Capacity Anode For Li-ion Batteries Research Articles

Three-dimensional flexible molybdenum oxynitride thin film as a high capacity anode for Li-ion batteries

With the fast development of flexible wearable electronics, mobile electronic equipment, electric tool and electric vehicles, high specific capacity, superior cycle stability and excellent fast-charge performance are required for lithium-ion batteries (LIBs). Nevertheless, commercial graphite with the limited theoretical capacity (372 mAh g−1) and short lifespan is difficult to satisfy the requirements of the new generation of LIBs. In this work, the three-dimensional flexible molybdenum oxynitride (MNO) thin films with non-binder were prepared by magnetron sputtering approach. The charge transfer resistance and Li-ion diffusion coefficient were measured by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), and the results show that molybdenum nitride is helpful to increase the diffusion and electron transfer of Li-ion. The MNO thin film annealed at 300 °C with irregular aggregate matrix structure shows a discharge capacity of 413 mAh g−1 after 180 cycles at 1 A g−1. The outstanding rate performance and cycle stability suggest that these binder-free thin film electrodes, especially nitrides, offer great opportunity for energy storage systems with fast-charge capabilities.

KCoxMn1-x[Fe(CN)6]/Carbon nanotube composite as high capacity anode for Li-ion batteries

• CoMnHCF/CNT is prepared by co-precipitation method with an improved conductivity. • CoMnHCF/CNT delivers superior cycling performance and rate capacity as anode material for LIBs. • Ex-situ XRD is carried out to explore the redox mechanism of CoMnHCF during cycling. To explore inexpensive electrode materials with high energy density is urgent for developing next generation Li-ion batteries (LIBs). In this paper, a multi-metal Prussian blue analogue composited with carbon nanotube (KCo x Mn 1-x [Fe(CN) 6 ]/CNT), synthesized via a simple solution precipitation method, is employed as the anode for LIBs, which exhibits superior electrochemical performance. When cycled at 0.1 A g −1 , it delivers the reversible capacity up to 727.5 mA h g −1 during initial de-lithiation. In addition, this material presents excellent rate capability, yielding 452.3 and 408.7 mA h g −1 at 1 and 2 A g −1 , respectively. The improved performance may be associated with the effective connection between CNT and CoMnHCF particles to enhance the charge-transfer kinetics and lower the electrical resistance. Regarding the charge/discharge mechanism, the full reduction of Co 2+ , Mn 2+ and Fe 2+ in the initial lithiation process and the redox of Fe 2 O 3 /Fe 0 , CoO/Co 0 , MnO/Mn 0 in the subsequent cycles is proposed.

One Step Synthesis of Core@Shell Sige@Si Nanoparticles and Their Use As Active Material in High Capacity Anodes for Li-Ion Batteries

In the frame of energy transition, silicon is a material of interest to develop Li-ion batteries with increased energy density. Nevertheless, the important volume change upon cycling (280 %) and reactivity towards electrolytes lead to rapid degradation of performances. Designing silicon-germanium structures is an efficient strategy to obtain stable performances of Li-ion batteries anodes. The synergetic effect of alloying silicon and germanium was demonstrated by Duveau et al [1], using micrometric particles obtained by ball-milling. The stability of the alloys was better than the stability of pure silicon and its capacity was higher than the capacity of pure germanium. This work presents the one step synthesis of nanoparticles of Si-Ge alloys by laser pyrolysis using silane and germane as gaseous precursors. The average chemical composition of the powders (Si/Ge ratio) appears well correlated with the silane to germane ratio introduced in the reactor. Using STEM-EDX, an original SiGe@Si core@shell heterostructure is observed on these particles; the alloy is surrounded by a silicon shell. Using in-situ temperature measurements, we found that the temperature in the reaction zone is above the stability zone of the alloy and favors migration of chemical species to the surface. Varying the ratio between precursor gases led to the synthesis of various Si100-xGex heterostructures with x = 0, 20, 47, 77, and 100.All the three alloy compositions were cycled at C/5 in coin cells vs lithium. The electrochemical performances outperform materials with similar compositions already published [1, 2, 3]. The capacity of all alloy compositions is higher when compared to germanium, whereas stability and coulombic efficiency upon cycling is better when compared to silicon. The best performances were obtained for Si53Ge47 with a reversible capacity of 1685 mAh.g-1 after 60 cycles.

3D microporous Sn-Sb-Ni alloy impregnated Ni foam as high-performance negative electrode for lithium-ion batteries

A novel, “active-active-inactive” type Tin-Antimony-Nickel alloy with dendritic morphology electrodeposited on 3D interconnected microporous Nickel foam (∼8 μm pore diameter) as a potential high capacity anode for Li-ion batteries is reported. The multiphase composition comprising of SnSb and Ni3Sn4 “reactant” intermetallics dispersed in Sn “matrix”, alleviates the volumetric stress generated during cycling by lithiating at different step potentials (0.84, 0.66, 0.57, 0.42, 0.40, and 0.38–0.25 V vs. Li/Li+). Nickel foam was synthesized by template-free hydrogen bubble-assisted electrodeposition and it successfully acts as a stress buffer preventing delamination. This combination of properties for Tin-Antimony-Nickel anode impregnated into Nickel foam results in 2nd cycle discharge capacity of 845 mAh/g, superior rate capability and stable cycle retention with a capacity loss of 16% in the last 50 cycles at a rate of 430 mA/g (0.5 C), while preserving its structural integrity and micro-architecture in comparison to a Tin-Antimony-Nickel anode deposited on a planar Nickel film as a current collector.

A Novel Multiphase Sn-Sb-Cu Alloy Electrodeposited on 3D Interconnected Microporous Cu Current Collector as Negative Electrode for Lithium Ion Battery

We report a novel, active-active-inactive-type tin-antimony-copper alloy with dendritic morphology electrodeposited on 3D interconnected microporous copper foam (~70 μm pore diameter) as a promising high specific capacity anode for Li-ion batteries. The multiphase composition, SnSb and Cu6Sn5 “reactant” intermetallics embedded in Sn “matrix,” alleviates the volumetric stress generated during cycling by lithiating at different step potentials (0.84, 0.66, 0.57, 0.42, 0.39, and 0.38 to 0.33 V vs Li/Li+). Copper foam successfully acts as a stress buffer preventing both pulverization and delamination. This combination of properties in tin-antimony-copper anode on copper foam results in 2nd cycle discharge capacity of 723 mAh/g, superior rate capability, and stable cycle retention with a capacity loss of 16 pct in the last 70 cycles at a rate of 400 mA/g (0.5 C) while preserving its structural integrity in comparison to tin-antimony-copper anode deposited on a planar copper foil as a current collector.

Mesoporous In2O3nanofibers assembled by ultrafine nanoparticles as a high capacity anode for Li-ion batteries

As a lithium storage material, In2O3has been hindered by its rapid capacity degradation due to the large volume change during the repeated lithiation and delithiation process, although an initial discharge capacity of more than 1600 mA h g−1.

High areal capacity, micrometer-scale amorphous Si film anode based on nanostructured Cu foil for Li-ion batteries

We report a feasible design to fabricate micrometer-scale Si films deposited on nanostructured Cu foil as high areal capacity anodes for Li-ion batteries with excellent cycling performance. Nanostructured copper oxides are prepared by anodic oxidation of Cu foil in alkaline solution. The resultant copper oxide nanofibers function as matrix for thick Si films (1–2 μm) loading. Metallic Cu nanofibers are obtained by in-situ electrochemical reduction at low potentials, which work as electrical highways for fast electron transport and a reliable mechanical matrix to accommodate volume changes during lithium–silicon alloy/dealloy processes. The engineered thick Si film anode exhibit both high areal capacity (0.48 mAh cm−2 for 1 μm Si film and 0.6 mAh cm−2 for 2 μm Si film after 200 cycles at 0.225 mA cm−2) and excellent rate capability (0.52 mAh cm−2 at 1.05 mA cm−2 for 2 μm Si film). The 2 μm silicon film electrode is able to recover to the initial value of 1 mAh cm−2 when the current rate is set back to 0.15 mA cm−2 even after cycling at high current rates. The reported concept can be a general method for high-loading-film electrodes, which is industrial scalable and compatible with current battery manufacturing processes.

Fabrication and Characterization of SnO₂/Graphene Composites as High Capacity Anodes for Li-Ion Batteries.

Tin-oxide and graphene (TG) composites were fabricated using the Electrostatic Spray Deposition (ESD) technique, and tested as anode materials for Li-ion batteries. The electrochemical performance of the as-deposited TG composites were compared to heat-treated TG composites along with pure tin-oxide films. The heat-treated composites exhibited superior specific capacity and energy density than both the as-deposited TG composites and tin oxide samples. At the 70th cycle, the specific capacities of the as-deposited and post heat-treated samples were 534 and 737 mA·h/g, respectively, and the corresponding energy densities of the as-deposited and heat-treated composites were 1240 and 1760 W·h/kg, respectively. This improvement in the electrochemical performance of the TG composite anodes as compared to the pure tin oxide samples is attributed to the synergy between tin oxide and graphene, which increases the electrical conductivity of tin oxide and helps alleviate volumetric changes in tin-oxide during cycling.

Nanostructured silicon/porous carbon spherical composite as a high capacity anode for Li-ion batteries

A nanostructured silicon/porous carbon spherical composite was prepared by a simple hydrothermal method using glucose as a carbon source and Pluronic F127 as a soft template/pore forming agent in the presence of silicon nanoparticles, and a subsequent carbonization process. In this composite, silicon nanoparticles were individually and separately coated with a porous carbon shell with a thickness of 15–20 nm and a pore size of 3–5 nm. The composite electrode exhibited excellent cycling stability and rate capability, delivering a stable capacity of 1607 mA h g−1 at a current density of 0.4 A g−1 after 100 cycles, and a reversible capacity of 1050 mA h g−1 even at a high current density of 10 A g−1. Detailed analysis of cyclic voltammetry and electrochemical impedance spectroscopy revealed that the composite showed favorable electrochemical kinetics due to the nano-sized porous carbon shell, which facilitated the formation of a solid electrolyte interface film and the transportation of Li ions and electrons, and decreased the charge transfer resistance, thus significantly improving the electrochemical performance compared with the bare nano-Si electrode.

Graphite microspheres decorated with Si particles derived from waste solid of organosilane industry as high capacity anodes for Li-ion batteries

We report the decoration of commercial graphite microspheres (GMs) with Si particles as anode materials for Li-ion batteries. The Si particles are obtained from solid Si waste of organosilane industry that is acid-washed to remove the impurities and further ground. The GMs with a size of 5–40 μm as main active material, Si particles with a size of 1–10 μm as an additive, and sucrose dissolved in water as a binder are mixed and followed by carbonization to obtain Si/C composites containing graphite, Si, and amorphous carbon generated from sucrose. It is found that the composite containing 60.5 wt% of GMs, 22.1 wt% of Si, and 17.4 wt% of amorphous carbon obtained at 800 °C for 5 h shows the best electrochemical performance with a specific capacity of 522.6 mA h g−1 at the current density of 50 mA g−1 and 306.9 mA h g−1 at 500 mA g−1, much higher than those of GMs. Its capacity retention at 500 mA g−1 attains 93.9% after 20 cycles. The work demonstrates the possibility for utilization of the industrial Si waste to enhance graphite anode materials in Li-ion batteries.

Porous SnS Nanorods/Carbon Hybrid Materials as Highly Stable and High Capacity Anode for Li-Ion Batteries

A new solid-liquid-gas-solid (SLGS) growth strategy has been exploited to prepare porous SnS nanorods directly on carbon hybrid nanostructure by using a sulfur-containing resin (s-resin) laden with crystalline SnO(2) nanoparticles and subsequent calcination promoted the development of porous SnS nanorods growing on carbon. As an anode material in Li-ion batteries (LIBs), SnS nanorods/C hybrid materials show highly stable and high capacity retention rate, which suggest that the novel hybrid materials have alluring prospect for electrochemical energy storage applications.

Graphene/Metal Oxide Composite Materials as High Capacity Anodes for Li-Ion Batteries

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SiOx Material as High Capacity Anode for Li-Ion Batteries

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Nanoflake CoN as a high capacity anode for Li-ion batteries

CoN films with nanoflake morphology are prepared by RF magnetron sputtering on Cu and oxidized Si substrates and characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM) and selected area electron diffraction (SAED) techniques. The thickness and composition of the films are determined by the Rutherford back scattering (RBS) technique confirming the stoichiometric composition of CoN with a thickness, 200 (± 10) nm. Li-storage and cycling behavior of nanoflake CoN have been evaluated by galvanostatic discharge–charge cycling and cyclic voltammetry (CV) in cells with Li–metal as counter electrode in the range of 0.005–3.0 V at ambient temperature. Results show that a first-cycle reversible capacity of 760 (± 10) mAhg − 1 at a current rate 250 mAg − 1 (0.33 C) increases consistently to yield a capacity of 990 (± 10) mAhg − 1 after 80 cycles. The latter value corresponds to 2.7 mol of cyclable Li/mol of CoN vs. the theoretical, 3.0 mol of Li. Very good rate capability is shown when cycled at 0.59 C (up to 80 cycles) and at 6.6 C (up to 50 cycles). The coloumbic efficiency is found to be 96–98% in the range of 10–80 cycles. The average charge and discharge potentials are 0.7 and 0.2 V, respectively for the decomposition/formation of Li 3N as determined by CV. However, cycling to an upper cut-off voltage of 3.0 V is essential for the completion of the “conversion reaction”. Based on the ex-situ-XRD, -HR-TEM and -SAED data, the plausible Li-cycling mechanism is discussed. The results show that nanoflake CoN film is a prospective anode material for Li-ion batteries.

Hybrid Tin Oxide Nanowires as Stable and High Capacity Anodes for Li-Ion Batteries

In this report, we present a simple and generic concept involving metal nanoclusters supported on metal oxide nanowires as stable and high capacity anode materials for Li-ion batteries. Specifically, SnO(2) nanowires covered with Sn nanoclusters exhibited an exceptional capacity of >800 mAhg(-1) over hundred cycles with a low capacity fading of less than 1% per cycle. Post lithiation analyses after 100 cycles show little morphological degradation of the hybrid nanowires. The observed, enhanced stability with high capacity retention is explained with the following: (a) the spacing between Sn nanoclusters on SnO(2) nanowires allowed the volume expansion during Li alloying and dealloying; (b) high available surface area of Sn nanoclusters for Li alloying and dealloying; and (c) the presence of Sn nanoclusters on SnO(2) allowed reversible reaction between Sn and Li(2)O to produce both Sn and SnO phases.

Amorphous silicon thin films as a high capacity anodes for Li-ion batteries in ionic liquid electrolytes

High lithiation capacity at low red-ox potentials in combination with good safety characteristics makes amorphous Si as a very promising anode material for rechargeable Li batteries. Thin film silicon electrodes were prepared by DC magnetron sputtering of silicon on stainless steel substrates. Their behavior as Li insertion/extraction electrodes was studied by voltammetry and chronopotentiometry at room temperature in the ionic liquid (IL) 1-methyl-1-propylpiperidinium bis(trifluoromethylsuphonil)imide containing 1 M Li bis(trifluoromethylsuphonil)imide. Li/Si cells containing this electrolyte showed good performance with a stable Si electrodes capacity of about 3000 mA h g −1 and a relatively low irreversible capacity. Preliminary results on cycling Si–LiCoO 2 cells using this IL electrolyte are also presented.