10 New Flow Battery Companies and Startups to Watch in 2026

Executive Summary: Which are the Top 10 Flow Battery Startups to Watch?

1. Halide Energy (Finland) – develops copper-based flow batteries for 8 to 12-hour grid storage.
2. ARKLE Energy Solutions (India) – builds vanadium redox flow batteries with decoupled architecture to enable scalable power and energy.
3. Flow-nano (Italy) – produces nanostructured electrodes via NanoJeD deposition for vanadium flow batteries.
4. HalioGen Power (UK) – delivers membraneless flow batteries using abundant materials.
5. R.Flo (Ukraine) – manufactures scalable iron flow batteries with recyclable electrolytes and 40 000-cycle lifespans.
6. Carbo Energy (USA) – creates organic flow batteries using industrial by-products.
7. Zion Technologies (New Zealand) – develops vanadium flow batteries offering >20,000 cycles and full depth-of-discharge.
8. i-battery (China) – supplies vanadium flow batteries under the ABTR series with containerized, modular designs.
9. GridFlow.tech (USA) – builds lithium-sulfur flow batteries with hybrid reservoirs for 20-hour storage.
10. Upthermo (Poland) – develops membraneless saltwater flow batteries using WiSE electrolytes.

Global Startup Heat Map highlights Emerging Flow Battery Startups to Watch

Through the Big Data & Artificial Intelligence (AI)-powered StartUs Insights Discovery Platform, covering over 9M+ startups, 20K+ technology trends, plus 150M+ patents, news articles & market reports, we identified top flow battery startups.

The Global Startup Heat Map below highlights emerging flow battery startups you should watch in 2026, as well as the geo-distribution of 50+ startups & scaleups we analyzed for this research.

According to our data, we observe high startup activity in Western Europe and the United States, followed by India. The top 5 Startup Hubs for flow battery are London, Bangalore, Melbourne, Milan, and Shenzhen.

Discover Emerging Flow Battery Startups to Watch in 2026

We hand-picked startups to showcase in this report by filtering for their technology, founding year, location, funding, and other metrics. These new flow battery companies work on solutions ranging from vanadium and iron flow to lithium-sulfur and saltwater designs.

1. Halide Energy – Copper‑Flow Long‑Duration Storage

• Founding Year: 2025
• Location: Espoo, Finland

Finnish startup Halide Energy develops a copper flow battery technology for long-duration energy storage. It stores energy in liquid electrolytes containing copper species, which are pumped through an electrochemical stack with a membrane or separator. In this membrane or separator, oxidation and reduction reactions convert electrical energy into chemical energy during charging and reverse those reactions during discharge.

The startup’s battery uses copper, a low-cost and abundant metal, rather than more expensive metals such as vanadium. It achieves long cycle life, low carbon footprint over a 20-year lifetime, a simple electrolyte preparation in a single step, and avoids the use of critical raw materials.

Halide Energy supports grid-scale or industrial users by providing cost-effective, durable storage for 8-12-hour durations to buffer renewable supply. This reduces curtailment, shifts peak load, delivers frequency containment, or offers backup power.

2. ARKLE Energy Solutions – Grid‑Scale Vanadium Redox Flow Battery

• Founding Year: 2023
• Location: Bangalore, India

Indian startup ARKLE Energy Solutions offers redox flow battery systems for grid-scale energy storage. It stores energy in electrolyte fluids and circulates them through a central stack where chemical reactions convert electrical energy into stored form during charge and reverse that process during discharge.

The startup’s technology supports long discharge durations of four hours or more. It includes a battery management system and an energy management system for operational efficiency and predictive maintenance. It uses a decoupled architecture so it adjusts energy capacity by changing electrolyte volume and power by stack surface area, and employs safe, non-flammable chemistries with minimal degradation over up to 25 years and thousands of cycles.

Therefore, it provides utilities, independent power producers, commercial and industrial users with sustainable, durable storage that smooths renewable variability, shifts load, provides backup or ancillary services, and reduces the total cost of ownership.

3. Flow-nano – Nanostructured Flow Battery Electrodes

• Founding Year: 2023
• Location: Milan, Italy

Italian startup Flow-nano develops nanostructured electrodes under its Flow- Nano Vanadis Solution for vanadium redox flow batteries. It uses NanoJeD technology, a plasma-assisted nanoparticle jet deposition process that ionises precursor molecules and generates spherical carbon nano-onions via a supersonic fluid-dynamic jet. Then it deposits them onto thin carbon paper or carbon cloth substrates, and then anneals the coating to produce stable nano-catalysts that adhere to the substrate fibers.

The startup’s electrodes offer high voltaic efficiency (> 80 % at 400 mW/cm²), sustain operation beyond 700 mW/cm², and deliver large electrolyte utilisation (> 70 % at 300 mA/cm²). It exhibits a very low energy efficiency drop per cycle (under 0.004 %) while maintaining low hydraulic and ohmic losses. Flow-nano provides grid-scale and decentralised energy storage systems with cost-effective power output, extended durability, and improved system flexibility.

4. HalioGen Power – Membraneless Long‑Duration Flow Storage

• Founding Year: 2023
• Location: Manchester, United Kingdom

UK-based startup HalioGen Power provides membraneless redox flow batteries for long-duration energy storage. Its technology removes the need for costly non-recyclable membranes and instead uses abundant raw materials to enable a more sustainable design. The system stores energy by circulating electrolytes through a flow cell where redox reactions convert electrical energy into chemical energy during charging and reverse the process during discharge.

HalioGen Power’s batteries provide non-flammable operation, maintain stability across extreme temperatures, and minimize long-term degradation that ensures reliable storage performance. They deliver cost efficiency by reducing reliance on critical raw materials and simplifying system architecture. The startup enables industries, utilities, transportation hubs, and micro-grids to integrate renewable energy more effectively, bridge supply-demand mismatches, and support a resilient clean energy transition.

5. R.Flo – Scalable Iron Flow Batteries

• Founding Year: 2023
• Location: Vinnytsia Oblast, Ukraine

Ukrainian startup R.Flo manufactures an Iron Flow Battery system for long-duration energy storage. It uses iron salts dissolved in liquid electrolytes in two tanks, pumps them through an electrochemical stack where oxidation and reduction reactions are stored. Then it releases energy, and relies on patented control and rebalancing systems together with stack, membrane, and electrode components.

The startup’s battery features fully recyclable, non-toxic materials for operation across a wide temperature range (–20°C to +50°C). Its non-flammable, non-explosive chemistry enhances the lifespan of around 40 000 cycles (≈50 years) with minimal capacity degradation. Its scalable, modular design suits indoor, outdoor, or underground deployment.

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6. Carbo Energy – CO₂‑Derived Organic Flow Storage

• Founding Year: 2024
• Location: Delaware, United States

US-based startup Carbo Energy creates a waste-based flow battery system for long-duration grid-scale energy storage. It sources industrial by-products and converts them into high-density electrolytes, which it circulates through tanks and stacks in a redox flow architecture to store and release energy.

Carbo Energy’s battery system features a modular design, non-flammable and fully recyclable materials, refillable electrolytes, and avoids rare earths or critical minerals while leveraging existing industrial supply chains. It provides utilities, industrial facilities, and distributed energy systems with durable, safe, and affordable storage.

7. Zion Technologies – Vanadium Flow Battery Storage

• Founding Year: 2024
• Location: Pokeno, New Zealand

New Zealand-based startup Zion Technologies develops vanadium flow battery systems for long-duration energy storage. It installs two electrolyte tanks that circulate vanadium electrolytes through an electrochemical stack in which oxidation and reduction occur during charge and discharge, while a membrane separates the half-cells.

The startup’s systems offer full depth-of-discharge, achieve more than 20 000 charge/discharge cycles with minimal degradation, and ensure safety with no risk of thermal runaway. This provides scalable capacity from kilowatts to megawatts, and supports applications like backup power, grid forming, energy arbitrage, and renewable integration.

8. i-battery – Modular Vanadium Flow Storage

• Founding Year: 2023
• Location: Suzhou, People’s Republic of China

Chinese startup i‑battery offers full vanadium redox flow battery systems, including its ABTR series for commercial, industrial, and residential storage. It operates by circulating vanadium electrolytes in two separate tanks through an electrochemical stack, where redox reactions convert electrical energy into chemical energy during charge and reverse it during discharge.

i-battery offers products such as the ABTR‑500 kW/1000 kWh system with 512–844.8 V DC, the ABTR‑125 kW/500 kWh system with 256–420 V DC, and the ABTR‑2.5 kW/15 kWh system with 16–26.4 V output. All are rated for 25‑year lifecycles and 16 000 cycles, with discharge times from 2 to over 10 hours, modular containerized designs, and IP54 protection for indoor and outdoor deployment.

Its systems incorporate micro‑structured stacks, new bipolar and end‑plate materials, hybrid sealing, and optimized flow fields to reduce resistance and improve efficiency.

9. GridFlow.tech – Lithium‑Sulfur Flow Storage

• Founding Year: 2024
• Location: Albuquerque, United States

US-based startup GridFlow.tech provides a lithium-ion flow battery system for long-duration energy storage. It employs a hybrid-flow architecture that separates lithium and sulfur into distinct liquid reservoirs and enables energy storage for over 20 hours. This design enhances safety by preventing direct interactions between lithium metal and sulfur. It reduces the risk of thermal runaway associated with traditional lithium-ion batteries.

The startup’s system offers ten times the energy density of conventional batteries and utilizes abundant, cost-effective materials that result in a more affordable solution. GridFlow’s battery delivers 120 kWh, outperforming existing power walls that provide just 13.5 kWh. Its scalable design makes it suitable for various applications, including residential, commercial, and grid-scale energy storage.

10. Upthermo

• Founding Year: 2024
• Location: Olsztyn, Poland
• Use For: Membraneless Saltwater Flow Storage

US-based startup Upthermo develops a membrane-less redox flow battery system for long-duration energy storage. It employs a water-in-salt (WiSE) electrolyte, a highly concentrated aqueous solution that suppresses hydrogen evolution and material dissolution, which enhances the electrochemical stability window and enables safe and efficient energy storage.

The startup’s technology features a scalable, modular design, low self-discharge rates, and the use of abundant, non-toxic materials that make it suitable for various applications, including grid stabilization and renewable energy integration.

Discover All Emerging Flow Battery Startups

The 10 flow battery startups showcased in this report are only a small sample of all startups we identified through our data-driven startup scouting approach. Download our free Industry Innovation Reports for a broad overview of the industry, or get in touch for quick & exhaustive research on the latest technologies & emerging solutions that will impact your company in 2026!