Energy storage, clean and simple.

Introducing the first safe and sustainable deep cycle battery.

Our unique Aqueous Hybrid Ion (AHI™) chemistry is made from abundant, nontoxic materials. Our deep cycle battery technology contains no heavy metals or toxic chemicals and is non-flammable and non-explosive, resulting in the cleanest and safest batteries for your home or business.  

Our Aspen batteries are the first and only in the world to be Cradle to Cradle Certified™, an esteemed quality mark for products made from sustainable materials and manufacturing processes.

AHI chemistry is composed of a saltwater electrolyte, manganese oxide cathode, carbon titanium phosphate composite anode, and synthetic cotton separator. The battery utilizes non-corrosive intercalation reactions at the anode and cathode. See how we compare to lithium ion and lead acid.

Aqueous Hybrid Ion (AHI) Chemistry

deep cycle battery

See the science behind our technology

See the science behind our technology

Take an in-depth look at our proprietary battery chemistry in this paper published in Energy Technology Journal, including an explanation of the active electrode materials in Aquion's batteries.

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How it all started.

Our technology is based on a simple idea: In order to meet the challenges of the world’s growing energy needs and increase the use of renewable power, we need large-scale energy storage systems that are high performance, safe, sustainable and cost-effective.

Our founder, Professor Jay Whitacre, set out to solve this problem and discovered a simple and elegant solution that is a twist on a 200 year-old technology: saltwater batteries.

Aquion developed this solution into our patented Aqueous Hybrid Ion (AHI™) chemistry. Aquion’s Aspen batteries are sealed electrochemical energy storage systems based on our unique saltwater electrolyte. Unlike flow batteries, lithium ion batteries, and lead acid batteries, our Aspen batteries are made using abundant, nontoxic materials and modern low cost manufacturing techniques.  Our saltwater batteries are maintenance-free and optimized for daily deep cycling.

Watch CTO and Founder Jay Whitacre’s TEDx talk at Carnegie Mellon University about the vision and story behind Aquion Energy’s battery technology:

How we stack up.




Learn about the advantages of AHI batteries vs. lead acid batteries.
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Learn about the advantages of AHI batteries vs. lithium ion batteries.
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What’s inside matters.


  • Aquion’s batteries are not flammable, corrosive, or explosive under any conditions, states of charge, or use conditions (with the exception of a severe overcharge leading to gas evolution, a situation that is not possible during transport).
  • AHI batteries have a safe water-based electrolyte, as compared to the flammable organic solvent in lithium ion batteries and caustic sulfuric acid in lead acid batteries.
  • This water-based system moderates the maximum temperature that the battery can reach – it is impossible for any internal reactions to drive the battery above 100°C, since at this temperature, all of the water will evaporate leading to an open circuit condition.
  • Thermal runaway events are simply not possible in the AHI chemistry for the reasons described above as well as the fact that lithium metal, dendrites, and SEI layers cannot form because they are all water soluble species and cannot build on the electrode surface and lead to short circuits.  See for yourself:


  • AHI batteries have an environmentally-friendly electrochemical design that contains no heavy metals, toxic chemicals, inorganic solvents, or other noxious materials.
  • AHI batteries rely on no heavy or toxic metals, such as lead, or caustic materials such as sulfuric acid or lithium hexafluorophosphate.
  • AHI batteries are safe enough to be disposed via traditional waste streams (always follow local regulations regarding disposal of any product).


  • The deep cycle batteries are completely sealed and do not require maintenance. They are self-balancing and therefore do not require an equalizing charge or a battery management system (BMS).
  • AHI batteries have no moving parts like flow batteries, complicated watering systems like some lead acid batteries, and do not require active cell balancing like lithium ion systems.
  • The aqueous electrolyte provides natural overcharge and overdischarge protection and, along with the high impedance of the system, allows AHI batteries to self balance in string configurations.


  • AHI batteries are tolerant to daily deep cycling, wide temperature ranges, and partial state of charge cycling with minimal degradation.
  • In addition to the safety and sustainability advantages of using water as electrolyte, another advantage is the thermal mass of the embodied water means that AHI products neither heat nor cool rapidly. As such, the products can operate in a very wide operating temperature window because they simply take so long to heat and to cool.
  • The AHI chemistry relies on charge/discharge mechanisms which are unaffected by partial state of charge – these batteries can sit indefinitely at partial, or even no state of charge, without irreversible capacity loss like lead acid batteries.

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