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SUMMARY:Computational Modelling Study of Structure and Stoichiometry of Ta
  Doped Tetragonal Li7La3Zr2O12 Oxide Garnet for Solid State Batteries.
DTSTART;VALUE=DATE-TIME:20210727T131500Z
DTEND;VALUE=DATE-TIME:20210727T133000Z
DTSTAMP;VALUE=DATE-TIME:20260712T021102Z
UID:indico-contribution-7102@events.saip.org.za
DESCRIPTION:Speakers: Refiloe Maphoto ()\nDue to the outstanding chemical 
 stability against high voltage electrode\, the oxide garnet with tetragona
 l structure Li7La3Zr2O12 (LLZO)\, is one of the most promising solid-state
  electrolytes for li-ion batteries. However\, it has low ionic conductivit
 y (~10-6 S.cm-1) at room temperature\, which limits its practical applicat
 ion. Doping with a supervalent cation such as Ta on the Zr site of LLZO is
  an effective way to improve Li+ conductivity and further stabilize the te
 tragonal phase. To this end\, the fundamental aspects regarding stability 
 of most stable structural configuration of Ta-doped LLZO structures are st
 ill not entirely clear.\nIn this study\, we have combined the first-princi
 ple calculations within the generalised gradient approximation (GGA) by de
 termining the structural and thermodynamic properties of pure and doped t-
 LLZO for high ionic conductivity. The negative energy of formation in pure
  t-LLZO shows that the structure is thermodynamically stable.  We further 
 employed the substitutional search (SS) module to identify all possible st
 ructures and provide a better understanding of doped supervalent cation Ta
  on the octahedral 16c Zr site of LLZO. The substitutional search was used
  to replace a fraction of Zr atoms with Ta atoms\, so that it can enable e
 xcess Li to occupy the disordered octahedral sites (occupied by Zr atoms)\
 , which could facilitate better li-ion transport and increase ionic conduc
 tivity. Furthermore\, the substitutional search generated 3 new multi-comp
 onent structures (monoclinic Li28La12Zr7TaO48\, orthorhombic Li14La6Zr3TaO
 24 and triclinic Li28La12Zr7TaO48) of Ta doped LLZO. The calculated lattic
 e parameters of doped LLZO are smaller than that of pure t-LLZO. The resul
 ts show that the distance between Li-Li in doped Ta-LLZO is smaller than i
 n pure t-LLZO\, which indicates that the smaller the difference between th
 e dopant ionic radius and the critical dopant radius\, the higher the cond
 uctivity. Therefore\, the structural properties of tantalum-doped structur
 es are shown to improve\, due to the smooth decrease in calculated lattice
  parameters. Hence\, it is important to understand the stability of Ta dop
 ed LLZO for the development of all solid-state Li batteries.\n\nhttps://ev
 ents.saip.org.za/event/206/contributions/7102/
LOCATION:North-West University Potchefstroom Campus
URL:https://events.saip.org.za/event/206/contributions/7102/
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