Design and fabrication of all-solid-state rechargeable lithium batteries using

ceramic electrolytes

Hirokazu Munakata, Jungo Wakasugi, Keisuke AndoMao Shoji, Kiyoshi Kanamura

Tokyo Metropolitan UniversityTOKYO METROPOLITAN UNIVERSITYTOKYO METROPOLITAN UNIVERSITYTOKYO METROPOLITAN UNIVERSITYTOKYO METROPOLITAN UNIVERSITY

International Symposium on Electrical Fatigue in Functional MaterialsSeptember 15, 2014

Sellin, Rügen, Germany

2

Outline1. Introduction

> Why all-solid-state?> Tasks in the development of all-solid-state batteries

2. Strategy (cell design)> 3D structured solid electrolyte> Sol-gel technique to construct a good electrode/electrolyte interface

3. Cell performance> All-solid-state rechargeable lithium battery using LLT

> All-solid-state rechargeable lithium battery using LLZ

4. Conclusions

3

Extending applications of LIBs

Portable electronic devices Electric vehicle

SafetyEnergy densityPower density

The safety is more important in large-scale batteries.

4

Electrolyte in LIBs

Charge

DischargeLi+

Anode(Graphite)

Cathode(LiCoO2)

Device

e‐

Liquid electrolyte(flammable organic solvents)Inorganic solid electrolyte

(non‐flammable)

5

Merits of inorganic solid electrolytes

Inorganic solid electrolytes:

● Non-flammability● Extending the upper limit of operating temperature● Low self-discharge● Simple package (bipolar batteries)● 3D structured battery

-> New battery applications

6

Current all-solid state batteries

Cathode

Anode

CeramicelectrolyteCeramicelectrolyte

Thin film battery (2D)

Device

2-dimensional (thin-layered) electrode configuration provides high rate performance due to fast lithium ion transport by short distance between cathode and anode, but…

Low capacity !

7

Capacity limitation by cell dimension

The electrode material situated away from an electrolyte layerdoes not work efficiently due to long diffusion length of lithium-ions.

Current collector

Current collector

Current collector

Current collector

It is difficult to obtain high cell capacity even though thick electrodes are prepared.

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http://www.cytech.com/products‐ips

Commercially available thin film batteries

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3D electrode configuration

Current collector

Current collector

Interdigitated electrode (3D) configuration

High cell capacity and high current density

Reduction of  internal resistance  by large electrochemical interface per unit volume

The distance between anode and cathode can be maintainedconstantly even when the amounts of electrode materials areincreased.

This kind of 3D electrode configurations have been suggested bymany research groups as a next generation battery structure not onlyfor all-solid-state batteries but also for conventional liquidelectrolyte batteries.

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3D patterned solid electrolyte

Micro‐size hole

Cathode material

Anode material

3D all‐solid‐state lithium battery

3D all-solid-state battery can be prepared by impregnation of cathode and anode materials into the holes on the top and bottom faces of a patterned ceramic electrolyte membrane.

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Li+-conducting solid electrolytes

solid electrolyte conductivity (S cm-1) tempreture (℃) reference

Li4.2Al0.2Si0.8O4 1.58×10-3 300 Y. Saito et al. Solid State Ionics . 40/41, 34 (1990)

Li1.3Al0.3Ti1.7(PO4)3 7×10-4 25 C. Masquelier et al. Solid State Ionics . 79, 98 (1995)

Li3.6Ge0.6V0.4O4 4×10-5 18 J. Kuwano et al. Mat. Res. Bull ., 15, 1661 (1980)

Li3N 6×10-3 25 T. Lapp et al., Solid State Ionics , 11, 97 (1983)

Li0.35La0.55TiO3 1.4×10-3 27 Y. Inaguma et al, Solid State Ionics . 86-88, 257 (1996)

O

A site ; Li, La, vacancy

B site ; Ti

Lithium lanthanum titanium oxide (LLT) was used to prepare a hole-array structured membrane due to high lithium-ion conductivity and mechanical strength.

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Hole array Li0.35La0.55TiO3

NGK INSULATORS Co., LTD.

Surface

LLT (Li0.35La0.55TiO3) = 1.2 10-3 S cm-1 at R.T.LLT (Li0.35La0.55TiO3) = 1.2 10-3 S cm-1 at R.T.

Perovskite structure

Li+ or La3+

Ti4+

O2-

Cross section180 m

180 m180 m

80 m200 holes on each side

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Powder impregnation

Cross sectionCross sectionNon-contactarea

SEM image

Active material powder + ethanol

Heat treatmentHeat treatment

High interfacial resistance !!

Very low capacity0.025 mA h g-1

LLT / electrodecomposite

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Application of precursor sol

LLT

LiMn2O4

Acetate Nitrate

Vacuum impregnation

Heat treatment700 C, 10 h

LiMn2O4 powder + Li-Mn-O sol

Precursor sol works as a binder to provide good contact.

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Charge/discharge test

2.9

3.2

3.5

3.8

4.1

4.4

0 1 2 3

Capacity / mA h g-1

E /

V (v

s.Li

/ Li

+ )

2.9

3.2

3.5

3.8

4.1

4.4

0 20 40 60 80

Capacity / mA h g-1

E /

V (L

i / L

i+ )

1.3 mA h g-1 42.2 mA h g-1

Acetate Nitrate

Cathode: LiMn2O4Anode: Li metalElectrolyte: Honeycomb LLT/PMMACurrent: 12.5 μA cm-2

Cuf off: 3.0 – 4.3V

LiMn2O4

PMMA gelLi metal

LLT

Au film

Theoretical capacity 148 mA h g-1

Without sol: 0.025 mA h g-1

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Formation of 3DOM LLT

3‐dimensionally ordered macroporous (3DOM) LLT 

Colloidal crystaltemplating method

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3DOM-hybrid hole-array

Short diffusion length of Li+Large contact area (Low internal resistance)

Li+

Simple hole-array 3DOM-hybrid hole-array

Li+Li+

Li+

Li+Li+

Solid electrolyte Solid electrolyte

Active material

Li+

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Charge/discharge test

2.9

3.2

3.5

3.8

4.1

4.4

0 30 60 90 120

Capacity / mA h g-1

E /

V (L

i / L

i+ )

Cathode: LiMn2O4Anode: Li metalElectrolyte: porous-layered honeycomb LLT / PMMACurrent: 12.5 mA cm-2

Cuf off: 3.0 – 4.3V

3DOM-fomed Hole-array LLT70.8 mA h g-1

Hole-array LLT42.2 mA h g-1

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Full cell preparation procedure

Calcination450 C, 30 min

Calcination450 C, 2 h600 C, 10 h

Vacuum impregnation

Li-Mn-O sol + LiMn2O4

Li-Mn-O sol + Li4Mn5O12

Vacuum impregnation

All-ceramic battery

Calcination450 C, 2 h700 C, 10 h

Calcination450 C, 30min

3 times

3 times

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Operation at room temperature

Operation of all-solid-state rechargeable lithium-ion battery at room temperature

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Li7La3Zr2O12

Li7La3Zr2O12 ( LLZ )

W. Weppner et al., Angew. Chem. Int. Ed., 46 ,1,(2007).

High lithium-ion conductivity (10-4 S cm-1 at R.T.)High stability against lithium-metal

Can lithium-metal (3861 mA h g-1)be used as anode?

New solid electrolyte

Advantages(garnet-like structure)

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Electrochemical window

LLTLLZ

-0.3

-0.2

-0.1

0

0.1

0.2

-0.5 0 0.5 1 1.5 2 2.5 3

1st cycle2nd cycle

I / mA cm-2

E / V

LLZLLT

Redox reaction of Ti

LLT shows the redox reaction of titanium at 1.8 V while LLZ is stable even at 0 V.

E / V vs. Li/Li+

=> Lithium-metal can be used as anode in the LLZ system.

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Li metal / LLZ / LiCoO2 cell

-2.0

-1.0

0.0

1.0

2.0

3.2 3.4 3.6 3.8 4 4.2

E/V vs. Li/Li+I

/ μ

A

Room temperatrue

Scan rate : 1 mV min-1

Cut off : 3.3 – 4.2 V vs. Li / Li+

LLZ pellet

LiCoO2

Li metal

230 C

Redox peaks of LiCoO2 were observed around at 3.9 V vs. Li/ Li+.

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Durability test

-1.0

-0.5

0.0

0.5

1.0

3.2 3.4 3.6 3.8 4 4.2

E/V vs. Li/Li+

I / μ

A

-2.0

-1.0

0.0

1.0

2.0

3.2 3.4 3.6 3.8 4 4.2

E/V vs. Li/Li+

I / μ

A

After a yearAs prepared

Scan rate : 1 mV min-1

Cut off : 3.3 – 4.2 V vs. Li / Li+

The prepared cell stably worked after a year.

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Bipolar-type battery

Bipolar-type battery

Current collector tab

Composite of cathode material and solid electrolyte

Solid electrolyte membrane with hole array structure

Lithium-metal anode

Current collector for anode (carbon/nickel composite)

Cathode material

3DOM structured solid-electrolyte

Honeycomb hole

Solid-electrolyte substrate

Current Collector

TabCell voltage: 200 VEnergy density: > 500 Wh kg-1

Fast charge/discharge: > 10 minHigh safetyLong life

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0

500

1000

1500

2000

0 250 500 750 1000

Lead acid

Nickel‐CadmiumNickel‐Metal Hydride

Gravimetric energy density / Wh kg‐1

Volumetric

 ene

rgy de

nsity

/ WhL‐1

LiCoO2 (LiNi1/3Mn1/3Co1/3O2) / graphite

High capacityelectrode materials

All‐solid‐state(bipolar‐type)

Lithium‐AirLithium‐Sulfur

Energy density

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Conclusions

3D electrode configuration is one of prospective ways toimprove the performance of all-solid-state rechargeablelithium batteries.

For further improvement of cell performance, the following developments areneeded:

• Higher aspect ratio in 3D electrode configuration

• Optimization of electrolyte/electrode interface

• Cell stacking for bipolar-type all-solid-state battery