Reinforced AEM Separators Based on Triblock

Copolymers for Electrode-Decoupled (ED-) RFBs

PI: Vijay Ramani, Washington University in St. Louis

Project Vision

Total project cost: $4.0M

Current Q / Total Project Qs Q16 / Q22

Highly permselective anion exchange membrane (AEMs)

separators + electrode-decoupled redox flow batteries (ED-RFBs)

= Inexpensive (<$0.05/kWh-cycle) extended duration energy

storage

DAYS

Annual Meeting

March 1 & 2, 2021

The Concept

Idea 1 : Metal oxide doped AEMs with enhanced Donnan effect enable long-life, low-

cost ED-RFBs

Idea 2: Novel ED-RFBs with earth-abundant elemental actives (Ti and Ce)

AEM + ED-RFB chemistry enables <$0.05/kWh-cycle extended-duration energy

storage1

TiO2

The Team

Context/history of project

• Prior group experience:

➢ Investigation of RFBs - 7 years

➢ Development of AEMs - 10 years

➢ ARPA-E “RANGE” program –

Focus on slurry based redox flow

batteries

Team member Location Role in project

St. Louis,

MO

Project lead

• IONICS Project: AEM + RFB expertise to enable electrode decoupled RFB operation

Vijay

Ramani

Shrihari

Sankarasubramanian

Yunzhu

Zhang

Jing

Xie

Benjamin

Kumfer

Erfan

AsadipourKrithika

Sharma

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Project Objectives - IONICS

Project status:

• Patent pending highly selective, durable AEM platform developed – Scale-up demonstrated with contract

manufacturer

• Patent pending earth-abundant, elemental-actives-based ED-RFB developed – Going down the cost

curve to <$0.05/KWh-cycle

Final targets achieved:

✓ Demonstration of roll-to-roll production of one or more platform AEMs

✓ Lab-scale ED-RFB cycled for 3 months with <1% cross-over

Additional targets (non-ARPA-E non-dilutive funding- LEAP grant)

• Scale-up to 1KWh ED-RFB with the next 6 months

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Project Objectives – DAYS adjacent

Project objectives:

1. ↑ energy density - ↓ CAPEX

2. ↑ cell performance – ↓ $/KW cost

3. ↑ RTE & cycle life – ↓ OPEX

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Results – Highly-permselective AEMs developed

Highly permselective

(beyond-Donnan exclusion)

Extremely stable in ED-RFB

actives

Made from 100cm2 to roll-to-roll In-situ, operandoEx-situ

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Results – Ti-Ce ED-RFB developed

Long cycle life

>3 day charge retention

Clear pathway to <$90/KWh installed cost and <$0.05/KWh-cycle

LCOS

56 days

New electrolyte

formulations double

energy density

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Challenges, Risks and Potential Partnerships

1. CHALLENGE 1: Meeting ASR targets with high permselectivity

RESOLUTION –

• Decoupled strength and degree of functionalization using reinforcements; judicious use of

additives

2. CHALLENGE 2: Increasing electrolyte concentrations to achieve higher energy density

RESOLUTION-

• Novel formulations achieving 2M concentrations have been identified – Looking for cells for high

power operations and input on management of slurry electrolytes

3. CHALLENGE 3: Stability of RFB test rig over long-duration cycling

RESOLUTION-

• New pump designs and other modifications being examined – feedback requested on

commercial solutions from other teams

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Challenges, Risks and Potential Partnerships (contd.)

Potential partnerships:

• Roll-to-roll manufacturing of membrane platform (LEAP award) – partner

identified and scale-up accomplished

• Scale-up of the ED-RFB (LEAP award) – on-going – Final stack evaluations

initiated

• Third-party evaluation, validation and adoption of membrane and ED-RFB

chemistries – We can provide separator samples (under NDA) for evaluation

by other teams/entities.

We will seek funding for scale-up and piloting of Ti/Ce ED-RFB following successful completion

of plus-up project

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Technology-to-Market

• Goal – To commercially deploy Ti-Ce ED-RFBs through a startup or JV

• Timeline to market (including ARPA-E funded and externally funded development)

• Partnerships needed with

• Utilities/microgrid operators for pilot deployments

• Established battery manufacturers for scale-up

20kW module deployment

Year 1 Year 2 Year 3

1.5kWh Gen-1 Ti-Ce RFB demonstrated

Gen-1.5 electrolytes

demonstrated

Gen-2 electrolytes demonstrated

Gen-2 Ti-Ce RFB demonstrated/validated

1.5kWh Gen-2 Ti-Ce RFB demonstrated

Start-up/JV in place

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Present day

Summary Slide

• The differentiator –

• Highly selective AEMs prevents cation cross-over and doubles capacity of mixed active RFBs.

• Low cost - hydrocarbon AEMs + Earth abundant elemental RFB actives.

• On-track to demonstrate 1.5 kWh Gen-1 Ti-Ce ED-RFB within the next 6 months.

• New Gen-1.5 and Gen-2 formulations with significantly higher energy densities under development.

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https://arpa-e.energy.gov

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