High energy density of cathode materials

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High energy & power density materials: Layered materials

Commercialized cathode LCO (3.9V, 140mAh/g) not enough for next generation LIB Need to research on high energy density cathode material

D. Andre et al.,(2015). JMCA, 3(13), 6709-6732

Layered structure

High specific capacity

  • - NMC, NCA : 3.8V,~200mAh/g
  • - Li-rich layered : 3.6V,~300mAh/g

Spinel structure

High redox potential

  • - LiMn2O4: 4.1V,~140mAh/g
  • - LiNi0.5Mn1.5O4: 4.7V,~150mAh/g

Challenging issue -> Research approaches

Spinel materials have high redox potential, but

  • 1) Metal dissolution problem at high T,V
  • 2) Low theoretical capacity (~150mAh/g)
  • Material Modification : surface coating, chemical substitution
  • Composite with layered : spinel-layered composite (theoretical capacity ~400mAh/g)

Layered materials have high energy density, but

  • 1) Energy loss (voltage & capacity fading)
  • 2) Low columbic efficiency (ex. O2 gas↑)
  • Powder Synthesis : atomic distribution, morphology control
  • Material Modification : surface coating, chemical substitution

High energy density cathode materials: F- containing materials

  • Poly-anion compounds with strong inductive effect → High operating potential
  • Binary metal fluorides for conversion mechanism → High theoretical capacity
  • Paradigm shift of battery material from oxides to fluorides with high energy density

F- containing polyanion groups; LiFeSO4F, LiVPO4F, LiFePO4F…

B. C. Melot, et al., Accounts
Chem. Res. (2013)

C. Masquelier, et al.,
Chemical Reviews (2013)

Challenges & Approaches

    Low electronic conductivity
  • Conductive matrix
  • Aliovalent doping
    Synthesis Process
  • Develop novel method
  • Phase analysis

Conversion metal fluorides; FeF2, FeF3, BiF3, CuF2

G. G. Amatucci, et al., Journal of
Fluorine Chem. (2007)

J. Cabana et al., Advanced
Energy Material(2010)

Challenges & Appr oaches

    Massive structural change
  • Porous template
  • Local environment analysis
    Large Voltage Hysteresis
  • Understanding mechanism
  • Pre-li thiated composite
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