NEWS MODELLING AND SIMULATION
Researchers develop new lithium-air battery design
Scientists have designed a beyond-lithium- ion battery cell that operates by running on air over many charge and discharge cycles. As reported in the journal Nature, a team
from the University of Illinois at Chicago and the US Department of Energy’s (DOE) Argonne National Laboratory produced the design. Larry Curtiss, co-principal investigator and Argonne Distinguished Fellow, observed that the team’s article was appealing because ‘others have tried to build lithium-air battery cells that run on air, but they failed because of little cycle life.’ The lithium-ion battery has transformed
the portable electronics industry and is making inroads into energy storage on the electric grid and electrically powered transportation. Research laboratories around the world are seeking to develop beyond- lithium-ion batteries that are even more powerful, cheaper, safer and longer lived as this could have a massive impact on both portable electronics and energy storage for automotive, commercial and even residential applications. Argonne’s newly developed battery
cell is a protective coating for the lithium metal anode, which prevents the anode from reacting with oxygen and hence deteriorating. It also includes a novel electrolyte mixture that allows the cell to operate in an air atmosphere. In tests under an air environment, this cell maintained
high performance during 700 cycles, far surpassing previous technology. According to Amin Salehi-Khojin, co- principal investigator and assistant professor at the University of Illinois at Chicago: ‘The energy storage capacity was about three times that of a lithium-ion battery, and five times should be easily possible with continued research. This first demonstration of a true lithium-air battery is an important step toward what we call beyond-lithium-ion batteries.’ The Argonne team’s computational
research helped to determine how this system operates in air and what factors contribute to the improved cycling stability – an important factor for increasing a batteries effective lifespan. This knowledge should prove crucial to scientists’ continued efforts to develop a full-size lithium-air battery. The researchers at the University of Illinois at Chicago built, tested, analysed
and characterised the battery cells, while those at Argonne mainly handled the basic science computational studies. Important to the project’s success was the use of the Argonne Leadership Computing Facility (ALCF) and the Center for Nanoscale Materials (CNM) for high-performance computing. The ALCF and CNM are DOE Office of Science User Facilities, both located at Argonne. Equally instrumental was the Research Resources Center at the University of Illinois at Chicago. The Nature article, published on March 22, is titled ‘Lithium-Oxygen Batteries with Long Cycle Life in a Realistic Air Atmosphere’. Argonne authors include Rajeev Assary, a chemist in the Materials Science division; Cong Liu, an assistant chemist in the Chemical Sciences and Engineering division; Badri Narayanan, an assistant materials scientist in the Materials Science division; and Anh Ngo, an assistant physicist in the Materials Science division. The research was funded in part by the National Science Foundation, DOE’s Office of Science and the State of Illinois. Several of the researchers received support from the Joint Center for Energy Storage Research, a DOE Energy Innovation Hub, and the Center for Electrical Energy Storage: Tailored Interfaces, a DOE Energy Frontier Research Center, both also supported by the Department’s Office of Science.
Project aims to develop software for energy-efficient computing HIGH-PERFORMANCE COMPUTING
A European project aims to overcome the energy efficiency challenges of heterogeneous computing architectures by developing a new software stack. The project, known as Low Energy Toolset
for Heterogeneous Computing (LEGaTO), is developing a toolset that will employ a highly efficient task-based programming model coupled to a dataflow runtime, while simultaneously ensuring security, resilience and programmability. Project coordinators Osman Unsal and
Adrian Cristal, commented: ‘Moore’s Law is slowing down, and as consequence hardware is becoming more heterogeneous. In the LEGaTO project, we will leverage task-based programming models to provide a software ecosystem for made-in-europe heterogeneous hardware composed of CPUs, GPUs, FPGAs and dataflow engines. Our aim is one order
36 Scientific Computing World April/May 2018
of magnitude energy savings from the edge to the converged cloud/high-performance computing (HPC).’ The LEGaTO project aims to increase energy efficiency by an order of magnitude through the use of the energy-optimised programming model and runtime, but it also has other plans to improve HPC performance and reliability. Specifically, LEGaTO aims to reduce the size of the trusted computing base by at least an order of magnitude, reduce meantime failure rate fivefold while decreasing the energy consumption while also improving FPGA programmer productivity by ‘leveraging novel features of dataflow hardware design’. This new project, first announced in
December 2017 is trying to solve a challenge that is becoming increasingly important as processor developers struggle to overcome the material limitations they face when
trying to design ever smaller transistors. This coupled with the heat density problems associated with packing an ever-increasing number of transistors in a unit area has caused Moore’s Law to slow down. Heterogeneity is the generally accepted
solution to this problem, but this also solutions also has its challenges. Incorporating more specialised compute units in the system hardware and utilising the most efficient compute unit for each computation has helped to drive performance. In recent years significant advances have been made to support heterogeneity for computing performance but power and energy-efficient computing it is lagging behind. This new project may help to overcome
some of these challenges, but it is not solely focused on developing HPC technology. The energy-efficient software toolset for
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