a r t i c l e i n f o High-performance microbial fuel cell (MFC) air cathodes were constructed using a combination of inexpensive materials for the oxygen reduction cathode catalyst and the electrode separator. A poly(vinyl alcohol) (PVA)-based electrode separator enabled high coulombic efficiencies (CEs) in MFCs with activated carbon (AC) cathodes without significantly decreasing power output....

Catalysts and catalyst binders are significant portions of the cost of microbial fuel cell (MFC) cathodes. Many materials have been tested as aqueous cathodes, but air-cathodes are needed to avoid energy demands for water aeration. Packed-bed air-cathodes were constructed without expensive binders or diffusion layers using four inexpensive carbon-based materials. Cathodes made from activated ca...

Fluorinated quaternary ammonium-containing polymers were used as catalyst binders in microbial fuel cell (MFC) cathodes. The performance of the cathodes was examined and compared to NAFION and other sulfonated aromatic cathode catalyst binders using linear sweep voltammetry (LSV), impedance spectroscopy, and performance tests in single chamber air-cathode MFCs. The cathodes with quaternary ammo...

Field emission cathodes are being considered for use on low-power electrostatic and electromagnetic propulsion systems as well as on electrodynamic tether systems. In these systems, field emission cathodes prevent negative spacecraft charging by emitting a lowpower electron beam that is accommodated by the ambient plasma. Prototype cathodes were tested at the University of Michigan as part of a...

Activated carbon (AC) is a cost-effective catalyst for the oxygen reduction reaction (ORR) in air-cathode microbial fuel cells (MFCs). To enhance the catalytic activity of AC cathodes, AC powders were pyrolyzed with iron ethylenediaminetetraacetic acid (FeEDTA) at a weight ratio of FeEDTA:AC = 0.2:1. MFCs with FeEDTA modified AC cathodes and a stainless steel mesh current collector produced a m...

Activated carbon (AC) air cathodes were constructed using variable amounts of carbon (43–171 mg cm) and an inexpensive binder (10 wt% polytetrafluoroethylene, PTFE), and with or without a porous cloth wipe-based diffusion layer (DL) that was sealed with PDMS. The cathodes with the highest AC loading of 171 mg cm, and no diffusion layer, produced 1255 ¡ 75 mW m and did not appreciably vary in pe...

There is great interest in hydrogen evolution in bioelectrochemical systems, such as microbial electrolysis cells (MECs), but these systems require non-optimal near-neutral pH conditions and the use of low-cost, non-precious metal catalysts. Here we show that molybdenum disulfide (MoS2) composite cathodes have electrochemical performance superior to stainless steel (SS) (currently the most prom...

The electron field-emission properties of carbon nanotubes enable the fabrication of cold cathodes for a variety of vacuum device applications. The utilization of these cathodes is an attractive alternative for the replacement of thermionic or hot cathodes for generating X-rays. Miniature X-ray tubes have been fabricated using triode-style carbon nanotubebased cathodes. In this paper we report ...

Low current x-ray tubes operating at 25–40 kV have been developed using monolithic carbon nanotube CNT cold cathodes as electron sources. The authors have tested CNT cathodes from various sources. They were systematically evaluated and conditioned in a vacuum chamber and then went through high temperature baking and high voltage processing of standard tube production processes. Acceptance crite...

Rechargeable Li/S batteries have attracted significant attention lately due to their high specific energy and low cost. They are promising candidates for applications, including portable electronics, electric vehicles and grid-level energy storage. However, poor cycle life and low power capability are major technical obstacles. Various nanostructured sulfur cathodes have been developed to addre...