SLIDE 1
Molecular Design of Organic Electrode Active Materials for Aqueous Rechargeable Magnesium-ion Battery Masato Ito (Kyushu Univ.)
- Sep. 22, 2015@PWTC, Kuala Lumpur
Molecular Design of Organic Electrode Active Materials for Aqueous - - PowerPoint PPT Presentation
Molecular Design of Organic Electrode Active Materials for Aqueous - - PowerPoint PPT Presentation
ISOC14 Molecular Design of Organic Electrode Active Materials for Aqueous Rechargeable Magnesium-ion Battery Masato Ito (Kyushu Univ.) Sep. 22, 2015@PWTC, Kuala Lumpur Toward Large-Scale Electricity Storage Commercial Rechargeable Batteries
SLIDE 2
SLIDE 3
Commercial Rechargeable Batteries using s-Block Element
Nickel-Metal hydride (NiMH) Lithium-ion (LiB) Sodium-sulfur (NaS) Advantage High power density High energy density Rare-metal free Disadvantage
- memory effect
- Flammable
- Less conductive
- High cost
- High operation temp.
- Corrosion of insulator
- Dendritic-Na growth
Electrolyte Aqueous (KOH aq.) Non-aqueous (Organic carbonate) Solid (β-Al2O3) Application Hybrid Vehicle Electric Vehicle Power Plant Accident example Nothing
- PC smoking and fire
- Boeing 787 (2013)
- Toko-Takaoka (2011)
- TEPCO (2013)
SLIDE 4
O2 generation (E = 1.23 – 0.059pH) H2 generation (E = – 0.059pH)
Stable Electrochemical Window
E (V) vs. NHE ‐1.5 ‐1.0 ‐0.5 0.0 0.5 1.0 1.5 14 12 10 8 6 4 2 pH
Stability Window of H2O
Clarke Number ionic radius, Å (CN6) standard electrode potential, V (vs. SHE) theoretical specific volume capacity, Ah/cc
3Li
0.006 0.76
- 3.045
2.05
11Na
2.63 1.02
- 2.714
1.13
12Mg
1.93 0.72
- 2.356
3.83
13Al
7.56 0.54
- 1.676
8.05
Energy Density = Voltage x Capacity
Characteristics of Selected Ions
SLIDE 5
Aqueous Rechargeable Battery: Historical Background
electrolyte cathode anode capacity (mAh/g) group (year) 5 M LiNO3 aq. LiMn2O4 VO2 10 Dahn (1994)
- sat. LiNO3 aq.
LiCoO2 LiV3O8 55 Wu (2007) 1 M Mg(NO3)2 aq. LiMn2O4 Pt 42 Munichandraiah (2008) 1 M Li2SO4 aq. LiFePO4 LiTi2(PO4)3 82 Okada (2008) 1 M Na2SO4 aq. Na0.44MnO2 AC 45 Whitacre (2010) 2 M Na2SO4 aq. Zn NaTi2(PO4)3 121 Okada (2011) 2 M Na2SO4 aq. Na0.44MnO2 NaTi2(PO4)3 42 Okada (2011) 5 M LiNO3 aq. LiCoO2 DANTCBI 71 Zhan (2014) 2 M MgSO4 aq. Zn DAAQ 260 This work (2014)
N N O O O O n DANTCBI O N O N 1,4-DAAQ
SLIDE 6
reduction
- xidation
- Chem. Rev. 1992, 92, 1227
Acta Cryst. E, 2005, 61, o1393 OH OH OH OH HO HO HO HO HO HO OH OH O O O O O O 8 H2O 2 H2O
Molecular Design of New Electrode Active Materials
X X X X X X X X X X X X X X X X X X X X X X X X
2e- 2e- 2e- 2e- 2e- 2e-
X = CR2. NR, O
■Hexagonal Radialenes : 6-electron redox reaction at maximum ■The parent C6O6 molecule can not exist without hydration
SLIDE 7
O O N N O O O N N N O N N N N N O O N N N N N N X6 = O4N2 X6 = O2N4 X6 = N6 O O O O X6 = O2C4 O N N O N N O O X6 = O2N2C2
Hetero[6]radialenes New Candidates for Electrode Active Materials
The two contiguous exocyclic double bonds in C6O6 are replaced
SLIDE 8
Experimental Setup and Conditions
CE WE Ni wire Ni mesh RE Zn foil Zn wire
WE composite hetero[6]radialene:AB:PTFE = 70:25:5 (by weight) electrolyte 2 M MgSO4 aq. CE Zn metal, 99.9% (Nilaco) RE Ag/AgCl (BAS) current density 0.2 mA/cm2 (constant)＠25 ℃ potential range －0.8～+0.6 V WE = working electrode, CE = counter electrode, RE = reference electrode AB = acetylene black (Denki Kagaku), PTFE = poly(tetrafluoroethylene) (Daikin)
SLIDE 9
Charge/Discharge Profiles： Diaza-anthraquinone
N N O O O O
1,4-DAAQ
N O O
- 1.0
- 0.5
0.0 0.5 1.0 Voltage (V) vs. Ag/AgCl 300 250 200 150 100 50 Capacity (mAh/g) 1st 2nd
- 1.0
- 0.5
0.0 0.5 1.0 Voltage (V) vs. Ag/AgCl 300 250 200 150 100 50 Capacity (mAh/g) 1st 2nd
- 1.0
- 0.5
0.0 0.5 1.0 Voltage (V) vs. Ag/AgCl 300 250 200 150 100 50 Capacity (mAh/g) 1st 2nd
- flat voltage plateau
- just above the lower limit
- clean reversible reaction
- initial capacity decrease
- significant loss of energy
SLIDE 10
N N O O N N O O
Pyrazine-substructure
N N O O
1,4-DAAQ
- 1.0
- 0.5
0.0 0.5 1.0 Voltage (V) vs. Ag/AgCl 300 250 200 150 100 50 Capacity (mAh/g) 1st 2nd
- 1.0
- 0.5
0.0 0.5 1.0 Voltage (V) vs. Ag/AgCl 300 250 200 150 100 50 Capacity (mAh/g) 1st 2nd
- 1.0
- 0.5
0.0 0.5 1.0 Voltage (V) vs. Ag/AgCl 300 250 200 150 100 50 Capacity (mAh/g) 1st 2nd
- flat voltage plateaus
- initial capacity decrease
SLIDE 11
para- vs ortho-Quinone
N N O O O N N O
1,4-DAAQ
- 1.0
- 0.5
0.0 0.5 1.0 Voltage (V) vs. Ag/AgCl 300 250 200 150 100 50 Capacity (mAh/g) 1st 2nd
- 1.0
- 0.5
0.0 0.5 1.0 Voltage (V) vs. Ag/AgCl 300 250 200 150 100 50 Capacity (mAh/g) 1st 2nd
- unattractive potential
- initial capacity decrease
SLIDE 12
Benzene Juncture
N N O O
The benzene ring possibly prevents 1,4-addition of water at the surface.
N N O O
1,4-DAAQ
- 1.0
- 0.5
0.0 0.5 1.0 Voltage (V) vs. Ag/AgCl 300 250 200 150 100 50 Capacity (mAh/g) 1st 2nd
- 1.0
- 0.5
0.0 0.5 1.0 Voltage (V) vs. Ag/AgCl 300 250 200 150 100 50 Capacity (mAh/g) 1st 2nd
SLIDE 13
Structural Change on Electrolysis : ex-situ IR
- 1.0
- 0.5
0.0 0.5 1.0 Voltage (V) vs. Ag/AgCl 300 250 200 150 100 50 Capacity (mAh/g) 1st 2nd
①Initial ②Mg insertion ③Mg extraction
Wavenumber [cm-1]
1 8 1 8 1 6 1 6 1 4 1 4 1 2 1 2 1 1 ② ③ ①
N N O O
e e
Mg2+ electrode electrolyte
260 mA/g: one Mg per one 1,4-DAAQ 1,4-DAAQ
SLIDE 14
MgMnSiO4
Summary
N N O O O N N O
1,4-DAAQ
■1,4-DAAQ as a promising electrode material for Mg ion battery ■Capacity of 260 mAh/g is largest ever for an aqueous battery ■Attractive potential for an anode material ■Judicious arrangement of four consecutive exocyclic double bonds
O2 generation (E = 1.23 – 0.059pH) H2 generation (E = – 0.059pH)
Stable electrochemical window of H2O
E (V) vs. NHE ‐1.5 ‐1.0 ‐0.5 0.0 0.5 1.0 1.5 14 12 10 8 6 4 2 pH
SLIDE 15
Acknowledgement
- Prof. S. Okada（
Kyushu Univ.)
- K. Chihara（
Tokyo Univ. of Science)
- K. Nakamoto （
Kyushu Univ.)
- T. Ikeda （