DESIGN OF MULTIFUNCTIONAL GRAPHENE NANOMATERIALS FOR SUPERCAPACITOR

超级电容器具有许多高冲击特性，例如快速充电、长充放电周期和宽工作温度范围，因此在混合动力或电动汽车、电子产品、飞机和智能电网中得到广泛应用。美国能源部也对超级电容器和电池给予了同样的重视。目前，低能量容量和受材料性能限制的循环稳定性极大地限制了它们的实际应用。本文提出了一种提高超级电容器电容、能量密度和稳定性的解决方案，即通过(1)石墨烯的合成、活化和氮掺杂来提高离子可及性和电子输运；(2)用水溶性巯基控制石墨烯的表面功能化，以定制石墨烯的表面性能。再配以导电聚合物和金属氧化物赝电容材料；(3)新颖的单层3D组装石墨烯与导电聚合物和金属氧化物形成独立薄膜，并集成电化学双层和伪电容机制，提高能量密度。所提出的先进多功能石墨烯纳米材料将具有独特的形态和多种长度尺度的尺寸，结合了传统活性炭和其他用于超级电容器电极的碳材料所不具备的许多显着特性。

Supercapacitors have a number of high-impact characteristics, such as fast charging, long charge-discharge cycles and broad operating temperature ranges, leading to widespread applications in hybrid or electrical vehicles, electronics, aircrafts, and smart grids for energy storage. The US Department of Energy has also assigned the same importance to supercapacitors and batteries. Currently, low energy capacities and cycle stability limited by materials performance have dramatically inhibited their practical applications. In this proposal, we propose a solution to improve the capacitance, energy density, and stability of supercapacitor by strategic designing multi-functional graphene materials through (1)Synthesis, activation and nitrogen doping of graphene to increase ion accessibility and electron transport; (2) Controlled surface functionalization of graphene with water-soluble sulfophenyl groups to tailor the surface properties of graphene. Then coupled with conducting polymers and metal oxide pseudocapacitoance materials; (3) Novel layer by layer 3D assembly graphene with conducting polymers and metal oxide to form a free-standing film and integrate electrochemical double layer and pseudocapacitive mechanisms to improve energy density. The proposed advanced multifunctional graphene nanomaterials will have a unique morphology with dimensions at multiple length scales that combine a number of remarkable properties unavailable from conventional activated carbon and other carbon materials for supercapacitor electrodes.