Polymeric Anion Exchange Membranes
Hydrogen is a valuable energy carrier that is widely used at present in the chemical industry. As a fuel, it has the potential to play a key role in enabling emission-free transportation. Hydrogen can be used to power a vehicle with a fuel cell, which emits only water and can fully recharge for a 300-mile range in minutes, similar to gasoline vehicles. However, mass adoption of fuel cell vehicles has been hampered by high prices largely attributed to the cost of the proton exchange membrane (PEM) fuel cell system that is commonly used. While significant technical progress has been made in the development of acidic PEM fuel cells, a key barrier is the need to use platinum catalysts for the reactions, which are both costly and limited in abundance. In addition, at current low volumes, the acidic membranes are costly. An alternative path is to develop alkaline membranes that have the potential to both eliminate the need for expensive catalysts, and also produced at lower cost and volumes. The alkaline pathway is also promising for the development of electrolyzers that split water into hydrogen and oxygen. The hydrogen can be used in current industrial processes such as ammonia production or in other applications, such as fuel cell vehicles or as storage for intermittent electricity generation. Eliminating expensive catalysts and lowering membrane costs will help reduce capital costs for electrolyzers, hastening their widespread use.
Project Innovation + Advantages:
3M will develop a new anion exchange membrane (AEM) technology with widespread applications in fuel cells, electrolyzers, and flow batteries. Unlike many proton exchange membrane (PEM) applications, the team’s AEM will operate in an alkaline environment, which means lower-cost electrodes can be used. The team plans to engineer a membrane that simultaneously meets key goals for resistance, mechanical and chemical stability, and cost. They will do this by focusing on simple, hydroxide-stable polymers, such as polyethylene, and stable cations, such as tetraalkylammonium and imidazolium groups. Positively-charged cation side chains attached to the polymer backbone will facilitate passage of hydroxide ions through the electrolyte, resulting in enhanced ionic conductivity. The proposed polymer chemistry is envisioned to be low cost and can be used in alkaline environments, and can be processed into mechanically robust membrane composites. This membrane technology has the potential to enable high volume, low-cost production of AEMs. The impact of this project can be transformational as the commercial availability of high-quality AEMs has been a limiting factor in developing AEM-based devices.
If successful, developments made under the IONICS program will create a fundamentally lower cost trajectory for electrochemical systems, such as fuel cells and electrolyzers, which are currently based on proton exchange membranes.
IONICS program innovations could contribute to energy storage and conversion solutions for transportation and the grid, lessening U.S. dependence on imported oil and improving grid resilience.
Greater integration of renewable resources into the power mix will reduce the need for other more carbon-intensive forms of electricity generation.
IONICS program innovations could permit the use of the oxygen and hydrogen electrodes with low-cost catalysts and other components, which could save over 50% of current fuel cell stack costs (at high volume) and reduce vehicle fuel cell system and combined heat and power system costs by about 25%.