▎ 摘　　要

NOVELTY - A flexible sodium ion capacitor comprises aluminum-plastic film (I), positive electrode (I), separator (I), a negative electrode, separator (II), positive electrode (II), and aluminum-plastic film (II), stacked sequentially and corrugatedly, and a sodium ion organic electrolyte filled in between. The positive electrodes are made of activated-carbon-modified flexible self-supporting graphene composite paper capacitor type active material. The material of the negative electrode (I) is an oxygen defect self-doped flexible self-supporting titanate nano array. USE - Flexible sodium ion capacitor is used in energy storage device. ADVANTAGE - The flexible sodium ion capacitor has short carrier diffusion path, excellent conductivity, and improved rate, cycle performance, capacitance, power density, energy density, and service life. The capacitor can be synthesized and assembled by a simple, environmentally-friendly and economical method. DETAILED DESCRIPTION - A flexible sodium ion capacitor comprises aluminum-plastic film (I), positive electrode (I), separator (I), a negative electrode, separator (II), positive electrode (II), and aluminum-plastic film (II), stacked sequentially and corrugatedly, and a sodium ion organic electrolyte filled in between. The positive electrodes are made of activated-carbon-modified flexible self-supporting graphene composite paper capacitor type active material. The material of the negative electrode (I) is an oxygen defect self-doped flexible self-supporting titanate nano array of formula: MxTiyOz-a, where M is sodium, potassium, calcium or magnesium. An INDEPENDENT CLAIM is included for preparation of capacitor.