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SUMMARY:Ion-Dynamics in materials for future solid state energy devices
DTSTART:20131101T141500
DTEND:20131101T150000
DTSTAMP:20260407T085028Z
UID:e7e780c4c6cf8ffeba7768d74a0e71a82158a0d50f3ac7a2d73c8541
CATEGORIES:Conferences - Seminars
DESCRIPTION:Martin Mansson\, Laboratory for Quantum Magnetism (LQM) - EPFL
 \, Laboratory for Neutron Scattering (LNS) - PSI\nOne of the most importan
 t scientific problems to solve for our modern society is how to convert an
 d store clean energy. In order to accomplish a paradigm shift in this fiel
 d\, we need to understand the fundamental dynamical processes that govern 
 the transfer of energy on an atomic scale. For future energy devices like 
 solid-state batteries (SSB) as well as solid-oxide fuel cells (SOFC)\, thi
 s means understanding and controlling the complex mechanisms of ion diffus
 ion in solid matter. Only recently\, developments of state-of-the-art larg
 e scale experimental facilities e.g. neutron/muon spallation sources as we
 ll as free electron lasers\, have opened new possibilities for studying su
 ch intrinsic material properties in a straightforward manner. I have in a 
 collaboration with Toyota Central Research and Development Laboratories in
  Japan\, developed a novel method that utilizes the muon-spin rotation/rel
 axation (m+SR) technique to probe the microscopic ion self-diffusion const
 ant (Dion) with high accuracy [1]. I will give a brief introduction to the
  method itself as well as summarize our extensive m+SR studies of Li-ion d
 iffusion in a wide range of battery cathode materials [2-6].\nIn the field
  of rechargeable batteries\, strong interest has recently been raised to f
 ind a replacement for traditional Li-ion technology. The main reason is th
 at such batteries are rather expensive and in addition the extraction of l
 ithium metal is problematic from an environmental point of view due to its
  high reactivity and relatively low abundance in the Earth’s crust (only
  20 ppm). One option to avoid these drawbacks may be to replace lithium (L
 i) with sodium (Na) in the electrode materials. Sodium is similar to lithi
 um in its chemical properties\, but approximately 1000 times more abundant
  in the Earth’s crust (26’000 ppm) as well as in the form of salt (NaC
 l) in normal seawater (15’000 ppm). This makes sodium based batteries po
 tentially more environmental friendly and easier to recycle as well as up 
 to five times less expensive.\nCurrently the most common Li-ion cathode ma
 terial is LiCoO2\, where the Na-analog consequently is NaCoO2\, making thi
 s compound a logical first step towards the development of Na-ion batterie
 s. To understand the Na-ion diffusion process in this material\, we have p
 erformed high-resolution neutron diffraction (ND) measurements as a functi
 on of temperature. Our data display a two-step "melting" of the Na-ion pla
 nes\, involving an intriguing crossover from 1D-to-2D Na-diffusion channel
 s [7]. Further\, it is evident that the onset and evolution of ion-diffusi
 on is intrinsically linked to a series of subtle structural transitions\, 
 which unlocks the diffusion pathways. Finally\, we have also performed m+S
 R [8] and pressure-dependent neutron scattering measurements [9]\, which r
 eveal novel and functional possibilities for tuning Na-ion diffusion using
  lattice-strains. In summary\, our current research has established a nove
 l and detailed insight into the ion-diffusion mechanisms in these compound
 s. This allows us to actively consider targeted tuning and smart design of
  energy related materials for the use in future solid state devices with o
 ptimized performance.\nREFERENCES\n[1] J. Sugiyama\, M. Månsson et al.\, 
 PRL 103\, 147601 (2009)\n[2] J. Sugiyama\, M. Månsson et al.\, PRB 82\, 2
 24412 (2010)  \n[3] J. Sugiyama\, M. Månsson et al.\, PRB 84\, 054430 (
 2011) \n[4] J. Sugiyama\, M. Månsson et al.\, PRB 85\, 054111 (2012)  
 \n[5] J. Sugiyama\, M. Månsson et al.\, PRB 87\, 024409 (2013)\n[6] M. M
 ånsson and J. Sugiyama\, Phys. Sc.\, Review Article in Press\n[7] M. Meda
 rde\, M. Månsson et al.\, PRL 110\, 266401 (2013)\n[8] M. Månsson et al.
 \, Submitted for Publication (2013)\n[9] M. Månsson et al.\, Manuscript i
 n preparation (2013)
LOCATION:PH L1 503 http://plan.epfl.ch/?lang=fr&room=Ph+L0+503
STATUS:CONFIRMED
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