Surface Modification Effect and Electrochemical Performance of LiOH-High Surface Activated Carbon as a Cathode Material in EDLC

Electrochemical and Catalytic Properties of Carbon Dioxide-Activated Graphite Felt

The commercial graphite felt GFA 10 was subjected to an activation process with the use of CO₂ at 900 °C for 35 and 70 min. Pristine and heat-treated materials were characterized using various methods: low-temperature N₂ adsorption, SEM, and EDS. Voltammetric measurements of GFA samples (before and after activation) as the working electrode were carried out. Voltammograms were recorded in aqueous solutions of 4-chlorophenol and sodium sulfate as supporting electrolyte. The catalytic activity of GFA samples in the process of 4-chlorophenol oxidation with the use of H₂O₂ was also investigated. The influence of graphite felt thermal activation in the CO₂ atmosphere on its electrochemical and catalytic behavior was analyzed and discussed. Results of the investigation indicate that GFA activated in CO₂ can be applied as an electrode material or catalytic material in the removal of organic compounds from industrial wastewater. However, the corrosion resistance of GFA, which is decreasing during the activation, needs to be refined.

Evaluation of Activated Carbon and Platinum Black as High-Capacitance Materials for Platinum Electrodes

The application of direct current (DC) produces a rapid and reversible nerve conduction block. However, prolonged injection of charge through a smooth platinum electrode has been found to cause damage to nervous tissue. This damage can be mitigated by incorporating high-capacitance materials (HCM) (e.g., activated carbon or platinum black) into electrode designs. HCMs increase the storage charge capacity (i.e., “Q value”) of capacitive devices. However, consecutive use of these HCM electrodes degrades their surface. This paper evaluates activated carbon and platinum black (PtB) electrode designs in vitro to determine the design parameters which improve surface stability of the HCMs. Electrode designs with activated carbon and PtB concentrations were stressed using soak, bend and vibration testing to simulate destructive in vivo environments. A Q value decrease represented the decreased stability of the electrode–HCM interface. Soak test results supported the long-term Q value stabilization (mean = 44.3 days) of HCM electrodes, and both HCMs displayed unique Q value changes in response to soaking. HCM material choices, Carbon Ink volume, and application of Nafion™ affected an electrode’s ability to resist Q value degradation. These results will contribute to future developments of HCM electrodes designed for extended DC application for in vivo nerve conduction block.