SJ-nano symposium, Tsukuba, March 5, 2013 Development of New Electrolyte and Electrode Materials for All-Solid-State Thin Film Lithium Batteries through Solution Process Kiyoharu TADANAGA, Akitoshi HAYASHI and Masahiro TATSUMISAGO Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Japan Mario Aparicio, Alicia Durán, Yolanda Castro, and Francisco Muñoz Instituto de Cerámica y Vidrio (ICV) , Consejo Superior de Investigaciones Científicas (CSIC), Spain Osaka Prefecture University, Japan 1
Members of the project Osaka Prefecture University Professor Masahiro Tatsumisago (Leader) Associate Professor Kiyoharu Tadanaga Assistant Professor Akitoshi Hayashi 1 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 Durán Dr. Yolanda Castro Dr. Francisco Muñoz 1 Post-doc, 1 Ph-D student, Osaka Prefecture University, Japan 2
Thin-film battery Thin film lithium batteries will be Solid Electrolyte Negative Electrode used in things like smart cards, 10 μ m RFID tags, and other low power Substrate portable devices. Positive Electrode Possible application of thin film lithium batteries Osaka Prefecture University, Japan 3
Electrode and electrolyte thin films for all-solid-state lithium rechargeable 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. Examples of preparation of thin film batteries by physical processes Sputtering ・・・ LiCoO 2 , LiMnO 2 , LiPON （ lithium phosphate oxynitride ） … Pulse Laser Deposition ・・・ LiCoO 2 , LiMnO 2 , Li-V-Si-O amorphous thin film Advantages of solution processes � 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. Solution processes are very attractive for the development of thin film batteries. Osaka Prefecture University, Japan 4
Purpose of our project 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. Osaka Prefecture University, Japan 5
Conceptual schematic of this project Current collector: Au Positive electrodes OPU: LiMn 2 O 4 Negative electrodes OPU: Li 4 Ti 5 O 12 CSIC: Li 4 Ti 5 O 12 Substrate Solid electrolyte Current collector: Au Pt, Au, Ti, Pt/Si, OPU: Li 7 La 3 Zr 2 O 12 SiO 2 glass, , etc. Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 CSIC: organic-inorganic hybrid Further development Multi layered Micro patterning battery Osaka Prefecture University, Japan 6
Solution-based processes Solution-based processes used in OPU, for the preparation Solution-based processes used in OPU, for the preparation of electrode and electrolyte thin films of electrode and electrolyte thin films ・ Sol-gel process ・ Sol-gel process ・ Mist-CVD process ・ Mist-CVD process ・ Electrophoretic deposition of particles prepared by sol-gel ・ Electrophoretic deposition of particles prepared by sol-gel ・ Aerosol deposition of particles prepared by sol-gel ・ Aerosol deposition of particles prepared by sol-gel Osaka Prefecture University, Japan 7
Mist CVD process Mist CVD process In the mist CVD process, aqueous solution of starting material is ultrasonically atomized to form mist particles with a size of about 3 μ m, and mists are transferred by a carrier gas to the substrate to form thin films. Liner source nozzle Mass Flowmeter Precursor Gas Solution Water Stage and heater Substrate Ultrasonic transducer Features 1. 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. Osaka Prefecture University, Japan 8
Preparation of LiMn 2 O 4 thin films by mist-CVD process Preparation of LiMn 2 O 4 thin films by mist-CVD process 0.06M Mn(OCOCH 3 ) 2 .4H 2 O + 0.033M Li( OCOCH 3 ) Molar ratio (Li : Mn=1.1:2) Flow rates 8 L/min Substrate temperature 200- 400 o C Substrates Heat-treated at 500-800 o C for 1h LiMn 2 O 4 has advantages of low-cost, environmental LiMn 2 O 4 thin films friendliness, and high abundance. Osaka Prefecture University, Japan 9
LiMn 2 O 4 thin films (substrate temperature: 200 o C) LiMn 2 O 4 thin films (substrate temperature: 200 o C) As prepared by mist-CVD process 5 μ m JCPDS LiMn 2 O 4 Au/SiO2 As prepared substrate Intensity( arb.unit 1 μ m After heat treatment After the heat treatment at 700 ℃ at 700 o C 750 nm 750 nm 10 20 30 40 50 60 70 80 2 θ / o (CuK α ) Spinel type LiMn 2 O 4 single-phase thin film was obtained. Osaka Prefecture University, Japan 10
Electrochemical behavior of heat-treated LiMn 2 O 4 thin film Electrochemical behavior of heat-treated LiMn 2 O 4 thin film 4.5 1st~10th beaker cell with three electrodes Cell voltage/V( Li + /Li) 4 R. E. Li film 3.5 25 C, 0.05 mA cm -2 1st~10th W.E. C.E . LiMn 2 O 4 Li film Film 3 electrolyte 2.5 0 20 40 60 80 100 1 M LiPF 6 (EC+DEC) Capacity/mAhg -1 The LiMn 2 O 4 thin-film electrode produced with the mist CVD method - Capacity is 80 mAhg -1 - Good cycle performance Osaka Prefecture University, Japan 11
Charge-discharge behavior of Li 4 Ti 5 O 12 thin films prepared by the mist-CVD Substrate temperature :400 o C + Heat-treatment at 700 o C for 1 h [Li] = 0.02 M, [Ti] = 0.025 M beaker cell with three electrodes 3 Ce ｌｌ potential vs . Li / V 500 nm 2.5 R. E. 10 th ← 1 st Li film 2 W.E. C.E . Li 4 Ti 5 O 12 Li film 1.5 Film 1 10 th ← 2 nd 1 st electrolyte 25 ℃ , 0.1 mA cm -2 1 M LiPF 6 (EC+DEC) 0.5 0 20 40 60 80 100 120 Capacity / mAh g -1 Thick film with cracks showed good cycle performance. Osaka Prefecture University, Japan 12
Preparation of Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 thin films by mist-CVD process Preparation of Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 thin films by mist-CVD process Solid electrolyte for thin film battery Electrolyte thin films are formed on electrode thin films => low temperature synthesis is expected. Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 (LAGP) electrolyte can be prepared with a rather low sintering temperature. Osaka Prefecture University, Japan 13
XRD pattern of the LAGP thin films LAGP As-prepared ( Stage temperature:400 o C) - Peaks due to LAGP were observed in the as-prepared thin film. Intensity( arb.unit Sintering at 600 o Cfor 2 h - LAGP phase was obtained as Sintering at 700 o Cfor 2 h single-phase. Sintering at 800 o Cfor 2 h - crystallinity increases with an increase in heat treatment temperature. 10 20 30 40 50 60 70 80 2 θ / ° (CuK α ) Osaka Prefecture University, Japan 14
Ionic conductivity of the LAGP thin film 10 -3 Conductivity / S cm -1 Conductivity in room temperature : about 2x10 -6 S cm -1 10 -4 Activation energy of conduction : About 40 kJ mol -1 10 -5 Heat treatment temperature 600 o C 10 -6 2 2.5 3 3.5 1000T -1 K -1 Osaka Prefecture University, Japan 15
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Conclusions Conclusions ・ LiMn 2 O 4 cathode thin films, Li 4 Ti 5 O 12 anode thin films, and Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 (LAGP) solid electrolyte thin films were prepared by the mist CVD process. ・ Li 4 Ti 5 O 12 anode thin films were prepared by a sol-gel process. ・ New lithium ion conductive inorganic-organic hybrid was developed. Osaka Prefecture University, Japan 18
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