Sediment-Based Redox Flow Batteries for Economically-Viable Grid-Scale Energy Storage

Tech ID: 30060 / UC Case 2019-165-0

Brief Description

This 5-redox state nitride-capped organometallic charge carrier offers higher tunability, stability, and recyclability at a lower cost than current redox batteries 


Economically-viable grid-scale energy storage becomes more important with increasing renewable energy adoption. Redox flow batteries (RFBs) are a promising new candidate for energy storage systems. However, despite their potential advantages over conventional electrochemical cell architectures (e.g., solid-state batteries), current RFB performance doesn't justify a widespread switch to RFBs. A new design paradigm that includes a redox-active sediment can be used to overcome the cost and performance barriers that restrict RFBs.


Researchers at the University of California, Santa Barbara have created a 5-redox state nitride-capped organometallic motif that can function as a highly stable symmetric charge carrier for a redox flow battery. The complex, based on a phthalocyanine framework, has several advantages as a charge carrier, including its synthetic accessibility, stability, fast kinetics, and ability to be cycled in a heterogeneous state when coupled with conductive carbon particles. This charge carrier can be used in a flow battery with a simplified design, where the phthalocyanine acts as both the positive and negative charge carrier, removing the need for an ion-exchange membrane. Additionally, the complex can be charged and discharged as a sediment, with conductive carbon particles acting as a mediator between the flow field and sediment. This system can surpass solubility limitations while achieving a lower viscosity than a traditionally slurry. This sediment-based architecture offers a practical method of achieving flow batteries with good performance metrics and low cost.



  • Increased stability
  • Uses Inexpensive membranes without accumulative capacity fade
  • Fast kinetics
  • Symmetric electrochemical profile
  • Surpasses solubility limitations while still retaining a lower viscosity than a traditional slurry
  • Can be recycled repeatedly through all 5 redox states with no apparent degradation


  • Renewable energy
  • Grid-level energy storage systems
  • Batteries

Related Materials

Patent Status

Patent Pending


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Other Information


indenergy, Renewable Energy, Grid-Level Energy Storage System, Symmetric Redox Flow Batteries, Symmetric Charge Carrier

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