SBIR-STTR Award

A zinc-water battery system for use in underwater environments is proposed, with an expected energy density significantly higher than lithium-ion batteries and slightly less than zinc-air batteries. The research proposed utilizes a concentrated electrolyte, which when combined with an outside water supply on a catalytic electrode surface acts as cathode of the zinc-water cell. The technology is low cost, completely flexible, thin, and scalable to any size and form factor. This proposal aims to demonstrate this system, and show that it can be used to free up payload capacity in unmanned underwater vehicles (UUVs) by utilizing the skin, dorsal fins, and tail of UUVs for high-capacity, flexible energy storage. The batteries are also useful for powering underwater sensors, as they are inherently environmentally friendly, and can be deployed in marine environments without risk of contamination.

Benefit:
A low-cost, flexible, non-toxic, zinc-water battery with an energy density higher than lithium-ion batteries has tremendous commercial potential. The energy in this system is proportionate to the amount of zinc and amount of water used, both of which are extremely low cost. Potential applications include unmanned underwater vehicles, power for underwater sensor networks for harbors and waterways, the gulf sea hydrophone network, and power for waste-water monitoring systems. Commercial applications include power for soil hydration management systems which can be coupled into irrigation systems for agricultural use where water is in short supply and must be managed efficiently. All of these applications require a low-cost, environmentally friendly source of power with a high energy density.

Keywords:
high energy density battery, high energy density battery, Electrochemical Cell, zinc-water battery, Unmanned Underwater Vehicles, Flexible power supply, Thin-film battery

We propose developing high energy density, non-toxic, environmentally friendly zinc-water battery system, which can be manufactured in various form factors including flexible cells, based on novel metal hydrated ruthenium (IV) oxide chemistry. The cells are flexible and have a low recharge voltage. This makes them useful in a variety application as well (mounted on air frame support elements to monitor structural integrity, for example.) The objectives of this proposal include: (i) building galvanic cells that benefit from a highly efficient cathode material, based on hydrated Ru(IV) oxide, and (ii) extending the operational time of the cells by using seawater based electrolytes and fuel. Anticipated benefits of the proposed approach include: (i) creating power sources with extended lifetime that can be adapted to system geometry and product requirements for a particular application envisioned; (ii) the cell can be re-fueled with electrolyte concentrates and rejuvenating solutions, to provide optimized cell performance, while minimizing self-discharge; (iii) as seawater or seawater with a small amount of added fortifying chemicals is used as the fuel, no extra load needs to be carried with the cell, and high energy densities up to values exceeding 2000 Wh L-1 are projected, depending on the specific cell configuration implemented.

Benefit:
All features of this battery system, including environmental friendliness, high energy density, availability of flexible form factors, and low potential cost are of interest to the Navy. These features enable space conservation in our power source, by taking advantage of form factors adapted to dorsal fins, the skin, and the tail of underwater unmanned autonomous vehicles (UAVs); conformal batteries can be designed for conventional shipboard applications, such as integrity monitoring. Other conformal applications, such as wearable batteries and conformable aeronautical batteries, are also possible. Possible submerged applications of these batteries include, but are not limited to underwater sensors (sonobuoys and underwater hydrophone network arrays). These batteries can be deployed without safety hazards, as they do not emit toxic gases, and do not contaminate the environment by any other means; hence, they can be utilized in harbors and waterways. By using novel high efficient cathode materials, these cells are expected to outperform metal/dissolved oxygen long-duration batteries, presently used in deep sea applications, where cells are operated in oxygen depleted water. Other applications include powering nodes in ad hoc distributed sensor networks, which require very little stand-by power 0x9D (on the order of tenths of microwatts) and short term bursts 0x9D for RF signaling. Node arrays are useful in airframe structural integrity monitoring and in intruder detection systems. Thesel batteries are ideal for active 0x9D platforms, similar to sonobuoys, both in form factor and power requirement. The enhanced energy density of the batteries enables longer unattended operation for sonobuoys than conventional batteries. When dropped from the air, they serve as jammers or decoys for incoming threats.

Keywords:
Novel zinc-ruthenium cell chemistry, and distributed sensor networks., high efficiency cathode materials, flexible ultrathin battery, long operation time galvanic cell, UAVs, renewable seawater electrolyte, sonobuoy powering