Fundamental Studies on Novel Double Layer Capacitors

电化学电容器（EC）能源技术，包括双电层电容器（DLC）和电化学双电层电容器（EDLC）在电动汽车（EV）或混合动力汽车中具有很好的潜力。EC最重要的优点是其高功率和能量密度。EC的其他优点包括循环寿命长（100，000 - 1，000，000次循环）和免维护性。EC的能量密度主要取决于比电容和施加的电压。EC的最大电容受电解质中离子浓度的限制。提高电化学电容器的能量密度的关键在于提高电解质的电化学窗口和离子浓度，以及改善金属氧化物膜中的传质。项目目标包括：新型电极的开发：将研究由碳和金属氧化物纳米膜组成的复合电极。新型电解质的开发：将研究有机液体作为电解质。充放电机制之模拟与研究。目前用于电致变色的金属氧化物薄膜厚度仅为微米级，制备工艺复杂。本研究提出一种新颖的氧化膜处理方法。该方法通过将金属吸附到活性炭上，再将其改性为金属氧化物，制备出纳米级厚度的金属氧化物膜，具有高能量密度和低内阻的特点，并进行了理论分析和初步实验，计算出了比能量。使用离子液体的电化学电容器单元获得1600-2000 Wh/kg的理论能量密度。预计本提案中概述的目标将导致开发具有高功率和能量密度的新电容器。

Electrochemical capacitor (EC) energy technologies, including double layer capacitor (DLC) and electrochemical double layer capacitor (EDLC) have promising potential in electric vehicles (EV) or hybrid vehicles. The most important advantages of EC are their high power and energy densities. Other EC advantages include long cycle life (100,000 - 1,000,000 cycles) and maintenance-free property.The energy density of EC mainly depends on specific capacitance and applied voltage. The maximum capacitance of EC is limited by the concentration of ions in the electrolyte. The key to increase the energy density of the electrochemical capacitors seems to rest in the increases in the electrochemical windows and ionic concentrations of the electrolytes, and improvement of mass transfer in metal oxide film. The project objectives include: Development of novel electrodes: Composite electrodes composed of carbon and nano-film of metal oxide will be investigated. Development of novel electrolytes: Organic liquids as electrolytes will be investigated. Modeling and investigation of charge-discharge mechanisms. Current metal oxide film used in EC has micrometer thickness and the fabrication is complicated. In this research, a novel oxide film processing method is proposed. By adsorbing metal to activated carbon and then modifying it to metal oxide, the new method will produce nano-meter-thick metal oxide film, having high energy density and low internal resistance.The theoretical analysis and preliminary experiments were conducted and specific energy was calculated. Theoretical energy density of 1600-2000 Wh/kg was obtained for electrochemical capacitor unit using ionic liquids.It is anticipated that the goals outlined in this proposal will lead to the development of a new capacitor with high power and energy densities.