High-Performance Lithium Battery Anodes Using Silicon Nanowires

Nature Nanotechnology (Impact Factor: 34.05). 01/2008; 3(1):31-5. DOI: 10.1038/nnano.2007.411
Source: PubMed


There is great interest in developing rechargeable lithium batteries with higher energy capacity and longer cycle life for applications in portable electronic devices, electric vehicles and implantable medical devices. Silicon is an attractive anode material for lithium batteries because it has a low discharge potential and the highest known theoretical charge capacity (4,200 mAh g(-1); ref. 2). Although this is more than ten times higher than existing graphite anodes and much larger than various nitride and oxide materials, silicon anodes have limited applications because silicon's volume changes by 400% upon insertion and extraction of lithium which results in pulverization and capacity fading. Here, we show that silicon nanowire battery electrodes circumvent these issues as they can accommodate large strain without pulverization, provide good electronic contact and conduction, and display short lithium insertion distances. We achieved the theoretical charge capacity for silicon anodes and maintained a discharge capacity close to 75% of this maximum, with little fading during cycling.

Download full-text


Available from: Robert A Huggins, Oct 04, 2015
249 Reads
  • Source
    • "Furthermore, these free spaces provide large active sites to accommodate lithium (Li + ) and create an easy path for electrolyte to access the entire electrode surface while reducing polarization which otherwise forms on the anode surface due to SEI (solid electrolyte interface) formation, hence improve the electrode service life eventually [10]. Within this scope, various studies have been conducted to form Si based nanorods such as laser irradiation [11], chemical vapor deposition [12], catalyst-free reactions [13] and lithography-based ion etching methods [14]. Other than that ''oblique angle deposition'' (OAD) via electron beam evaporation method has also become remarkable as it has the ability of avoiding the hazardous handling of flammable, explosive or cancerogen nanoparticles. "
    [Show abstract] [Hide abstract]
    ABSTRACT: An ion assisted oblique angle (80) electron beam deposition method was used to form well-aligned nanorods of a multi-layered Cu/Si film. For comparison, a flat multilayered Cu/Si film was coated at 0 angle using the same electron beam deposition system. The galvanostatic test results demonstrated that both electrodes performed better cycleability compared to bulk Si anode because the multilayer structure of the films enhanced the degree of atomic interactions between Cu and Si to form nano-sized intermetallics. Moreover, Cu buffered the mechanical stresses caused by lithiation and improved the electrical conductivity of the whole film which also affected the cycle life of the multilayered thin film anodes. Galvanostatic half-cell measurements showed that the Cu/Si film made of well aligned nanorods exhibited 1700 mA h g1 as initial discharge capacity then it decreased to 500 mA h g1 after 1st cycle (with 99% coulombic efficiency) and became stable for 100 cycles. The remarkable high coulombic efficiency, capacity retention and stable performance of the electrode are related to its unique structural morphology: the high surface area of nanorods increased the contact area of the anode with Li, decreased polarizations and enhanced mechanical resistance against volumetric changes due to the homogenously distributed nano-sized interspaces among them.
    Journal of Alloys and Compounds 08/2015; 622(2015):418-425. · 3.00 Impact Factor
  • Source
    • "Besides electronics, non-planar nanostructures have also found many novel applications in research areas such as energy storage [19], energy generation [20] [21], lasers [22] [23] and non-linear optics [8] [24]. Here what makes the " bottom-up " approaches particularly interesting is that they offer a way to synthesize nanocrystals with controlled size and shape. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The ability to rationally tune the morphology of nanostructures is a fundamental milestone in nanoscale engineering. In particular, the possibility to switch between different shapes within the same material system represents a further step in the development of complex nanoscale devices and it increases the potential of nanostructures in practical applications. We recently reported a new form of InAs nanostructures growing epitaxially on Si substrates as vertical V-shaped membranes. Here we demonstrate the possibility of modifying the shape of these nanomembranes and turning them into nanowires by modulating the surface roughness of the substrate by varying the surface treatment. We show that the growth of nanomembranes is favored on smooth surfaces. Conversely rough surfaces enhance the growth of nanowires. We also show that the V/III ratio plays a key role in determining the absolute yield, i.e. how many nanostructures form during growth. These results envisage a new degree of freedom in the engineering of bottom-up nanostructures and contribute to the achievement of nanostructure networks.
    Journal of Crystal Growth 06/2015; 420. DOI:10.1016/j.jcrysgro.2015.01.040 · 1.70 Impact Factor
  • Source
    • "Even though nanotechnology [4] has shed lights on the practical application of Si as the anode material, a thorough understanding of the complicated electro-chemomechanical problem involved in the (de)lithiation process of Si is still missing. In particular, further advanced nanomaterial designs, such as those making use of doublewalled Si tubes [5], Si-C yolk-shell and pomegranate [6,7], or nanoporous Si [8,9] require such improved mechanical understanding. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Silicon is considered as a promising anode material for lithium ion batteries. Despite the great attention on Si anode materials, a consistent description of the diffusion and reaction mechanism at the reaction front of crystalline silicon, amorphous silicon, and delithiated amorphous silicon has not yet been proposed. To better understand those mechanisms, a new reaction-controlled diffusion formulation is proposed. The new formulation makes use of the bond-breaking energy barrier E 0 as the key physical quantity. With the consideration of different values of E 0 , the two-phase diffusion during initial lithiation of both crystalline Si and amorphous Si can be well represented with an evident reaction front. In addition, by varying E 0 , the one phase lithiation of amorphous Si, obtained after the delithiation process, can be captured with the new formulation. The effect of deformation, hydrostatic pressure at the reaction front, and Li concentration level on the reaction front velocity is taken into account in the proposed model. Numerical simulations are provided to support the model.
    04/2015; DOI:10.1016/j.eml.2015.04.005
Show more