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Beyond Lithium-Ion Workshop Nice, Oct. 2nd 2018
Yuichi Aihara
Samsung R&D Institute Japan (SRJ)
2 / 25 Beyond Lithium-Ion Workshop Nice, Oct. 2nd 2018
1
Background
2
Pelletized cell: intrinsic characteristics
3
Prototype cell: current status
Conclusions
4
3 / 25 Beyond Lithium-Ion Workshop Nice, Oct. 2nd 2018
1
Background
2
Pelletized cell: intrinsic characteristics
3
Prototype cell: current status
Conclusions
4
4 / 25 Beyond Lithium-Ion Workshop Nice, Oct. 2nd 2018
Energy density
Ni-MH LIB Next Generation
1.2 V
Aqueous liquid
KOH-aq.
3.7 V
Non aqueous liquid
(1M-LiPF6-EC/DMC)
> ~5 V?
Solid electrolyte
Water electrolysis Decomposition of organic material
- Desired properties - Electrochemical stability Ideal Li+ transport and reaction Safety (Strategy for Li-metal anode)
Research motivation
Safety
Li ~3V
5 / 25 Beyond Lithium-Ion Workshop Nice, Oct. 2nd 2018
Key characteristics in sulfide based ASSBs
1. Softness of sulfide based electrolyte 2. High ionic conductivity >2 mScm-1, t+=1 3. Buffer layer on cathode active material
Issues: - Process (compression/tact time) - Supply chain - Operation pressure - Hydrolysis of sulfide materials
Large format cell
resolution Mass Production
6 / 25 Beyond Lithium-Ion Workshop Nice, Oct. 2nd 2018
Softness of sulfide SEs
a-Li3PS4 (Li2S:P2S5=75:25) (Prepared by ball milling)
~0.2mScm-1
@25℃
(d=ca.1.6-1.7)
Cold press
7 / 25 Beyond Lithium-Ion Workshop Nice, Oct. 2nd 2018
Buffer layer
NCA
S.E.
O
S
Mutual diffusion must be prevented.
RCT↑at high SOC
Ito et al., Journal of Power Source 248 (2014)943-950
8 / 25 Beyond Lithium-Ion Workshop Nice, Oct. 2nd 2018
~2010 2014 2018
0.2 mScm-1 ⇒ 2 mScm-1 (5 mScm-1) 120 mAhg-1 ⇒ 210 mAhg-1
275 mAhg-1 310 mAhg-1 3862 mAhg-1
1 mAh max. 5 Ah 1 Ah
σ25
P (S.C.)
N(S.C.)
Cell Q
R&D time line at Samsung
9 / 25 Beyond Lithium-Ion Workshop Nice, Oct. 2nd 2018
1
Background
2
Pelletized cell: intrinsic characteristics
3
Prototype cell: current status
Conclusions
4
10 / 25 Beyond Lithium-Ion Workshop Nice, Oct. 2nd 2018
Preliminary test of a pelletized cell
0.8~1.5 mAh Graphite, Si, Li/SE/LMeO, S Characterization of materials No binder (pellet) 13 mmΦ (1.33cm2)
Test cell for materials evaluation. (Neglect energy density.) No binder → Ideal performance
11 / 25 Beyond Lithium-Ion Workshop Nice, Oct. 2nd 2018
Over 99.9% coulombic efficiency Negligible impact of reaction products
0 500 1000 1500 20000
20
40
60
80
100
Cycle
Cap
acit
y re
ten
tio
n (
%)
114 mAh/g (cathode)
90
95
100
105
110
87 mAh/g (76%) (cathode)
Co
ulo
mb
ic e
ffic
ien
cy (
%)
0.5C CCCV/CC cycle @25℃
76% retention @2K cycle
0.5C ≒ 0.4mAcm-2
Cycleability
Pellet
Item Spec.
Negative Li foil t=30μm
Positive (wt%) NCA:SE:C=60:35:5
Loading 0.83 mAh/cm2
Cap. Ratio N/P 26
SE LPSX
Cell capacity 1.1mAh
(cathode)
12 / 25 Beyond Lithium-Ion Workshop Nice, Oct. 2nd 2018
Rate capability
Item Spec.
Negative Li foil t=30μm
Positive (wt%) NCM:SE:C=60:35:5
Loading 0.6 mAh/cm2
Cap. Ratio N/P 21
SE LiCl-Li2S-Li3PS4
Cell capacity 0.8 mAh (cathode)
High rate discharge capability of a solid-state lithium secondary cell
13mmΦ pellet cell
0 20 40 60 80 100 120 140 160
2.5
3.0
3.5
4.0
50C
108.6
72.0%1C
152.1
100.9%
0.33C
150.8150C
87.2
57.8%
Term
inal voltage / V
Specific capacity / mAh g-1
10mg loading
Ref (HV, 150C) : Y. Kato et al., Nature Energy, 2016.30
@100℃
58% discharge at 150C (24sec) @100℃ Pellet
NCM: LiNi0.8Co0.1Mn0.1O2
Y. Kato et al., ARTICLE NUMBER: 16030 | DOI: 10.1038/NENERGY.2016.30
13 / 25 Beyond Lithium-Ion Workshop Nice, Oct. 2nd 2018
Continuous, large scale processes require wet process and binders. Unlike conventional LiBs, binders in ASSBs are insulator. → Significant reduction in electronic/ionic conductivity
A large gap : Pellet and Prototype cell
• Takada et al. propose dry process
14 / 25 Beyond Lithium-Ion Workshop Nice, Oct. 2nd 2018
1
Background
2
Pelletized cell: intrinsic characteristics
3
Prototype cell: current status
Conclusions
4
15 / 25 Beyond Lithium-Ion Workshop Nice, Oct. 2nd 2018
0 100 200 300 400 500 600 700 800 900
2.0
2.5
3.0
3.5
4.0
4.5
E/
V
Specific capacity (cathode) / mAh
10 50 100 200 300 400 500 600 700
t = 60 ℃
0.5/0.5C CC charge/discharge cycle @ 60℃ Under an external pressure.
Cyclability
2017 ver. Cell
16 / 25 Beyond Lithium-Ion Workshop Nice, Oct. 2nd 2018
1
Background
2
Pelletized cell: intrinsic characteristics
3
Prototype cell: current status
Conclusions
4
17 / 25 Beyond Lithium-Ion Workshop Nice, Oct. 2nd 2018
Conclusions
2: Adaptation of Li-metal anode
i) Need external pressure ii) Micro short circuit
1: Sulfide solid electrolyte
• Applicable(Stable operation at Li potential. High voltage is more challenging.)
• 700 cycles、demonstrated 60℃ operation
3: Deposition-type Secondary ASSB
Very promising, but many outstanding issues and need to ensure safety
• Excellent C.E.:No excess Li required • Remaining issues:
18 / 25 Beyond Lithium-Ion Workshop Nice, Oct. 2nd 2018
• Organization committees • Samsung Advanced Institute Technology • SRJ/SAIT research staff
Acknowledgement