Presentation on theme: "Eco-Materials group 空氣電池的開發與應用 Development and Application of Air-battery Speaker : Prof. Chao-Ming Huang (K. S. U.) Department of Materials Engineering."— Presentation transcript:
Eco-Materials group 空氣電池的開發與應用 Development and Application of Air-battery Speaker : Prof. Chao-Ming Huang (K. S. U.) Department of Materials Engineering Dec
Eco-Materials group From:http://euanmearns.com/global-energy-trends-bp-statistical-review-2014/ 2013 Global energy consumption 87% !
Eco-Materials group Statistic of World Energy Petroleum Natural Gas Coal From:http:/ BP Statistical Review of World Energy /
Eco-Materials group What is a hydrogen fuel cell ? Hydrogen fuel cells (HFCs) are a type of electrochemical cell. HFCs generate electricity by reduction and oxidation reactions within the cell. They use three main components, a fuel, an oxidant and an electrolyte. HFCs operate like batteries, although they require external fuel. HFCs are a thermodynamically open system. HFCs use hydrogen as a fuel, oxygen as an oxidant, a proton exchange membrane as an electrolyte, and emit only water as waste.
Eco-Materials group Different type of fuel cell comparsion
Eco-Materials group Fuel (H 2 ) is first transported to the anode of the cell Fuel undergoes the anode reaction Anode reaction splits the fuel into H+ (a proton) and e- Protons pass through the electrolyte to the cathode Electrons can not pass through the electrolyte, and must travel through an external circuit which creates a usable electric current Protons and electrons reach the cathode, and undergo the cathode reaction How do they work?
Eco-Materials group Zn-Air Chemistry Schematic representation of Zn-air cell operation:
Eco-Materials group Zn-Air Applications Commercial, primary Zn-air batteries have been used for many years: –Initially used as large batteries for applications such as railroad signaling, remote communications, and ocean navigational units requiring long term, low rate discharge. –With the development of thin electrodes, used in small, high capacity primary cells, such as for hearing aids, small electronics, and medical devices.
Eco-Materials group Refuelable Zn-Air Cells Santa Barbara Municipal Transit District “Downtown Waterfront Electric Shuttle” Powered by refuelable Zn-air cells. Road test underscored potential of such vehicles. –250 mile range between refueling –Rapid refueling (10 minutes) –Highway safe acceleration
Eco-Materials group Refuelable Zn-Air cells
Eco-Materials group Summary Primary Zn-air batteries have been very successful commercially. To take the technology to the next level, i.e, developing secondary, electrically rechargeable batteries, or using Zn-air technologies for vehicle propulsion, significant challenges must still be overcome: –Understand the chemistry of the zincate anion in an alkaline solution. –Develop stable bifunctional catalysts for both the oxygen reduction reaction and oxygen evolution reaction. –The air electrode should be optimized to reduce internal resistance.
Eco-Materials group Current Battery Outlook Metal-air batteries have attracted much attention recently as a possible alternative, due to their extremely high energy density compared to that of other rechargeable batteries:
Eco-Materials group Extremely high specific capacity of Li anode material (3842 mAh g ‑ 1 for lithium, vs. 815 mAh g -1 for Zinc) The couple voltage of Li-O 2 in alkaline electrolytes is 2.91 V (compared to 1.65 for Zn-O 2 ) The Li-air battery, when fully developed, could have practical specific energies of 300 Wh kg -1 Li-air cell electrically rechargeable Why Li-air ?
Eco-Materials group Different type of battery comparsion
Eco-Materials group Secondary Li-Air Cells How are Li-air cells rechargeable? In 2006, Bruce et al. demonstrated that Li 2 O 2 is formed on charging and decomposes according to the reaction below: Li (s) → Li + + e - (anode reaction) Li + + ½O 2 + e - → ½Li 2 O 2 (cathode reaction) Li + + e - + ¼O 2 → ½Li 2 O (cathode reaction) Li 2 O 2 → O 2 + 2Li + + 2e -
Eco-Materials group Li - air Architectures From: 锂空气电池多孔碳电极材料的制备及性能研究
Eco-Materials group The critical differences between Li-ion and Li-Air are: Li-Air battery is an open system, because of oxygen is obtained from air catalyst O2O2 O 2 + 2H 2 O + 2e - 4OH - Discharge ( Oxygen Reduction Reaction ) Charge ( Oxygen Evolution Reaction ) Anode: Cathode: Configuration of Li - air
Eco-Materials group MnOx based catalysts Nano--structure has higher capacity, duo to high surface area The structure of α- MnO 2 possesses 2x2 tunnels a rate of 70 mA/cm 2 & 1 atm O 2 Capacity can achieve ~3000 mAh/g Catalysts will not only affect ORR & OER potential, but they also influence the specific capacity MnO 2 is the most common ORR catalyst for metal-air battery, because it is cheap & stable; Besides, their ORR-catalytic activity (ORR poential ~ 2.6 V) can compare with most efficient catalyst—Pt( 2.6 V) The Bruce group had investigated various MnO x catalysts( α,β,γ, -MnO 2 & Mn 2 O 3, Mn 3 O 4 )
Eco-Materials group Air Electrode Requirements Cathode must be able to sustain an oxygen reduction reaction (and oxidation if battery is rechargeable). Cathode must be highly porous. Catalysts are typically incorporated into the carbon layer.
Eco-Materials group Most metals are unstable in water and react with the electrolyte to corrode the metal, resulting in self-discharge. Electrode carbonation: Absorption of CO 2 (since the cell is an open system), results in crystallization of carbonate in the air electrode, clogging pores and decreasing performance. Water transpiration: Movement of water vapor either into or out of the cell. –Excessive water loss can lead to drying of the cell and premature failure. –Excessive gain of water can dilute the electrolyte. Factors that affect performance
Eco-Materials group 22 LaMnO 3 Perovskite system oxygen reduction reaction (ORR) good redox properties, thermochemical stability, tunable catalytic performance. P123 (Triblock Copolymer) Template Journal of the Taiwan Institute of Chemical Engineers 45 (2014) 2334–2339 (SCI, IF = 2.637)
Eco-Materials group 23 P123. ↑ specific surface area. ↑ pore volume. ↑ irregular ↓ foamy structure ↓ very fine particles macroporous mesoporous
Eco-Materials group 24 Discharge voltages ↑ LMP-20, 1.158V LMP-10, 1.158V LMP-6, 1.140V LMP-2, 1.128V LM, 1.090V 25 mA/cm s/cycle Energy density = 885 W h/kg(Zn consumption) current density =25 mA/cm 2 discharge voltage = 1.18 V ↑ cycling stability ↑ discharge voltage V→1.158 V pure phase. LaMnO 3 large surface area. 2.8X high pore volume. 4X
Eco-Materials group (μ m)(mm) star-MnO 2 /SS 庫倫效率 =60% Pure-SS ElementWeight% C K4.99 O K32.15 Na K5.04 S K3.30 Cr K3.14 Mn K41.54 Fe K9.84 Totals Ch-dis: 10mA Time: 5 min
Eco-Materials group From: 北京國信博研信息中心 Global air battery prediction
Eco-Materials group New Tesla Patent: 400-Mile Battery Pack Using Metal-Air & Lithium-Ion Batteries
Eco-Materials group Aluminium Zinc Lithium Air Battery System 1) 2) 3) From: 北京國信博研信息中心
Eco-Materials group New Tesla Patent: Electric Vehicle Extended Range Hybrid Battery Pack System ▪ Patent : US ▪ A power source comprised of a first battery pack (e.g., a non-metal-air battery pack) and a second battery pack (e.g., a metal-air battery pack) is provided, wherein the second battery pack is used when the user selects an extended range mode of operation. Minimizing use of the second battery pack prevents it from undergoing unnecessary, and potentially lifetime limiting, charge cycles. Abstract From:http://www.google.com/patents/US
Eco-Materials group Conclusions Metal-air batteries offer great benefits if they can be harnessed to their fullest potential. Recap of Zn-air vs. Li-air: