.

An electrode's conductivity, ion diffusion rate, and flexibility are critical factors in determining its performance in a lithium-ion battery. In this study, NiO-carbon fibers were modified with multifunctional graphene sheets, resulting in flexible mats. These mats displayed high conductivities, and the transformation of active NiO to inert Ni(0) was effectively prevented at relatively low annealing temperatures in the presence of graphene. The mats were also highly flexible and contained large gaps for the rapid diffusion of ions, because of the addition of graphene sheets. The flexible NiO-graphene-carbon fiber mats achieved a reversible capacity of 750 mA h/g after 350 cycles at a current density of 500 mA/g as the binder-free anodes of lithium-ion batteries. The mats' rate capacities were also higher than those of either the NiO-carbon fibers or the graphene-carbon fibers. This work should provide a new route toward improving the mechanical properties, conductivities, and stabilities of mats using multifunctional graphene.

Morphology-Tuned Synthesis of NiCo2 O4 -Coated 3D Graphene Architectures Used as Binder-Free Electrodes for Lithium-Ion Batteries.

Nanostructured NiCo2O4 is directly grown on the surface of three-dimensional graphene-coated nickel foam (3D-GNF) by a facile electrodeposition technique and subsequent annealing. The resulting NiCo2O4 possesses a distinct flower or sheet morphology, tuned by potential or current variation electrodeposition, which are used as binder-free lithium-ion battery anodes for the first time. Both samples exhibit high lithium storage capacity, profiting from the unique binder-free electrode structures. The flower-type NiCo2O4 demonstrates high reversible discharge capacity (1459 mAh g(-1) at 200 mA g(-1)) and excellent cyclability with around 71% retention of the reversible capacity after 60 cycles, which are superior to the sheet-type NiCo2O4. Such superb performance can be attributed to high volume utilization efficiency with unique morphological character, a well-preserved connection between the active materials and the current collector, a short lithium-ion diffusion path, and fast electrolyte transfer in the binder-free NiCo2O4 coated 3D graphene structure. The simple preparation process and easily controllable morphology make the binder-free NiCo2O4/3D-GNF hybrid a potential material for commercial applications.

Forcespinning: A new method for the mass production of Sn/C composite nanofiber anodes for lithium ion batteries

The development of nanostructured anode materials for rechargeable Lithium-ion Batteries has seen a growing interest. We herein report the use of a new scalable technique, Forcespinning (FS) to produce binder-free porous Sn/C composite nanofibers with different Sn particle size loading. The preparation process involves the FS of Sn/PAN precursor nanofibers and subsequently stabilizing in air at 280°C followed by carbonization at 800°C under an inert atmosphere. The Sn/C composite nanofibers are highly flexible and were directly used as binder-free anodes for lithium-ion batteries. The produced Sn/C composite nanofibers showed an improved discharge capacity of about 724mAhg−1 at a current density of 100mAg−1 for over 50cycles compared to most nanofiber electrodes prepared by electrospinning and centrifugal spinning. The FS method clearly produces Sn/C nanofiber composite electrodes that have a high specific capacity and excellent cyclic performance, owing to the unique structure and properties of the nanofibers. The FS technology is thus a viable method for the large scale production of nano/micro fibers for battery electrodes, separators, and other applications. To the best of our knowledge, this is the first time to report results on the use of Forcespinning technology to produce composite nanofiber anodes for lithium-ion batteries.

Hollow Carbon Cloth Enhances the Performance of Red Phosphorus for Flexible Lithium Ion Battery

Discovering the potential materials and developing the flexible lithium ion batteries (LIBs) are of a great significance. Red phosphorus (P) is considered to be a potential anode material due to its high theoretical capacity of 2596 mAh g−1. In this paper, a flexible hollow carbon cloth was prepared by carbonization treatment and shows a dependable stability when used as the binder-free anode for LIBs, which indicating it can be used as a flexible substrate for red P loading. Then amorphous red P/carbon cloth (P/C) composite with a high P content of 73.0 (wt%), was prepared via a vaporization adsorption method. The as-prepared P/C composite exhibits a flexible character and also shows excellent electrochemical performance when used in LIBs. At the first discharge the capacity is 1063 mAh g−1, and its cycle performance is remarkable improved by coating on graphene oxide (GO), up to 82.7% retention of the initial capacity after 200 cycles. The P/C hybrid also shows a potential in the application of flexible LIBs.

Self-assembly of ultrathin mesoporous CoMoO4 nanosheet networks on flexible carbon fabric as a binder-free anode for lithium-ion batteries

Novel hierarchical CoMoO4 networks assembled by ultrathin mesoporous nanosheets are directly grown on flexible carbon fabric as integrated anodes for highly efficient and reversible lithium storage.

A compressible and hierarchical porous graphene/Co composite aerogel for lithium-ion batteries with high gravimetric/volumetric capacity

Graphene-based electrodes with high gravimetric and high volumetric capacity simultaneously are crucial to the realization of high energy storage density, but still proved to be challenging to prepare. Herein, we report a three-dimensional porous graphene/Co aerogel with hierarchical porous structure and compressible features as a high-performance binder-free lithium-ion battery anode. In this composite aerogel, graphene nanosheets interconnect to form continuous macropores, and cobalt nanoparticles stemming from decomposition of cobalt salt not only react with carbon atoms of graphene to form nanopores on the graphene nanosheets, but also increase the conductivity of the aerogel. With efficient ion and electron transport pathways as well as high packing density, the compressed porous graphene/Co electrode exhibits significantly improved electrochemical performance including high gravimetric and volumetric capacity, excellent rate capability, and superior cycling stability. After compression, such a porous graphene/Co nanocomposite can deliver a gravimetric capacity of 900 mA h g−1 and a volumetric capacity of 358 mA h cm−3 at a current density of 0.05 A g−1. Furthermore, after 300 discharge/charge cycles at 1 A g−1, the specific capacity still remains at 163 mA h cm−3, corresponding to 90.5% retention of its initial capacity.

Controllable synthesis of carbon-coated Sn⿿SnO2⿿carbon-nanofiber membrane as advanced binder-free anode for lithium-ion batteries

A carbon-coated composite consisting of Sn, SnO2, and porous carbon-nanofiber membrane (Sn⿿SnO2⿿CNF@C) was successfully prepared via electrospinning followed by carbonization and low-temperature hydrothermal treatment. The thickness of the carbon overlayer formed by using sucrose as the carbon source could be well controlled by adjusting the sucrose concentration. The three-dimensional (3D) nanofiber network structure allowed the Sn⿿SnO2⿿CNF@C membrane to be used directly as an anode in lithium-ion batteries without adding any polymer binders or electrical conductors. The composite electrodes of this material exhibited a high discharge capacity of 712.2mAhg⿿1 at a high current density of 0.8Ag⿿1 after 200 cycles, as well as good cycling stability and excellent rate capability, which can be ascribed to the improved electrochemical properties of the Sn⿿SnO2 particles provided by the protective carbon coating and the 3D carbon nanofiber membrane. The composite can thus be widely used as an advanced binder-free anode material in high-current rechargeable lithium-ion batteries and extended to the fabrication of flexible electrodes.

Back Cover: Three‐Dimensional Interconnected Network of Graphene‐Wrapped Silicon/Carbon Nanofiber Hybrids for Binder‐Free Anodes in Lithium‐Ion Batteries (ChemElectroChem 11/2015)

The Back Cover picture represents a binder-free anode for lithium-ion batteries by encapsulation of Si nanoparticles in 1D carbon nanofibers, followed by wrapping with 2D graphene sheets. The nanostructure are favorable for the fast charge transfer and diffusion of lithium ions. More details can be found in the Article by L.-Z. Fan and co-workers on page 1699 in Issue 11, 2015 (DOI: 10.1002/celc.201500187).

Graphene-Protected 3D Sb-based Anodes Fabricated via Electrostatic Assembly and Confinement Replacement for Enhanced Lithium and Sodium Storage.

Alloy anodes have shown great potential for next-generation lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). However, these applications are still limited by inherent huge volume changes and sluggish kinetics. To overcome such limitations, graphene-protected 3D Sb-based anodes grown on conductive substrate are designed and fabricated by a facile electrostatic-assembling and subsequent confinement replacement strategy. As binder-free anodes for LIBs, the obtained electrode exhibits reversible capacities of 442 mAh g(-1) at 100 mA g(-1) and 295 mAh g(-1) at 1000 mA g(-1), and a capacity retention of above 90% (based on the 10th cycle) after 200 cycles at 500 mA g(-1). As for sodium storage properties, the reversible capacities of 517 mAh g(-1) at 50 mA g(-1) and 315 mAh g(-1) at 1000 mA g(-1), the capacity retention of 305 mAh g(-1) after 100 cycles at 300 mA g(-1) are obtained, respectively. Furthermore, the 3D architecture retains good structural integrity after cycling, confirming that the introduction of high-stretchy and robust graphene layers can effectively buffer alloying anodes, and simultaneously provide sustainable contact and protection of the active materials. Such findings show its great potential as superior binder-free anodes for LIBs and SIBs.

Membranes of MnO Beading in Carbon Nanofibers as Flexible Anodes for High-Performance Lithium-Ion Batteries.

Freestanding yet flexible membranes of MnO/carbon nanofibers are successfully fabricated through incorporating MnO2 nanowires into polymer solution by a facile electrospinning technique. During the stabilization and carbonization processes of the as-spun membranes, MnO2 nanowires are transformed to MnO nanoparticles coincided with a conversion of the polymer from an amorphous state to a graphitic structure of carbon nanofibers. The hybrids consist of isolated MnO nanoparticles beading in the porous carbon and demonstrate superior performance when being used as a binder-free anode for lithium-ion batteries. With an optimized amount of MnO (34.6 wt%), the anode exhibits a reversible capacity of as high as 987.3 mAh g−1 after 150 discharge/charge cycles at 0.1 A g−1, a good rate capability (406.1 mAh g−1 at 3 A g−1) and an excellent cycling performance (655 mAh g−1 over 280 cycles at 0.5 A g−1). Furthermore, the hybrid anode maintains a good electrochemical performance at bending state as a flexible electrode.

High-Performance Silicon Battery Anodes Enabled by Engineering Graphene Assemblies.

We propose a novel material/electrode design formula and develop an engineered self-supporting electrode configuration, namely, silicon nanoparticle impregnated assemblies of templated carbon-bridged oriented graphene. We have demonstrated their use as binder-free lithium-ion battery anodes with exceptional lithium storage performances, simultaneously attaining high gravimetric capacity (1390 mAh g(-1) at 2 A g(-1) with respect to the total electrode weight), high volumetric capacity (1807 mAh cm(-3) that is more than three times that of graphite anodes), remarkable rate capability (900 mAh g(-1) at 8 A g(-1)), excellent cyclic stability (0.025% decay per cycle over 200 cycles), and competing areal capacity (as high as 4 and 6 mAh cm(-2) at 15 and 3 mA cm(-2), respectively). Such combined level of performance is attributed to the templated carbon bridged oriented graphene assemblies involved. This engineered graphene bulk assemblies not only create a robust bicontinuous network for rapid transport of both electrons and lithium ions throughout the electrode even at high material mass loading but also allow achieving a substantially high material tap density (1.3 g cm(-3)). Coupled with a simple and flexible fabrication protocol as well as practically scalable raw materials (e.g., silicon nanoparticles and graphene oxide), the material/electrode design developed would propagate new and viable battery material/electrode design principles and opportunities for energy storage systems with high-energy and high-power characteristics.

Nanotubular Heterostructure of Tin Dioxide/Titanium Dioxide as a Binder-Free Anode in Lithium-Ion Batteries.

Titanium dioxide (TiO2 ), tin dioxide (SnO2 ), and heterostructured TiO2 /SnO2 nanotube (NT) arrays have been fabricated by template-assisted atomic-layer deposition (ALD) for use as anodes in a lithium-ion battery (LIB). TiO2 NT arrays with 8 nm thick walls showed higher capacity (≈250 mA h g(-1) after the 50th cycle at a rate of C/10) than the typical theoretical capacity of bulk TiO2 and a radically improved capacity retention property upon cycling. SnO2 NT arrays with different wall thicknesses (8, 10, 13, and 20 nm) were also fabricated and their electrochemical performances were measured. All of the SnO2 NT arrays showed substantially higher initial irreversible capacity and higher reversible capacity than those of bulk TiO2 . Thinner walls of the SnO2 NTs result in better capacity retention. Heterotubular structures of TiO2 (5 nm)/SnO2 (10 nm)/TiO2 (5 nm) were successfully fabricated, and displayed a sufficiently high capacity (≈300 mA h g(-1) after 50 cycles) with exceptionally improved cycling performance up to the 50th cycle.

Electrospun porous carbon nanofiber@MoS2core/sheath fiber membranes as highly flexible and binder-free anodes for lithium-ion batteries

Self-standing membranes of porous carbon nanofiber (PCNF)@MoS2 core/sheath fibers have been facilely obtained through a combination of electrospinning, high-temperature carbonization and the solvothermal reaction. PCNF fibers with porous channels are used as building blocks for the construction of hierarchical PCNF@MoS2 composites where thin MoS2 nanosheets are uniformly distributed on the PCNF surface. Thus, a three-dimensional open structure is formed, which provides a highly conductive pathway for rapid charge-transfer reactions, as well as greatly improving the surface active sites of MoS2 for fast lithiation/delithiation of Li(+) ions. The highly flexible PCNF@MoS2 composite membrane electrode exhibits synergistically improved electrochemical performance with a high specific capacity of 954 mA h g(-1) upon the initial discharge, a high rate capability of 475 mA h g(-1) even at a high current density of 1 A g(-1), and good cycling stability with almost 100% retention after 50 cycles, indicating its potential application as a binder-free anode for high-performance lithium-ion batteries.

Facile and large-scale fabrication of hierarchical ZnFe2O4/graphene hybrid films as advanced binder-free anodes for lithium-ion batteries

Hierarchical ZnFe2O4/graphene hybrid films are deposited on copper foils as a promising binder-free lithium-ion battery anode.

Stannous ions reducing graphene oxide at room temperature to produce SnOx-porous, carbon-nanofiber flexible mats as binder-free anodes for lithium-ion batteries

SnOx-porous carbon nanofiber flexible mats deliver a high reversible capacity of 545 mA h g−1 after 1000 cycles at 200 mA g−1.

A general strategy of decorating 3D carbon nanofiber aerogels derived from bacterial cellulose with nano-Fe3O4for high-performance flexible and binder-free lithium-ion battery anodes

A novel flexible nano-Fe3O4-decorated three-dimensional carbon nanofiber aerogel derived from bacterial cellulose was fabricatedviaa hydrothermal approachfollowed by carbonization.