Hello, A yearly allocation for the LCRC cluster has been requested with the following updated information: Submitter/PI: Maria Chan Project Name: CEES-Si Division: CNM Project title: Investigations of silicon surfaces and interfaces for lithium ion batteries Associated funding: DOE Energy Frontier Research Center -- Center for Electrical Energy Storage (CEES) Other Systems: CNM Carbon Science: This project uses density functional theory (DFT) to investigate silicon as an anode material for lithium ion batteries. Silicon is attractive as an alternative to carbon-based anode materials due to enhanced safety and superior capacity. A key question that arises in the design and operation of Si-based anodes concerns the ability of these anodes to ad(b)sorb lithium ions; numerous studies suggest that the Si lithiation process involves a rich combination of adsorption and absorption phenomena, together with surface reconstructions, highly localized volumetric expansions of the Si lattice, and phase transitions between crystalline and amorphous structures. At the atomic and nanoscales, however, even the simplest details of these processes remain poorly understood. We aim to providing atomistic insights on these processes by carrying out DFT studies of the adsorption, initial stages of insertion, vibrational spectra, and diffusion of Li in the surfaces, interfaces b etween phases, and nanowires. Furthermore, we will consider the effects of surface and subsurface impurities. This will aid the design of optimal surface and interfacial structures for battery performance and stability. Project description: We will use total energy DFT calculations to evaluate the adsorption and absorption energy and nudged elastic band migration barriers of Li on and near Si (100), (111) and (110) surfaces with low energy reconstructions. We will also calculate the effects of adsorbed and substitutional impurities on the energetics and kinetics. I will consider 6 types of impurities, 2-3 types of reconstruction per surface orientation, and 10-20 Li position, and combinations thereof. This will amount to 1000-2000 calculations of 100-200 core-hours each. Vibrational frequencies from DFT forces dynamical matrices will be computed in order to aid comparisons with experiments. In addition, energetics and kinetics of Li in nanowires, at the interface between crystalline and amorphous silicon, and between Si and inorganic minerals found to be present at electrode interfaces, will be studied. Interface and nanowire calculations will each consume 500-2000 core-hours and 50-10 0 calculations will be performed. Using the projector-augmented wave method, only valence electrons will be included which reduces computational costs. We will use well-established DFT codes VASP and GPAW, which use a plane wave basis set and real space grids respectively. For large systems such as nanostructures, VASP has been tested on Fusion for computation involving systems with up to 7000 electrons. For routine surface calculations, hard scaling efficiency of 70%-80% has been demonstrated for 64 to 128 cores compared to 8 cores, thus enabling efficient calculations of large numbers of configurations. Please note that I am requesting an allocation for FY2011 significantly higher than that will have been used by the end of FY2010 because my FY2010 allocation did not start until March 2010 and from March to September 2010 I still have access to other machines from previous affiliations that I will no longer have access to in FY2011. Project URL: http://www.anl.gov/energy-storage-science/ Current FY Hours Used: undetermined amount New FY Requested allocation: 400000 Justification: Thank You, The LCRC Accounts System