Strategic Elements self-charging battery scaling produces 14V output by harvesting moisture from the air

Strategic Elements Ltd (ASX:SOR) has fabricated a prototype battery pack with 20 scaled-down connected battery ink cells, which successfully produced a 14-volt output solely by harvesting moisture from the air. The size of the battery ink cells was reduced from 1 square centimetre in previous work to 25 square millimetres, achieving a four-times reduction. It has demonstrated the important potential for the self-charging battery ink cells to be ‘scaled’ down in size but more batteries can be assembled in the same space, leading to increased density and power output. Self-charging battery ink technology The battery ink technology differs significantly from current battery technologies that generally use a small number of alkaline or lithium battery cells to power electronics. Battery ink is being designed to be printed into a battery pack of a larger number of connected battery cells. The ability to potentially scale battery ink cells is a significant advantage as more batteries can be assembled in the same space, leading to increased density of power output. A similar development pathway occurred in computer chips, where greater performance has been achieved by scaling smaller memory cells. Printed electronics The battery ink cells are designed to be printed, which has the advantage of: Enabling the batteries to be manufactured outside of billion-dollar manufacturing facilities (such as lithium); Fabricating light, thin and flexible batteries; and Simplifying production and reduce costs. Screen printing is a mature manufacturing technology widely used in many commercial electronic devices. Silver inks are widely used to print electrodes used in sensors and are able to be screen printed down to a small feature size of 1mm in width, providing great promise for the battery ink cells to be substantially scaled-down. Market relevance The potential ability for the high humidity levels of the human skin to be harvested by battery ink cells and the need for a less bulky and flexible power source make the electronic skin patch sector a natural fit for the Battery ink technology. Increasing the power output and the scaling down in size also provides strong benefits to design freedom for applications that can be powered. Battery ink geometry is able to be tailored to utilise available space, unlike traditional bulky batteries, which have forced the product to be designed to accommodate them. This is particularly relevant to the devices that are attached to the human body. SOR is focusing on applications in this sector initially, with a view to expand into other areas. The initial market focus is on wearables and IoT related devices such as cosmetic, pressure, environmental and health (eg diabetes or cardiovascular monitoring) as they have lower energy output requirements. Higher performance applications will include development of a capacitor for energy storage/regulation and will be focused on at a later date. Skilled team and collaboration The battery ink is being developed by integrating significant existing ink formulation and printed electronics intellectual property from the company’s Nanocube Memory Ink technology with an advanced graphene oxide material. Development is being conducted under an Australian Research Council part-funded collaboration with the University of New South Wales (UNSW) and the CSIRO. The group at UNSW has developed deep experience in printed electronic inks, energy harvesting and storage over the past nine years and are applying that experience in development of the battery ink technology. Hybrid electric generator The technology is being designed to be a hybrid electric generator-battery cell fabricated with a printable ink. Development to date has been focused on voltage and the ability to harvest energy from humidity in the air. The recent mechanical flexibility testing results demonstrate another potential competitive advantage of the technology over current battery technologies that are bulky and rigid. The early-stage potential to scale the technology has been demonstrated through these latest results. Next development milestone The next development milestone is to develop a screen printable prototype in the second quarter of 2021. Screen printing is a widely used printing technology of choice for printed electronics as it is an existing industrial production method and is capable of producing components at a very small scale. Electronic Inks are highly advanced functional materials that operate on the nanoscale level. To enable the battery ink to be screen printed, significant engineering and optimisation must be undertaken. Once this has been achieved, the team will focus on the extended stability of overall power output.