Fuel cells convert hydrogen into heat, electricity and water. They are an environmentally friendly power source. They are gaining immense popularity as primary and backup power sources for residential, commercial, industrial, and transportation applications. To achieve high efficiency, fuel cells require a conductive material for the bipolar plates, gas diffusion layers, and catalysts. Graphite, which is low-cost and has superior mechanical properties, is preferred because it offers high electrical conductivity. But obtaining pure graphite can be difficult due to flake size, and the fact that it's not readily available. Graphene, a form of carbon, is a promising alternative. Although graphene is extremely thin, it has a large surface area that can conduct electrons faster than graphite. This can boost the efficiency of fuel cells.
Currently, there are six scenarios of carbon-based electrode materials evaluated: graphite (scenario 1), graphene/graphite bilayers (scenario 2), and high-temperature gasification (htg) reversible cathode/anode (scenario 3) and deionized water (control) in the anodic and cathodic chambers. Evaluations are performed under batch tests with a temperature of 25°C and an exterior resistance level 100
Modifying the surfaces of electrodes has been done in a variety of ways to improve their performance. One of these techniques is to coat the electrodes in metal oxides. This can enhance the direct electron transfer from microorganisms to the anode and promote growth. Some of these include the additions of carbon nanotubes or conducting polymers, which can increase morphology and surface roughness.
This research uses an automatic pencil stroking machine for graphite electrodes fabrication. It is equipped with graphtec plotter, a force detector and an automatic pencil stroke detection device. The device can maintain the same force applied to the FSR sensor, reducing fabrication time as well as human involvement to achieve uniformity. Additionally, the device is capable of drawing multiple strokes varying in length and force to test for their impact on the graphite adherence and stability.
Raman spectroscopy was used to characterize the graphite electrodes. This allowed their structure to be identified. It was found that they had the G-1581 cm bands assigned to carbon and D-1350 cm bands assigned to disorder. For fuel cell performance, graphene/graphite-bilayers and HTG were compared against their noncoated counterparts. EDX analyses were also performed to evaluate the differences between surface elements compositions of both types electrodes. Results showed that graphite electrodes produced by the automated device were more uniform, accurate, and repeatable than those created manually. The device can also achieve repeatable, high-precision strokes in the 200-300 range with an average force between 2.15 N. This device produces electrodes that can generate a maximum power output of 20 W.
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