Flow Battery Open Circuit Voltage via Non-Aqueous Electrolytes

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Solution Overview

Problem

Current flow battery technologies face challenges in achieving high open circuit voltage, energy density, and cost-effectiveness due to limitations in materials and engineering, hindering widespread commercial adoption for large-scale energy storage.

Innovation Solution

A flow battery system utilizing aqueous, all-liquid active materials with high open circuit voltage (>1.4 V) is developed, incorporating metal ligand coordination compounds and redox active materials to enhance energy density and efficiency, reducing system size and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If conventional flow battery materials and engineering are used, then system scalability and cost are limited, but achieving high open circuit voltage and energy density remains unattainable

Engineering Contradiction:
Improveopen circuit voltageVSAvoidsystem cost
Core Design Contradiction:
PowerVSEase of manufacture

Solution Approach 1:

The patent changes the chemical parameters of the electrolyte system by using non-aqueous solvents (such as acetonitrile, dimethyl carbonate, ethyl methyl carbonate) instead of conventional aqueous solutions. This parameter change enables higher open circuit voltages (>1.4V) while maintaining system scalability and reducing manufacturing costs through improved energy density and cell efficiency

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material strategies by combining specific redox-active compounds (such as iron tris(bipyridine) dichloride, ruthenium complexes, osmium complexes) with optimized non-aqueous electrolyte compositions. These composite material systems achieve high voltage operation while maintaining stability and reducing overall system costs through improved performance

Inventive Principle:
Principle #40Composite materials

2Productivity

If existing flow battery systems are deployed, then round trip energy efficiency and cycle life are limited, but achieving high energy density and voltage efficiency is not possible

Engineering Contradiction:
Improveenergy densityVSAvoidround trip efficiency
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

By changing from aqueous to non-aqueous electrolyte systems, the patent achieves higher energy density through increased voltage operation while simultaneously improving round trip efficiency by reducing parasitic reactions and minimizing energy losses during charge-discharge cycles

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses stable, soluble redox-active complexes that operate efficiently over many cycles without degradation. The use of stable coordination compounds (such as iron-bipyridine complexes and noble metal complexes) ensures long cycle life while maintaining high energy density and voltage efficiency throughout operation

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system achieves increased energy density, higher electrochemical cell/stack voltage efficiency, and lower costs, resulting in improved round-trip energy conversion efficiencies and modularity, addressing scalability and cost limitations of existing flow batteries.

Implementation Method 1

a first redox active material in a first aqueous electrolyte... a second redox active material in a second aqueous electrolyte... capable of being oxidized and reduced

Methodology Applied
Scientific EffectRedox reactions: Redox Reactions

Implementation Method 2

a separator disposed between the two electrodes... separating the two electrodes and the two electrolytes

Methodology Applied
Scientific EffectIon exchange: Ion Exchange

Data Source

PatentEP2878021B1Electrochemical systems featuring high open circuit potential
Publication Date: 2020.12.09 LOCKHEED MARTIN ADVANCED ENERGY STORAGE LLC
  • EP2878021B1 patent drawingFigure 1~2
  • EP2878021B1 patent drawingFigure 3~4
  • EP2878021B1 patent drawingFigure 5~6

AI summary

The invention concerns flow batteries comprising: a first aqueous electrolyte comprising a first redox active material; a second aqueous electrolyte comprising a second redox active material; a first electrode in contact with the first aqueous electrolyte; a second electrode in contact with the second aqueous electrolyte and a separator disposed between the first aqueous electrolyte and the second aqueous electrolyte; the flow battery having an open circuit potential of at least 1.4 V, and is capable of operating or is operating at a current density at least about 50 mA/cm2, wherein both of the first and second redox active materials remain soluble in both the charged and discharged states. In certain embodiments, the redox active materials are metal ligand coordination compounds. The disclosure also describes systems comprising these flow batteries and methods of them.