Osaka Prefecture University, Japan 1

Kiyoharu TADANAGA, Akitoshi HAYASHI and Masahiro TATSUMISAGODepartment of Applied Chemistry, Graduate School of Engineering,

Osaka Prefecture University, Japan

Mario Aparicio, Alicia Durán, Yolanda Castro, and Francisco MuñozInstituto de Cerámica y Vidrio (ICV), Consejo Superior de Investigaciones

Científicas (CSIC), Spain

Development of New Electrolyte and Electrode Materials for All-Solid-State Thin Film Lithium

Batteries through Solution Process

SJ-nano symposium, Tsukuba, March 5, 2013

Osaka Prefecture University, Japan 2

Members of the projectOsaka Prefecture University

Professor Masahiro Tatsumisago (Leader)Associate Professor Kiyoharu TadanagaAssistant Professor Akitoshi Hayashi1 Post-Doc, 2 Ph-D students, 1 Master course student 1 Research assistant

Consejo Superior de Investigaciones Científicas (CSIC), Instituto de Cerámica y Vidrio (ICV)

Dr. Mario Aparicio (Leader)Professor Alicia DuránDr. Yolanda CastroDr. Francisco Muñoz1 Post-doc, 1 Ph-D student,

Osaka Prefecture University, Japan 3

Solid Electrolyte

Substrate

Negative Electrode

Positive Electrode

Thin-film battery

10 μm

Thin film lithium batteries will be used in things like smart cards, RFID tags, and other low power portable devices.

Possible application of thin film lithium batteries

Osaka Prefecture University, Japan 4

Large area and good quality, or nano-structured thin films can be prepared

Chemical compositions of thin films can be controlled.Rather thick films are easily obtained.

Examples of preparation of thin film batteries by physical processesSputtering・・・LiCoO2, LiMnO2, LiPON（lithium phosphate oxynitride）…Pulse Laser Deposition・・・ LiCoO2, LiMnO2, Li-V-Si-O amorphous thin film

Advantages of solution processes

Electrode and electrolyte thin films for all-solid-state lithium rechargeable batteries

Solution processes are very attractive for the development of thin film batteries.

Thin film battery is an important element in realizing next-generation sheet devices, as it needs to be formed as a small, thin-film device.

Osaka Prefecture University, Japan 5

Our project attempts to develop electrolyte and electrode materials for all-solid-state thin film lithium batteries using solution processes, as a clean and efficient energy production and storage device.

Safe, thin-film lithium secondary cells which are free from such hazards as liquid leakage and/or fires will be developed by employing electrolytes prepared from inorganic or inorganic-organic hybrid solid-state materials by using solution processes.

Purpose of our project

Osaka Prefecture University, Japan 6

Positive electrodesOPU: LiMn2O4

Solid electrolyteOPU: Li7La3Zr2O12

Li1.5Al0.5Ge1.5(PO4)3CSIC: organic-inorganic hybrid

Negative electrodesOPU: Li4Ti5O12CSIC: Li4Ti5O12

Current collector: Au

Current collector: AuSubstratePt, Au, Ti, Pt/Si,SiO2 glass, , etc.

Conceptual schematic of this project

Multi layered battery

Further development

Micro patterning

Osaka Prefecture University, Japan 7

Solution-based processes used in OPU, for the preparation of electrode and electrolyte thin films

・Sol-gel process・Mist-CVD process・Electrophoretic deposition of particles prepared by sol-gel・Aerosol deposition of particles prepared by sol-gel

Solution-based processes used in OPU, for the preparation of electrode and electrolyte thin films

・Sol-gel process・Mist-CVD process・Electrophoretic deposition of particles prepared by sol-gel・Aerosol deposition of particles prepared by sol-gel

Solution-based processes

Osaka Prefecture University, Japan 8

Mist CVD processMist CVD process

Features1. This process does not need vacuum systems because it is operated at atmospheric conditions. 2. Various precursor solutions can be used for the source, including innocuous and nonpoisonous ones.3. This process possesses various advantages such as: safety, cost-effectiveness, environmentally friendly, and the ability to apply to various types of materials.

In the mist CVD process, aqueous solution of starting material is ultrasonically atomized to form mist particles with a size of about 3 μm, and mists are transferred by a carrier gas to the substrate to form thin films.

MassFlowmeter

Gas

PrecursorSolution

Water

Ultrasonic transducer

Liner source nozzle

SubstrateStage and heater

Osaka Prefecture University, Japan 9

Preparation of LiMn2O4 thin films by mist-CVD processPreparation of LiMn2O4 thin films by mist-CVD process0.06M Mn(OCOCH3) 2.4H2O+ 0.033M Li( OCOCH3)

Molar ratio (Li : Mn=1.1:2)

Heat-treated at 500-800oC for 1h

Flow rates 8 L/minSubstrate temperature 200-400oC

Substrates

LiMn2O4 has advantages of low-cost, environmental friendliness, and high abundance.LiMn2O4 thin films

Osaka Prefecture University, Japan 10

LiMn2O4 thin films (substrate temperature: 200oC)LiMn2O4 thin films (substrate temperature: 200oC)

As prepared

10 20 30 40 50 60 70 80

After heat treatment at 700℃

Inte

nsity

( arb

.uni

t

2 θ / o (CuKα)

750 nm

5 μm

As prepared by mist-CVD process

After the heat treatment at 700oC

1 μm

750 nm

JCPDS LiMn2O4Au/SiO2 substrate

Spinel type LiMn2O4 single-phase thin film was obtained.

Osaka Prefecture University, Japan 11

Electrochemical behavior of heat-treated LiMn2O4 thin filmElectrochemical behavior of heat-treated LiMn2O4 thin film

0 20 40 60 80 1002.5

3

3.5

4

4.5

Capacity/mAhg-1

25 C, 0.05 mA cm-2

Cel

l vol

tage

/V( L

i+ /Li

)

1st~10th

1st~10th

beaker cell with three electrodes

W.E. LiMn2O4Film

R. E. Li film

C.E .Li film

electrolyte1 M LiPF6 (EC+DEC)

The LiMn2O4 thin-film electrode produced with the mist CVD method- Capacity is 80 mAhg-1

- Good cycle performance

Osaka Prefecture University, Japan 12

0.5

1

1.5

2

2.5

3

0 20 40 60 80 100 120

Charge-discharge behavior of Li4Ti5O12 thin films prepared by the mist-CVD

Capacity / mAh g-1

25 ℃, 0.1 mA cm-2

Ceｌｌ

pote

ntial

vs . L

i / V

10 th←1 st

1 st10 th←2 nd

500 nm

Substrate temperature :400 oC + Heat-treatment at 700 oC for 1 h

[Li] = 0.02 M, [Ti] = 0.025 M

Thick film with cracks showed good cycle performance.

beaker cell with three electrodes

W.E. Li4Ti5O12Film

R. E. Li film

C.E .Li film

electrolyte1 M LiPF6 (EC+DEC)

Osaka Prefecture University, Japan 13

Solid electrolyte for thin film battery

Li1.5Al0.5Ge1.5(PO4)3 (LAGP) electrolyte can be prepared with a rather low sintering temperature.

Preparation of Li1.5Al0.5Ge1.5(PO4)3 thin films by mist-CVD processPreparation of Li1.5Al0.5Ge1.5(PO4)3 thin films by mist-CVD process

Electrolyte thin films are formed on electrode thin films => low temperature synthesis is expected.

Osaka Prefecture University, Japan 14

XRD pattern of the LAGP thin films

10 20 30 40 50 60 70 80

Sintering at 800oCfor 2 h

Inten

sity(

arb.u

nit

As-prepared

2 θ/° (CuKα)

LAGP

Sintering at 700oCfor 2 h

Sintering at 600oCfor 2 h

( Stage temperature:400 oC)- Peaks due to LAGP were observed in the as-prepared thin film.

- crystallinity increases with an increase in heat treatment temperature.

- LAGP phase was obtained as single-phase.

Osaka Prefecture University, Japan 15

1000T-1K-1

Cond

uctiv

ity /

S cm

-1

2 2.5 3 3 .5

Heat treatment temperature600oC

Ionic conductivity of the LAGP thin film

Conductivity in room temperature: about 2x10-6 S cm-1

Activation energy of conduction: About 40 kJ mol-1

10-6

10-5

10-4

10-3

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Osaka Prefecture University, Japan 18

ConclusionsConclusions

・ LiMn2O4 cathode thin films, Li4Ti5O12 anode thin films, and Li1.5Al0.5Ge1.5(PO4)3(LAGP) solid electrolyte thin films were prepared by the mist CVD process.

・ Li4Ti5O12 anode thin films were prepared by a sol-gel process.

・New lithium ion conductive inorganic-organic hybrid was developed.