Organic Flow Battery for Energy Storage

Harvard University
Small Organic Molecule Based Flow Battery for Grid Storage
ARPA-E Award: 
Cambridge, MA
Project Term: 
02/01/2013 to 03/25/2017
Project Status: 
Technical Categories: 
Critical Need: 
Our national electric grid has limited ability to store excess energy, so electricity must constantly be over-generated to assure reliable supply. Though wind and solar power are promising clean alternatives to fossil fuels, their natural unpredictability and intermittency make them incapable of delivering the power on-demand necessary to operate today's grid. The U.S. needs technologies that can cost-effectively store renewable energy for future grid-use at any location. Flexible, large-scale storage would create a stronger and more robust electric grid by enabling renewables to contribute to reliable power generation.
Project Innovation + Advantages: 
Harvard is developing an innovative grid-scale flow battery to store electricity from renewable sources. Flow batteries store energy in external tanks instead of within the battery container, permitting larger amounts of stored energy at lower cost per kWh. Harvard is designing active material for a flow battery that uses small, inexpensive organic molecules in aqueous electrolyte. Relying on low-cost organic materials, Harvard's innovative storage device concept would yield one or more systems that may be developed by their partner, Sustainable Innovations, LLC, into viable grid-scale electrical energy storage systems.
Potential Impact: 
If successful, Harvard's organic flow battery design could hold up to 10 times more energy by volume compared to other flow batteries.
A more efficient and reliable grid would be more resilient to potential disruptions.
Electricity generation accounts for over 40% of U.S. carbon dioxide (CO2) emissions. Enabling large-scale contributions of wind and solar power for our electricity generation would result in a substantial decrease in CO2 emissions.
Increases in the availability of wind and solar power would reduce fossil fuel demand, resulting in reduced fuel prices and more stable electricity rates.
Innovation Update: 
(As of May 2016)
Since the project began in 2013, Harvard has demonstrated promising performance in a battery cell based on low-cost organic materials that incorporates safer liquids, no precious metals, and components made of inexpensive, corrosion-resistant materials. Harvard plans to have a pilot-sale storage system for external testing soon. Meanwhile, the team’s partner, Sustainable Innovations, is developing a 3 kW flow battery using the battery chemistry Harvard designed to demonstrate the commercial potential of this low-cost electrochemical platform for a variety of storage systems. 
During its ARPA-E project, the Harvard team used innovative computer simulation and screening to help identify a suitable low-cost, organic molecule from the quinone family for use in its flow battery. After using computational design to evaluate more than one million quinone-based molecules, the team selected twelve for further synthesis and testing in a quinone-bromide redox flow cell configuration.  Selection of the best chemistry was coupled with work on design and materials for the cell, with the goal of minimizing cost while optimizing performance. The team’s cell has demonstrated promising results, including projected long cycle life, low materials and system costs, and >70% round trip efficiency at power density of 0.35A/cm2.  
For a detailed assessment of the Harvard team's project and impact, please click here.
ARPA-E Program Director: 
Dr. Grigorii Soloveichik
Project Contact: 
Mr. Paul Karoff
Sustainable Energy Solutions
Release Date: