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Printed Electronics World
Posted on January 26, 2022 by  & 

Battery Ink Cells Generate Electricity from Interaction with Moisture

Battery Ink Cells Generate Electricity from Interaction with Moisture
Strategic Elements Ltd has reported Battery Ink cells that generate electricity directly from their interaction with moisture. The technology is developed by Australian Advanced Materials (100%) and the University of New South Wales.
In a significant achievement prototype Battery Ink cells were screen printed onto flexible plastic and successfully generated over 250mAh (milliamp hours) of electrical charge solely from moisture. In addition, over 5mA (milliamps) of electrical current was achieved under load over a 3-day testing period. The outstanding results detail a 150% increase in electrical charge compared to previous reporting September 29th, 2021. It is envisaged that one of the first electronic devices to be powered by the Battery Ink cells will be electronic skin patches that monitor health, well-being, sports performance, etc... Printed/flexible electronics are extremely well suited to wearable skin patches due to their low weight, flexibility/conformality, and potential for high-throughput, low-cost manufacturing of these disposable items. For further information see the IDTechEx report on Conductive Ink Markets 2020-2030: Forecasts, Technologies, Players.
These devices have lower power requirements but still have a very large existing market that is growing rapidly. Most electrical current needs are lower (0.5mA - 5mA) less capacity is needed (< 220mAh) and duration needs are shorter (7-14 days) than for other electronic devices. Notwithstanding this, electronic skin patch annual revenues in 2021 were over USD 10 billion with USD 30 billion forecast by 2031. See the IDTechEx report on Electronic Skin Patches 2021-2031.
Managing Director Charles Murphy said "Traditionally the electrical charge produced by emerging battery technologies only increases by small, incremental amounts each year. To achieve a 150% increase and generate 250mAh of electrical charge solely from moisture so early in development is an exceptional outcome for both the team and the Company. The Battery Ink technology is at an exciting stage of development where fundamental limits of aspects such as battery cell size, power output, duration, energy density, etc... are still unknown. One of the challenges with printed electronics is that the processes are so new that trial-and-error and testing is critical to success. Fortunately, this does also provide significant opportunities for unforeseen breakthroughs."

Battery Ink Cell Structure

In solar cells or batteries two electrodes (top and bottom) are needed to collect current (mobile ions). Which then will move from an area of high concentration of ions to low concentration of ions, creating electron current flow (i.e. electricity). These electrodes are connected to loads such as sensors or other electronic components that need power.
An important aspect of the latest prototype is that the electrodes used in the Battery Ink cell structure were also screen printed. An electrode ink was optimised at UNSW for use with prototype Battery Ink cells and screen-printed directly on top of screen-printed Battery Ink cells for the first time. Ultraviolet photoelectron spectroscopy(UPS) experiments show potential for significant electrical power output. Expanded investigation of attributes such as adhesion properties, screen printability and permeability will be conducted.
Screen printing is the optimum method to produce printable electronics due to greater precision and ability to create more sophisticated devices. Equipment at the University of New South Wales has the capacity to screen print features as small as 100 micrometres and as large as a 1m x 3m. Electronic skin patches remain the immediate focus for Q1, 2022 although investigation into other uses of the Battery Ink technology have commenced.
Development conducted in Q4 2021 resulted in significant technical breakthroughs that have been covered by patent application. For the remainder of Q1, 2022 Australian Advanced Materials has committed to providing the technical team with freedom to pursue deep research and development and trial-and-error materials engineering with the aspiration of achieving a further step change in moisture induced electrical energy generated from the Battery Ink.

Printed Moisture Power

Traditional battery technologies reduce the freedom of design for new electronic devices. The Battery Ink technology is being designed to be a simple sandwiched architecture consisting of a top and bottom electrode with a functionalised material enclosed between. With this simple architecture, the Battery Ink cells can be printed in a variety of different shapes and sizes potentially enabling the technology to fit new electronic devices with different flexibility, size and shape requirements.
Screen printed graphene-oxide based cells that harvest energy from airborne water molecules could potentially directly power a device, compliment a battery to extend device life or provide energy for battery storage. These different use cases provide alternative commercialisation and partnering options for the Company. Potential benefits include:
  • Self-charging through ambient moisture mechanisms § Environmentally friendly
  • Non-flammable
  • Low cost
  • Attractive and flexible form factor
  • Ease of production and integration
  • Facilitates widespread development of non-conventional electronic devices
Source and top image: Strategic Elements
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