High performance PVDF HFP_RuO2 supercapacitors production by supercritical drying

The use of a supercritical CO2 assisted drying process for the preparation of RuO2 nanoparticles loaded PVDF HFP aerogels is reported in this work. Morphological, mechanical, and electrochemical analyses were performed on the obtained nanocomposites, to ascertain their performance as supercapacitor devices. The supercritical process allowed a homogeneous distribution of the additive in the polymeric matrix and avoided gel shrinkage. Cycling voltammetry and charge/discharge measurements demonstrated an excellent behavior for the nanocomposites. The supercapacitor, at 60% w/w RuO2, exhibited a specific capacitance of 149.3 F/g at a scan rate of 10 mVs−1, and a Coulombic efficiency of 98%. Through the integration of the discharge curves, the specific capacitances were also calculated. In particular, doubling the current density, e.g., from 1.0 A/g to 2.0 A/g, the specific capacitance only reduced of about 20%.