Hybrid Fuel Cell-Battery System

Project Term:
09/17/2014 - 11/20/2015

Critical Need:

Centralized power generation systems offer excellent economy of scale but often require long transmission distances between supply and distribution points, leading to efficiency losses throughout the grid. Additionally, it can be challenging to integrate energy from renewable energy sources into centralized systems. Fuel cells—or devices that convert the chemical energy of a fuel source into electrical energy—are optimal for distributed power generation systems, which generate power close to where it is used. Distributed generation systems offer an alternative to the large, centralized power generation facilities or power plants that are currently commonplace. There is also a need for small, modular technologies that convert natural gas to liquid fuels and other products for easier transport. Such processes are currently limited to very large installations with high capital expenses. Today’s fuel cell research generally focuses on technologies that either operate at high temperatures for grid-scale applications or at low temperatures for vehicle technologies. There is a critical need for intermediate-temperature fuel cells that offer low-cost, distributed generation both at the system and device levels.

Project Innovation + Advantages:

SiEnergy Systems is developing a hybrid electrochemical system that uses a multi-functional electrode to allow the cell to perform as both a fuel cell and a battery, a capability that does not exist today. A fuel cell can convert chemical energy stored in domestically abundant natural gas to electrical energy at high efficiency, but adoption of these technologies has been slow due to high cost and limited functionality. SiEnergy’s design would expand the functional capability of a fuel cell to two modes: fuel cell mode and battery mode. In fuel cell mode, non-precious metal catalysts are integrated at the cell’s anode to react directly with hydrocarbons such as the methane found in natural gas. In battery mode, the system will provide storage capability that offers faster response to changes in power demand compared to a standard fuel cell. SiEnergy’s technology will operate at relatively low temperatures of 300-500ºC, which makes the system more durable than existing high-temperature fuel cells.

Potential Impact:

If successful, SiEnergy’s hybrid fuel cell-battery will operate at intermediate temperatures with high efficiency, high energy density, and quick response time while representing a dramatic improvement over the functionality of existing fuel cells.


Enabling more efficient use of natural gas for power generation provides a reliable alternative to other fuel sources—a broader fuel portfolio means more energy security.


Natural gas produces roughly half the carbon dioxide emissions of coal, making it an environmentally friendly alternative to existing sources of power generation.


Distributed generation technologies would reduce costs associated with power losses compared to centralized power stations and provide lower operating costs due to peak shaving.


ARPA-E Program Director:
Dr. Paul Albertus
Project Contact:
Dr. Masaru Tsuchiya
Press and General Inquiries Email:
Project Contact Email:


Harvard University

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