High Energy Storage Capacity Iron Flow Battery Research Receives ARPA-E Plus-Up

The Advanced Research Projects Agency-Energy (ARPA-E) of the U.S. Department of Energy has awarded a plus-up of funds in the amount of $1,172,105, with an additional cost share of $500,000, to Dr. Robert Savinell and Dr. Jesse Wainright for their work on a high energy storage capacity iron flow battery. The total ARPA-E funding for this project is now $3,247,910 with an additional $617,643 in cost share. Fusion Power Systems has also awarded Case Western Reserve University a research contract of $172,000 to serve as cost-share towards the ARPA-E award. Fusion Power Systems is an Australian company delivering uninterruptible power solutions to the IT industry.

The all-Iron flow battery energy uses abundant, low cost, safe, and non-toxic materials to provide energy storage. Further, the development of a slurry electrode for the negative half-cell will decouple the amount of energy stored from the power delivered, thereby driving down cost and expanding applications. The impact of the all-Iron flow battery is expected to be significant, as it addresses most of the estimated $228 billion market for energy storage in stationary grid/renewable applications over the next 10 years. Additionally, this storage technology would enable increased grid efficiency and reliability.  The use of non-toxic materials decreases the adverse environmental effects of energy generation and distribution. Cost benefits over the current state of the art are anticipated to be significant, with capital cost of $200/kW and $20/kWh for 10 hours of energy storage.

In 2013, ARPA-E first provided $560,000 in funding for a one-year seedling project to demonstrate the concept of the slurry electrode iron flow battery.  Success of this project led to additional funding of about $1.5million to advance the science and engineering further in a full-project over two years. The current award is a plus-up to support the next phase of this development effort and lead the technology towards commercialization.

The high energy storage capacity iron flow battery has led to the development of significant new intellectual property.  To date, five IP disclosures have been submitted, and three patents have been filed with one issued.  A license for the slurry iron flow battery has been issued to Fusion Power System with mile-stone requirements leading towards commercialization of the technology for energy storage applications.  Additionally, eleven journal papers have been published and fourteen conference talks, university talks, and poster papers have been delivered.  The iron flow battery has also been a boon for student, graduate student, and post-doc support.

Overall ARPA-E Project Objective and Deliverables

Through this project, the Case Western University project team sets out to demonstrate a viable battery technology to attract partners for design / scale-up, manufacturing and testing. This team will develop pre-metallization to increase initial slurry conductivity with low-cost seed particles and map slurry stability and rheology characteristics as a function of state of charge. Tasks will include the optimization of electrode and cell design for desired current distribution and uniform reactant accessibility. Feasibility and reliability will be demonstrated on prototype cells that include scale-up and cycle testing activities. Electrochemical performance will be predicted by modeling full cells and stacks under a variety of conditions. The final milestones for this project consist of demonstrating a capital expenditure of $100/kW, $25/kWh for a 4 hour system, round trip energy efficiency of 75%, and 200 charge-discharge cycles in 400 cm2 prototype cells.


The overall objective of the plus up period is to close the technical gap of a 25X scale-up and reduce risk to enable commercial investment required to develop a slurry iron flow battery product. A specific objective is to demonstrate 150 cycles of performance exceeding 70% energy efficiency with a 10-cell stack of 1156 cm2 cells operating at 100 mA/cm2.  The 10-cell short stack will have a power delivery rating of approximately 1 kW, which represents a size commensurate with the requirements of our commercialization partner, Fusion Power Systems. The final deliverable for this period is a 1 kW, 6 kWh slurry flow battery, with complete balance of plant, ready for testing at an ARPA-E ‘Charges’ site with an estimated capital cost less than $45/kWh for a six-hour system (excluding power electronics).