Supercapacitors are energy storage devices critical to enabling high-power applications such as efficient electric vehicles and compact electronic devices. For these applications, supercapacitors must deliver high energy and power densities. Such devices exploit the combination of electric double layer capacitance (EDLC) and pseudocapacitance. EDLC, which allows for high power densities, operates through the electrostatic adsorption of charges onto high-surface area materials such as carbon fiber and carbon nanotubes (CNTs). On the other hand, pseudocapacitance relies on redox activity provided by metal oxides and redox-active organic materials such as phthalocyanines.However, CNTs are prohibitively costly for mass production. Therefore, much work has gone towards exploring devices based on reduced graphene oxide (rGO), which can be easily solution-processed and derived from low-cost and abundant graphite powder. Supercapacitor devices fabricated from rGO exhibit high capacitance and power densities due to its high electron mobility and high surface area, yet require further optimization to improve its energy densities.To this end, pseudocapacitive materials can be combined with rGO. In particular, the intercalation of conjugated redox-active metal complexes such as dilithium phthalocyanine between graphene sheets is hypothesized to present with synergistic effects. This combination provides a conductive channel for redox reactions to occur in phthalocyanines, while minimizing aggregation effects in rGO, increasing the effective surface area.Composite binderless electrodes fabricated through ultrasonication, acoustic mixing, and subsequent vacuum filtration of rGO sheets with dilithium phthalocyanine yielded a synergistic electrode that exhibits higher power and energy densities relative to the singular components. Various wt% loadings of phthalocyanine on graphene were evaluated for optimal performance. Characterization of the composite electrodes will be presented, including cyclic voltammetry and galvanostatic charge/discharge data to evaluate capacitance and power/energy densities, Raman spectroscopy to verify the reduction of graphene oxide, and scanning electron microscopy (SEM) to evaluate surface morphology.

Dilithium phthalocyanine/graphene binderless composite electrodes for supercapacitors

247th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.