[1] The storage of CO 2 in deep subsurface porous rocks is being developed worldwide for the mitigation of emission from large industrial sources such as power plants and steel manufacturing. A main concern of this technology is in ensuring that the upwardly buoyant CO 2 does not migrate to the surface. Simulation studies suggest that substantial amounts of CO 2 can be trapped within permeable sections of a reservoir by capillary forces and intra-reservoir heterogenities, but there is little experimental observation of these phenomena. We report the results of CO 2 core flooding experiments at high pressure and temperature performed to investigate the impact of natural capillary heterogeneity in a sandstone rock on CO 2 saturation buildup and trapping. CO 2 and water were injected through a Mt. Simon sandstone core at 9 MPa pore pressure and 50°C. The core had two regions of distinct capillarity: An upstream 10 cm long region of the core consisted of a relatively high permeability and homogenous sand. A downstream 3 cm long region of the core consisted of a low permeability region characterized by significant crossbedding and a high capillary entry pressure for CO 2 . During a drainage process of CO 2 displacing water, CO 2 builds up upstream of the capillary barrier. Once in place, CO 2 on the upstream side of the barrier cannot be displaced during 100% water flooding leading to trapped saturations that are a factor 2-5 times higher than what would be expected from residual trapping alone.

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A flexible solid-state supercapacitor based on vapor phase polymerized (VPP) PEDOT into cellulose paper matrix (PEDOT/CP) was successfully fabricated. The PEDOT/CP composite material worked as both current collector and electrode in constructed test cells. It had a low sheet resistance of 14 Ω/square and survived the Scotch tape test for adhesion. It also showed excellent stability with no significant conductivity drop after 1000 cycles of bending. The PEDOT from electrode obtained the mass specific capacitance of 179 F/g at scan rate of 10 mV/s, which was among the highest specific capacitances ever reported. This high capacitance was attributed to the combination of the VPP technique and the porous fibrous structure of the cellulose matrix. The EDOT vapor penetrated and polymerized through the CP matrix made of nanometer to micrometer level CP fibers. The highest electrode volumetric capacitance achieved was 13.7 F/cm3. The whole device achieved an energy density of 0.76 mWh/cm3 and a power density of 0.01 W/cm3. Bending the supercapacitor to 90° or rotating to 45° caused no major change in capacitance. Owing to the all nonmetallic materials used to construct the supercapacitor, it can be easily disposed. The incineration of the supercapacitor does not release significant hazardous exhaust.

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