Yuichi Aihara Samsung R&D Institute Japan (SRJ)

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


1

Background

2


3


Conclusions

4


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


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


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


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


~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


1

Background

2


3


Conclusions

4


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


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)


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


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


1

Background

2


3


Conclusions

4


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


1

Background

2


3


Conclusions

4


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：


• Organization committees • Samsung Advanced Institute Technology • SRJ/SAIT research staff

Acknowledgement

Yuichi Aihara Samsung R&D Institute Japan (SRJ)

Documents

Transcript of Yuichi Aihara Samsung R&D Institute Japan (SRJ)