Platinum-Free Fuel Cell Cathode Technology Achieves Performance Level Comparable to Conventional FCs
|ACAL replaces the cathode in a conventional PEM fuel cell (left) with a liquid, non-precious metal catalyst system (right). Click to enlarge.|
ACAL Energy Ltd. has obtained peak power density figures from a development proton exchange membrane (PEM) fuel cells using its platinum-free cathode technology (FlowCath, earlier post) that consistently exceed 570mW/cm2 since late December 2008.
This represents a new record power density level from a liquid platinum-free cathode system. Further improvements are expected in 2009, with an ultimate peak power density target of over 1W/cm2, according to the company.
FlowCath replaces the expensive precious metal catalyst found in conventional fuel cells with a proprietary low cost liquid catalyst. This not only reduces the cost of the fuel cell, but also provides significant durability and reliability benefits through system simplification and the elimination of the most common failure mechanisms found in standard fuel cells.
|ACAL’s stages of development. Source: ACAL Energy. Click to enlarge.|
ACAL’s core technology is the liquid catalyst chemistry. The company started with a polyoxometallate inorganic association complex that offers the same power density as platinum (unpressurized), with an additional 100% performance improvement possible. For its next-generation system, the company is developing a transition metal-ligand complex capable of delivering 2-3x the performance of platinum, according to ACAL.
The circulating catalyst solution was originally invented by Ford Motor in 1950s, but abandoned because the chemical system couldn’t deliver enough oxygen. ACAL leverages advances in detergent chemistry over the past 50 years.
ACAL is currently running a 50W prototype, and plans to introduce a 1 kW demonstration system in 2009.
In November 2008, the company raised £3.3 million (US$4.8 million) in venture financing. Led by CT Investment Partners LLP, all existing venture capital investors, Rising Stars Growth Fund (RSGF), NorthStar Equity Investors Ltd, Porton Capital Ltd and Synergis Technologies Ltd, invested in the round and were joined by new investments from Solvay SA and a leading Japanese corporation.