Hybrid Carbon-Polymer Supercapacitors for High Energy Storage and Power Delivery

Drexel University, Philadelphia PA

Investigators

Abstract

This project aims to develop enhanced energy storage devices, in particular, supercapacitors, that can store large amounts of energy or charge per unit weight of the material and deliver them at high power. The ability to store large amounts of charge will enable their use in high-demand applications such as electric and hybrid vehicles. High power will ensure that these devices can be charged at a fast rate with charging times of a few seconds to a few minutes (unlike rechargeable batteries that require several hours for charging). The potential improvement in energy storage attributes will, for example, contribute very significantly to technology that supports electric vehicles. This project will provide two PhD graduate and several undergraduate students with an interdisciplinary educational experience in nanomaterials and renewable energy. The specific research objective of this project is to fabricate and study process-structure-performance correlation in a novel hybrid supercapacitor electrode composed of porous carbon-electroactive polymer core-shell nanofibers. The fabrication will be conducted via a simple two-step process. In Step 1, nanofibers of blends of two polymers; carbon precursor and sacrificial polymer, will be fabricated via electrospinning followed by high temperature pyrolysis to convert the carbon precursor to carbon and decompose out the sacrificial polymer, resulting in hierarchically-porous carbon nanofibers exhibiting high specific surface area (>1500 m2/g). In Step 2, the porous carbon nanofibers will be shrink-wrapped with an ultrathin shell of conducting polymer of thiophene, pyrrole or aniline using a novel "liquid-free" chemical vapor deposition (CVD) approach. The aim is integrate electric double layer capacitance from porous carbon nanofibers with pseudocapacitance from thin and conformal polymer coatings to achieve synergistic performance effects including optimized energy density and power delivery and improved cycling performance. Collaboration with industrial partners will enable a feasible path for future manufacturing.